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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

Dendrimer light-emitting diodes

Stevenson, Stuart G. January 2008 (has links)
The electronics industry today is one that stands as a multi-billion dollar industry that is increasingly incorporating more and more products that have ever escalating applications in our everyday life. One of the main sectors of this industry, and one that is likely to continue expanding for a considerable number of years are flat-panel displays. Traditionally, the displays market has been dominated by cathode ray tube (CRT) and liquid crystal displays (LCDs) display types. The drawback of such display displays is that they can be bulky, heavy and/or expensive and so there is considerable room for an alternative and superior technology. One possibility is organic semiconductor displays where light-emitting molecules can be dissolved in common solvents before being inkjet printed, spin-coated or even painted onto any surface giving the benefits of simple and cost effective processing. Organic light-emitting diodes (OLEDs) have recently become ever more evident as a major display type. This thesis focuses on the advancement of light-emitting dendrimers towards flat-panel display applications. The particular interest in dendrimers arises because it has been found they are capable of giving solution-processed phosphorescent devices with high efficiency. Throughout the thesis the benefits of the dendrimer concept are repeatedly shown revealing why this could become the ideal organic material for display applications. The thesis introduces various techniques of electroluminescence and photoluminescence measurements before applying such methods to study a large number of light-emitting dendrimers in order to explore the role of intermolecular interactions, how they are related to molecular structure, and how this determines photophysical and charge transporting properties of the dendrimers. By such studies a number of highly efficient solution-processed phosphorescent light-emitting dendrimers have been identified while the efficiency of devices made from these dendrimers has been improved. This has been demonstrated in each of the three primary display colours of red, green and blue. The work detailed thus brings closer the prospect of dendrimer light-emitting diodes being the future flat-panel display type of choice.
102

THE ROLE OF HABITAT STRUCTURE AND COMPETITION IN THE ECOLOGY OF LISTERIA SPECIES IN FOOD-RELATED AND OTHER ENVIRONMENTS

Sally Chiu Unknown Date (has links)
Listeria monocytogenes is a foodborne pathogen with a high mortality rate in susceptible populations and is of great public health concern with regard to food safety. The ability to grow at refrigeration temperatures during storage and at low pH levels during food processing has enabled the species to establish and sustain growth on processed food. Some food products particularly at risk of contamination by L. monocytogenes are deli or processed meat products, seafood, processed vegetables, dairy products and other food that do not require heating or reheating before consumption. The aims of this study are therefore to investigate firstly the prevalence rates of the species in high risk food products and a food processing plant in Brisbane. Secondly, to determine whether food isolates are better than environmental isolates at surviving the stress factors in food processing environments, or if their lineage groupings are a better indicator of their survival. Thirdly, to compare the survival of food and environmental isolates under temperature stress in co-cultures. A survey of more than 100 high-risk food products at supermarkets was carried out to investigate the prevalence of L. monocytogenes and other Listeria species in food. Isolates were also obtained from a food processing plant during routine tests. This study has found a low prevalence rate (under 10%) of L. monocytogenes in the processed vegetables and meat products tested. Other products tested included processed and raw seafood and processed fresh fruit. More L. monocytogenes isolates were isolated from the food processing plant (101) than from the food survey (25). Listeria grayi (73 isolates), a non-pathogenic species, was more frequently isolated from the food survey. The characterisation of those isolates has revealed their lineage groupings and REP-PCR profiles, which did not appear to be related to their sources. A selected group of 25 isolates were also serotyped for further identification. A larger number of lineage II isolates (70) were found compared to lineage I isolates (25), and were more common in food than the environments; while some (7) produced inconclusive results in the lineage PCR. The REP-PCR did not separate isolates of different sources, lineages or serotypes. In order to investigate the survival fitness of L. monocytogenes isolates whilst under environmental stress relevant to food safety, ten isolates from the food survey and food processing plant were chosen. Five isolates each from lineages I and II were subjected to temperatures ranging from 4ºC to 30ºC and pH levels from 4.0 to 6.0 for two weeks continuously, with their growth monitored by either optical density or plate counts. It was found that the isolates were most susceptible at the combination of pH 4.0 and 4ºC, where the growth of the isolates was completely inhibited. Again no relationship was observed between the lineage or the sources and the survival fitness of the chosen isolates. Due to the frequency of L. monocytogenes being co-isolated with other Listeria species as well as other food-borne pathogens, the relative competitive fitness of four of the isolates from the survival fitness experiment were compared in co-cultures at 4ºC and 30ºC at pH 7.4 in a small-scale preliminary study. The four isolates from food and environments were grown in broth cultures in pairs with the plate counts performed on antibiotic-supplemented selective TSA agar. The isolates were distinguished on agar supplemented with tetracycline which the isolates had acquired resistance to for this purpose. No significant difference (P>0.05) was observed between the lineages or the sources and the competitive fitness of the isolates in this study. The isolates always produced slightly more colonies in the antibioticresistant form compared to the wildtype form but did not seem to relate to the competitive fitness of the isolates. It would seemed that within the scope of this study, neither the lineage, serotype nor source of the isolates indicated any isolate with a better ability of survival while at low temperatures and low pH levels in pure and mixed cultures. However, other classifying groups such as serotypes, RAPD profiles may reveal possible co-relations, as well as a wider isolate pool. Furthermore, different stress factors could be included as part of an investigation on the survival of L. monocytogenes, as this study focused on food safety during processing.
103

THE ROLE OF HABITAT STRUCTURE AND COMPETITION IN THE ECOLOGY OF LISTERIA SPECIES IN FOOD-RELATED AND OTHER ENVIRONMENTS

Sally Chiu Unknown Date (has links)
Listeria monocytogenes is a foodborne pathogen with a high mortality rate in susceptible populations and is of great public health concern with regard to food safety. The ability to grow at refrigeration temperatures during storage and at low pH levels during food processing has enabled the species to establish and sustain growth on processed food. Some food products particularly at risk of contamination by L. monocytogenes are deli or processed meat products, seafood, processed vegetables, dairy products and other food that do not require heating or reheating before consumption. The aims of this study are therefore to investigate firstly the prevalence rates of the species in high risk food products and a food processing plant in Brisbane. Secondly, to determine whether food isolates are better than environmental isolates at surviving the stress factors in food processing environments, or if their lineage groupings are a better indicator of their survival. Thirdly, to compare the survival of food and environmental isolates under temperature stress in co-cultures. A survey of more than 100 high-risk food products at supermarkets was carried out to investigate the prevalence of L. monocytogenes and other Listeria species in food. Isolates were also obtained from a food processing plant during routine tests. This study has found a low prevalence rate (under 10%) of L. monocytogenes in the processed vegetables and meat products tested. Other products tested included processed and raw seafood and processed fresh fruit. More L. monocytogenes isolates were isolated from the food processing plant (101) than from the food survey (25). Listeria grayi (73 isolates), a non-pathogenic species, was more frequently isolated from the food survey. The characterisation of those isolates has revealed their lineage groupings and REP-PCR profiles, which did not appear to be related to their sources. A selected group of 25 isolates were also serotyped for further identification. A larger number of lineage II isolates (70) were found compared to lineage I isolates (25), and were more common in food than the environments; while some (7) produced inconclusive results in the lineage PCR. The REP-PCR did not separate isolates of different sources, lineages or serotypes. In order to investigate the survival fitness of L. monocytogenes isolates whilst under environmental stress relevant to food safety, ten isolates from the food survey and food processing plant were chosen. Five isolates each from lineages I and II were subjected to temperatures ranging from 4ºC to 30ºC and pH levels from 4.0 to 6.0 for two weeks continuously, with their growth monitored by either optical density or plate counts. It was found that the isolates were most susceptible at the combination of pH 4.0 and 4ºC, where the growth of the isolates was completely inhibited. Again no relationship was observed between the lineage or the sources and the survival fitness of the chosen isolates. Due to the frequency of L. monocytogenes being co-isolated with other Listeria species as well as other food-borne pathogens, the relative competitive fitness of four of the isolates from the survival fitness experiment were compared in co-cultures at 4ºC and 30ºC at pH 7.4 in a small-scale preliminary study. The four isolates from food and environments were grown in broth cultures in pairs with the plate counts performed on antibiotic-supplemented selective TSA agar. The isolates were distinguished on agar supplemented with tetracycline which the isolates had acquired resistance to for this purpose. No significant difference (P>0.05) was observed between the lineages or the sources and the competitive fitness of the isolates in this study. The isolates always produced slightly more colonies in the antibioticresistant form compared to the wildtype form but did not seem to relate to the competitive fitness of the isolates. It would seemed that within the scope of this study, neither the lineage, serotype nor source of the isolates indicated any isolate with a better ability of survival while at low temperatures and low pH levels in pure and mixed cultures. However, other classifying groups such as serotypes, RAPD profiles may reveal possible co-relations, as well as a wider isolate pool. Furthermore, different stress factors could be included as part of an investigation on the survival of L. monocytogenes, as this study focused on food safety during processing.
104

THE ROLE OF HABITAT STRUCTURE AND COMPETITION IN THE ECOLOGY OF LISTERIA SPECIES IN FOOD-RELATED AND OTHER ENVIRONMENTS

Sally Chiu Unknown Date (has links)
Listeria monocytogenes is a foodborne pathogen with a high mortality rate in susceptible populations and is of great public health concern with regard to food safety. The ability to grow at refrigeration temperatures during storage and at low pH levels during food processing has enabled the species to establish and sustain growth on processed food. Some food products particularly at risk of contamination by L. monocytogenes are deli or processed meat products, seafood, processed vegetables, dairy products and other food that do not require heating or reheating before consumption. The aims of this study are therefore to investigate firstly the prevalence rates of the species in high risk food products and a food processing plant in Brisbane. Secondly, to determine whether food isolates are better than environmental isolates at surviving the stress factors in food processing environments, or if their lineage groupings are a better indicator of their survival. Thirdly, to compare the survival of food and environmental isolates under temperature stress in co-cultures. A survey of more than 100 high-risk food products at supermarkets was carried out to investigate the prevalence of L. monocytogenes and other Listeria species in food. Isolates were also obtained from a food processing plant during routine tests. This study has found a low prevalence rate (under 10%) of L. monocytogenes in the processed vegetables and meat products tested. Other products tested included processed and raw seafood and processed fresh fruit. More L. monocytogenes isolates were isolated from the food processing plant (101) than from the food survey (25). Listeria grayi (73 isolates), a non-pathogenic species, was more frequently isolated from the food survey. The characterisation of those isolates has revealed their lineage groupings and REP-PCR profiles, which did not appear to be related to their sources. A selected group of 25 isolates were also serotyped for further identification. A larger number of lineage II isolates (70) were found compared to lineage I isolates (25), and were more common in food than the environments; while some (7) produced inconclusive results in the lineage PCR. The REP-PCR did not separate isolates of different sources, lineages or serotypes. In order to investigate the survival fitness of L. monocytogenes isolates whilst under environmental stress relevant to food safety, ten isolates from the food survey and food processing plant were chosen. Five isolates each from lineages I and II were subjected to temperatures ranging from 4ºC to 30ºC and pH levels from 4.0 to 6.0 for two weeks continuously, with their growth monitored by either optical density or plate counts. It was found that the isolates were most susceptible at the combination of pH 4.0 and 4ºC, where the growth of the isolates was completely inhibited. Again no relationship was observed between the lineage or the sources and the survival fitness of the chosen isolates. Due to the frequency of L. monocytogenes being co-isolated with other Listeria species as well as other food-borne pathogens, the relative competitive fitness of four of the isolates from the survival fitness experiment were compared in co-cultures at 4ºC and 30ºC at pH 7.4 in a small-scale preliminary study. The four isolates from food and environments were grown in broth cultures in pairs with the plate counts performed on antibiotic-supplemented selective TSA agar. The isolates were distinguished on agar supplemented with tetracycline which the isolates had acquired resistance to for this purpose. No significant difference (P>0.05) was observed between the lineages or the sources and the competitive fitness of the isolates in this study. The isolates always produced slightly more colonies in the antibioticresistant form compared to the wildtype form but did not seem to relate to the competitive fitness of the isolates. It would seemed that within the scope of this study, neither the lineage, serotype nor source of the isolates indicated any isolate with a better ability of survival while at low temperatures and low pH levels in pure and mixed cultures. However, other classifying groups such as serotypes, RAPD profiles may reveal possible co-relations, as well as a wider isolate pool. Furthermore, different stress factors could be included as part of an investigation on the survival of L. monocytogenes, as this study focused on food safety during processing.
105

Senzorické hodnocení vybraných sýrů a analogových produktů / Sensory evaluation of selected cheeses and analogue products

LAFATOVÁ, Veronika January 2014 (has links)
This diploma thesis is focused on the evaluation of processed sliced products (cheese and analogues). For this purpose, was carried out sensory analysis of these products, a serial test and a questionnaire. Evaluation carried out a total of 65 assessors - 23 men and 42 women. The analysis of ranking showed that in the group of assessors was best evaluated processed wafer product (analogue) (average rank of 2,6) and processed sliced cheese (average rank of 2,7). For sensory analysis was found a significant role of fat on the dry basis of the product and the presence of added substances (extract from peppers, Emmental) on the perception of assessors. The survey was focused on the preference of the attractiveness of packaging of selected processed cheese slices and sliced processed products, furthermore focused on understanding the concept of the analogue product. Assessors have demonstrated their knowledge of the concept of analogue product only in 14% of cases.
106

Análise molecular do gene IAP de Listeria monocytogenes isoladas de alimentos no Rio Grande do Sul / Molecular analisys of iap gene of Listeria monocytogenes isolated from foods on Rio Grande do Sul

Mello, Jozi Fagundes de January 2007 (has links)
A bactéria Listeria monocytogenes é reconhecida como um importante patógeno humano estando amplamente distribuída no ambiente e é responsável pela contaminação de alimentos crus e processados. O mecanismo de patogenicidade é determinado pela presença de genes no cromossomo da bactéria e entre eles estão os genes iap e hly que são essenciais para o mecanismo de invasão e atividade hemolítica do microorganismo, respectivamente. O obejtivo do presente estudo foi confirmar as cepas de L. monocytogenes usando a ténica de PCR para o gene hly e análise da variação nucleotídica do domínio central do gene iap, que é caracterizado pela presença de seqüências repetidas dos aminoácidos treonina e asparagina. Vinte e seis cepas de L. mnocytogenes, previamente isoladas de produtos lácteos e identificdas por métodos clássicos, se mostraram positivas para a PCR espécie-específico e então submetidas à determinação da seqüência nucleotídica. Os resultados mostraram variações na seqüência nucleotídica contendo substituições, inserções, deleções e um número de seqüências similares entre as cepas isoladas e a cepa controle EGD-e. Vinte e três cepas exibiram a mesma deleção que compreende 24 pares de bases dentro da seqüência de repetição e alterações similares na proteína traduzida. Apenas três cepas mostraram tamanhos diferentes de deleções e diferentes alterações na proteína. De acordo com estes resultados, a maioria das cepas apresentou uma característica molecular comum, diferentes da cepa padrão e este perfil predominante pode ser considerado como a característica das L. monocytogenes isoladas de produtos lácteos no Sul do Brasil. / The bacterium Listeria monocytogenes is recognized as an important human pathogen being omnipresent in the environment and is responsible for contamination in raw and processed foods. The mechanism of pathogenicity is established by presence of some genes on chromosome of bacteria between them, iap and hly genes that are essential to the invasion mechanism and hemolytic activity of microorganism, respectively. The aim of present study was confirm the strain L. monocytogenes using PCR to hly gene and analysis the nucleotide variability of central domain of iap gene characterized by the presence of similar sequences of threonine and asparagine amino acids. Twenty-six strains previously isolated from dairy products and classified by classic methods to L. monocytogenes were positive to specie-specific PCR and than submitted to nucleotide sequence determination. The results showed a sequence variation containing nucleotide substitutions, insertions, deletions and a number of repeated sequences among the isolates and control strain EGD-e. Twenty-three strains exhibited the same gap that includes a deletion of 24 base pairs inside of the repeated sequence and similar alterations in the translated protein. Just three strains showed different sizes of gaps and different protein alterations. According to these results, the majority strains displayed a common molecular characteristic different from the strain pattern and this predominant profile can be considerate as characteristic to L. monocytogenes isolated from dairy products in South Brazil.
107

Aproveitamento de resíduos de cenoura e beterraba da indústria de minimamente processados para elaboração de ingredientes funcionais

Dalla Costa, Anne Porto January 2015 (has links)
Com a crescente conscientização da importância dos alimentos para a promoção da saúde, os consumidores têm buscado opções saudáveis associadas à praticidade, e desta forma destacam-se os vegetais minimamente processados. No entanto, a indústria destes gera grandes volumes de resíduos que impacta nos âmbitos econômicos, ambientais e nutricionais, já que pesquisas vêm apontando que estes resíduos vegetais são ricos em diversos compostos funcionais, tais como fibras, compostos fenólicos, carotenoides e betalaínas. Assim, o objetivo deste trabalho foi estudar o potencial de aproveitamento dos resíduos (cascas, aparas e pedúnculos) de beterraba e cenoura da indústria de vegetais minimamente processados para obtenção de ingredientes com apelo funcional e sustentável, como farinhas vegetais e corante. Foi avaliada a melhor forma de obtenção de uma farinha vegetal de resíduos de beterraba, onde foi verificado que a temperatura a 70 °C, independentemente da etapa de cloração, melhorou os aspectos de conteúdo total de betalaína e atividade antioxidante. O corante obtido com resíduo de beterraba foi analisado durante 45 dias e apresentou cor característica com estabilidade até o 20° dia e atividade antioxidante ao longo de todos os dias de análise. Com o resíduo de cenoura foi elaborada uma farinha vegetal com o intuito de enriquecer massas secas e substituir os aditivos utilizados atualmente em massas elaboradas com trigo da espécie Triticum aestivum L. As amostras produzidas com 20 % de farinha cenoura apresentaram um acréscimo de 126 % em relação ao conteúdo de carotenoides totais, 110 % em capacidade antioxidante, 615 % em fibras totais, além de aumento nos parâmetros de cor, quando comparadas às massas acrescidas de β-caroteno comercial. A massa com adição desta farinha vegetal de resíduo de cenoura obteve alto índice de aceitação dos provadores (acima de 70 %) na avaliação sensorial. Os resultados obtidos com este estudo são promissores para a utilização de resíduos de beterraba e cenoura minimamente processadas como uma fonte alternativa para elaboração de ingredientes naturais, com apelo sustentável e funcional devido ao alto teor de betalaína e carotenoides (respectivamente), fibras e demais compostos antioxidantes. / With the growing awareness of the importance of food for health promotion, consumers have sought healthy options associated with practicality, standing out minimally processed vegetables. However, these industries generate large amounts of waste that impact on economic, environmental and nutritional areas, since studies have indicated that these plant residues are rich in functional compounds, such as fibers, phenolics, carotenoids and betalains. The objective of this work was to investigate the feasibility of utilizing beet and carrot residues (peel, chip and peduncle) from minimally processed vegetable industry to obtain ingredients with practical and sustainable appeal, such as vegetable flours and dyes. It was evaluated a method to obtain a beet waste flour, and it was found that the temperature of 70 °C, regardless of the chlorination step, had improve the total content of betalain and antioxidant activity. The dye obtained from beet waste was analyzed for 45 days and showed characteristic color stability until the 20th day and the antioxidant activity during every day of analysis. A plant flour was prepared using carrots residue in order to enhance dry pasta and replace the additives currently used in the pasta produced with wheat specie Triticum aestivum L. The samples produced with 20 % carrot flour showed an increase in the content of carotenoids (126 %), in antioxidant capacity (110 %), in total fiber (615 %), as well as it causes improvements in the color parameters, compared to the pastas with commercial β-carotene. Pasta with this carrot residue flour had obtained high level of taster acceptance (over 70 %) in the sensory evaluation. The results obtained in this study are promising regarding to the use of minimally processed beet and carrot waste as an alternative source of natural ingredients, standing out the sustainable and functional appeal due to the high content of betalaína and carotenoids (respectively), as well as fiber and yet antioxidant compounds.
108

Detecção de betalactamases de espectro expandindo (ESBL) em cepas de coliformes isolados de hortaliças minimante comercializadas na cidade de Fortaleza -CE / Detention of extendedspectrum β-betalactamases (ESBL) in cepas of isolated coliformes of minimally processed vegetables (MPV),marketed in the city of Fortaleza-Ceará

Cunha, Francisco Afrânio January 2007 (has links)
CUNHA, Francisco Afrânio. Detecção de betalactamases de espectro expandindo (ESBL) em cepas de coliformes isolados de hortaliças minimante comercializadas na cidade de Fortaleza -CE. 2007100 f : . Dissertação (mestrado) - Universidade Federal do Ceará, Centro de Ciências Agrárias, Departamento de Tecnologia de Alimentos, Fortaleza-CE, 2007 / Submitted by Nádja Goes (nmoraissoares@gmail.com) on 2016-06-06T13:34:15Z No. of bitstreams: 1 2007_dis_facunha.pdf: 3336053 bytes, checksum: c193599fd7b4044ea639d9c9eaa1b454 (MD5) / Approved for entry into archive by Nádja Goes (nmoraissoares@gmail.com) on 2016-06-06T13:34:28Z (GMT) No. of bitstreams: 1 2007_dis_facunha.pdf: 3336053 bytes, checksum: c193599fd7b4044ea639d9c9eaa1b454 (MD5) / Made available in DSpace on 2016-06-06T13:34:28Z (GMT). No. of bitstreams: 1 2007_dis_facunha.pdf: 3336053 bytes, checksum: c193599fd7b4044ea639d9c9eaa1b454 (MD5) Previous issue date: 2007 / Minimally processed vegetables (MPV) normally consist of fresh raw vegetables, washed, peeled, cut, disinfected, centrifugal dryed packed and kept under refrigeration. Vegetables are potential vehicle of microorganisms that can be associated to the outbreaks of foodborne. Countless are the causes for the presence high microbial load in that product type, among which are: the cultivation techniques, storage, transport and distribution for consumption, the practice of the use of organic fertilizer, the use of polluted water for irrigation, the transport accomplished in open crates and the hygiene conditions in the handling and preparation of meals, mainly when such foods are consumed raw. The objective of this study was to determine the presence of extendedspectrum β-betalactamases (ESBL) in strains of Enterobacteriaceae isolated of MPV marketed in the city of Fortaleza and to verify if the analyzed vegetables assists the Brazilian Food Sanitation Standard, RDC N° 12, 02 of january 2001. 80 samples of MPV were collected marketed in Fortaleza. Were collected vegetables studied: 8 samples beet; 10 lettuce; 8 of cherry-colored tomato; 8 purple cabbage, green cabbage; 10 carrot and green bean; 8 grated carrot; 10 grated carrot, green cabbage and purple cabbage; 10 salads; 8 cilantro, onion and parsley pricked. The analyses were accomplished of april from 2006 to may of 2007. The countings of mesophiles aerobic, varied from 5,60 to 13,35 log UFC / g of MPV. The countings of moulds and yeasts, varied from 5,54 to 9,88 log UFC / g MPV. The counting of total coliforms and fecal coliforms were quite high. The main isolated and identified mold was the Penicillium spp. All of the beet samples, grated carrot, carrot and green bean, grated carrot, purple cabbage and green cabbage, cilantro and parsley pricked met inappropriate for the consumption, because they presented amounts superior of 100 fecal coliforms / g samples. Of the samples of lettuce 50% they presented fecal coliforms counting above legislation. Of the tomatoes cherry analyzed 75% were inside patterns of the Brazilian legislation, for fecal coliforms. Of the samples of purple cabbage, green cabbage 87% were with fecal coliforms counting above. Of the samples of salad 80% were out of the patterns. Salmonellas were not detected in the samples of MPV analyzed. The main isolated Enterobacteriaceae were E. coli, K. pneumoniae and E. aerogenes. All of the strains of K. pneumoniae and E. aerogenes were resistant to the ampicillin. Strains of E. coli, K pneumoniae and E. aerogenes with multidrug resistance were detected. Resistance to ciprofloxacin, ceftazidime and imipenem was not observed. Enterobacteriaceae samples producing of ESBL were not detected. Were not identified strains of E. coli O15:H7 among the strains of E. coli isolated of MPV. The hygienicsanitary conditions of those products can be improved with the application of Good Practices in the whole productive chain. / Hortaliças minimamente processadas (HMP) normalmente consistem de hortaliças frescas, cruas, lavadas, descascadas, cortadas, sanitizadas, centrifugadas, empacotadas e acondicionadas sob refrigeração. Hortaliças são potenciais veículos de microrganismos que podem estar associadas à doenças transmitidas por alimentos. Inúmeras são as causas para a presença de elevada carga microbiana nesse tipo de produto, entre as quais estão: as técnicas de cultivo, armazenamento, transporte e distribuição para consumo, a prática do uso de adubo orgânico, a utilização de água contaminada para rrigação, o transporte realizado em engradados abertos e as condições de higiene no manuseio e preparo de refeições, principalmente quando tais alimentos são consumidos crus. O objetivo desse estudo foi determinar a presença de Enzimas Betalactamases de Espectro Expandido (ESBL) em cepas de Enterobacteriaceae isoladas de HMP comercializadas na cidade de Fortaleza e verificar se as hortaliças analisadas a atendem a RDC N° 12 de 02 de janeiro de 2001, que rege o padrão microbiológico dos alimentos no Brasil. Foram coletadas 80 amostras de HMP comercializadas em Fortaleza. As hortaliças estudadas foram: 8 amostras de acelga; 10 alface; 8 tomate cereja; 8 repolho roxo, repolho verde; 10 cenoura e vagem; 8 cenoura ralada; 10 cenoura ralada, repolho verde e repolho roxo; 10 saladas; 8 coentro, cebola e salsa picados. As análises foram realizadas de abril de 2006 a maio de 2007. As contagens de microrganismos aeróbios mesófilos variaram de 5,60 a 13,35 log UFC/ g de HMP. As contagens de bolores e leveduras variaram de 5,54 a 9,88 log UFC/ g de HMP. A contagem de coliformes totais e coliformes a 45°C foram bastante elevadas. O principal bolor isolado e identificado foi o enicillium spp. Todas as amostras de acelga, cenoura ralada, cenoura e vagem, cenoura ralada, repolho roxo e repolho verde, coentro e salsa picados encontravam-se impróprias para o consumo, pois apresentaram quantidades superiores a 100 coliformesa 45ºC/g de amostra. Das amostras de alface 50% apresentavam contagem decoliformes a 45ºC acima do permitido peça legislação. Dos tomates cereja analisados 75% estavam dentro padrões microbiológicos exigidos pela legislação brasileira, para coliforme a 45ºC. Das amostras de repolho roxo, repolho verde 87% estavam com contagem de coliformes acima do permitido. Das amostras de salada 80% estavam fora dos padrões. Não foram detectadas Salmonellas nas amostras de HMP analisadas. As principais cepas de Enterobacteriaceae isoladas foram E. coli, K. pneumoniae e E. aerogenes. Todas as cepas de K. pneumoniae e E. aerogenes foram resistentes à ampicilina. Foram detectadas cepas de E. coli, K pneumoniae e E aerogenes com multiresistência aos antibióticos testados. Não foi observada resistência a ciprofloxacina, ceftazidima e imipenem. Não foram detectadas amostras de enterobactérias produtoras de ESBL. Não foram identificadas cepas de E. coli O15:H7 entre as cepas de E. coli isoladas de HMP. As condições higiênico-sanitárias desses produtos podem ser melhoradas com a aplicação de Boas Práticas em toda a cadeia produtiva.
109

Aproveitamento de cinza pesada e lodo de anodização do alumínio para a produção do cimento sulfoaluminato de cálcio belítico / Using of bottom ash and aluminum anodizing sludge for the production of calcium sulfoaluminate belite cement

Costa, Eugenio Bastos da January 2016 (has links)
A produção de cimento gera um impacto ambiental negativo, principalmente relacionado à emissão de dióxido de carbono (CO2). O clínquer do cimento sulfoaluminato de cálcio belítico (CSAB) possui um menor teor de óxido de cálcio e é produzido com uma reduzida temperatura de sinterização (aproximadamente 200ºC a menos em relação ao clínquer Portland), sendo considerado mais eco-amigável. Para a produção do cimento CSAB são necessárias matérias-primas ricas em alumínio e convencionalmente a bauxita é o minério utilizado para compor a farinha, o que mais onera a produção desse tipo de cimento. Soma-se ainda o fato que a geração de resíduos e subprodutos industriais torna-se inerente aos processos e o coprocessamento de resíduos vem sendo cada vez mais utilizado por razões ambientais e energéticas. Logo, fontes alternativas de alumina são fundamentais para a viabilização deste cimento e o aproveitamento de resíduos agregaria um valor econômico e sustentável ao produto final. De modo estequiométrico, a bauxita pode ser completamente substituída pelo lodo de anodização do alumínio (LAA), o qual também pode complementar o conteúdo de alumínio de outros resíduos, valorizando-os. O objetivo deste estudo foi avaliar a produção e as propriedades de clínqueres/cimentos CSAB a partir da substituição da bauxita por cinza pesada e LAA. Para a caracterização das matérias-primas, clínqueres e cimentos nos estados anidro e hidratado foram utilizadas as seguintes técnicas: fluorescência de raios X; microscopia eletrônica de varredura e espectrometria por energia dispersiva; termogravimentria; calorimetria; e difração de raios X com refinamento pelo método de Rietveld. A partir dos resultados obtidos, a substituição da bauxita foi limitada a nível parcial devido à elevada formação de belita e periclásio. Nos clínqueres produzidos, foi constatado que a presença da cinza pesada favorece a formação da estrutura cristalina ortorrômbica da fase ye’elimita. A presença dos resíduos altera a quantificação das fases, porém não compromete a estabilização das mesmas. A presença dos resíduos na composição dos cimentos afeta o período inicial de hidratação devido à redução do conteúdo de ye’elimita. Nos clínqueres produzidos com cinza pesada, ocorre a formação de até 12,6% da fase alita a 1250ºC, principal constituinte do clínquer Portland. / Cement production generates high negative environmental impact, mainly associated to CO2 emissions. Calcium sulfoaluminate belite cement clinker (CSAB) has lower content of calcium oxide, and sintering reduced temperature (about 200°C lower than that used for Portland clinker), being considered as eco-friendly binder. For its production high amount of alumina is required, however the scarcity and high cost of bauxite make these cements costly. Additionally, the generation of waste and by-products becomes a drawback in the industrial processes and the coprocessing of wastes in cement plants is increasing for environmental and energy savings reasons. Alternative sources of alumina would add an economic and sustainable value to the final product and previous work has shown that the aluminum anodizing sludge can replace bauxite in the production process. Other sources of wastes can also be a possibility to increase the production and reduce the raw materials costs of these cements. Thus, the objective of this study was the evaluation of novel CSAB cements produced with bauxite replacement by bottom ash and aluminum anodizing sludge. CSAB cements were produced in the laboratory from different amounts of sludge and ashes. The raw materials, clinkers/cements and hydration products were physicaly-chemicaly and mechanical characterized. Results showed that the mineralogy composition of CSAB clinker was strongly affected due to the addition of bottom ash. The amount of bottom ash waste replacing bauxite controls the belite and periclase formation. Also it influences the early age hydration due the reduced ye’elimite formation and important changes in the crystalline structures of this phase occurs in the clinkers. Clinkers prepared from these replacement, are able to form 12.6% of alite (main phase Portland clinker), not normally found in CSAB clinkers, being sintered at 1250°C.
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Consumo alimentar e associação com ganho de peso em adolescente: Estudo Longitudinal de Avaliação Nutricional de Adolescentes (ELANA). / Food consumption and its association with weight gain in adolescents: Adolescent Nutritional Assessment Longitudinal Study (ELANA).

Luana Azevedo de Aquino 31 March 2015 (has links)
Essa tese teve como objetivo avaliar a associação do consumo de padrões alimentares e produtos alimentícios ultraprocessados (UP) sobre indicadores antropométricos e sua variação entre adolescentes. Para tal, foram analisados os dados de 1.031 estudantes de quatro escolas privadas e duas escolas públicas da região metropolitana do Rio de Janeiro que foram acompanhados por três anos consecutivos (2010 a 2012) no Estudo Longitudinal de Avaliação Nutricional de adolescentes (ELANA). Os resultados estão apresentados em três manuscritos que compõem a tese. O primeiro manuscrito identificou três padrões alimentares: Ocidental, composto por massas, embutidos e bacon, carnes, doces, bebidas açucaradas, salgados e fast food, biscoito, pães e cereais, leite e derivados e ovos, o Saudável, caracterizado por peixes, hortaliças, verduras, raízes e feculentos, frutas e sucos e o Arroz/Feijão, composto pelo consumo de arroz, feijão e café. Na análise dos dados na linha de base o padrão Ocidental associou-se a um menor índice de massa corporal (IMC) e não foi observada associação estatisticamente significativa em relação ao percentual de gordura corpórea (%GC) e o padrão em questão. Adicionalmente, foi verificada uma associação negativa entre o padrão Arroz/Feijão e ambos os indicadores antropométricos sugerindo que esse padrão de consumo tradicional possa ser protetor para a obesidade. No segundo manuscrito avaliou-se a relação entre o consumo de UP e indicadores de qualidade da dieta. O consumo de UP foi avaliado em gramas por dia e em gramas/total de calorias. Observou-se um aumento das variáveis marcadoras de alimentação não saudável e saudável com o aumento do consumo de UP. No entanto, quando relacionados ao aumento de consumo de UP/energia observou-se um aumento de marcadores de alimentação não saudável e, com exceção da vitamina C, uma redução de marcadores de alimentação saudável. Assim, a densidade do consumo de UP mostrou-se um bom indicador de qualidade da dieta entre adolescentes. No terceiro manuscrito avaliou-se a associação entre o consumo de UP e a evolução temporal do IMC e %GC. A análise longitudinal por modelos lineares mistos, que levam em conta todas as observações ao longo do tempo, indicou que nas análises não ajustados havia uma associação negativa entre consumo de UP e o IMC e %GC, porém nas análises de UP/energia e nas análises ajustadas por atividade física e uma variável de controle para a qualidade do relato não mais foram observadas associações com o consumo de UP e as medidas antropométricas de adiposidade. Pode-se concluir que não evidenciamos associação do consumo de UP com medidas antropométricas de obesidade uma vez que o consumo elevado de UP associado ao crescimento do %GC nas análises transversais, não se manteve nas análises longitudinais. A discrepância entre os achados dos estudos seccionais e os longitudinais pode decorrer de confundimento residual nos estudos seccionais. Conclui-se, que para redução do ganho excessivo de peso, orientações relativas exclusivamente a um padrão de alimentação saudável que incorpora a ideia de UP, devem ser acompanhadas de redução da quantidade de alimentos consumidos. / This thesis had as an objective to evaluate the association of the consumption of dietary patterns and ultra-processed food products (UP) on anthropometrics indicators and its variation among adolescents. Thus, the data of 1,031 students of four private schools and two public schools of the metropolitan region of Rio de Janeiro were analyzed during three consecutive years (2010 through 2012) at the Adolescent Nutritional Assessment Longitudinal Study (ELANA). The results are presented in three manuscripts that compose the thesis. The first manuscript identified three dietary patterns: Western, compounding pasta, processed meat and bacon, meat, sweets, sugar sweetened beverages, savoury snacks and fast-food, cookies, bread and cereals, milk and dairy products and eggs, the Healthy, characterized by fish, vegetables, greens, roots and starchy, fruits and juices and the Rice/ Beans, compounded by the consumption of rice, beans and coffee. In the data analyses of baseline the Western pattern was associated to a lower body mass index (BMI) and a statistically significant association regarding the percentage of body fat (%BF) and the related pattern was not noticed. Additionally, a negative association between the Rice and Beans pattern and both anthropometric indicators could be verified suggesting that this traditional dietary pattern could be protective for obesity. On the second manuscript, the relationship between the UP consumption and the diet quality markers was estimated. The UP consumption was reported in grams per day and in grams per total calories. An increase of not only of non-healthy diet quality markers but also healthy markers ones were observed with UP consumption increases. However, when related to the growth of UP/energy consumption, an increase on the non-healthy diet quality markers and, with the exception of vitamin C, a reduction of healthy markers could be observed. The UP consumption density proved to be a good marker of diet quality among adolescents. On the third manuscript, were evaluated the association between UP consumption and temporal evolution of BMI and %BF. The longitudinal analyses by linear mixed models, which take into account all the observations during the time, indicated that on crude analyses there was a negative association between the UP consumption, BMI and %BF, however in the UP/energy analyses and adjusted analyses for physical activity and a control variable for the reporting quality no more associations were observed with the UP consumption and anthropometric adiposity measures. It is possible to conclude that there was no association of UP consumption and anthropometric adiposity measures since the high UP associated with the increase of %BF in the cross sectional analyses no remained in the longitudinal analyses. The discrepancy between the findings of cross-sectional studies and longitudinal may be due to residual confounding in cross-sectional studies. It could be concluded that, for reduction of excessive weight gain, guidelines exclusively related to the healthy eating pattern that incorporates an idea of UP, must be accompanied by reduction of consumed foods quantity.

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