Orientadores: Miriam Dupas Hubinger, Rosiane Lopes da Cunha / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-04T15:44:33Z (GMT). No. of bitstreams: 1 SanjinezArgandona_ElianaJanet_D.pdf: 1300468 bytes, checksum: c20ca032f56d49e321e696c01f4057ad (MD5) Previous issue date: 2005 / Doutorado / Doutor em Engenharia de Alimentos

>Magister Scientiae - MSc / Drought stress is a major contributor to reduced soybean crop yield and quality, this can however be mitigated by the plant’s antioxidant defence mechanisms. One group of antioxidant enzymes that are active in these defence mechanisms are glutathione peroxidases (GPXs). GPXs are antioxidant proteins which are able to reduce H2O2, a toxic reactive oxygen species which accumulates under stress conditions. This study aims at isolating the protein encoded by Glyma01g42840 and determining if it has Phospholipid hydroperoxidase glutathione peroxidase (PHGPX) and/or Thioredoxin dependent peroxidase (TRX-PX) activity as well as assaying the effect of Drought stress on the expression of this putative GPX . This will be accomplished by molecular cloning, sequencing as well as the expression of the isolated protein to assay it enzymatic activity. It was found that the enzyme encoded by Glyma01g42840 is able to use glutathione and thioredoxin as electron donors for the detoxification peroxides, however enzymatic activity is more efficient when using glutathione as an electron donor. In conclusion it was found that glyma01g42840 encodes an enzyme which is able to utilise more than one electron donor and as glutathione produces the greatest amount of enzymatic activity it can be said that glyma01g42840 encodes a GPX.

Please read the abstract in the section 00front of this document. / Thesis (DPhil)--University of Pretoria, 2010. / Chemistry / unrestricted

Made available in DSpace on 2016-01-26T18:56:20Z (GMT). No. of bitstreams: 1 PAULO ROBERTO COSTA.pdf: 691880 bytes, checksum: 9c1227e2bd33119238b57603b29f4ca2 (MD5) Previous issue date: 2006-01-30 / The germination decreasing as a water deficit function is a wide spread occurrence in agricultural systems. This assay was divided in two steps. Firstly, the actions of different osmotic in the simulation of water deficit during germination were tested determining what is the most efficient. The second part was done using mannitol to determine the effect of water deficit in soybean of different sizes. In the first navy bean seeds cv 'IAC-Carioca-80-SH' were germinated at different water deficit potentials (zero; -0.6; -1.2 and 1.8 MPa) of mannitol, CaCl2, KCl and NaCl. In the second soybean seeds cv 'IAC-18' classified in sizes 12 and 13 and 'IAC-22' in 12, 13 and 14 were germinated in mannitol solutions with the same potentials used in the first. Experiment were carried out as completely random with four repetitions per treatment. The treatment evaluation was done by germination, first germination counting , vigour classification, hypocotil and shoot length and by shoot and root dry weight. The results showed that KCl and NaCl solutions had also the toxicity effect on the seeds, and they were not recommended as water deficit simulators. In relation to seed size, in higher water deficits the germination was bigger in larger seeds. Germination was less affected in both experiments then the seedling development in the different water potentials. / A diminuição da germinação em função de deficiência hídrica é ocorrência comum em sistemas agrícolas. Este estudo foi subdividido em duas etapas. Na primeira etapa, procurou-se discutir a ação de diferentes osmóticos na simulação de deficiência hídrica na germinação de sementes determinando-se o osmótico mais eficiente. Posteriormente, utilizou-se o osmótico manitol para determinar o efeito da deficiência hídrica em sementes de soja de diferentes tamanhos. No primeiro estudo, sementes de feijão cv. IAC Carioca-80SH foram germinadas em diferentes potenciais osmóticos (zero; -0,6; -1,2 e 1,8 MPa) obtidos com soluções de manitol, CaCl2, KCl e NaCl. No segundo, sementes de soja cv. IAC-18 e IAC-22 , classificadas em peneiras nos tamanhos 12 e 13, e, 12, 13 e 14, respectivamente, foram germinadas em soluções de manitol de concentrações iguais à primeira etapa. Os experimentos foram conduzidos em delineamento inteiramente casualizado com quatro repetições por tratamento. Para avaliação dos tratamentos foram quantificadas a germinação, primeira contagem de germinação, classificação de vigor, comprimento de hipocótilo e raiz e massa seca de parte aérea e raiz. Os resultados indicaram que as soluções de KCl e NaCl, além de funcionarem como reguladores osmóticos, manifestaram toxidez às sementes, não sendo recomendadas, portanto, como simuladores de deficiência hídrica. Quanto ao tamanho de sementes, para ambos os cultivares, em potenciais menores ocorre maior germinação das sementes maiores. A germinação foi menor afetada, em ambos os experimentos, que as avaliações de desenvolvimento de plântula, nos diferentes níveis de potencial.

Made available in DSpace on 2016-07-18T17:51:05Z (GMT). No. of bitstreams: 1 PAULO ROBERTO COSTA.pdf: 691880 bytes, checksum: 9c1227e2bd33119238b57603b29f4ca2 (MD5) Previous issue date: 2006-01-30 / The germination decreasing as a water deficit function is a wide spread occurrence in agricultural systems. This assay was divided in two steps. Firstly, the actions of different osmotic in the simulation of water deficit during germination were tested determining what is the most efficient. The second part was done using mannitol to determine the effect of water deficit in soybean of different sizes. In the first navy bean seeds cv 'IAC-Carioca-80-SH' were germinated at different water deficit potentials (zero; -0.6; -1.2 and 1.8 MPa) of mannitol, CaCl2, KCl and NaCl. In the second soybean seeds cv 'IAC-18' classified in sizes 12 and 13 and 'IAC-22' in 12, 13 and 14 were germinated in mannitol solutions with the same potentials used in the first. Experiment were carried out as completely random with four repetitions per treatment. The treatment evaluation was done by germination, first germination counting , vigour classification, hypocotil and shoot length and by shoot and root dry weight. The results showed that KCl and NaCl solutions had also the toxicity effect on the seeds, and they were not recommended as water deficit simulators. In relation to seed size, in higher water deficits the germination was bigger in larger seeds. Germination was less affected in both experiments then the seedling development in the different water potentials. / A diminuição da germinação em função de deficiência hídrica é ocorrência comum em sistemas agrícolas. Este estudo foi subdividido em duas etapas. Na primeira etapa, procurou-se discutir a ação de diferentes osmóticos na simulação de deficiência hídrica na germinação de sementes determinando-se o osmótico mais eficiente. Posteriormente, utilizou-se o osmótico manitol para determinar o efeito da deficiência hídrica em sementes de soja de diferentes tamanhos. No primeiro estudo, sementes de feijão cv. IAC Carioca-80SH foram germinadas em diferentes potenciais osmóticos (zero; -0,6; -1,2 e 1,8 MPa) obtidos com soluções de manitol, CaCl2, KCl e NaCl. No segundo, sementes de soja cv. IAC-18 e IAC-22 , classificadas em peneiras nos tamanhos 12 e 13, e, 12, 13 e 14, respectivamente, foram germinadas em soluções de manitol de concentrações iguais à primeira etapa. Os experimentos foram conduzidos em delineamento inteiramente casualizado com quatro repetições por tratamento. Para avaliação dos tratamentos foram quantificadas a germinação, primeira contagem de germinação, classificação de vigor, comprimento de hipocótilo e raiz e massa seca de parte aérea e raiz. Os resultados indicaram que as soluções de KCl e NaCl, além de funcionarem como reguladores osmóticos, manifestaram toxidez às sementes, não sendo recomendadas, portanto, como simuladores de deficiência hídrica. Quanto ao tamanho de sementes, para ambos os cultivares, em potenciais menores ocorre maior germinação das sementes maiores. A germinação foi menor afetada, em ambos os experimentos, que as avaliações de desenvolvimento de plântula, nos diferentes níveis de potencial.

Os produtos com umidade reduzida têm-se evidenciados como proposta alternativa para disponibilizar produtos de origem vegetal caracterizados pelo alto teor de umidade e vida útil curta, proporcionando, assim, um produto diferenciado, estável, com maior tempo de vida útil, além de possibilitar diversificação no consumo e aplicações. Este trabalho teve como objetivo a desidratação de minitomates inteiros do híbrido Sweet Grape, pelo processo de secagem convectiva adiabática e as interferências do pré-tratamento osmótico e adição de antioxidante, além da comparação do produto desidratado e liofilizado. O tratamento osmótico consistiu de cinco combinações de soluções osmóticas compostas por açúcar invertido, sacarose e cloreto de sódio. A desidratação adiabática foi caracterizada por duplo estágio a 80°C/ 2h em seguida a diferentes temperaturas: 50, 60, 70 e 80°C, até atingir umidade do produto de aproximadamente 30%. Foram aplicados antioxidantes e acidulante (ácido ascórbico, metabissulfito de sódio e ácido cítrico), no intuito de minimizar as alterações durante a desidratação. Em seguida, foi realizado um comparativo entre minitomates desidratados e liofilizados, acondicionados em embalagem laminada e mantidos a 5°C por 120 dias. O tratamento osmótico composto por açúcar invertido (60°Brix), sacarose (15%) e NaCl (5%) a 25°C por 50 min foi o processo mais eficaz, que apresentou menor incorporação de sólidos, maior perda de massa e menor atividade de água, associado à aplicação de 750mg.L-1 de ácido ascórbico, 50mg.L-1 de metabissulfito de sódio e 3g.L-1 de ácido cítrico. Os minitomates desidratados em duplo estágio a 80°C/2h e 70°C/11h apresentaram melhor aceitação quando comparados aos liofilizados, visto que a liofilização promoveu redução acentuada da cor e umidade, tornando o produto mais rígido. As características dos produtos desidratados e liofilizados foram mantidas estáveis por um período de 90 dias, aproximadamente, e o tratamento osmótico promoveu maior estabilidade aos produtos durante o armazenamento. / Products with low humidity have been considered an alternative for vegetable products characterized by high humidity content and short shelf life. Thus low-humidity products provide stable with longer shelf life products, enabling diversity for consumption and applications. This study investigated dehydration of whole cherry tomatoes of the Sweet Grape variety by the process of adiabatic convective drying and interference of osmotic pretreatment and antioxidant addition, comparing to dehydrated and lyophilized tomatoes. The treatment consisted of five combinations of osmotic solutions composed by inverted sugar, saccharose and sodium chloride. Adiabatic dehydration was characterized by double stage at 80°C/2 h followed by different temperatures: 50, 60, 70 and 80°C until the product reached moisture of 30%. Antioxidants and acidulants were applied (ascorbic acid, sodium metabisulphite and citric acid) to minimize changes during dehydration. Afterward, we compared dehydrated and lyophilized cherry tomatoes, packed in laminated packaging and kept at 5°C for 120 days. The osmotic treatment with inverted sugar (60° Brix), sucrose (15%) and sodium chloride (5%) at 25°C for 50 min was the most effective process. This process showed lower incorporation of solids, greater weight loss and lower water activity, associated with the application 750 mg.L-1 of ascorbic acid, 50 mg.L-1 of sodium metabisulphite and 3 g.L-1 of citric acid. The cherry tomatoes dehydrated in a double stage at 80°C/2 h and 70°C/11 h showed better acceptance when compared to lyophilized ones as freeze-drying caused greater color and moisture reduction, making the product more rigid. Characteristics of dehydrated and lyophilized products were kept stable for roughly 90 days and the osmotic treatment on the products promoted greater stability during storage.

The performance of regenerated cellulose (RC) films and capsules was investigated for their applications in oral controlled drug delivery. Regenerated cellulose films were prepared by non-solvent-mediated, phase inversion of native and depolymerized cotton linter solutions (methylolcellulose; cellulose dissolved in dimethyl sulfoxide/ paraformaldehyde solvent system) in water as well as by phase inversion of native cotton linter solutions in organic non-solvents followed by thermal annealing. These films were monolithic in dry state and formed porous structures when hydrated. Irrespective of the degree of polymerization of the starting cellulose source or the use of organic non-solvents, the cellulose chain length was not significantly altered and cellulose was in an amorphous state. Flux analysis in diffusion cells, using ethanol-water mixtures as the solvent medium, indicated that the films take up solvent to form porous routes for transport of solute. The amount of solvent uptake required to form these routes was greater for films prepared from depolymerized cotton linter. Ionic and hydrophobic solutes traverse the films using the porous pathways following hydration of the film. Blended RC films were prepared by combining native and depolymerized cotton linter solutions in varying ratios and phase-inverting in water, followed by thermal annealing. Porosity, pore size and water uptake of the hydrated films decreased, while the length of the transport pathway (tortuosity) increased, as the fraction of depolymerized cellulose increased in the blended films. Differences in methylene blue dye adsorption on phase-inverted vs. phase-inverted and thermally annealed RC films indicated that the type of non-solvent utilized for phase-inversion does not affect the internal RC film structure during the phase-inversion process. However, as the boiling point of the non-solvent increased, the amount of irreversible polymer consolidation and formation non-swelling domains (hornification) increased during the thermal annealing process. This, in turn, led to reduced porosity and solute flux through these RC films. Two-piece cellulose capsules were fabricated by phase-inversion of methylolcellulose solutions in water using a dip-coating approach. Zero-order release rates for a number of drugs increased as their water solubility increased. The release of water soluble drugs occurred by osmotically-driven convection and diffusion through the pores in the capsule wall, while the release of moderate to poorly soluble drugs predominantly occurred by diffusion. Moreover, as the drug solubility increased, the apparent permeability of the drugs through the capsule wall decreased, which indicated that the inward osmotic flux of water reduced the diffusivity of the drug through the pores. The hydraulic permeability of the cellulose capsules was determined to be higher than for conventional ethylcellulose and cellulose acetate coated osmotic drug delivery systems, indicating that the cellulose-based capsules may be better suited for osmotic drug delivery.

The rapidly expanding of the global population in the 21st-century forces people facing two serious problems: water scarcity and energy shortage. Enormous continuous studies focus on providing enough fresh water and energy in a sustainable way. This thesis aims at exploring novel membrane processes based on thermally responsive ionic liquids with the upper critical solution temperature (UCST ILs) for water desalination and energy conversion from low-grade heat energy to electricity. A UCST IL protonated betaine bis(trifluoromethylsulfonyl)imide ([Hbet][Tf2N]) was first experimentally studied as a novel draw solute in a thermal forward osmosis (FO). A 3.2 M [Hbet][Tf2N] solution can be obtained via spontaneous phase separation from an IL and water mixture at room temperature. By heating and maintaining the temperature above 56°C, this solution can draw water from high-salinity solution up to 3.0 M, 5 times salty as the sea water. The IL draw solution can be easily regenerated by phase separation. Conducting the FO process at higher temperatures can also increase the water flux. According to the different choices of the freshwater polishing step, the electric energy consumption in this novel process was estimated as 26.3% to 64.2% of conventional one-step sea water reverse osmosis. Two UCST ILs with better performance, [Hbet][Tf2N] and choline bis(trifluoromethylsulfonyl)imide ([Choline][Tf2N]), were selected as the agents in a novel closed-loop thermally responsive IL osmotic heat engine (TRIL-OHE) to convert low-grade thermal energy to electricity. The specific energies of the [Hbet][Tf2N] system and the [Choline][Tf2N] system are 2500 kJ/t and 3700 kJ/t, which are 2.7 and 4.0 times of the seawater and river water system, respectively. The maximum power density measured from a commercial FO membrane is 1.5 W/m2 for the [Hbet][Tf2N] system and 2.3 W/m2 for the [Choline][Tf2N] system, leaving a big room to improve if highly permeable membranes are used. Another notable advantage of the TRIL-OHE is the heat released from the cooling stage can be largely recovered. A rigorous energy balance showed with a 70% heat recovery, the energy efficiency could be increased from around 20% to 70% of the Carnot efficiency in both UCST ILs systems.

The compacted bentonites are used as buffer and backfill materials for engineering barriers for high-level nuclear waste repositories located underground. For this purpose, it is very important to evaluate the swelling characteristics of this clay. The swelling capacity is one of the most important properties of the bentonite clay. The swelling behaviour is due two mechanisms, the crystalline swelling and the osmotic swelling. These mechanisms produce an increase in the distance between the layers of montmorillonite which is one component of bentonite. The result of the swelling capacity is the swelling pressure. It has been studied in several investigations. The results of experimental tests have been collected and compared in this thesis, considering only the Na-dominant bentonite and sand and distilled water as test solution. The experimental tests show that there is only an unique relation between different bentonites in the Na-dominant bentonite and sand mixture swollen depending on its final dry density. Also, the relation between the swelling pressure and the clay void ratio shows the mechanism of the swelling pressure. On the other hand, a mechanistic model is used to predict the swelling pressure of fully saturated bentonite and sand mixture in distilled water. Firstly, it has been compared with the results of experimental tests and it should be pointed out that the model gives good predictions. In addition, the model has been used to make sensitivity analysis with different parameters of bentonite. The most important conclusions in this section show that the swelling pressure mainly depends on the distance among particles. Also, the sensitivity analyses indicate which parameters should be fitted more carefully for future studies to validate this model with different bentonites.

Forward osmosis (FO) as a novel membrane separation technology has recently been investigated in various water treatment applications. The natural mass transfer process between two solutions driven by the osmotic pressure difference leads to many operational advantages in the FO process, such as low energy consumption and minimal fouling problems. It makes FO a feasible technology for the treatment of produced water (PW). Although previously, the treatment of PW using FO has been investigated, osmotic backwashing (OB) is not systematically examined for water flux recovery of the PW fouled FO membranes. Moreover, the cleaning of FO membranes used for the simultaneous treatment of different PW streams was never previously attempted. In this study, OB was thoroughly investigated for the cleaning of PW-fouled FO membranes. Also, FO membrane chemical cleaning using SDS and NaOH solutions was examined too. To investigate OB, the cleaning efficiency of a 60 min OB cleaning protocol was examined under different FO operating modes in (5 x 20 h) experiments using synthetic desalter effluent as FO feed solution (FS) and 1.2 M NaCl solution or water-oil separator outlet (WO) as draw solutions (DS). The AL-FS (active layer facing FS) mode outcompeted the AL-DS (active layer facing DS) mode, achieving a flux of 12.9 LMH and 80.1% water reclamation when using WO as a DS. Therefore, this FO configuration 5 was selected when evaluating the cleaning protocols. Moreover, after evaluating different OB methods, the 30 min OB protocol achieved the highest system efficiency rate of 95% and was studied for the treatment of real PW streams. The SDS and NaOH chemical cleaning methods achieved flux recovery rates of 99% and 98% by the end of the third treatment cycle, respectively, outperforming the 89% flux recovery rate of the optimized OB protocol. Although the investigated cleaning methods were able to restore the system performance, a substantial increase in RSF was observed due to mainly irreversible colloidal fouling. This study demonstrates the feasibility of OB and chemical cleaning in restoring FO system performance for the simultaneous treatment of PW streams