Dissertations / Theses on the topic 'Biological and chemical aspects'
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1
Evmorfopoulos, Evangelos. "Chemical and biological aspects of mercury in seafoods." Thesis, Loughborough University, 1995. https://dspace.lboro.ac.uk/2134/27859.
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Two open wet oxidation methods are described for the digestion of selected seafoods prior to total mercury determination using a cold vapour atomic absorption spectrophotometric technique. The first employs two acids (i.e. HNO3 and H2SO4) and two oxidants (i.e. KMnO4 and K2S2O8), and is suitable for use with a Perkin-Elmer Mercury Analysis System (MAS) and a Perkin-Elmer Mercury Analyzer 50A (MA). Excellent recoveries were obtained for mussel samples spiked with various quantities of inorganic mercury [Hg(N03)2]. For the optimum part of the calibration curve of the MAS (0.1–0.7 μg/ml Hg), the percentage recovery (%R) fluctuated between 98.26 and 101.98. The limit of detection (LOD) was calculated to be 18.7 ng of mercury per sample analysed and sensitivity of 0.011 μg of mercury was obtained. Results for fish samples determined with both units showed excellent agreement and precision (RSD = 3.23 -4.25). However, the MA was found inadequate for the determination of the low mercury levels encountered with the mussel samples. It was shown that a desiccant assembly must be installed whenever samples with low mercury content are analysed, i.e. less than 0.5 μg per sample digested.
2
Snip, Erwin. "Industrial, chemical and biological aspects of phosphorus-containing heterocycles." Thesis, University of Leicester, 1999. http://hdl.handle.net/2381/30036.
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This thesis presents three different topics in phosphorus-containing heterocycles. The first topic is about novel phosphorus-containing flame-retardants to be used in poly-urethane foams. The background and importance of flame-retardants is discussed as well as the synthesis and testing data of compounds that were expected to have good flame-retardant properties. More importantly, these compounds represent a class of flame-retardants that can be chemically incorporated into the polymer, which will overcome current negative aspects such as leaching and fogging. The test results show that the tested compounds perform about as well as commercially available materials and that there are indications that they are chemically incorporated into the polymer. The second topic is about the cytotoxic effects of aziridines. The phosphate moiety of a DNA-chain can act as a nucleophile that ring-opens an aziridine. This reaction results in the formation of a phosphate triester with a potential nucleophile, namely an amino group, in a beta-position. These two factors make the hydrolysis of the DNA chain at this particular point much more likely. A model study was designed to investigate the likelihood of DNA-chain cleavage by aziridines as these form an important class of anti-tumour agents. From this model study it can be concluded that the cytotoxic effects of aziridines have to be contributed to alkylation of other nucleophilic sites at DNA than to strand cleavage preceded by alkylation of the phosphate backbone. The last topic covers a stereochemical investigation of the metal catalysed hydrolysis of a cyclic nucleotide. It presents the first stereochemical assignment of the metal catalysed hydrolysis of a phosphate ester. In line with most enzyme catalysed hydrolyses of phosphate esters the reaction investigated here was assigned to go with inversion of configuration.
3
Widestrand, Johan. "Assessment of trichothecene contamination : chemical aspects and biological methodology /." Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 2001. http://epsilon.slu.se/avh/2001/91-576-5808-0.pdf.
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4
Yachnin, Jeffrey R. "Chemical, pharmacokinetic and biological aspects of platinum-based drugs /." Stockholm, 2005. http://diss.kib.ki.se/2005/91-7140-221-7/.
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5
De, Silva Michael S. W. "Chemical and biological aspects of using dredged river Clyde sediments for land restoration." Thesis, University of Strathclyde, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.292081.
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6
Nengovhela, Nkhangweleni Ryneth. "Kinetics of the chemical and biological iron (II) oxydation." Diss., University of Pretoria, 2003. http://hdl.handle.net/2263/30337.
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7
Botello-Ruvalcaba, Martin Armando. "Physical, chemical, biological and management aspects of coastal ecosystems facing eutrophication : the Guaymas Bay, Sonora, Mexico." Thesis, University of Hull, 1999. http://hydra.hull.ac.uk/resources/hull:16865.
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The present study has encompassed a series of field observations and theoretical considerations related to physical, chemical, and biological factors defining the process of eutrophication in the Guaymas system. Additionally, the work has produced the basic ecosystem model of the system through the modelling of the hydrodynamics, sediment dynamics, budget dynamics, net ecosystem metabolism and the potential for eutrophication. These findings produce an overall assessment of the system, which together with the environmental legislation and socio-economic concerns, allows those factors influencing decision making to be highlighted. In general, the knowledge of the hydrodynamic features indicates that the flushing capacity of the system may be insufficient to remove pollution discharged into the Guaymas sub-system and Estero el Rancho. There is a residual mass of water that exchanges from the Empalme sub-system to the Guaymas sub-system. Simulation of the trends for potential net transport of sediment indicates that bedload transport is likely to occur toward the head of the Guaymas sub-system. For the Empalme subsystem, there was a net bedload displacement toward the mouth. Mathematical interrelationships between measured phytoplankton biomass and environmental parameters shows through a MRA model that nearly 100% of its variance is influenced by nutrients, pH, temperature and salinity. The stoichiometric Redfield approach indicates that nitrogen is a limiting factor of the phytoplankton biomass growth in the Guaymas system, when other factors such as light, sinking, grazing, temperature and salinity gradients are not. However, an analysis of the two major subsystems shows that nutrients limiting in the Guaymas sub-system are closely related to phosphorus loads from wastewater sources, whereas for the Empalme sub-system, nutrient limitation was alternately by nitrogen and phosphorus. A primary quantitative outcome of the eutrophic status is given, using a simple biochemical budgetary approach, indicating that the Guaymas system is a net heterotrophic system, with a value of -4811.72 mmol.C.m^.y'1. Using a simple box model to characterise the potential hyper-trophic conditions suggests that phosphorus reduction in the system is accompanied by an improvement in water quality, hence management strategies must encourage P control from wastewater discharges into the sub-system. An analysis of the particular case of the Guaymas system in the context of the Mexican Environmental Legislation indicates that the quality standards set for the system will depend very much upon the designation ultimately used for the system. For instance, if some areas of the Guaymas sub-basin are designated for industrial use, a polluted influence is likely to occur in an area near the development. However, the areas influenced by this development must not pose a threat for the people living the Guaymas basin as stated in the Mexican Environmental Legislation.
8
Fajardo, Norma N. "Biological and chemical aspects of agrocin 434 as a supplementary biocontrol agent for crown gall /." Title page, table of contents and summary only, 1995. http://web4.library.adelaide.edu.au/theses/09PH/09phf175.pdf.
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Thesis (Ph. D.)--University of Adelaide, Dept. of Crop Protection and Plant Science, 1996.Copies of author's previously published articles inserted. Includes bibliographical references (leaves 72-90).
9
Juraimi, Abdul Shukor. "Studies on some biological aspects, competitive ability and chemical control of Bermudagrass (Cynodon dactylon (L.) Pers.)." Thesis, University of Reading, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363407.
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10
Wei, Xi. "Environmental screening of endocrine-disrupting chemicals and biological characterization of their effects on reproductive health." HKBU Institutional Repository, 2011. http://repository.hkbu.edu.hk/etd_ra/1225.
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11
Ramahlo, Masetle Nelson. "Physico-chemical and biological characterization of soils from selected farmlands around three mining sites in Phalaborwa, Limpopo Province." Thesis, University of Limpopo (Turfloop Campus), 2013. http://hdl.handle.net/10386/1127.
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Thesis (M.Sc. (Soil Science)) --University of Limpopo, 2013The study was conducted to assess the impact of mining activities on selected soil physical, chemical and microbial properties on farmlands around three selected mining sites. Nine soil samples were collected from each of the following farms : Hans Merensky, Mogoboya and Leon Tom, Foskor Mine and JCI mining sites, respectively. Additional nine soil samples were collected from non-polluted Waterbok farm that serves as a control for the purpose of comparison. The samples were taken at 0–15, 15–30, 30–45 cm depths at three sampling points on each farm for physical, chemical and biological studies. However, soil samples collected for microbial (fungi, bacteria and actinomycetes) counts were surface (0–15 cm) soil samples. Soil chemical properties determined include pHw, electrical conductivity (ECe), exchangeable acidity (EA), organic carbon, available phosphorous, exchangeable cations as well as heavy metal (i.e. Mn, Zn, Cu, Pb, Cd, As and Sb) concentrations. The physical parameters determined include texture (sand, silt and clay) as well as bulk density. Soil pHw and ECe values decreased with depth; and ranged from 6.94 to 6.50 and from 12.24 to 10.76 mS cm-1, respectively. Exchangeable acidity showed a gradual increase with depth and ranged from 0.72 to 0.80 cmol(+)(kg), while percent organic carbon decreased with depth ranging from 1.41 to 2.19 %. Exchangeable cations, particularly K and Mg increased with depth while Ca decreased marginally with soil depth. Available phosphorous content decreased following increases in distance from the pollution source while heavy met.al contamination decreased with soil depth but increased further away from the pollution source. Significantly high loads of Pb, As and Sb were recorded at all depths on the three farms around the mining sites, which were largely responsible for the pollution but worse on the Leon Tom farm; with Pb constituting the greatest pollutant. The concentration of extractable heavy metals in the studied areas was in the order: As >Sb>Pb>Zn>Cu >Mn >Cd. Cadmium level appeared generally very low in all samples while elevated levels of Mn, Cu and Zn were detected at all depths in the polluted soils.Significant differences in microbial levels were detected at the various sampling points. The highest count of 3.82 and 6.20 CFU g-1 for fungi and actinomycete, respectively were both from the Leon Tom farm, while 6.46 CFU g-1 counts for bacteria was obtained from Mogoboya farm. Interestingly, fungal and actinomycetes activities were more sensitive to heavy metal contamination than bacteria that were significantly increased following soil pollution.
National Research Foundation (NRF)
12
Jankovic-Karasoulos, Tanja. "A case study of the physical, chemical and biological factors affecting dissolved organic carbon in the Warren Reservoir, South Australia /." Title page, table of contents and abstract only, 2004. http://web4.library.adelaide.edu.au/theses/09PH/09phj339.pdf.
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13
Retamales, Roberto. "A study of semi-intensive shrimp culture in Ecuador in relation to physical, chemical and biological conditions in the production ponds during El Nino and La Nina events (1996 to 1999)." Thesis, University of Stirling, 2002. http://hdl.handle.net/1893/3286.
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Once every three, four or even seven years, the Southeast trade winds which blow west-ward across the tropical zone of the Pacific Ocean, from the shores of South America towards the Asian land mass, weaken and sometimes even reverse their direction. This phenomenon is known as El Nino. Conversely, the climatic condition known as La Nina is characterised by unusually cold ocean temperatures in the equatorial Pacific, as compared to El Nino. Global climate anomalies associated with La Nina tend to be opposite to those of El Nino. A study of shrimp culture in Ecuador was carried out to analyse the temporal changes in pond water quality, phytoplankton composition and diversity, and bacterial composition and diversity in the intestines of cultured Litopenaeus vannamei in Ecuador. These parameters were studied in relation to their impact on the growth, survival and production in a semi-intensive shrimp culture farm situated in the Chone River Estuary, Ecuador. Five culture periods were studied during the climatic events of El Nino, La Nina and transition periods (1996 to 1999 ). Shrimp were stocked in ponds at 10 PL/m2. Pond management included pond drying, inorganic fertilisation, and feeding with a commercial pellet twice a day. The physicochemical characteristics of the pond water and the phytoplankton and bacterial counts were estimated at intervals of 7-15 days of culture during each period of study. The concentrations of nitrite, nitrate, sulphide, ammonia, pH and suspended solids in the pond water in all ponds during the five culture periods fluctuated within ranges considered compatible with shrimp farming. Phosphorus, silica, temperature and salinity, however, showed significant differences during the five periods of shrimp culture, reaching sub-optimal levels during some culture periods. The species composition and diversity of phytoplankton was different during El Nino, La Nina events and transition periods, with a decrease in the diatom community and an increase in the cyanophytes algae community associated with changes in nutrients and nutrient ratios, and temperature, salinity is discussed. A low diversity of bacterial genera with a predominance of Vibrio spp., particularly V. harveyi and V. parahaemolyticus, was observed in shrimp intestines during disease outbreaks in the transition and La Nina periods associated with significant environmental changes in temperature and salinity. Shrimp performance was significantly different between El Nino, La Nina and transition climatic periods. Survival, feed conversion ratio and yield were better during El Nino periods because of the positive effects of higher pond water temperature and salinity (29°C and 28 psu) on the shrimp stocks.
14
Souza, Natalia Medeiros de [UNESP]. "Gonipterus platensis (Coleoptera: Curculionidae): infestação em eucalipto, aspectos morfológicos e biológicos e controle." Universidade Estadual Paulista (UNESP), 2016. http://hdl.handle.net/11449/144401.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Gonipterus platensis (Coleoptera: Curculionidae) é um inseto desfolhador do eucalipto de origem australiana presente no Brasil há mais de 30 anos. Após um longo período sendo controlado naturalmente com sucesso pelo parasitoide de ovos Anaphes nitens (Hymenoptera: Mymaridae) esse inseto voltou a causar danos em várias regiões produtoras de São Paulo, Paraná e Rio Grande do Sul, reforçando que ainda há necessidade de entendimento da dinâmica da praga no país e de elementos que auxiliem no seu manejo. Esse trabalho teve por objetivos realizar um levantamento de áreas de eucalipto atacadas pela praga, avaliar a morfometria de ootecas e sua relação com o total de ovos e a taxa de parasitismo em diferentes áreas do estado de São Paulo, avaliar o consumo foliar, viabilidade e desenvolvimento de larvas em diferentes espécies de eucalipto e avaliar a ação de diferentes inseticidas contra adultos dessa praga. Em estudo conduzido em parceria com empresas florestais, foi verificada a existência de dez espécies de eucalipto, quatro delas relatadas pela primeira vez além de cinco híbridos hospedeiros de Gonipterus spp. no Brasil, com o grau de severidade de desfolha variável, chegando a mais de 75% em alguns materiais; devido a ressurgência recente da praga há pouca informação sobre perdas em produtividade. Foi verificado que as estratégias de monitoramento e controle da praga não são padronizadas em todas as empresas. Em estudo para avaliação de ootecas a campo, foi observada correlação entre o comprimento das mesmas e o numero total de ovos. As taxas de parasitismo e razão sexual variaram de acordo com a região e foi verificado um grande número de parasitoides mortos dentro das ootecas. Em avaliação de consumo foliar de larvas de G. platensis em Eucalyptus urophylla e E. camaldulensis não foram observadas diferenças no consumo entre os 2 hospedeiros; o desenvolvimento em E. camaldulensis foi mais longo. Foram testados diversos produtos para o controle de adultos de G. platensis sendo eficientes bifentrina e Beauveria bassiana por ação tópica e bifentrina por ação de contato/ingestão. Os dados apresentados nesse trabalho podem ser utilizados para o ajuste de planos de manejo da praga.
Gonipterus platensis (Coleoptera: Curculionidae) is an Australian eucalypt defoliator present in Brazil for over 30 years. After a long period being naturally and successfully controlled by the egg parasitoid Anaphes nitens (Hymenoptera: Mymaridae) this insect is once again causing damage in several producing regions of São Paulo, Paraná and Rio Grande do Sul, highlighting that there is a need to understand the pest dynamics in the country and elements to improve its management. This study aimed to assess the eucalyptus areas attacked by the pest, verify egg capsules morphometry and its relation with total number of eggs and parasitism rate in different areas in the state of Sao Paulo, assess larval leaf consumption, viability and development on different species of eucalyptus and evaluate the effectiveness of different insecticides against adults. In a study conducted in partnership with forestry companies, ten species of eucalyptus, and five hybrid were reported as hosts of Gonipterus spp. in Brazil, four of those were reported for the first time. Defoliation levels varied, reaching over 75% in some hosts. Due to the recent ressurgence of the pest there is little information about productivity loss. Monitoring strategies and pest control are not standardized in all companies. In a study to evaluate egg capsules on the field, a correlation between their length and the total number of eggs was verified. The parasitism rates and sex ratio varied according to the region and a large number of parasitoids were found dead inside the egg capsules. Assessment of G. platensis larvae leaf consumption on Eucalyptus urophylla and E. camaldulensis did not show differences of consumption between these hosts; development on E. camaldulensis was slower. Several products were tested to control G. platensis adults. Only bifenthrin and Beauveria bassiana topic action bifenthrin contact/ingestion action were effective. The data presented in this work can be used for adjustment of pest management plans.
CNPq: 130604/2014-3
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Silva, Alineaurea Florentino. "Uso de resíduo orgânico na produção de mandioca em transição agroecológica, no Projeto Pontal, Petrolina-PE." Universidade Federal da Paraíba, 2017. http://tede.biblioteca.ufpb.br:8080/handle/tede/9159.
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The soils of most of the rain-dependent areas farms of the semiarid region of the northeastern Brazil have low levels of elements such as nitrogen and phosphorus, hampering the achievement of results of production that allow the satisfactory maintenance of the agricultural activity in these areas. As a result, year after year the expected yields become increasingly rare and many farmers no longer believe in the viability of cultivation of some species, even those that have historically occupied spaces in these important properties, such as maize, beans and cassava. Cassava is a species of great importance in semi-arid environments, presenting great versatility in the production of fresh and processed foods and fodder. The use of organic residues from the properties for soil fertilization and improvement of growth of the vegetal species is one of the internationally recommended practices for a sustainable ecologically based agriculture. The objective of this work was to evaluate cassava (Manihot esculenta cranz) production and soil fertility with the use of organic residue in agroecological transition in the Pontal Project, Petrolina-PE. Semistructured interviews, soil collection, of residues and of the production in the communities were held in the communities Vira Beiju, Lajedo and Amargosa. The soil analyzes were carried out at Embrapa Semiarid and revealed the need for soil acidity correction (pH between 4,2 and 5,5) in all communities, addition of sources of phosphorus (P available< 3,8 mg.dm-3), organic matter (<5,5 g.kg-1) and zinc (< 6,95 mg.dm-3), especially in community Vira Beiju. Various activities that generate agricultural waste that can be used in local agriculture were identified, but in this study period (drought) only goat manure was found in greater quantity (5,0m3 per month), in all communities, being sold for obtaining income. Livestock production was one the most generating of waste, along with the crops, also mentioned as big generators of residues, by most of the interviewee (89%). The stable was the place with highest generation of residues in the property, during the study period (88.9 %). The response of the plant to the use of the tested residue (manure) or phosphorus application has been directly related to the soil type and hydric conditions during the plant cycle, being these conditions highly variable in this study in the three communities studied. The correction of the soil showed significant results when associated to the use of manure, being very promising to increase the yield of cassava in an agroecological transition system.
Os solos da maioria das propriedades de áreas dependentes de chuva, da região semiárida do nordeste brasileiro, possuem baixos teores de elementos como nitrogênio e fósforo, dificultando o alcance de resultados de produção que permitam a manutenção satisfatória da atividade agrícola nessas áreas. Como consequência, ano após ano, as safras esperadas tornam-se cada vez mais raras e muitos agricultores passam a não mais acreditar na viabilidade do cultivo de algumas espécies, mesmo aquelas que historicamente têm ocupado espaços importantes nessas propriedades, como milho, feijão e mandioca. A mandioca é uma espécie de grande importância nos ambientes semiáridos, apresentando grande versatilidade na produção de alimentos in natura e processados e forragem. O uso de resíduos orgânicos das propriedades para fertilização do solo e melhoria das condições de crescimento das espécies vegetais é uma das práticas internacionalmente preconizadas para uma agricultura de base ecológica. O presente trabalho teve como objetivo avaliar a produção de mandioca (Manihot esculenta cranz) e a fertilidade do solo com uso de resíduo orgânico, em transição agroecológica no Projeto Pontal, Petrolina-PE. Foram realizadas entrevistas semiestruturadas, coleta de solo, de resíduos e da produção nas comunidades Vira Beiju, Lajedo e Amargosa. As análises do solo e dos resíduos orgânicos encontrados nas propriedades foram realizadas na Embrapa Semiárido e revelaram a necessidade de correção da acidez (pH entre 4,2 e 5,5) em todas as comunidades, adição de fontes de fósforo (P disponível<3,8mg.dm-3), matéria orgânica (<5,5 g.kg-1) e zinco (<6,95 mg.dm-3), principalmente na Comunidade Vira Beiju. Foram identificadas diversas atividades geradoras de resíduos que podem ser utilizados na agricultura local, porém no período avaliado (estiagem) apenas o esterco caprino foi encontrado em maior quantidade (5,0m3/mês), em todas as comunidades, sendo comercializado para obtenção de renda. A criação de animais foi uma das atividades mais geradora de resíduos, junto com os cultivos, também apontados como grandes geradores de resíduos, pela maioria dos entrevistados (89%). O curral foi o local de maior geração de resíduos na propriedade, no período avaliado (88,9%). A resposta da planta ao uso do resíduo testado (esterco) ou aplicação de fósforo esteve diretamente relacionado ao tipo de solo e condições hídricas no período do ciclo da planta, sendo estas condições altamente variáveis no presente estudo nas três comunidades trabalhadas. A correção do solo mostrou resultados significativos quando associado ao uso do esterco, sendo bastante promissor para elevar a produtividade da mandioca em sistema de transição agroecológica.
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Laurent, Fabien. "Impact de l'oxydation chimique et de la refonctionnalisation sur des paramètres physico-chimiques et biologiques de terres contaminées au HAP." Thesis, Université de Lorraine, 2012. http://www.theses.fr/2012LORR0033/document.
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Afin de dépolluer et de réhabiliter les sols contaminés par des hydrocarbures aromatiques polycycliques (HAP), différentes techniques ont été développées durant les dernières décennies, mais leur impact sur les fonctions du sol est rarement pris en compte. L'objectif de ce travail était d'évaluer l'impact des traitements par oxydation chimique sur différents paramètres physico-chimiques et biologiques de terres contaminées aux HAP et de proposer des solutions pour restaurer le fonctionnement biologique des terres oxydées. Les différentes expérimentations de laboratoire et de terrain ont montré que l'efficacité des réactions d'oxydation chimique (réaction de Fenton et persulfate activé) sur la teneur en HAP dépendait de la disponibilité de la pollution et des propriétés physico-chimiques des terres. Par ailleurs, des processus d'acidification ont été observés sur des terres non carbonatées, altérant fortement et durablement les paramètres physico-chimiques et biologiques. Cette altération était plus forte après utilisation du persulfate activé, engendrant ainsi des pertes en éléments traces métalliques dans les eaux de percolations. L'apport de matériaux susceptibles d'augmenter le pH a permis la restauration des activités biologiques et la capacité des terres à supporter la végétation lorsque les terres ont fortement été acidifiées. L'association de traitements d'oxydation chimique et de refonctionnalisation pourrait présenter un moyen de réhabilitation efficace. Un indice, dont l'objectif était de représenter l'état du sol en fonction du poids accordé à différents paramètres, a été proposé et a permis d'évaluer les variations induites par les traitements d'oxydation et les procédés de refonctionnalisationIn order to clean up polycyclic aromatic hydrocarbon (PAH) contaminated soils, various techniques have been developed during the last decades, but their impact on soil functions was rarely considered. The objective of this study was to assess the impact of chemical oxidation treatments on different physico-chemical and biological parameters of PAH contaminated soil and to propose solutions to improve the biological functioning of oxidized soil. Various laboratory and field experiments have shown that the efficiency of chemical oxidation reactions (Fenton reaction and activated persulfate) on PAH concentrations depended on pollutant availability and soil physico-chemical properties. Besides, intense acidification processes have been observed on uncarbonated soil with a strong impact on soil physico-chemical and biological parameters. Moreover, this alteration was higher with activated persulfate treatment, leading to the loss of trace metals in water percolation. In the strongly acidified soil, the input of materials, suitable for pH increase, resulted in the restoration of biological activities and soil capacity to support vegetation. The association of chemical oxidation treatment and restoration techniques could present a good mean for soil rehabilitation. Finally, an index, which aimed to represent soil conditions based on the weight given to different parameters, was proposed and was used to evaluate changes induced by oxidation treatments and restoration techniques
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Yukseler, Hande. "Biological And Chemical Sludge Filtration." Phd thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608608/index.pdf.
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Up to date, sludge filterability has been characterized by the Ruth&rsquos classical filtration theory and quantified by the well-known parameter specific cake resistance (SCR). However, the complexity of the actual phenomenon is clearly underestimated by the classical filtration theory and SCR is often not satisfactory in describing filterability. Although many scientific studies were conducted for a better analysis and understanding of the filtration theory, still a practically applicable solution to replace the classical theory for a better description of filterability has not been proposed yet. In the present study, blocking filtration laws proposed by Hermans and Bredé
e, dating back to 1936, which have been extensively used in the membrane literature for the analysis of fouling phenomenon and the multiphase filtration theory developed by Willis and Tosun (1980) highlighting the importance of the cake-septum interface in determining the overall filtration rate have been adopted for the analysis of filterability of sludge systems. Firstly, the inadequacy of the classical filtration theory in characterizing the filterability of real sludge systems and also the lack of the currently used methodology in simulating filtration operation was highlighted. Secondly, to better understand the effect of slurry characteristics and operational conditions on filtration, model slurries of spherical and incompressible Meliodent particles were formed. Finally, a methodology was developed with the gathered filtration data to assess the filterability of the sludge systems by both theories. The results clearly show that both approaches were superior to the classical approach in terms of characterizing the filterability of sludge systems. While blocking laws yielded a slurry specific characterization parameter to replace the commonly used SCR, the multiphase theory provided a better understanding of the physical reality of the overall process.
18
Sader, Kasim Stefan. "Aspects of biological electron microscopy." Thesis, University of Leeds, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.434150.
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Altschul, Stephen Frank. "Aspects of biological sequence comparison." Thesis, Massachusetts Institute of Technology, 1987. http://hdl.handle.net/1721.1/102708.
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Thesis (Ph. D)--Massachusetts Institute of Technology, Dept. of Mathematics, 1987.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Bibliography: leaves 165-168.
by Stephen Frank Altschul.
Ph.D
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Noatch, Matthew R. "An Evaluation of Chemical, Biological, and Combined Chemical-Biological Approaches for Controlling Snails in Aquaculture Ponds." OpenSIUC, 2010. https://opensiuc.lib.siu.edu/theses/198.
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Digenetic trematodes are a common pest problem in aquaculture where their unappetizing appearance often reduces the marketability of food fish. Aquatic snails are intermediate hosts in the trematode lifecycle and are commonly targeted with control measures to prevent the crop fish from becoming infected. I evaluated several chemical and biological snail control strategies as alternatives to the potentially invasive black carp. Copper sulfate, hydrated lime slurry, and several fish and decapod species were tested for effectiveness against physid (Physa spp.) and planorbid (Helisoma spp.) snails in laboratory aquaria trials. Hydrated lime demonstrated effectiveness with the least potential to be toxic to cultured fish in regional application. Hybrid sunfish (redear × green sunfish) consumed large quantities of both snails in ad libitum feedings. The most effective biological (redear × green sunfish) and chemical (hydrated lime) control methods identified in the laboratory were evaluated further in research ponds. Hydrated lime applications of 9.07 kg over 9.14 m2 were found to be effective against Helisoma spp. confined to enclosures along the pond shoreline; average survival was 2%. When stocked in aquaculture ponds, hybrid redear sunfish did not significantly influence snail capture rates; however ponds stocked with redear sunfish experienced a gradual decrease in snail populations throughout the 2008 growing season. Hydrated lime and a combination of redear sunfish and hybrid redear sunfish were evaluated separately and in tandem as a combined chemical/biological treatment in the 2009 growing season. Evaluation occurred under mock production conditions in which hybrid striped bass were raised in the research ponds to determine snail treatment effects on trematode abundance. Ponds stocked with sunfish at 494 fish/ha had snail densities significantly (P ≤ 0.05) lower than control ponds after two months. Ponds treated with hydrated lime at 31.7 kg/31.5 m of shoreline in a 1 m swath experienced 99% estimated reductions in snail densities following application, but snail populations rebounded to previous levels within two months. The mean snail density in ponds treated with both hydrated lime and sunfish was significantly lower than control one month post treatment; this mean rebounded slightly by the conclusion of the trial, but not as much as in the chemical treatment group. Hybrid striped bass examined thoroughly for trematodes revealed a positive relationship between trematode abundance in fish and increasing Helisoma densities. This relationship was most apparent when estimates of snail density from only the beginning of the trial were used. Based on these results, it appears that a nearly complete reduction of Helisoma, particularly at the time of stocking fingerlings, is necessary to avoid a high abundance of trematodes in cultured fish. To this end, an early-season application of molluscicides followed closely by stocking of predator sunfish has potential to achieve a uniformly low density of snails throughout the growing season.
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Edwards, John W. "Biological monitoring of occupational chemical exposure /." Title page, contents and summary only, 1990. http://web4.library.adelaide.edu.au/theses/09PH/09phe2652.pdf.
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Peyfoon, Elham. "Chemical and biological properties of propolis." Thesis, University of Strathclyde, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.510828.
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Zhang, Zhibing. "Novel micromanipulation studies of biological and non-biological materials." Thesis, University of Birmingham, 2016. http://etheses.bham.ac.uk//id/eprint/6512/.
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Many biological and non-biological materials in the form of microscopic particles (or microparticles) are used to produce functional products for a wide range of industrial sectors including pharmaceutical and medical, chemical, agrochemical, food and feed, personal and household care. Understanding their mechanical properties is essential for predicting their behaviour in manufacturing and processing, and for maximising their performance in end-use applications. However, it had not been possible to determine the mechanical properties of single microparticles until the author, as the main contributor, developed a novel micromanipulation technique at the University of Birmingham. The technique is capable of determining the mechanical properties of both biological and non-biological particles as small as 400 nm in diameter, and can be used for obtaining force-displacement data of single microparticles at large deformations, including those corresponding to rupture. The technique was enhanced by mathematical modelling and finite element analysis in order to allow intrinsic material properties to be determined, for example, the particle (or particle wall) elastic modulus, viscoelastic and plastic properties, and stress/strain at rupture. For biological materials, applications of this technique include understanding mechanical damage to animal cells in suspension cultures, yeast and bacterial disruption in downstream processing equipment, biomechanics of chondrocytes and chondrons for tissue engineering, and adhesion and cohesion of biofilms and food fouling deposits. For non-biological materials, applications include understanding and controlling particle breakage in processing equipment, and the formulation of microcapsules with optimum mechanical strength to achieve controlled release and targeted delivery of functional active ingredients. The research on micromanipulation has been sponsored by BBSRC, EPSRC, DEFRA, DTI, EU, the Royal Society K C Wong Fellowships and 19 national and international companies, and has resulted in more than one hundred academic publications. The knowledge generated has also assisted these companies to commercialise particulate functional products.
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Josefsson, Ann. "Postpartum Depression : Epidemiological and Biological Aspects." Doctoral thesis, Linköping : Univ, 2003. http://www.ep.liu.se/diss/med/07/81/index.html.
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Tullett, Jayne Margaret. "Chemical and biological properties of S-nitrosothiols." Thesis, University of Leicester, 1997. http://hdl.handle.net/2381/30786.
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Since its discovery, nitric oxide (NO) has been identified to influence a large number of physiological processes. This project examines S-nitrosothiols (RSNO) as pro-drugs of NO. The overall aim of this project was to improve our present understanding of the chemical and biological properties of RSNOs. This project has demonstrated that under physiological conditions the stability of RSNOs varies with structure. Results have shown that S-nitrosocysteine and S-nitroso-L-cysteinylgylcine were the least stable of the RSNOs investigated, whereas S-nitroso-N-acetyl-L-cysteine, S-nitroso-3-mercaptopropionic acid and S-nitroso-2-mercapto-ethane sulphonic acid were the most stable. The decomposition of certain RSNOs is catalysed by trace amounts of copper. This phenomenon was particularly evident with the RSNOs, S-nitrosocysteine and S-nitroso-L-cysteinylglycine. Copper catalysed decomposition appears to occur more readily with RSNOs that allow the formation of a stable ring structure, in which Cu+ is bound to the nitrogen of the NO group and another electron-rich atom such as the nitrogen of an amino group. Copper catalysed the decomposition of S-nitrosoglutathione and S-nitroso-L--glutamyl-L-cysteine, but to a lesser extent. Investigations have shown that the decomposition of a stable RSNO is more rapid in the presence of a thiol which gives rise to an unstable RSNO via a transnitrosation reaction. In contrast, decomposition of an unstable RSNO is slower in the presence of a thiol which leads to the formation of a stable RSNO. All RSNOs studied inhibited platelet aggregation and relaxed vascular smooth muscle in a dose dependent manner. In addition, all the RSNOs exhibited a dose-dependent inhibition of growth of A549 cells. Generally no real correlation between the chemical and biological properties of RSNOs was observed. It is clear that there are many factors controlling the release of NO from RSNOs which may have implications regarding the biological activity of these compounds.
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Bunyan, Kerry Emma. "Chemical and biological studies of manganese transferrin." Thesis, University of Edinburgh, 2003. http://hdl.handle.net/1842/15569.
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This thesis is concerned with the loading of transferrin with manganese and some of its chemical and biological properties. Manganese is bound to transferrin as Mn(III) with a characteristic ligand (Tyr) to metal (Mn(III) charge-transfer band at a wavelength of 430 nm. Caeruloplasmin is shown to enhance the uptake of manganese from MnC12 by apo-hTf. However binding is often incomplete and slow. A novel method of loading hTf with Mn using KMnO4 is reported. This method leads to rapid uptake and inductively coupled plasma atomic emission spectroscopy (ICP-AES) determinants confirmed the binding of at least two Mn per hTf molecule. The possible oxidising effects of MnO4- on protein amino acid side chains was considered. In model systems MnO4- oxidises methionine to methionine sulfoxide and methionine sulfone. Evidence of structural changes in apo-hTf induced by Mn(III) binding was obtained by studies using [e-13C]Met-hTf. Preliminary work suggests that Mn(III), like several other metals studied, preferentially binds to the C-lobe first, although this may result in an open domain conformation. Fe(III) as Fe(NTA)2 was found to displace Mn(III) from hhTf but displacement was slower when hTf had been loaded using KMnO4 rather than MnCl2. KMnO4 was not able to displace Fe(III) from Fe2-hTf. Attempts to crystallise Mn-hTf to characterise these structural changes proved difficult. Crystals grew but were of poor quality and did not diffract. Many large crystals were obtained from solutions of Fe2-hTf. The crystals were red/orange and ellipsoidal in shape. Of the Fe2-hTf crystals grown, one diffracted to 3.3 Å with the data being complete to 90%, but not enough information was gained for adequate molecular replacement and structural solution.
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Jiang, Lu. "Chemical synthesis of peptides with biological importance." Thesis, University of Edinburgh, 1996. http://hdl.handle.net/1842/12302.
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Thinnes, Cyrille Christophe. "Chemical and biological studies on human oxygenases." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:455f2e65-f294-461b-b44f-cd53796b14a0.
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As depicted in Chapter I, 2-oxoglutarate- (2OG) dependent oxygenases are ubiquitous in living systems and display a wide range of cellular functions, spanning metabolism, transcription, and translation. Although functionally diverse, the 2OG oxygenases share a high degree of structural similarities between their catalytic sites. From a medicinal chemistry point of view, the combination of biological diversity and structural similarity presents a rather challenging task for the development of selective small molecules for functional studies in vivo. The non-selective metal chelator 8-hydroxyquinoline (8HQ) was used as a template for the generation of tool compound I for the KDM4 subfamily of histone demethylases via application of the Betti reaction. Structural analogue II was used as the corresponding negative control (Figure A). These compounds were characterised in vitro against a range of 2OG oxygenases and subsequently used for studies in cells. I displays selectivity for KDM4 and increases the level of the H3K9me3 histone mark in cells. It has an effect on the post-translational modification pattern of histone H3, but not other histones, and reduces the viability of lung cancer cells, but not normal lung cells, derived from the same patient. I also stabilises hypoxia-inducable factor HIF in cells via a mechanism which seems to be independent from prolyl hydroxylase inhibition. This work is described in Chapters II and III. The chemical biology research in epigenetics is complemented by qualitative analysis conducted in the social sciences at Said Business School. With a global view on how innovation occurs and may actively be fostered, Chapter IV focuses on the potential of epigenetics in drug discovery and how this process may actively be promoted within the framework of open innovation. Areas of focus include considerations of incremental and disruptive technology; how to claim, demarcate, and control the market; how knowledge brokering occurs; and insights about process, management, organisation, and culture of open innovation. In contrast to the open-skies approach adopted for the development of a tool compound in Chapters II and III, a focused-library approach was taken for the generation of a tool compound for the OGFOD1 ribosomal prolyl hydroxylase. The development of a suitable in vitro activity assay for OGFOD1 in Chapter V enabled the development of lead compound III in Chapter VI. III is selective for OGFOD1 against the structurally closely related prolyl hydroxylase PHD2.
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Björkman, Barbro. "Ethical aspects of owning human biological material." Licentiate thesis, KTH, Philosophy and History of Technology, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-610.
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Sylvén, Sara M. "Biological and Psychosocial Aspects of Postpartum Depression." Doctoral thesis, Uppsala universitet, Obstetrik & gynekologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-170818.
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Postpartum depression (PPD) is one of the most common complications of childbirth around the world. Despite several studies on the underlying mechanisms, the pathophysiology remains elusive. The aims of this thesis were to assess possible associations between the risk for self reported PPD and serum levels of leptin, the season of delivery, the gender of the newborn, and the history of premenstrual symptoms, respectively. A population based cohort of 2318 newly delivered women in Sweden were screened five days, six weeks and six months postpartum, using the Edinburgh Postnatal Depression Scale. This cohort comprised 60% of the total population, and the prevalence of self reported PPD was 11.1% six weeks after the delivery. A negative association between leptin levels at delivery and self reported PPD at six weeks and six months postpartum was evident, even after adjusting for confounding factors. An increased risk for self reported PPD was noted among women delivering during the last three months of the year, compared to those giving birth in April through June. This is of clinical importance, since women delivering at the end of the year could benefit from a closer follow-up after delivery. Despite previous varying findings – depending on study population and consequently different cultural settings – in our study, no association between infant gender and self reported PPD could be detected at six weeks or six months postpartum. However, women giving birth to baby boys had a higher risk for postpartum blues. Lastly, an increased risk for self reported PPD among women with a history of premenstrual symptoms was noted. Interestingly, after stratification for parity, the association between PPD and premenstrual symptoms remained only among multiparas. The association between PPD and premenstrual symptoms might shed light on the many possible routes by which hormonal changes may influence mood in women. In conclusion, this population based study strengthens the notion that PPD is a complex multifactorial disorder, with biological, social and psychological parameters shaping each individual’s risk. Further research is needed in this field, in order to investigate underlying pathophysiological mechanisms, propose more effective diagnostic tests and assess therapeutic interventions.UPPSAT
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Loop, Franciscus Theodorus Lambertus van der. "Cell biological aspects of muscle cell differentiation." Maastricht : Maastricht : Universitaire Pers Maastricht ; University Library, Maastricht University [Host], 1996. http://arno.unimaas.nl/show.cgi?fid=7288.
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Hovenga, Sjoerd. "Clinical and biological aspects of multiple myeloma." [S.l. : [Groningen : s.n.] ; University Library Groningen] [Host], 2007. http://irs.ub.rug.nl/ppn/30102636X.
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Björkman, Barbro. "Ethical aspects of owning human biological material /." Stockholm : Division of Philosophy, Department of Philosophy and the History of Technology, Royal Institute of Technology, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-610.
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Maffulli, Nicola. "Achilles tendon ailments : clinical and biological aspects." Thesis, University of Aberdeen, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265637.
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This thesis reports studies on the epidemiology, pathology, biochemistry, imaging and management of Achilles tendon ailments. Ultrasonography is a sensitive tool to diagnose Achilles tendinopathy and Achilles tendon rupture (ATR), and to follow its healing non-invasively. Muscle fibre composition of the triceps surae does not show significant association with ATR. In patients with a suspected ATR, when two of the commonly used clinical tests are positive for a rupture, an ATR can confidently be diagnosed. The association between ATR and sciatica was investigated by questionnaire in patients who underwent repair of an ATR, and in individuals nominated by the patients, matched for age, sex and occupation. Although the two groups were well matched, 35% of the patients and 12% of the controls had experienced sciatic pain prior to rupture. This association could be due to impaired afferent signals from the lower leg, or to similar collagen or vascular anomalies of the vertebral disc and of the Achilles tendon. A reproducible rat model of acute Achilles tendinopathy was created, and the effects of pulsed electromagnetic fields examined. Some frequencies of pulsed electromagnetic fields result in better collagen fibre alignment following injury. Growth factors in an in vitro rat tendon healing model result in faster healing following wounding, and their possible application in clinical practice is exciting. A minimally invasive procedure for the management of chronic tendinopathy shows that such approach gives a good chance of success when paratendinopathy is not present. A technique of open repair of ATR is presented, and the results in a group of 47 patients reported, and the rationale of management of patients with an ATR is detailed. Finally, the incidence of ATR in Scotland over a 15 year period has been studied: the condition has become significantly more common since 1986.
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Matthew, Caroline Zoe. "Biological and molecular aspects of Sodalis glossinidius." Thesis, University of Edinburgh, 2007. http://hdl.handle.net/1842/29872.
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Lewis, Randy Stewart. "Nitric oxide kinetics in biological systems." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/36947.
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Berg, Michael C. Ph D. Massachusetts Institute of Technology. "Biological applications of weal polyelectrolyte multilayers." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/33599.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2005.Includes bibliographical references.
This thesis research focused on biological applications of ultra-thin weak polyelectrolyte multilayers with specific emphasis on cell patterning, drug delivery, and antibacterial coatings. All of these very different applications were studied using three different polymers - polyacrylic acid (PAA), poly(allylamine hydrochloride) (PAH), polyacrylamide (PAAm). The first part of this thesis focuses on patterning polyelectrolyte multilayers found to resist mammalian cell adhesion, with ligands that promote specific interactions for adhesion. It was found that by patterning PAH on polyelectrolyte multilayers, the patterned functional group density and thickness could be tuned through ink pH adjustment. By changing the surface density of amine groups in the PAH patterns, the ligand density could also be altered using specific chemistry to attach peptides containing the tri-peptide sequence, RGD, which is known to promote cell adhesion in a number of cell types. The RGD density in the patterned regions determined the number of cells attached and the amount of cytoskeletal protein organization. The second part is an evaluation of porous polyelectrolyte multilayers as a delivery system for controlled release of small molecule drugs. The loading and releasing properties of porous PAH/PAA multilayers were investigated using the two drugs, ketoprofen and cytochalasin D. It was determined that the amount of drug released was proportional to the number of porous layers. Nanoporous films showed zero-order release, whereas microporous films displayed Fickian diffusion. The efficacy of the released drugs was checked by monitoring the effect of released cytochalasin D on fibroblasts' division.
(cont.) In the final part of this thesis, the antibacterial properties of both silver-loaded polyelectrolyte multilayers and superhydrophobic multilayers are examined. It was found that silver loaded multilayers killed bacteria to an extent greater than 99.99% for both airborne and waterborne models. Superhydrophobic films showed excellent anti-fouling properties for proteins, mammalian cells, and bacteria.
by Michael C. Berg.
Ph.D.
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Domijan, Mirela. "Mathematical aspects of chemical reaction networks." Thesis, University of Warwick, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.495019.
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Chemical and biological processes present a challenge when it comes to modelling and analysis. The models usually have to take into account many chemicals and complex interactions and in turn, they are often described by large ODE systems with complicated nonlinear terms. If there is a lack of quantitative information about the chemical interactions, there will also be parameter uncertainty in the systems. Such systems present a challenge to analyse. In response, an increasing consensus calls for emphasis on the underlying chemical reaction network structure and the use of network information to predict possible system dynamics.
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Hale, Waverly Mitchell. "Surface chemical aspects of microbubble flotation." Thesis, Virginia Tech, 1987. http://hdl.handle.net/10919/45816.
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In order to demonstrate the ability of microbubble flotation to superclean coal to ash levels of less than 2%, several Eastern U. S. coals have been tested. The results show that the process is capable of producing superclean coal with improved recovery as compared to the conventional flotation process.
To further improve and understand the microbubble flotation process, electrokinetic studies of the hydrocarbon oils used in flotation as collectors have been conducted. Also, the effect of oil emulsifiers on the zeta potential of oil droplets has been studied. In general, oil droplets are negatively charged and negative zeta potential is reduced with the addition of nonionic and cationic surfactants. On the other hand, the negative charge is increased with the addition of an anionic reagent. It has also been shown that the negative zeta potential of oil droplets increases with increasing hydrocarbon chain length.
The effects of different collectors on induction time and flotation have been determined by conducting microflotation and induction time experiments using an Elkhorn seam coal sample. The results show that industrial oils combined with the coal have the shortest induction times and, therefore, the highest flotation yields as compared to pure hydrocarbon oils. It has also been shown that oil emulsifiers tend to increase flotation yield and reduce particle/bubble induction time.
Master of Science
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Batarseh, Eyad. "Chemical and Biological Treatment of Mature Landfill Leachate." Doctoral diss., University of Central Florida, 2006. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2698.
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This dissertation is about treatment of the nonbiodegradable organic content of landfill leachate by chemical oxidation combined with biological treatment. It is divided into three parts. In the first part, ferrate was compared to Fenton's reagent for the purpose of removing non-biodegradable organic compounds from mature leachate. Oxidation conditions (time, pH, and dose) were optimized to yield maximum organic removal using two leachate samples from 20 and 12-year old solid waste cells. Results from this research demonstrated that ferrate and Fenton's reagent had similar optimum pH ranges (3-5), but different organic removal capacities, ranging from 54 to 79 % of initial leachate organic contents. An advantage of ferrate was that it was relatively effective over a wide pH range (Fenton's reagent lost its reactivity outside optimum pH range). Advantages associated with Fenton's reagent include a higher organic removal capacity, production of more oxidized organic compounds (measured as chemical oxygen demand/dissolved organic carbon), and production of more biodegradable byproducts (measured as 5-day biochemical oxygen demand/chemical oxygen demand). Finally, both treatments were found to oxidize larger molecules (>1000 dalton) and produce smaller molecules, as indicated by an increase in smaller molecule contribution to organic carbon. In part two, effects of Fenton's reagent treatment on biodegradability of three landfill leachates collected from a Florida landfill were evaluated using biochemical oxygen demand (BOD), biochemical methane potential (BMP), and tertamethylammonium hydroxide (TMAH) thermochemolysis gas chromatography/mass spectrometry (GC/MS). The hypothesis was that Fenton's reagent will remove refractory compounds that inhibit biodegradation and will produce smaller, more biodegradable organic molecules which will result in an increase in BOD and BMP values. Both BOD and BMP results demonstrated that Fenton's reagent treatment did not convert mature leachate to biodegradable leachate, as indicated by a low BOD5 expressed as C /dissolved organic carbon (DOC) ratio of almost 0.15 in treated samples and a low net methane production / theoretical methane potential (less than 0.15). Ultimate BOD only slightly increased. However the first-order BOD reaction rate increased by more than five fold, suggesting that Fenton's reagent removed refractory and inhibitory compounds. BMP results demonstrated that the ratio of CO2/CH4 produced during anaerobic biodegradation did not increase in treated leachate (compared to untreated), indicating that small biodegradable organic acids produced by oxidation were removed by coagulation promoted by Fenton's reagent. Finally, the TMAH thermochemolysis results showed that several of the refractory and inhibitory compounds were detected fewer times in treated samples and that carboxylic acids did not appear in treated samples. In the third part of this dissertation the application of flushing/Fenton's reagent oxidation to produce sustainable solid waste cells was evaluated. A treatment similar to pump and treat process utilizing Fenton's reagent on-site treated leachate combined with in-situ aeration was proposed. Treated leachate would be recycled to the landfill cell flushes releasable nonbiodegradable carbon from the cell and oxidizes it externally. This technique was demonstrated to have treatment cost and time benefits over other alternatives for producing completely stable solid waste cells such as anaerobic flushing and biological and/or mechanical pretreatment of solid waste (used in the EU).Ph.D.
Department of Civil and Environmental Engineering
Engineering and Computer Science
Environmental Engineering
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Tsang, Wing Yin. "The chemical and biological activities of β-sultams." Thesis, University of Huddersfield, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.417289.
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Da, Silva Paula Maria Alexandra. "Chemical and biological studies on African Crypolepis species." Thesis, King's College London (University of London), 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300913.
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Elsnini, Ruwida Mansour. "Chemical characterization and biological activity of African propolis." Thesis, University of Strathclyde, 2016. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=28825.
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Propolis or bee glue, is collected by bees and contains secondary metabolites largely derived from trees or shrubs; it has been used traditionally as a natural remedy with a wide range of biological activities. Its chemical composition is highly complex and variable, and it has been studied in detail worldwide except in Africa. This study investigated the chemical composition and activity of African propolis against blood stream form of Trypanosoma brucei, the causative agent for sleeping sickness that threatens a large population of both humans and animals in sub-Saharan Africa. Extracts of propolis samples (n=12) collected from different regions in Nigeria and one sample collected from South Africa were chemically profiled by using various analytical techniques. These included high performance liquid chromatography (HPLC), coupled with different detection systems including evaporative light scattering detection (ELSD), ultraviolet detection (UV), and high resolution mass spectrometry (HRMS), along with gas chromatography- mass spectrometry (GC-MS) and proton-nuclear magnetic resonance (1H-NMR).Principal components analysis (PCA) of the processed LC-MS data collected was used in order to characterize samples according to their chemical composition. PCA demonstrated the uniqueness in chemical composition of some samples that were also active against Trypanosoma brucei. Therefore, the study proceeded to investigate in detail four samples collected mainly from the southern part of Nigeria. An optimized medium pressure chromatographic technique was used to isolate some of the component(s) responsible for the anti-trypanosomal activity. Two samples collected from Rivers State Nigeria had a different appearance from the rest of the propolis samples, being red in colour and had the highest trypanocidal activity (EC50=4.2 and 6.9 μg/mL) respectively. Their chemical composition was comparable to that of Brazilian red propolis. Fractionation work led to the isolation of ten phenolic compounds including calycosin, liquiritigenen, pinocembrin, vestitol, medicarpin, 8-prenylnaringenin, 6-prenylnaringenin, propolin D, macarangin and a new benzofuran. All compounds structurally elucidated by 1D and 2D Nuclear Magnetic Resonance (NMR) spectroscopy and LC-MSn. Some compounds showed strong inhibitory activity against trypanosomes such as medicarpin (MIC=11.5 μM) and propolin D (MIC=7.4 μM), macarangin (EC50 =18.5 μM), 8-prenylnaringenin (EC50= 17.9 μM), and vestitol (EC50= 30.5 μM). The new benzofuran was moderately active with (EC50=58.01 μM). Fractionation of the propolis sample collected from the Ugelli/Delta sample led to isolation of three compounds 1,3,7-trihydroxy-2,8-di-(3-methylbut-2-enyl) xanthone, 1,3,7-trihydroxy-4,8-di-(3-methylbut-2-enyl) xanthone and a new xanthone. These compounds were tested against T. brucei and presented high activities of EC50= 3.9, 11.04, 14.7 μM respectively. Triterpenes were the main fingerprint compounds in a sample collected from Ijebu-Ode/Ogun; three compounds were isolated and elucidated as ambonic acid, mangiferonic acid and α-amyrin. These compounds had EC50 values against T. brucei of 39.5, 25.5 and 20.9 μM respectively. Finally, sample D46SA from South Africa was found to contain mainly flavonols and diterpenic acids; three compounds pinocembrin, acetylimbricatolic acid and (-)-pimara-8 (14), 15-dien-19-oic acid were isolated and tested. All were moderately active against T. brucei.with MIC ranging from 41.4-137.3 μMIn conclusion, this work has proved the variabiliy of propolis collected even from the same region and the widespread activity of propolis against (blood stream form) T. brucei. It is likely that some of the propolis samples contain compounds with even higher activity that have not yet been isolated.
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Bora, Mihail. "Chemical and biological sensors based on organic semiconductors." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/53203.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2009.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 101-109).
In this thesis I designed, fabricated and characterized two types of sensors: chemical sensors based on organic thin film transistors, and a miniaturized surface plasmon resonance biosensors for biotechnology and medical diagnostics applications. During completion of my research projects I designed and optimized several device architectures using numerical simulations and fundamental physical evaluation of sensing mechanism and performance. Fabricated devices were tested in custom built experimental setups in microfluidic testing chambers using automatic data measurement. Surface functionalization of device surface using self assembled monolayer techniques was employed for experiments that required specificity towards analyzed biological species.
by Mihail Bora.
Ph.D.
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Wang, XiuZhu. "Investigation of biological and chemical interactions by AFM." Thesis, University of Cambridge, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.615986.
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Matheson, Christopher. "Chemical and biological studies with Nek2 kinase inhibitors." Thesis, University of Newcastle upon Tyne, 2012. http://hdl.handle.net/10443/2024.
Full textAbstract:
The aim of modern cancer chemotherapy is to develop targeted drugs designed to exploit pharmacological differences between tumour cells and healthy tissues. One focus of this effort has been the identification of protein kinases that are expressed at elevated levels or in mutated forms, indicating a reliance of the tumour on specific kinase function. Nek2 is a human serine/threonine protein kinase related to the fungal protein NIMA, a critical mediator of mitosis. Interestingly, Nek2 is found to be upregulated in a variety of tumour cell lines derived from breast, cervical and prostate carcinomas, as well as lymphomas. Human Nek2 is implicated in the regulation of the centrosome and formation of a bipolar spindle, a framework that is vital for correct separation of sister chromatids during mitosis. It is proposed that Nek2 may complex with, and phosphorylate, proteins accumulated at the centrosome, possibly playing a role in intercentriolar linker cleavage during the centrosome cycle. Abnormalities in centrosome number and function are common in many cancers, indicating that loss of centrosome cycle regulation may be a major contributing factor in tumour progression. Overexpression of Nek2 may result in premature centrosome disjunction, and deregulation of this tightly controlled mitotic machinery leads to chromatid segregation errors, aneuploidy and chromosomal instability, common genetic abnormalities observed in tumour cells. This indicates a role for abnormal Nek2 function in tumourigenesis, and Nek2 depletion in a number of tumour cell lines has been shown to cause growth suppression and apoptosis. Nek2 is thus a potentially attractive cancer therapeutic target for small-molecule kinase inhibitors. Previous studies identified substituted purine derivatives as modest inhibitors of Nek2, leading to the discovery of two distinct inhibitor classes, exhibiting ATP-competitive and irreversible inhibition of the kinase, respectively. Purine-based compounds bearing substituents at the 8-position have emerged as modest competitive inhibitors of Nek2 that occupy the kinase ATP-domain through an unusual binding orientation (45; IC = 51.8 M). Additional possible interactions within the ATP- 50 binding site available to inhibitors of this class were explored, with the objective of developing tight-binding type II reversible inhibitors of Nek2. Structure-activity relationship studies resulted in a 10-fold improvement in activity over the initial hit compounds and a substantial improvement in drug-like properties (e.g. 129; IC = 5.1 M)). However, all 50 efforts to improve the potency of this series were unsuccessful. 6-Ethynylpurines have been identified as irreversible inhibitors of Nek2 through covalent modification of an active-site cysteine residue. The initial hit compound (147; IC = 0.14 50 M) was found to be a potent and selective inhibitor of the kinase in vitro, but with poor cellular activity attributed to limited permeability. Extensive structural modification of the 2- arylamino side-chain of this series afforded cell permeable analogues with improved potency, both in vitro and in vivo (e.g. 177; IC = 0.062 ± 0.01 M). 50 Biochemical studies using 177 suggested that inhibition of Nek2 resulted in an increase in mitotic abnormalities and a delay in mitotic progression, despite poor cellular growth inhibition being observed in initial tumour cell lines. Further cellular growth inhibition and cytotoxicity studies with selected compounds identified several sensitive tumour cell lines. However, kinase-inactive control compounds essentially devoid of Nek-inhibitory activity (e.g. 425; IC > 100 M) retained growth-inhibitory activity, indicating an alternative locus 50 of activity for the 6-ethynylpurine chemotype.
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Nascimento, Raimundo Regivaldo Gomes do. "Study Chemical and Biological Margaritopsis carrascoana Wright (Rubiaceae)." Universidade Federal do CearÃ, 2014. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=13424.
Full textAbstract:
FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgicoMargaritopsis carrascoana is a small shrub belonging to the Rubiaceae family and endemic from northeastern of Brazil flora growing in the sandy soils of the region of Ibiapaba and Araripe plateaus â Cearà state. The absence of reports of phytochemical studies related to this species, combined with occurrence of bioactive alkaloids in the genus, motivated us to perform chemical study. The plant specimen was collected in Araripe plateu, in MoreilÃndia-PE county. The phytochemical investigation of the ethanolic extract from the stems yielded the alkaloids calycosidine, hodgkinsine, N-8â-formyl-calycosidine and N-8â-methyl-N-1â-desmethylisocalycosidine, besides neolignan dihydrodehydrodiconiferyl alcohol 4-O-β-D-glucopyranoside, the flavonol luteolin 7-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranosyl, the triterpenes lupeol and ursolic acid, and the mixture of β-sitosterol and stigmasterol steroids, as aglycones and glycosylated. From the ethanolic extract of the leaves were isolated the flavonoid luteolin 7-O-[β-D-apiofuranosyl-(1→6)]-β-D-glucopyranoside, chrysoeriol 7-O-[β-D-apiofuranosyl-(1→6)]-β-D-glucopyranoside, luteolin 7-O-{β-D-apiofuranosyl-(1→6)-[β-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranosyl} and luteolin 7-O-{α-L-rhamnopyranosyl-(1→6)-[β-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranosyl}. The alkaloids N-8"-formyl-calycosidine, N-8â-methyl-N-1â-desmethylisocalycosidine, luteolin 7-O-{β-D-apiofuranosyl-(1→6)-[β-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranosyl} and luteolin 7-O-{α-L-rhamnopyranosyl-(1→6)-[β-L-rhamnopyranosyl-(1→2)]-β-D-glucopyra-nosyl}, are being reported for the first time in the literature, and the other secondary metabolites are unprecedented in the genus Margaritopsis. The secondary metabolites were isolated using classical chromatography techniques; including adsorption chromatography on silica gel, exclusion chromatography on Sephadex LH-20, reverse phase chromatography (C-18), and high performance liquid chromatography (HPLC). For structural characterization were used infrared spectroscopy, mass spectrometry and nuclear magnetic resonance techniques including uni (1H NMR and 13C NMR and DEPT 135) and two-dimensional experiments (HMBC, HSQC, COSY and NOESY), and comparison with the literature data. In addition, the flavonoids flavonol luteolin 7-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranosyl, luteolin 7-O-[β-D-apiofuranosyl-(1→6)]-β-D-glucopyranoside, luteolin 7-O-{β-D-apiofuranosyl-(1→6)-[β-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranosyl} and luteolin 7-O-{α-L-rhamnopyranosyl-(1→6)-[β-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranosyl, sho-wed antioxidant activity greater than the BHT and quercetin standards, while ethanol extracts of stems and leaves showed inhibitory activity on the acetylcholinesterase enzyme. On the other hand, hodgkinsine showed potent cytotoxic activity against ovary, glioblastoma and colon cancer cells lines. The ethanol extract of the leaves and its alkaloidal fraction were submitted to nociception test and yielded good results. The ethanolic extract of the leaves was subjected to gastric antiulcer activity test, leading to a significant reduction in gastric lesions induced by ethanol in mice.
Margaritopsis carrascoana à um pequeno arbusto pertencente à famÃlia Rubiaceae e endÃmico da flora do Nordeste brasileiro, que cresce em solos arenosos do planalto da Ibiapaba e serra do Araripe - CearÃ. A ausÃncia de relatos acerca de estudos fitoquÃmicos relacionados à espÃcie, aliada a ocorrÃncia de alcalÃides bioativos no gÃnero, nos motivou ao seu estudo quÃmico. Desta forma, o espÃcimen vegetal foi coletado na chapada do Araripe, municÃpio de MoreilÃndia-PE. A investigaÃÃo fitoquÃmica do extrato etanÃlico dos talos resultou no isolamento dos alcalÃides calicosidina, hodgkinsina, N-8â-formilcalicosidina e N-8â-metil-N-1â-desmetilisocalicosidina, da neolignana Ãlcool 4-O-β-D-glicopiranosil-di-hidro-desidrodiconiferÃlico, do flavonÃide 7-O-[α-L-ramnopiranosil-(1→2)-β-D-glicopiranosil luteolina, dos triterpenos lupeol e o Ãcido ursÃlico, e da mistura de esterÃides β-sitosterol e estigmasterol, como agliconas e nas formas glicosiladas. A partir do estudo do extrato etanÃlico das folhas foram isolados os flavonÃides 7-O-[β-D-glicopiranosil-(1→6)-β-D-apiofuranosil] luteolina, 7-O-[β-D-glicopiranosil-(1→6)-β-D-apiofuranosil] crisoeriol, 7-O-{β-D-apiofuranosil-(1→6)-[α-L-ramnopiranosil-(1→2)-β-D-glicopiranosil} luteolina e 7-O-{α-L-ramnopiranosil - (1→6) - [α-L-ramnopiranosil-(1→2)-β-D-glicopiranosil} luteolina. Os alcalÃides N-8â-formilcalicosidina e N-8â-metil-N-1â-desmetilisocalicosidina, e os flavonÃides 7-O-{β-D-apiofuranosil-(1→6)-[α-L-ramnopiranosil-(1→2)-β-D-glicopiranosil} luteolina e 7-O-{α-L-ramnopiranosil-(1→6)-[α-L-ramnopiranosil-(1→2)-β-D-glicopiranosil} luteolina, estÃo sendo relatados pela primeira vez na literatura, enquanto todas as demais substÃncias possuem carÃter inÃdito no gÃnero Margaritopsis. O isolamento dos metabÃlitos secundÃrios foi conduzido atravÃs de tÃcnicas cromatogrÃficas clÃssicas, incluindo cromatografia de adsorÃÃo em gel de sÃlica, cromatografia por exclusÃo molecular em Sephadex LH-20, cromatografia de fase reversa (C-18) e cromatografia lÃquida de alta eficiÃncia (CLAE). Para a caracterizaÃÃo estrutural foram utilizadas tÃcnicas espectroscÃpicas utilizando infravermelho, espectrometria de massas e ressonÃncia magnÃtica nuclear, incluindo tÃcnicas uni (RMN 1H e RMN 13C e DEPT 135) e bidimensionais (HMBC, HSQC, COSY e NOESY), alÃm de comparaÃÃo com dados descritos na literatura. Em adiÃÃo, os flavonÃides 7-O-[α-L-ramnopiranosil-(1→2)-β-D-glicopiranosil luteolina, 7-O-[β-D-glicopiranosil-(1→6)-β-D-apiofuranosil] luteolina, 7-O-{β-D-apiofuranosil-(1→6)-[α-L-ramnopiranosil-(1→2)-β-D-glicopiranosil} luteolina e 7-O-{α-L-ramnopiranosil-(1→6) - [α-L-ramnopiranosil-(1→2)-β-D-glicopiranosil} luteolina apresentaram atividade antioxidante maior que os padrÃes BHT e quercetina, enquanto os extratos etanÃlicos dos talos e folhas apresentaram atividade inibidora da enzima acetilcolinesterase. Por outro lado, o alcaloide hodgkinsina apresentou potencial citotÃxico frente Ãs cÃlulas de ovÃrio, glioblastoma e colon. No teste de nocicepÃÃo, realizado com o extrato etanÃlico das folhas e a fraÃÃo alcalÃidica, foram observados resultados positivos para ambas as fraÃÃes. O extrato etanÃlico das folhas foi submetido a teste de atividade antiÃlcera gÃstrica, levando a uma reduÃÃo significativa da Ãrea de lesÃo gÃstrica induzida pelo etanol em camundongos.
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Carvalho, Jarbas Lima de. "Chemical and biological study of Bauhinia pulchella Benth." Universidade Federal do CearÃ, 2014. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=13413.
Full textAbstract:
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgicoThis present work reports the chemical and biological analysis of the stem and leaves from Bauhinia pulchella. In this study, the ethanol extract from stems was obtained by maceration, subjected to chromatographic fractionation, leading to isolation of three flavonoids: (+)-3â,4â-dihydroxyphenyl-chroman-7-ol (BP-2), (-)-fisetinidol (BP-3) and (+)-epicatechin (BP-4); a mixture of triterpenes taraxerone and β-amyrenone (BP-1); a mixture of steroids sitosterol and stigmasterol (BP-5); and a bibenzyl named 2-hydroxy-3â,5â-dimethoxybibenzyl (BP-6). It is notewhorthy to mention that BP-1 and BP-4 substances are unprecedented in the genus, while BP-2 is unpublished. Chemical structures of secondary metabolites obtained were elucidated by 1H and 13C NMR; IR and MS associated with comparison of data described in the literature. Chemical composition of the essential oil from leaves of B. pulchella, obtained by hydrodistillation, was determined and quantified by gas chromatography-mass spectroscopy (GC/MS) and gas chromatography-flame ionization detector (GC/FID), which identified 95,68% of all constituents. α-pinene (23.89%); caryophyllene oxide (22.43%) and β-pinene (12.19%) were the major components. The essential oil was tested against Aedes aegypti larvae and showed LC50 value of 105.93 Â 1.48 μg/mL. The cytotoxic activity of essential oil was evaluated on human tumor cell lines (HL-60; MCF-7; NCI-H292 and HEP-2) was evaluated, showing IC50 values with confidence intervals of 9.941 (8.238 to 12.00), 53.05 (41.39 to 67.99), 48.98 (44.22 to 54.25) and 50.42 (42.47 to 59.87) μg/mL, respectively and the cell line HL-60 the most sensitive among the cells tested. This is the first report of the chemical study of Bauhinia pulchella, as well the investigation of larvicidal activity and cytotoxicity of the essential oil from its leaves.
O presente trabalho relata o estudo quÃmico e biolÃgico do caule e das folhas de Bauhinia pulchella. Nesse estudo, o extrato etanÃlico do caule, obtido por maceraÃÃo, foi submetido a fracionamento cromatogrÃfico levando ao isolamento de trÃs flavonoides (+)-3â-4âdiidroxifenil-cromano-7-ol (BP-2), (-)-fisetinidol (BP-3) e (+)-epicatequina (BP-4); da mistura de triterpenos taraxerona e β-amirenona (BP-1); da mistura de esteroides sitosterol e estigmasterol (BP-5) e de um bibenzil denominado 2-hidrÃxi-3â-5â-dimetoxibibenzila (BP-6). Cabe ressaltar que as substÃncias BP-1 e BP-4 sÃo inÃditas no gÃnero, enquanto BP-2 à inÃdita na literatura. As estruturas dos metabÃlitos secundÃrios isolados foram elucidadas por RMN 1H e 13C; IV e EM, juntamente com a comparaÃÃo com os dados descritos na literatura. A composiÃÃo quÃmica do Ãleo essencial das folhas de B. pulchella, obtido por hidrodestilaÃÃo, foi determinada e quantificada por cromatografia gasosa acoplada à espectrometria de massas (CG-EM) e detector de ionizaÃÃo por chama (CG-DIC), sendo, portanto, identificados 95,68% dos seus constituintes: α-pineno (23,89%), Ãxido de cariofileno (22,43%) e β-pineno (12,19%) foram os constituintes majoritÃrios. O Ãleo essencial teve sua atividade larvicida sobre Aedes aegypti avaliada, sendo obtido um valor de CL50 igual a 105,93  1,48 μg/mL. O poder citotÃxico do Ãleo essencial foi avaliado sobre as linhagens tumorais humanas HL-60, MCF-7, NCI-H292 e HEP-2, sendo obtidos valores de CI50 e intervalos de confianÃa iguais a 9,941 (8,238 a 12,00); 53,05 (41,39 a 67,99); 48,98 (44,22 a 54,25) e 50,42 (42,47 a 59,87) μg/mL, respectivamente, sendo a linhagem celular HL-60 a mais sensÃvel dentre as cÃlulas testadas. Este à o primeiro relato do estudo quÃmico de Bauhinia pulchella, bem como da investigaÃÃo da atividade larvicida e citotÃxica do Ãleo essencial de suas folhas.
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Aguiar, Gisele Rocha. "Chemical and biological evaluation of propolis of Alagoas." Universidade Federal do CearÃ, 2015. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=15888.
Full textAbstract:
The red propolis originally from the state of Alagoas has a chemical composition rich in isoflavones and has been used as traditional popular medicine presented as an
antioxidant and antiviral properties. Its relevance to this study is mainly due to the same present several biological properties, among them: antimicrobial, anti-cancer, cytotoxic and anti-tumor. In this work it was performed the study of the fixed compounds present in hexane fraction of propolis, which presented three esters: the methyl hexadecanoate (15,20%), the methyl tetracosanoate (10,40%) and the methyl octadecanoate (2,39%). Four isoflavanes were isolated from the thanolic extract (2'-hydroxy-4',7-dimethoxyisoflavane [PV-1], 2',7-dihydroxy-4'-methoxyisoflavane [PV-3],4',7-dihydroxy-2'-methoxyisoflavane [PV-4] and 2',4'-ihydroxy-7-methoxyisoflavane [PV-5]), one chalcone (2',4 ',4-trihydroxychalcone [PV-6]) and a triterpene (lup-20(29)-en-3-ol [PV-2]), known in red propolis. The structural determination of substances were performed by spectroscopic methods IR, 1H NMR, 13C-BB NMR,13C NMR DEPT-135Â, COSY, HSQC, HMBC and GC-MS. It was performed the determination of total phenols, using a spectrophotometer, in the ethanolic extract (EEPV), which presented a phenolic content of 133.3  4.35 mg GAE / g sample, a result lower than those reported in the literature. Another test was performed on the antioxidant activity, the scavenging method using DPPH radical, both ethanolic extract and the hexane, dichloromethane, ethyl acetate and metanol fractions, with satisfactory results and higher than standart Vitamin C. Besides the antioxidant test, if was performed the inhibition of acetylcholinesterase assay by colorimetric method, of the ethanolic extract and hexane, dichloromethane, ethyl acetate and metanol fractions, that yielded positive results in almost all, regarding standart Eserine salt.A prÃpolis vermelha oriunda do Estado de Alagoas possui uma composiÃÃo quÃmica rica em isoflavonoides e tem sido usada como remÃdio tradicional na medicina popular por apresentar propriedades antioxidante e antiviral. Sua relevÃncia decorre, principalmente, por apresentar diversas propriedades biolÃgicas, dentre elas: antimicrobiana, anti-cancerÃgena, citotÃxica e antitumoral. Neste trabalho foi realizado o estudo dos compostos fixos presentes na fraÃÃo hexÃnica da prÃpolis, o qual apresentou trÃs Ãsteres: o hexadecanoato de metila (15,20%), o tetracosanoato de metila (10,40%) e o octadecanoato de metila (2,39%). Foram isoladas do extrato etanÃlico quatro isoflavanas (2â-hidroxi-4â,7-dimetoxiisoflavana [PV-1], 2â,7-dihidroxi-4â-metoxiisoflavana [PV-3], 4â,7-dihidroxi-2â-metoxiisoflavana [PV-4] e 2â,4â-dihidroxi-7-metoxiisoflavana [PV-5]), uma chalcona (2â,4â,4-trihidroxichalcona [PV-6]), e um triterpeno (lup-20(29)-en-3-ol [PV-2]), jà conhecidos na prÃpolis vermelha. A determinaÃÃo estrutural das substÃncias foi realizada atravÃs de mÃtodos espectroscÃpicos de IV, RMN de 1H, RMN de 13C-BB, RMN de 13C-DEPT 135Â, COSY, HSQC, HMBC e CG-EM. Realizou-se a determinaÃÃo de fenÃis totais, usando espectofotÃmetro, no extrato etanÃlico (EEPV), o qual apresentou um teor de compostos fenÃlicos de 133,3  4,35 mg de EAG/ g de amostra, resultado inferior aos relatados na literatura. Outro teste realizado foi o de atividade antioxidante, usando o mÃtodo de sequestro do radical DPPH, tanto no extrato etanÃlico, quanto nas fraÃÃes hexÃnica, diclorometano, acetato de etila e metanÃlica, apresentando resultados satisfatÃrios e superiores ao do padrÃo Vitamina C. AlÃm deste, foi realizado o ensaio de inibiÃÃo da enzima acetilcolinesterase, atravÃs de mÃtodo colorimÃtrico, no extrato etanÃlico e nas fraÃÃes hexÃnica, diclorometano, acetato de etila e metanÃlica, quase todos apresentando resultados positivos em relaÃÃo ao padrÃo sal de Eserina.
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Hildreth, J. L. "Chemical and biological studies of technetium nitrosyl complexes." Thesis, Loughborough University, 1992. https://dspace.lboro.ac.uk/2134/33014.
Full textAbstract:
A simple and widely applicable method for the synthesis of technetium nitrosyl complexes containing either [99Tc] or [99mTc] has been developed using hydroxylamine as a reducing agent. A number of readily available complexes such as [TcO4]- or [TcX6]2- (X = Cl, Br, I) may be employed as the starting material.