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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.
41

Efeito das condições de processo na cinetica de secagem de cogumelo (Agaricus blazei) / Effect of process conditions on drying kinetics of mushrooms (Agaricus blazei)

Kurozawa, Louise Emy, 1980- 20 September 2005 (has links)
Orientador: Fernanda Elizabeth Xidieh Murr / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-05T02:07:54Z (GMT). No. of bitstreams: 1 Kurozawa_LouiseEmy_M.pdf: 1139488 bytes, checksum: 483f34ed208f1269e0f4f231ab7713a5 (MD5) Previous issue date: 2005 / Mestrado / Mestre em Engenharia de Alimentos
42

Soluções salina hipertônica intravenosa (7,5%) e eletrolítica oral no tratamento de bezerros com diarréia osmótica induzida / Intravenous hypertonic saline (7,5%) and oral electrolytic solutions in the treatment of induced osmotic diarrhea in calves

Marta Lizandra do Rêgo Leal 13 May 2005 (has links)
Com o objetivo de validar um protocolo de indução de diarréia osmótica e avaliar comparativamente a eficácia de três diferentes tratamentos, foram utilizados 18 bezerros holandeses hígidos, com idade entre oito e 30 dias, e peso variando entre 37 e 50 Kg. A diarréia e a desidratação foram induzidas por via oral, através da administração de leite integral (16,5 ml/Kg), de quatro gramas de sacarose por quilo e de dois tipos de diuréticos (espirolactona e hidroclorotiazida, em dose de 2mg/Kg), a cada oito horas, por um período de 48 horas. Os bezerros foram distribuídos aleatoriamente por três grupos experimentais, cada um com seis animais, que receberam as seguintes soluções: solução salina hipertônica à 7,5% (SSH-4ml/kg IV), solução eletrolítica oral (SEI-60ml/kg) e a associação dessas duas soluções (SSH+SEI), sendo a SEI administrada por mais duas vezes com um intervalo de oito horas. O exame físico e as colheitas de sangue para determinações do hemograma, de dosagens hemogasométricas e de componentes bioquímicos séricos e plasmáticos foram realizadas nos seguintes momentos: 0h (antes da indução), 24 e 48 horas pós-indução(PI) de diarréia, e com 1, 3, 6, 12, 24, 48 e 72 horas pós-tratamento (PT).As amostras de fezes e urina foram colhidas às 0h, 24 e 48 horas PI, e 24, 48 e 72 horas PT. O protocolo de indução da diarréia obteve 100% de resposta produzindo diarréia aquosa e desidratação severa (equivalente a 13% do peso corpóreo) acompanhada de azotemia pré-renal, aumentos no volume globular, no teor de hemoglobina e na proteína total; hipercalemia; hiperlactemia; hiperfosfatemia; acidose metabólica; elevado déficit de volume plasmático; aumentos da densidade urinária, da concentração de uréia e creatinina urinárias e do lactato urinário e fecal; diminuições da pressão venosa central, do pH urinário e fecal. Os animais tratados com SSH+SEI diminuíram de forma rápida e substancial os valores do volume globular e do déficit de volume plasmático; aumentaram o pH sangüíneo e a pressão venosa central entre 1hPT e 3hPT, além de manterem as concentrações de glicose próximas aos valores basais durante todo o período de tratamento. A SEI também promoveu o restabelecimento das variáveis anteriormente citadas, porém de forma mais lenta quando comparada com o uso da SSH+SEI. Os animais tratados apenas com SSH exibiram, no monitoramento através de exames físico e laboratoriais, sinais de desidratação, de depressão clínica e de acidose metabólica ainda às 24hPT, indicando que o uso isolado dessa solução não é eficaz no tratamento da diarréia em bezerros neonatos. / With the purpose of validating a protocol for osmotic diarrhea induction and to comparatively evaluate the efficacy of three different treatments, 18 healthy Holstein calves, with eight to 30 days old, and 37 to 50 Kg of body weight were used. The diarrhea and dehydration were orally induced, through the administration of whole milk (16.5 ml/Kg bwt), sucrose 4g/Kg bwt and two types of diuretics (spironolactone and hydrochlorothiazide, in a dosage of 2mg/Kg bwt), every eight hours, for a total period of 48 hours. The calves were randomly distributed into three experimental groups, each one with six animals, which received the following solutions: 7.5% hypertonic saline solution (HSS - 4ml/Kg bwt, IV), oral electrolytic solution (OES - 60ml/Kg bwt) and the association of both solutions (HSS+OES), being the OES administered two more times with an interval of eight hours. The physical examination and blood sampling for hemogram determinations, hemogasometric dosages and serum and plasmatic biochemical components were done in the following moments: 0h (before the induction), 24 and 48h post-induction (PI) of diarrhea, and within 1, 3, 6, 12, 24, 48 and 72 hours post-treatment (PT). The protocol for osmotic diarrhea induction had a 100% response with aqueous diarrhea and severe dehydration (corresponding to 13% of body weight), followed by pre-renal azotemia, increases in the globular volume, and hemoglobin and total protein levels; hyperkalemia; hyperlactemia; hyperphosphatemia; metabolic acidosis; high plasmatic volume deficit; increases of urinary density, urinary urea and creatinine concentrations and urinary and fecal lactate; diminished central venous pressure and urinary and fecal pH. The animals treated with HSS+OES rapidly and substantially diminished the values of globular volume and plasmatic volume deficit; had the blood pH and central venous pressure increased between 1hPT and 3hPT, besides they maintained glucose concentrations near basal values along the period of treatment. The OES also promoted the reestablishment of the cited variables, although in a slower manner when compared with the use of HSS+OES. The animals treated only with HSS showed, through the physical and laboratory exams, signs of dehydration, clinical depression and metabolic acidosis still at 24hPT, indicating that the isolated use of this solution is not efficient in the treatment of neonatal diarrhea in calves.
43

Estudo do processo de desidratação osmotica e secagem de files de mapara (Hypophthalmus edentatus)

Ribeiro, Suezilde da Conceição Amaral 28 February 2005 (has links)
Orientador: Satoshi Tobinaga / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-04T02:31:59Z (GMT). No. of bitstreams: 1 Ribeiro_SuezildedaConceicaoAmaral_D.pdf: 14833718 bytes, checksum: 885ff1d5699fbb022622bd073beda170 (MD5) Previous issue date: 2005 / Doutorado / Engenharia de Alimentos / Doutor em Engenharia de Alimentos
44

The effects of nitric oxide on soybean superoxide dismutase activity during osmotic stress

Jack, Babalwa Unice January 2012 (has links)
>Magister Scientiae - MSc / Nitric oxide (NO) is a signaling molecule involved in mediating plant responses to various biotic and abiotic stresses. Major abiotic stresses (drought, salinity, cold) induce common cellular responses, causing osmotic stress in plants. This results in oxidative stress due to increased production of reactive oxygen species (ROS). The increased ROS levels simultaneously induce the antioxidative system (including antioxidant enzymes such as superoxide dismutase) that regulates ROS toxicity and enhance stress tolerance in plants. It is suggested that the scavenging of ROS by antioxidant enzymes can be controlled by NO. The aim of this study was to evaluate the role of exogenously applied NO on soybean (Glycine max L. Merr.) during osmotic stress, with the purpose of determining the effects of NO on the superoxide dismutase (SOD) activity in response to osmotic stress. This study also aimed at identifying and characterising SOD isoforms induced in soybean in response to osmotic stress and exogenous NO. To achieve these aims, soybean plants were treated with sorbitol (to induce osmotic stress), an NO donor [2,2'-(hydroxynitrosohydrazono)bis-ethanimine, DETA/NO] and its respective control (Diethylenetriamine, DETA). The results showed that exogenous NO alleviated osmotic stress-induced damage by reducing the superoxide radical content, lipid peroxidation levels and also maintaining cell viability in soybean leaves, nodules and roots. Only two SOD isoforms i.e. manganese SOD (MnSOD) and copper/zinc SOD (CuZnSOD) were identified and characterised in soybean leaves and roots, iron SOD (FeSOD) was not induced. The isoforms identified exhibited low SOD activity in response to osmotic stress, with the exception of a few isoforms that had increased activity. The SOD activity was regulated by exogenously applied NO. The enzymatic activity of SOD isoforms was up-regulated by exogenous NO, except for a few SOD isoforms that were not responsive to NO. The results also showed that the increased SOD activity was associated with reduced lipid peroxidation levels. The results obtained from this study suggest that exogenous NO improves osmotic stress tolerance in soybean by regulating and increasing the SOD activity of only specific isoforms. The increased SOD activity maintains the redox homeostasis balance by detoxifying and controlling the superoxide radical levels, subsequently reducing lipid peroxidation and maintaining cell viability.
45

Estudo para a agregação de valor aos produtos de caju : elaboração de formulações de fruta e castanha em barras / Study for the aggregation of value to the cashew products: fruit and chestnut in bars formularizations elaborations

Lima, Antonio Calixto 20 October 2004 (has links)
Orientador: Nelson Horacio Pezoa Garcia / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-04T01:19:17Z (GMT). No. of bitstreams: 1 Lima_AntonioCalixto_D.pdf: 1805819 bytes, checksum: ea139fe6e1ab6890ae9fa0148511ea3b (MD5) Previous issue date: 2004 / Resumo: A pesquisa objetivou contribuir para a redução das perdas do pseudofruto de caju, estimadas em 1 bilhão kg/ano. Realizou-se a desidratação osmótica a vácuo do pseudofruto de caju do clone CCP 76, empregando-se suco de caju clarificado e concentrado a vácuo com 65°Brix como agente osmótico. A partir da Metodologia de Superfície de Respostas foram definidas as combinações do binômio tempo*temperatura que permitem a obtenção dos melhores rendimentos do processo: 40°C/100min e 36°C/140min. Nestas condições obteve-se, respectivamente, perda de peso da ordem de 32,67 e 31,50%, incorporação de sólidos de 5,37 e 6,20% e perda de umidade de 38,58 e 36,37%. Na desidratação osmótica à pressão ambiente de rodelas de pedúnculos de caju, foram testados os fatores tempo (90, 112, 165, 218 e 240min), temperatura (30; 35; 40; 45 e 50°C) e concentração do suco de caju (55, 60, 65, 70 e 75°Brix). Verificou-se aumento da perda de peso, da perda de umidade, de sólidos totais e da incorporação de sólidos com a elevação dos níveis das variáveis independentes. Foram realizados testes de aceitação sensorial de nove formulações que permitiram selecionar três barras de caju cujos pedúnculos foram desidratados por processos de liofilização, em secador solar e por ar quente em estufas, após terem sido submetidos à desidratação osmótica. As três barras de caju selecionadas foram estocadas por 360 dias, e a intervalos de 45-60 dias foram realizadas análises que demontraram serem estáveis física, química e microbiológicamente. As características sensoriais de todas as barras se mantiveram sem alterações e apresentaram boa aceitação ao longo de todo o período de avaliação, recebendo notas para intenção de compra acima de quatro (4) e médias superiores a sete (7) para os atributos textura, aparência, sabor e aceitação global / Abstract: The aim of this research was to contribute to reduction of cashew apple losses, estimated at 1 billion kg/year. Vacuum osmotic dehydration of the cashew apple clone CCP 76 was done using clarified cashew juice concentrated to 65oBrix as the osmotic agent. Response Surface Methodology was used to define the best time temperature combinations: 40°C/100min and 36°C/140min. Under these conditions the following results were obtained, respectively, 32.67 and 31.50% weight loss, 5.37 and 6.20% solids incorporation, 38.58 and 36.37% moisture loss. For the osmotic dehydration at ambient pressure of cashew apple discs, the factors tested were time (90, 112, 165, 218 and 240min), temperature (30, 35, 40, 45 and 50°C) and cashew juice concentration (55, 60, 65, 70 and 75°Brix). Increases in the levels of the independent variables resulted in increases in weight loss, moisture loss and total solids and solids incorporation. Acceptance tests were performed for nine formulations allowing for the selection of three cashew bars, whose peduncles were dried by freeze drying, solar drying and hot air, after being osmotically dried. The three cashew bars selected were stored and analyzed every 45-60 days for their physical, chemical and microbiological stability. The sensoriy characteristics of all the bars remained unchanged and presented good acceptability throughout the period studied, receiving scores for purchase intent above four (4) and averages above seven (7) for the the attributes of texture, appearance, flavor and overall acceptability / Doutorado / Doutor em Tecnologia de Alimentos
46

Modelling Transpiration and Growth of Salinity and Drought Stressed Tomatoes

Karlberg, Louise January 2002 (has links)
Irrigation with saline waters is an agricultural practicethat is becoming increasingly common as competition for freshwater increases. In this thesis the mechanisms behind salinityand drought stress has been studied using data from fieldexperiments in combination with a modelling tool, theCoupModel. Measurements from field experiments on salinity,boron toxicity and drought stressed tomatoes grown during twoclimatically different seasons in the Arava desert, Israel,showed a linear relationship between relative growth andevapotranspiration, for all treatments and seasons. Data fromthe spring was used to concurrently simulate growth andtranspiration, hence accounting for feedback mechanisms betweenthe plant and the environment. Salinity stress was modelled asan osmotic effect (reduction of water uptake at high soilsalinities, W approach) or a toxicity effect (direct reductionof photosynthesis with soil salinity, G approach). Goodagreement between simulated growth and transpiration wasachieved with both salinity stress approaches, with twoexceptions. When growth and transpiration were simulated withthe W approach at different salinity levels, transpiration wasunderestimated at high stress. The G approach resulted in anunderestimation of growth at high water stress under moderatesalinity. A direct decrease of photosynthesis leads to adecreasing water-use efficiency with salinity while water-useefficiency remains constant with salinity when the salinitystress is modelled as a reduction in water uptake. Measurementsshowed decreasing water-use efficiency for the salinitygradient, explaining why the W approach was not applicable. Itwas not possible to detect any considerable differences betweenthree different approaches for water uptake tested in thestudy. <b>Keywords:</b>Water-use efficiency; osmotic effect; iontoxicity; semi-arid. / NR 20140805
47

Mathematical Modeling of the Osmotic Fragility of Rabbit Red Blood Cells

Orcutt, Ronald H., Thurmond, T. Scott, Ferslew, Kenneth E. 01 January 1995 (has links)
The osmotic fragility (OF) test is used to determine the extent of red blood cell hemolysis (RBCH) produced by osmotic stress. RBCH is dependent upon cell volume, surface area, and functional integrity of cell membranes. The variation of cell lysis with stress reflects underlying cell subpopulations and their membranes' cytoskeletal functionality. OF was determined on blood from New Zealand white rabbits. The dependence of RBCH on NaCl concentration ([NaCl]) was determined spectrophotometrically by measuring absorbance (Abs) from hemoglobin release at 545 nm. Abs data were fitted to the equation Abs = p3 erfc( ([NaCl] - p1) p2) where p3 reflects maximum RBCH, p1 measures the [NaCl] at 50% RBCH, and p2 shows the dispersion in [NaCl] producing the RBCH. Parameter values for control blood were p1 = 0.4489 ± 0.0016; p2 = 0.0486 ± 0.0016; and p3 = 0.4366 ± 0.0022. Addition of indomethacin (9.6 μg/mL) produced an increased fragility in the RBC's characterized by increased values of p1 and p2. Normalization of the data to p3 did not change the values of p1 or p2. Our equation satisfactorily describes the variation in RBCH as a function of [NaCl]. The parameters of the equation can be used to quantitatively characterize Abs/[NaCl]. The compare pharmacological, Toxicological, and pathological effects on the OF of RBC's.
48

Osmotic Swelling Behavior of Ionic Microgels

Alziyadi, Mohammed Obaid January 2020 (has links)
This dissertation studies the thermodynamic and structural properties of aqueous dispersions of ionic microgels ? soft colloidal particles composed of cross-linked polymer gels that swell in a good solvent. Starting from a coarse-grained model of microgel particles, we perform computer simulations and theoretical calculations using two complementary implementations of Poisson- Boltzmann (PB) theory. Within the framework of a cell model, the nonlinear PB equation is exactly solved and used to compute counterion distributions and osmotic pressures. By varying the free energy with respect to microgel size, we obtain exact statistical mechanical relations for the electrostatic component of the single-particle osmotic pressure. Explicit results are presented for equilibrium swelling ratios of charged microcapsules and of charged cylindrical and spherical microgels with fixed charge uniformly distributed over the surface or volume of the particle. Molecular dynamics simulations validate the theoretical findings. In the second method, within a one-component model framework, based on a linear-response approximation for effective electro- static interactions, we develop Monte Carlo (MC) simulations to compute the equilibrium swelling ratio, bulk osmotic pressure, radial distribution function, and static structure factor. Results presented in this dissertation demonstrate that swelling of ionic microgels increases with increasing microgel charge and decreases with increasing concentration of salt and microgels. In addition, results demonstrate that the microion distributions and osmotic pressure determine equilibrium swelling of microgels. Cell model predictions for bulk osmotic pressure agree well with data from MC simulations of the one-component model. The MC simulations also provide access to structural properties and to swelling behavior of microgels in highly concentrated suspensions. Taken together, results obtained in this work provide insight into factors of importance for practical use of microgels as drug delivery systems, in tissue engineering, and for other biomedical applications.
49

The Effects of Osmotic Potential on Ammonification, Immobilization, Nitrous Oxide Production, and Nitrification Rates in Penoyer Soil

Low, Andrew P. 01 May 1996 (has links)
An isotopic dilution method was used to test the effects of osmotic potential, (IJ' ,), upon nitrification, ammonification, N-immobilization, and nitrous oxide production rates in soil at solute concentrations encountered in Penoyer soil. A nitrification potential assay was also performed to approximate maximum nitrification rates. Nitrification potential rates in soil slurries exponentially declined in response to decreased osmotic potential. However, nitrification was independent of salt concentration at the ambient NIL+ concentrations of the soil. The differential response was attributed to the variable NIL+ substrate quantities. The effects of osmotic potential were secondary to NIL+ substrate levels in controlling nitrification rates. Ammonification rates declined exponentially as a function of decreased osmotic potential; however, the 33% reductions in ammonification rates were restricted to a range of osmotic potentials between 0 and -500 kPa. Ammonification rates were independent of osmotic potential at potentials between -500 and -1800 kPa. Immobilization rates of both NH/ and N03- declined exponentially as osmotic potential decreased. Absolute rates ofN03- immobilization exceeded those of N~ • by a factor of 4, indicating that under N~+ limited conditions, substantial N03- assimilation occurred. However, the generalization that N~ + is the preferred N source was in fact supported by the data, where immobilization rates relative to the respective pool sizes clearly favored NH4 + assimilation. Nitrous oxide production rates increased linearly as osmotic potential decreased. An NH4 + dependence indicated the evolved N20 was derived from nitrification rather than denitrification.
50

Environmental Influence on the Physiological Consequences of Feeding in Rainbow Trout, ONCORHYNCHUS MYKISS

Bucking, Carol 06 1900 (has links)
Ionic and osmotic homeostasis, and the intricately linked mechanisms of acid-base balance are critical for the survival of fish. To date, the role of the gastrointestinal (GI) tract in these processes has received only limited study, and our knowledge has been gained almost exclusively through studies conducted in fasting animals. The impacts of feeding and digestion, ubiquitous processes in the natural environment, are likely to be significant but have been overlooked. The current thesis addressed these shortfalls in our current understanding. Research focused on the rainbow trout (Oncorhynchus mykiss), a euryhaline species capable of withstanding the opposing challenges of life in seawater (diffusive influx of ions and loss of water) and freshwater (diffusive loss of ions and gain of water), and concentrated on its physiological response to ingestion of a meal of commercial, dry trout food, containing concentrated salts and little water. The net absorption and secretion of ions and water was tracked in each section of the GI tract of the rainbow trout over a detailed time course using an experimental diet that contained a simple inert marker, in the presence of external freshwater or seawater. Additionally, changes in overall blood chemistry were investigated to examine changes in osmotic, ionic and acid-base regulation during digestion. Feeding in freshwater resulted in the loss of endogenous water to the GI tract during digestion. Additionally, the meal provided much needed ions to balance those lost by diffusion; indeed all of the ingested ions were assimilated along the GI tract except for sodium which was absorbed in the stomach, but secreted in the intestine such that overall sodium balance was close to zero. Feeding also created a metabolic base load (an increase in the concentration of base, or HC03- due HCl secretion into the stomach lumen) that alkalinized the blood (i.e. caused a rise in pH), a phenomenon known as an alkaline tide. The base load was subsequently removed from the blood through increasedexcretion of base to the water via the gills. In seawater, the commercial diet again provided an avenue for water loss. This was potentially deleterious to an organism already suffering from diffusive water loss to the environment. Ion absorption from the diet was negligible, except for potassium and calcium, which were readily assimilated. As in freshwater, digestion resulted in an alkaline tide, however the mechanism of acid-base homeostasis differed with the excess base likely being excreted into the intestine. In contrast to freshwater fish, the gills took up additional base from the external environment, prolonging the acid-base disturbance in seawater fish. Overall, feeding was a dynamic process with far reaching systemic physiological effects. The research described highlighted intimate interactions between the processes of feeding and digestion and ion, water and acid-base homeostasis, and elucidated mechanisms that enable fish to inhabit a wide range of environments. / Thesis / Doctor of Philosophy (PhD)

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