Orientador: Maria Valnice Boldrin Zanoni / Banca: Hideko Yamanaka / Banca: Ronaldo Censi Faria / Banca: Mauro Aquiles La Scalea / Banca: Iolanda da Cruz Vieira / Resumo: O Poli ácido glutâmico (PAG) é um poliaminoácido sintético formado por unidades repetitivas de glutamato, que apresentam grupos carboxilas ao longo de sua cadeia principal. A preparação de eletrodos de carbono vítreo modificados com filmes de PAG foi investigada utilizando-se três diferentes procedimentos: eletropolimerização do ácido glutâmico (MONO); deposição direta de poli ácido glutâmico (PAG) e poli ácido glutâmico:glutaraldeído (PAG:GLU) seguida de secagem a temperatura ambiente. Após secagem, o eletrodo modificado foi submetido a ciclos sucessivos entre -0,8 a +2,0 V sob velocidade de varredura de 100 mV s-1. O ácido ascórbico foi usado como composto modelo para os eletrodos modificados, os quais apresentaram um efeito eletrocatalítico na oxidação do mesmo. Os eletrodos modificados foram caracterizados por microscopia de força atômica (AFM) e espectroscopia de impedância eletroquímica (EIS). O recobrimento sobre a superfície pela adição de PAG apresentou a melhor performance exibindo filmes nanoestruturados e uniformes com baixa resistência à transferência de carga. Os eletrodos modificados por filmes PAG foram usados para estudar a oxidação do flavonóide rutina. Os resultados mostraram um par de picos redox em +0,46/+0,43 V, usado para a pré-concentração da rutina. Uma curva analítica foi obtida no intervalo de 0,9 a 9,0 μmol L-1 e o método proposto foi aplicado para análise do antioxidante em formulação farmacêutica. Os eletrodos modificados por filmes PAG foram também usados para determinação de ácido cafêico. Um par de pico redox reversível em +0,42/+0,45 V foi obtido para o ácido cafêico em tampão B-R pH 3,5. O método foi aplicado para a determinação de ácido cafêico em amostra de vinho tinto, detectando nível de concentração de 34,8μg mL-1 sem tratamento...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The poly glutamic acid (PAG) is a syntetic poliamonacid composed by repetitive glutamate units that shows carboxylic groups in the long of the principal chain. Films of PAG on the glassy carbon electrode was investigated by three diferents procedures: glutamic acid eletropomelimerization (MONO), direct deposition of the poly glutamic acid (PAG) and poly glutamic acid:glutaraldehyde (PAG:GLU), followed by drying at room temperature. After solvent evaporation, the modified electrode was submitted by cycles sucessives from -0.8 to +2.0 V at scan rate of 100 mV s-1. The ascorbic acid was used as a model compound in the modified electrodes, which presented an electrocatitic effect in the oxidation of the ascorbic acid. The modified electrodes were characterized by atomic force microscopy (AFM) and electrochemistry impedance spectroscopy (EIS). Coantings by poly glutamic acid onto the surface presented best performance by addition of PAG films that exhibits films nanostructured and uniforms with lower resistance to charge transfer. The modified electrode by PAG films were investigated to oxidation of rutin flavonoid. The results showed a redox pair of peaks at +0.46/+0.43 V, and linear analytical curve at 0.9 to 9.0 x 10-6 mol L-1. The method proposed was successful applied for rutin determination in pharmaceutical formulation. The modified electrode by PAG films was also used to determine cafeic acid. A reversible redox peak pair at +0.42/+0.45 V was obtained for cafeic acid at B-R buffer pH 3,5. The method was applied for cafeic acid determination in the red...(Complete abstract click electronic access below) / Doutor

O uso de atmosfera modificada (ATM) na embalagem de cortes cárneos tem sido uma alternativa para melhorar a qualidade do produto. Diante disto, o objetivo deste trabalho foi observar a vida útil de carnes armazenadas neste tipo de embalagem. Foram retiradas 96 amostras de 4 novilhos anelorados, divididas em três tratamentos: Tratamento 1 (T1) – referente às amostras analisadas no dia da desossa; Tratamento 2 (T14) – referente às amostras analisadas aos 14 dias de armazenamento; Tratamento 3 (T28) – referente às amostras analisadas aos 28 dias de armazenamento. Cada tratamento tinha oito amostras de cada um dos quatro músculos estudados: Longissimus dorsi (Contrafilé) – LD, Quadricepis femoris (Patinho) – QF, Semitendinosus (Lagarto) - ST e Supraspinatus (Peixinho) – SS, sendo quatro delas (A, B, C e D) usadas para análises de força de cisalhamento, perdas de água ao cozimento e por exsudação, pH e cor, e as outras quatro para análises microbiológicas. As amostras foram embaladas em sacos do tipo masterpack com mistura de gases na proporção de 75% O2 e 25% CO2 e armazenadas por 28 dias em câmara de resfriamento com temperatura de 0 a 1ºC. Ao longo do período de armazenamento foi observada uma redução linear da força de cisalhamento nos músculos LD, ST e QF, e uma associação quadrática em relação ao músculo SS, com um aumento da força após 14 dias. Em relação às perdas de água ao cozimento houve uma interação significativa entre o tempo de armazenamento e os músculos, e as perdas por exsudação apresentaram uma relação linear com o tempo de armazenamento, com valores crescentes de perdas do T1 em relação ao T2 e T3. Os valores de pH apresentaram uma associação linear e quadrática em relação ao tempo de armazenamento. Para as características de cor, o tempo de armazenamento apresentou associação linear e quadrática com o croma L*, quadrática com o croma a* e linear e quadrática com o croma b*. Não foram detectadas presenças de Salmonella e de Coliformes fecais, e nem de Clostridium em nenhuma das amostras analisadas, e as contagens detectadas de Coliformes totais estão abaixo do limite especificado para carne crua. Desta forma, foi concluído que carnes armazenadas em ATM, por um período de até 28 dias, não comprometem a qualidade visual e sensorial dos produtos. / Modified atmosphere packaging and case ready beef have been used to improve quality of beef cuts. With this objective in mind this work was designed to study the shelf life of this kind of packaging on beef cuts and 24 samples from 4 Nellore steers, were collected from each muscle: Longissimus dorsi (LD), Quadriceps femoris (QF), Semitendinosus (ST) and Supraspinatus (SS) in a total of 96 samples which were packaged in masterpack bags with a MAPAX gas with 75% O2 and 25% CO2 and aged for 1, 14 or 28 days or treatment T1 samples analyzed on day 1, T14 samples analyzed on day 14 and T28 samples analyzed on day 28, respectively. Every treatment had 8 samples from every one of the 4 muscles studied (A, B, C, e D). Four samples were used for shear force, cooking losses, pH and color and, the other 4 samples for microbiological analyses. A linear decrease in shear force with aging time was observed for LD, ST and QF muscles. A quadratic association for the SS muscle was seen after 14 days of aging. For cooking losses there was a significant interaction between aging time and muscle, as exudative loss showed a linear relation with aging time, improving loss, when comparing T1 in relation to T2 and T3. Differences were observed for pH showing a linear and quadratic relation with aging time. Muscle color among treatments and results were within acceptable values for both characteristics and results. No Salmonellae, Clostridium or Fecal Coli forms were observed in any of the samples as well as total Coli forms were within acceptable ranges for raw beef.

No presente trabalho, foi utilizada a microscopia eletroquímica de varredura (SECM) com o intuito de obter informações sobre a topografia, reatividade e possíveis intermediários formados em superfícies eletródicas. Foram estudados, em uma etapa inicial, modelos que proporcionaram a aprendizagem do manuseio e tratamento de dados utilizando a SECM. Em uma segunda etapa, a SECM foi aplicada no estudo da reatividade de substratos de cobre que passaram por um processo de ativação eletroquímica. A ativação foi realizada imergindo uma superfície de cobre em uma solução de Na2SO4 0,1 mol L-1 (pH = 2) e posterior aplicação de pulsos de potencial para oxidação de cobre (500 mV vs. Ag/AgCl(KCl sat.)) e subseqüente redução de íons Cu(II) (-250 mV vs. Ag/AgCl(KCl sat.)). Esse procedimento confere um aumento na sensibilidade na determinação de nitrato e nitrito. Para o estudo foram obtidas curvas de aproximação as quais foram correlacionadas com o tempo empregado na ativação. Também foram obtidas informações sobre a geração de Cu(I), estabilizado na presença de íons cloreto, durante o processo de ativação e sua influência na determinação de nitrato e nitrito. Por fim, a SECM foi utilizada no estudo de um sistema biomimético de cobre que catalisa a redução de oxigênio. Foram obtidas imagens com informações sobre a reatividade da superfície, homogeneidade do recobrimento do substrato e o mecanismo da reação. / Scanning electrochemical microscopy (SECM) was employed in order to obtain information on the topography, reactivity, and possible intermediates generated at electrodic surfaces. Standard chemical systems were firstly investigated as an attempt to understand the principles of the technique. Then, SECM was used to study the reactivity of copper substrates upon activation by an electrochemical protocol. The surface activation was achieved by immersing a copper surface in a solution of 0.1 mol L-1 Na2SO4 (pH = 2) for further anodic oxidation of copper (500 mV vs. Ag / AgCl(sat. KCl)) and subsequent reduction of Cu (II) (-250 mV vs. Ag / AgCl(sat. KCl)). An enhanced sensitivity was noticed for the determination of nitrate and nitrite at the modified copper surface and the approach curves were correlated with the activation time. Information on the generation of Cu (I), which was stabilized in the presence of chloride ions during the activation process, was also obtained, as well as the influence of this intermediate on the determination of nitrate and nitrite. Finally, SECM was used in the study of a copper biomimetic system which is able to catalyze the reduction of oxygen. Information on the reactivity of the surface, the homogeneity of the coated substrate and the reaction mechanism were obtained by analyzing the SECM results.

O estudo de polímeros condutores desperta um enorme interesse científico e tecnológico devido às diversas aplicações possíveis para esses materiais, como o desenvolvimento de dispositivos eletro-eletrônicos e sensores. Através de processos de dopagem esses polímeros tornam-se eletroativos, possibilitando por meio de técnicas eletroquímicas a determinação de diversas substâncias. Na agropecuária, a utilização intensiva e crescente de produtos químicos como pesticidas e fertilizantes, tem provocado diversas contaminações e agressões, despertando interesse na utilização de sensores para o monitoramento dessas substâncias em tempo real. Os eletrodos modificados com polímeros condutores têm-se apresentado como uma alternativa devido a algumas peculiaridades como alta estabilidade física e química e excelentes possibilidades analíticas devido à versatilidade da polimerização eletroquímica. Este trabalho teve como objetivo o desenvolvimento de novos materiais de eletrodos modificados com polímeros condutores para a determinação eletroanalítica de pesticidas. Os pesticidas estudados foram os herbicidas 2,4-D, bentazon, glifosato, paraquat e o inseticida paration metílico. Foram realizadas medidas voltamétricas e de impedância com eletrodos de carbono vítreo, pasta de carbono e eletrodos modificados com polianilina e polipirrol, visando a obtenção de sensores para a detecção destes pesticidas. Estudos de interação dos pesticidas com os polímeros foram realizados utilizando-se a técnica de espectrofotometria de UV-visível para a determinação da concentração dos pesticidas em estudos cinéticos. Também utilizou-se a espectroscopia de impedância eletroquímica para auxiliar no entendimento das interações entre os pesticidas e os polímeros condutores. Adicionalmente foi aplicada uma metodologia de análise de fluxo descontínuo (BIA), utilizada com sucesso na determinação de metais, para a determinação de pesticidas. Os resultados mostraram uma seletividade nas interações entre os polímeros condutores e os pesticidas. Por meio da resposta voltamétrica dos polímeros condutores, os eletrodos de pasta modificados com polianilina e polipirrol mostraram-se hábeis na detecção dos pesticidas não eletroativos como o 2,4-D, o bentazon e o glifosato, bem como na determinação do paraquat. Estes resultados atribuem aos eletrodos modificados desenvolvidos neste trabalho a característica de sensores de diagnóstico da presença destes pesticidas em solução. A metodologia de BIA na determinação de pesticidas, apresentou inúmeras vantagens do ponto de vista analítico, como a não renovação da superfície de eletrodo, micro-volumes de injeção de amostra, dezenas de análise sem troca do eletrólito suporte, tempos de análise inferiores a um segundo bem como a possibilidade de utilização de dispositivo portátil para análises em campo. / Studies of conducting polymers have great technological and scientific interest due to many possibilities of applications like the development of electronic devices and sensors. By means of a doping process these polymers became electroactives, allowing the determination of substances that specifically interact with the polymers. In agriculture the intensive and constant use of chemical substances as pesticides and fertilizers are causing several environmental contamination and the development of sensors for real time analysis has been a research field of intense interest. Electrodes modified with conducting polymers have several interesting characteristics as their high physical and chemical stability and excellent analytical possibilities, due to the versatility of the electrochemical polymerization. The objective of the present work was the development of electrode materials modified with conducting polymers for the electroanalytical determination of pesticides. The pesticides studied were the herbicide 2,4-D, bentazon, gliphosate and paraquat and the insecticide methylparathion. Voltammetric measurements were performed on glassy carbon and carbon paste electrodes modified with polianiline and polipirrol to obtain a procedure for the pesticides measurement. Studies of interaction between the pesticides and the polymers were performed using UV-visible spectrophotometry for pesticide concentration determination kinetic sorption experiments and the electrochemical impedance technique was also used to evaluate such sorption processes. Batch Injection Analysis (BIA), a technique successfully used for the analysis of metals, was also tested for the determination of the herbicide paraquat. Results obtained from the kinetic studies and the voltammetric and impedance experiments showed some selectivity for the interaction of the pesticide with the two polymers. By means of the voltammetric response of the polymers, the carbon paste electrode modified with polianiline showed to be very suitable for the detection of the herbicide 2,4-D, bentazon and gliphosate, but not for paraquat and methilparathion. On the other hand the carbon paste electrode modified with polipirrol detect only the gliphosate and paraquat. The results shows that the detection of the paraquat and the gliphosate by the polipirrol are not influenced by protonation, whereas the detection of the 2,4-D, bentazon and gliphosate by the polianiline are due to sorption and consequent doping of the polymer by the pesticides, which have acidic behavior. The BIA technique used for the detection of the pesticide paraquat, showed a good sensitivity and could be used in the future for the analysis of such substances with many advantages when compared with conventional electroanalytical procedures.

Os fornos de pirólise, feitos a partir da liga HP modificada, são equipamentos destinados à produção de hidrocarbonetos leves na indústria petroquímica. A partir da pirólise, é possível obter etileno e outros produtos que são matérias-primas para obtenção de manufaturados formados por polímeros. Nesse processo, grandes moléculas de hidrocarbonetos, na forma gasosa, são craqueadas em condições especiais de temperatura e pressão. Durante o craqueamento, o teor de carbono dos materiais que constituem os fornos é aumentado por meio do ingresso de carbono através da superfície interna dos tubos, sendo oriundo da massa reativa que atravessa as colunas e, como consequência disso, ocorre uma alteração das propriedades mecânicas do material. Aliado a esse fato, existe o depósito nocivo de uma camada de coque a partir da superfície interna das tubulações, que funciona como um isolante térmico, diminuindo a temperatura do gás e exigindo uma maior temperatura de trabalho para o forno, além de causar tensões que podem resultar em trincas ou danos para as colunas dos fornos de pirólise. Durante a carburização, a liga metálica dos fornos de pirólise desenvolve propriedades tipo ferromagnéticas, as quais são resultado do processo de ingresso de carbono. Nesta etapa, a camada magnetizada do material coincide com a região onde houve propagação da carburização. Sendo assim, uma medida da magnetização do material pode resultar em uma medida direta do nível de carburização em que o forno se encontra. Neste trabalho, serão apresentadas técnicas para simulação de ambientes carburizantes em alta temperatura, e as amostras serão testadas tendo o tempo de exposição ao carbono como sua principal variável e as suas propriedades mecânicas serão avaliadas, além da alteração de sua composição química e sua microestrutura. / The pyrolysis heaters, made of HP-modified alloy, are equipments designed to produce lightweight hydrocarbon in the petrochemical industry. Because of the pyrolysis, it is possible to obtain ethylene and other products that are raw material to gain manufactured polymer. In this process, big gaseous hydrocarbon molecules suffer a cracking process under special conditions of temperature and pressure. During the steam cracking process, the amount of carbon from the constituent material of the heaters is increasing as a consequence of the carbon entrance through the inside surface of the tubes. This carbon comes from the reactive mass that crows the columns and, eventually, produces a change in the mechanical proprieties of the material. Besides that, there is a harmful deposit of a coke layer that comes from the internal surface of the heater tubes. This layer works as a thermal insulation and is responsible for the decreasing of the gas temperature and as a consequence, the heater demands a higher temperature to work properly. As a result, rupture or damages can occur in the pyrolysis heater columns. During the carburization, the above mentioned alloy presents magnetic properties in consequence of the increase of the carbon amount in the material. The magnetic layer is observed in the region where the carburization process happened. Therefore, a measure of the material magnetization can lead to a direct measure of the carburization level in which the heater is on. In this work, simulation techniques of the carburizing environment under high temperature will be presented, and the samples will be tested regarding the correlation between carbon exposition time and the mechanical properties, microstructural changes and chemical composition that occur as a result.

No presente trabalho, foi utilizada a microscopia eletroquímica de varredura (SECM) com o intuito de obter informações sobre a topografia, reatividade e possíveis intermediários formados em superfícies eletródicas. Foram estudados, em uma etapa inicial, modelos que proporcionaram a aprendizagem do manuseio e tratamento de dados utilizando a SECM. Em uma segunda etapa, a SECM foi aplicada no estudo da reatividade de substratos de cobre que passaram por um processo de ativação eletroquímica. A ativação foi realizada imergindo uma superfície de cobre em uma solução de Na2SO4 0,1 mol L-1 (pH = 2) e posterior aplicação de pulsos de potencial para oxidação de cobre (500 mV vs. Ag/AgCl(KCl sat.)) e subseqüente redução de íons Cu(II) (-250 mV vs. Ag/AgCl(KCl sat.)). Esse procedimento confere um aumento na sensibilidade na determinação de nitrato e nitrito. Para o estudo foram obtidas curvas de aproximação as quais foram correlacionadas com o tempo empregado na ativação. Também foram obtidas informações sobre a geração de Cu(I), estabilizado na presença de íons cloreto, durante o processo de ativação e sua influência na determinação de nitrato e nitrito. Por fim, a SECM foi utilizada no estudo de um sistema biomimético de cobre que catalisa a redução de oxigênio. Foram obtidas imagens com informações sobre a reatividade da superfície, homogeneidade do recobrimento do substrato e o mecanismo da reação. / Scanning electrochemical microscopy (SECM) was employed in order to obtain information on the topography, reactivity, and possible intermediates generated at electrodic surfaces. Standard chemical systems were firstly investigated as an attempt to understand the principles of the technique. Then, SECM was used to study the reactivity of copper substrates upon activation by an electrochemical protocol. The surface activation was achieved by immersing a copper surface in a solution of 0.1 mol L-1 Na2SO4 (pH = 2) for further anodic oxidation of copper (500 mV vs. Ag / AgCl(sat. KCl)) and subsequent reduction of Cu (II) (-250 mV vs. Ag / AgCl(sat. KCl)). An enhanced sensitivity was noticed for the determination of nitrate and nitrite at the modified copper surface and the approach curves were correlated with the activation time. Information on the generation of Cu (I), which was stabilized in the presence of chloride ions during the activation process, was also obtained, as well as the influence of this intermediate on the determination of nitrate and nitrite. Finally, SECM was used in the study of a copper biomimetic system which is able to catalyze the reduction of oxygen. Information on the reactivity of the surface, the homogeneity of the coated substrate and the reaction mechanism were obtained by analyzing the SECM results.

Wong Wai Mei. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 175-192). / Abstracts in English and Chinese. / Declaration --- p.ii / Acknowledgements --- p.iii / Abstract --- p.iv / Abbreviation --- p.vi / Table of Contents --- p.vii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter Section I --- The Making of Genetically Modified Organisms --- p.2 / Chapter 1.1 --- Conventional breeding in agriculture --- p.2 / Chapter 1.2 --- What is genetic engineering? --- p.4 / Chapter 1.3 --- Plant transformation --- p.5 / Chapter 1.3.1 --- Agrobacterium-mediated --- p.6 / Chapter 1.3.2 --- Direct gene transfer --- p.8 / Chapter 1.3.2.1 --- Microparticle bombardment --- p.8 / Chapter 1.3.2.2 --- Protoplasts --- p.9 / Chapter 1.3.3 --- Gene silencing --- p.10 / Chapter 1.4 --- Examples of genetically modified crops --- p.13 / Chapter 1.5 --- Foreign genes commonly found in transgenic plants --- p.14 / Chapter Section II --- Benefits and Environmental Concern of GMOs --- p.17 / Chapter 2.1 --- Mechanism of GMO --- p.17 / Chapter 2.1.1 --- Herbicide tolerant crops --- p.18 / Chapter 2.1.2 --- Insect resistant crops --- p.19 / Chapter 2.1.3 --- Delayed ripening crops --- p.20 / Chapter 2.1.4 --- Virus resistant crops --- p.20 / Chapter 2.2 --- Benefits of GMOs --- p.21 / Chapter 2.3 --- Impact of GM foods to human health and the environment --- p.22 / Chapter 2.3.1 --- Human health --- p.22 / Chapter 2.3.1.1 --- GM potatoes --- p.23 / Chapter 2.3.1.2 --- CaMV risks? --- p.24 / Chapter 2.3.1.3 --- Food allergy --- p.25 / Chapter 2.3.2 --- Environmental concerns --- p.26 / Chapter 2.3.2.1 --- Horizontal gene transfer --- p.27 / Chapter 2.3.2.1.1 --- Selectable marker genes --- p.27 / Chapter 2.3.2.1.2 --- Herbicide resistant genes --- p.29 / Chapter 2.3.2.1.3 --- Insect resistant genes --- p.29 / Chapter 2.3.2.2 --- Ecology --- p.30 / Chapter 2.3.2.2.1 --- Monarch butterfly --- p.30 / Chapter Section III --- Future developments of GMO --- p.32 / Chapter 3.1 --- Designer Food and engineered plants --- p.32 / Chapter 3.1.1 --- Insect resistance --- p.33 / Chapter 3.1.2 --- Viral resistance --- p.33 / Chapter 3.1.3 --- Fungal resistance --- p.34 / Chapter 3.1.4 --- Nutritional quality --- p.34 / Chapter 3.1.5 --- Modifications of oil composition --- p.35 / Chapter 3.1.6 --- Medical applications --- p.37 / Chapter 3.1.7 --- Environmental applications --- p.40 / Chapter 3.1.7.1 --- Tolerance to high salinity and drought --- p.40 / Chapter 3.1.7.2 --- Tolerance to frost --- p.41 / Chapter 3.1.7.3 --- Bioremediation --- p.42 / Chapter 3.1.7.4 --- Biodegradable products --- p.43 / Chapter Section IV --- Regulation of GMO --- p.44 / Chapter 4.1 --- The question of labeling --- p.44 / Chapter 4.1.1 --- Moral and ethical issues --- p.44 / Chapter 4.1.2 --- Animal welfare --- p.45 / Chapter 4.2 --- International practice in GMO labeling --- p.46 / Chapter 4.2.1 --- United States of America --- p.46 / Chapter 4.2.2 --- Canada --- p.48 / Chapter 4.2.3 --- European Union --- p.49 / Chapter 4.2.4 --- Australia and New Zealand --- p.50 / Chapter 4.2.5 --- Japan --- p.51 / Chapter 4.2.6 --- Republic of Korea --- p.52 / Chapter 4.2.7 --- China --- p.53 / Chapter 4.2.8 --- Taiwan --- p.53 / Chapter 4.2.9 --- Hong Kong --- p.54 / Chapter Section V --- Uses of crops --- p.56 / Chapter 5.1 --- Uses of crops --- p.56 / Chapter 5.1.1 --- Soybean --- p.56 / Chapter 5.1.2 --- Corn --- p.57 / Chapter 5.1.3 --- Tomato --- p.58 / Chapter 5.1.4 --- Potato --- p.59 / Chapter 5.1.5 --- Rice --- p.60 / Chapter 5.1.6 --- Rapeseed --- p.61 / Chapter 5.1.7 --- Oil --- p.62 / Chapter 5.2 --- "Food additives, hormones and flavourings" --- p.63 / Chapter Chapter 2 --- Materials & Methods --- p.65 / Chapter 2.1 --- Materials --- p.66 / Chapter 2.1.1 --- Growth media & agar --- p.66 / Chapter 2.1.2 --- Reagents for agarose gel electrophoresis --- p.67 / Chapter 2.1.3 --- Reagents for preparation of competent cells --- p.67 / Chapter 2.1.4 --- Reagents for measurement of DNA concentration --- p.68 / Chapter 2.1.4.1 --- Measurement of DNA concentration by PicoGreen --- p.68 / Chapter 2.1.5 --- Reagents for Southern hybridization --- p.68 / Chapter 2.2 --- Methods --- p.70 / Chapter 2.2.1 --- Restriction endonuclease digestion --- p.70 / Chapter 2.2.2 --- Agarose gel electrophoresis of DNA --- p.70 / Chapter 2.2.3 --- DNA recovery from agarose gel --- p.71 / Chapter 2.2.3.1 --- QIAquick® gel extraction --- p.71 / Chapter 2.2.4 --- Ligation of purified DNA fragment into vector --- p.72 / Chapter 2.2.5 --- Transformation --- p.72 / Chapter 2.2.6 --- Rubidium chloride method for making competent cells --- p.12 / Chapter 2.2.7 --- Plasmid DNA preparation --- p.73 / Chapter 2.2.7.1 --- Concert Rapid Mini Prep --- p.73 / Chapter 2.2.7.2 --- QIAprep® Miniprep --- p.74 / Chapter 2.2.8 --- Extraction of plant genomic DNA --- p.75 / Chapter 2.2.8.1 --- Qiagen DNeasy´ёØ Plant Mini Kit --- p.75 / Chapter 2.2.9 --- Southern Hybridization --- p.75 / Chapter 2.2.9.1 --- Denaturation --- p.76 / Chapter 2.2.9.2 --- Blot transfer --- p.76 / Chapter 2.2.9.3 --- Pre-hybridization --- p.77 / Chapter 2.2.9.4 --- Synthesis of radiolabelled probe --- p.77 / Chapter 2.2.9.5 --- Hybridization of radiolabelled probe on filter --- p.77 / Chapter 2.2.9.6. --- Detection of hybridized probes --- p.78 / Chapter 2.2.10 --- Measurement of DNA concentration --- p.78 / Chapter 2.2.10.1 --- Determination of DNA on EtBr stained gel --- p.78 / Chapter 2.2.10.2 --- Determination of DNA by UV spectrophotometer --- p.78 / Chapter 2.2.10.3 --- Determination of DNA by PicoGreen --- p.79 / Chapter 2.2.11 --- DNA sequencing --- p.80 / Chapter 2.2.11.1 --- Automated sequencing by ABI Prism 377 --- p.80 / Chapter Chapter 3 --- PCR Diagnostics --- p.81 / Chapter 3.1 --- Applications of PCR to processed foods --- p.82 / Chapter 3.1.1 --- DNA quality --- p.82 / Chapter 3.1.2 --- PCR & Multiplex PCR --- p.83 / Chapter 3.1.3 --- Choice of primers --- p.84 / Chapter 3.1.4 --- Inhibitors --- p.84 / Chapter 3.2 --- Materials & Methods --- p.85 / Chapter 3.2.1 --- Selection of primers --- p.85 / Chapter 3.2.2 --- Amplification of target sequences --- p.86 / Chapter 3.2.3 --- Multiple amplification of target sequences --- p.87 / Chapter 3.3 --- Results --- p.88 / Chapter 3.4 --- Discussion --- p.93 / Chapter Chapter 4 --- Quality Control in GMO detection --- p.95 / Chapter 4.1 --- Standardization of pre- and post- PCR analysis --- p.96 / Chapter 4.1.1 --- General guidelines --- p.96 / Chapter 4.1.2 --- UV irradiation --- p.97 / Chapter 4.1.3 --- Inactivation protocols --- p.93 / Chapter 4.1.4 --- Positive and negative controls --- p.99 / Chapter 4.1.5 --- PCR verification --- p.99 / Chapter 4.1.6 --- Equipment decontamination --- p.100 / Chapter 4.2 --- Materials & Methods --- p.101 / Chapter 4.2.1 --- Selection of primers for external control --- p.101 / Chapter 4.2.2 --- Development of the external control --- p.101 / Chapter 4.2.3 --- Selection of primers for internal control --- p.103 / Chapter 4.3 --- Results --- p.104 / Chapter 4.4 --- Discussion --- p.107 / Chapter Chapter 5 --- DNA extraction from food samples --- p.110 / Chapter 5.1 --- Introduction --- p.111 / Chapter 5.2 --- Reagents and Buffers for DNA extraction from food samples --- p.112 / Chapter 5.2.1 --- Cetyltrimethylammonium bromide (CTAB) extraction method --- p.112 / Chapter 5.2.2 --- Organic-based extraction method --- p.113 / Chapter 5.2.3 --- Potassium acetate/sodium dodecyl sulphate precipitation method --- p.113 / Chapter 5.2.4 --- Hexane-based extraction method --- p.114 / Chapter 5.3 --- Weight and names of samples --- p.115 / Chapter 5.4 --- DNA extraction methods --- p.115 / Chapter 5.4.1 --- CTAB extraction method --- p.115 / Chapter 5.4.2 --- Qiagen DNeasy´ёØ plant mini kit --- p.116 / Chapter 5.4.3 --- Promega Wizard® genomic DNA purification --- p.116 / Chapter 5.4.4 --- Promega Wizard® Magnetic DNA purification system --- p.117 / Chapter 5.4.5 --- Promega Wizard® DNA Clean-Up system --- p.118 / Chapter 5.4.6 --- Qiagen QIAshreddrer´ёØ and QIAamp spin column --- p.119 / Chapter 5.4.7 --- Chelex-based extraction method --- p.119 / Chapter 5.4.8 --- Organic-based extraction method --- p.120 / Chapter 5.4.9 --- Nucleon PhytoPure extraction and purification method --- p.120 / Chapter 5.4.10 --- Potassium acetate/SDS precipitation method --- p.121 / Chapter 5.4.11 --- Hexane-based extraction method --- p.122 / Chapter 5.5 --- Results --- p.123 / Chapter 5.5.1 --- Comparison of eleven extraction methods --- p.123 / Chapter 5.5.2 --- Comparison of DNA extraction on selected methods --- p.125 / Chapter 5.6 --- Discussion --- p.132 / Chapter Chapter 6 --- Quantitative Analysis --- p.136 / Chapter 6.1 --- Introduction --- p.137 / Chapter 6.1.1 --- Chemistry of quantitative PCR --- p.138 / Chapter 6.1.2 --- PCR system --- p.140 / Chapter 6.2 --- Materials & Methods --- p.142 / Chapter 6.2.1 --- Design of primers and probes --- p.142 / Chapter 6.2.2 --- Methods --- p.145 / Chapter 6.3 --- Results --- p.146 / Chapter 6.3.1 --- Selection of primer/probe --- p.146 / Chapter 6.3.2 --- Primer optimization --- p.149 / Chapter 6.3.3 --- Quantitative analysis of real samples --- p.158 / Chapter 6.4 --- Discussion --- p.152 / Chapter Chapter 7 --- Conclusion --- p.168 / References --- p.175 / Appendix --- p.193

by Lam Lai Ming, Regina, Tang Oi Tai. / Thesis (M.B.A.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 65-66). / Questionnaire also in Chinese. / ABSTRACT --- p.ii / TABLE OF CONTENTS --- p.iv / LIST OF TABLES --- p.vi / LIST OF FIGURES --- p.vii / ACKNOWLEDGEMENT --- p.ix / Chapter / Chapter I. --- INTRODUCTION --- p.1 / Genes and GM Food --- p.1 / Examples of GM Food Available in the Market --- p.2 / Potential Benefits and Risks of GM Food --- p.2 / Scientific Evidence for the Safety of GM Food --- p.5 / The International Scene of GM Food Labeling System --- p.6 / Pros and Cons of GM Food Labeling --- p.7 / Consumers' Perception and Acceptance of GM Food --- p.9 / Situation in Hong Kong --- p.11 / Hong Kong Public´ةs Concern --- p.13 / Chapter II. --- RESEARCH OBJECTIVES AND METHODOLOGY --- p.15 / Research Objectives --- p.15 / Methodology --- p.15 / Research Design --- p.15 / Questionnaire --- p.16 / Data Collection --- p.17 / Data Analysis Method --- p.17 / Chapter III. --- FINDINGS AND IMPLICATIONS --- p.19 / General Public's knowledge about / awareness of GM food --- p.19 / Consumers' Perception and Attitudes towards GM Food and Traditionally Produced Food --- p.22 / Quality --- p.25 / Nutritional Value --- p.27 / Price --- p.29 / Safety of consumption --- p.31 / Consumers' Purchasing Behavior --- p.34 / To evaluate consumers' opinions and reactions to the GM Food labeling system in Hong Kong --- p.40 / Profiles of the respondents --- p.43 / Limitations --- p.46 / Chapter IV. --- RECOMMENDATIONS --- p.48 / For Government --- p.48 / For GM Food Manufacturers --- p.50 / For Suppliers --- p.51 / APPENDIX --- p.53 / BIBLIOGRAPHY --- p.65

This thesis explores topics related to the formation and development of the large-scale structure in the Universe, with the focus being to compute properties of the evolved non-linear density field in an approximate way. The first three chapters form an introduction: Chapter 1 contains the theoretical basis of modern cosmology, Chapter 2 discusses the role of N-body simulations in the study of structure formation and Chapter 3 considers the phenomenological halo model. In Chapter 4 a novel method of computing the matter power spectrum is developed. This method uses the halo model directly to make accurate predictions for the matter spectrum. This is achieved by fitting parameters of the model to spectra from accurate simulations. The final predictions are good to 5% up to k = 10 hMpc-1 across a range of cosmological models at z = 0, however accuracy degrades at higher redshift and at quasi-linear scales. Chapter 5 is dedicated to a new method of rescaling a halo catalogue that has previously been generated from a simulation of a specific cosmological model to a different model; a gross rescaling of the simulation box size and redshift label takes place, then individual halo positions are modified in accord with the large scale displacement field and their internal structure is altered. The final power spectrum of haloes can be matched at the 5% level up to k = 1 hMpc-1, as can the spectrum of particles within haloes reconstituted directly from the rescaled catalogues. Chapter 6 applies the methods of the previous two chapters to modified gravity models. This is done in as general a way possible but tests are restricted to f(R) type models, which have a scale-dependent linear growth rate as well as having 'chameleon screening' - by which modifications to gravity are screened within some haloes. Taking these effects into account leads to predictions of the matter spectrum at the 5% level and rescaled halo distributions that are accurate to 5% in both real and redshift space. For the spectrum of halo particles it is demonstrated that accurate results may be obtained by taking the enhanced gravity in some haloes into account.

The purpose of the current study was to understand public opinion formation by determining what factors influence opinion leaders in the organic food community to engage in the genetically modified food debate, and how opinion leaders describe American lay publics' engagement in the debate.