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Papers by Maria Magdalena Ferreira Ribas

Histology and histopathology, 2003

Widespread genetic alterations are a common feature of most colorectal cancers. While specific re... more Widespread genetic alterations are a common feature of most colorectal cancers. While specific recurrent alterations may reveal the involvement of a gene or set of genes in the biology of the disease, the cumulated genomic damage is likely to reflect the biological history of the neoplastic cells. Furthermore, the functional implications behind many of these genetic changes may show the evolutionary potential of the neoplastic cells. Different approaches, ranging from the gross determination of total nuclear DNA content to cytogenetic and molecular approaches, reveal different types of chromosomal and subchromosomal alterations and have been applied to measure generalized genomic damage in colorectal carcinomas. High levels of genomic damage usually appear associated with increased aggressiveness in colorectal cancer, and the use of different assessments of genomic damage as independent prognostic factors has been proposed. Therefore, appropriate definition of the extent of cumulate...

Scientia Agricola, 2003

Manipueira, wastewater of cassava (Manihot esculenta) processing, can be treated by anaerobic bio... more Manipueira, wastewater of cassava (Manihot esculenta) processing, can be treated by anaerobic biodigestion. To study the start-up process of a plug-flow digester for manipueira treatment, this work consisted of two stages: gradual decrease of the hydraulic retention time (HRT) to the preset time of 4 days or maintaining a fixed HRT of 4 days with gradual increase of the substrate concentration. A digester of 1980 mL capacity was opperated, at constant temperature (32 ± 1º C), with substrate pH corrected between 5.5 and 6.0. The first stage had durations of 16.6; 13.6; 11.6; and 9.6 days and the organic loads were 3.1; 2.0; 2.3; and 2.9 COD L-1 d-1, (chemical oxigen demand) respectively. The second stage was characterized by a fixed HRT (4 days) and organic loads of 0.48; 0.86; 1.65; and 2.46 g COD L-1 d-1. Total solids (TS), volatile solids (VS), COD, alkalinity and volatile acidity were determined in the substrate and in the effluent. During the first stage, the HRT of 9.6 days and...

Brazilian Archives of Biology and Technology, 2010

The wastewater of the processing of cassava's flour (manipueira) was submitted to the anaerobic t... more The wastewater of the processing of cassava's flour (manipueira) was submitted to the anaerobic treatment in two phases: acidogenic and methanogenic. In the acidogenic phase, the wastewater was stabilized with NaOH (ASH) and with limestone (ASL). After that, both stabilized effluents were treated by a methanogenic reactor. Then, the effluent of the methanogenic reactor was used as fertilizer on maize in the initial growth stage (30 days), cultivated in pots in a greenhouse. The treatments were T1: control without urea addition (only N from soil); T2: NPK (2.2 g of urea with 45% of N); T3: ASH (84 mL.kg soil-1); T4: ASL (102 mL.kg soil-1); T5: double dose ASH (168 mL.kg soil-1) and T6: double dose ASL (204 mL.kg soil-1). Each treatment was composed by 4 plants/pot in five repetitions. It was observed that all the treatments with stabilized wastewater had favorable effect to the soil pH (> than 7.5) and basis saturation (V%) in the soil around to 90%. The performances of nitrogen absorption by the maize plants were 64, 54, 80 and 78% for T3, T4, T5 and T6, respectively.

Scientia Agricola, 2003

Manipueira, wastewater of cassava (Manihot esculenta) processing, can be treated by anaerobic bio... more Manipueira, wastewater of cassava (Manihot esculenta) processing, can be treated by anaerobic biodigestion. To study the start-up process of a plug-flow digester for manipueira treatment, this work consisted of two stages: gradual decrease of the hydraulic retention time (HRT) to the preset time of 4 days or maintaining a fixed HRT of 4 days with gradual increase of the substrate concentration. A digester of 1980 mL capacity was opperated, at constant temperature (32 ± 1 o C), with substrate pH corrected between 5.5 and 6.0. The first stage had durations of 16.6; 13.6; 11.6; and 9.6 days and the organic loads were 3.1; 2.0; 2.3; and 2.9 COD L -1 d -1 , (chemical oxigen demand) respectively. The second stage was characterized by a fixed HRT (4 days) and organic loads of 0.48; 0.86; 1.65; and 2.46 g COD L -1 d -1 . Total solids (TS), volatile solids (VS), COD, alkalinity and volatile acidity were determined in the substrate and in the effluent. During the first stage, the HRT of 9.6 days and organic load of 2.9 g COD L -1 d -1 resulted in the best performence; reductions in COD, total and volatile solids were 60, 44 and 60%, respectively. During the second stage, with a 4-day HRT, the best results were achieved with the 0.86 g COD L -1 d -1 organic load, which provided reductions in COD, total and volatile solids of 71, 58 and 79%, respectively. The start-up of the plug-flow digester for manipueira treatment can be made by gradually by decreasing the HRT, or fixing HRT and increasing substrate concentration.

Engenharia Sanitaria e Ambiental, 2007

Sistemas de tratamento anaeróbios são sensíveis às mudanças de condições ambientais que influenci... more Sistemas de tratamento anaeróbios são sensíveis às mudanças de condições ambientais que influenciam no metabolismo dos microrganismos responsáveis pela estabilidade do processo. Os objetivos deste trabalho foram (i) avaliar a acurácia de métodos que determinam os parâmetros de controle ácidos graxos voláteis (AGV) e alcalinidade a bicarbonato (AB) em amostras preparadas com concentrações de 50 a 1000 mg/L e, (ii) verificar diferentes procedimentos de remoção de CO2 formado durante titulação ácida das amostras. A partir do teste estatístico de Tukey aplicado aos resultados obtidos, observou-se que os métodos Kapp e DiLallo & Albertson com utilização de ultra-som para a remoção de CO2 do meio líquido apresentaram os melhores resultados para AGV. Os métodos da Condutividade, Kapp e Jenkins se destacaram na determinação de AB.

Brazilian Archives of Biology and Technology, 2009

The aim of this work was to investigate the anaerobic biomass formation capable of treating vinas... more The aim of this work was to investigate the anaerobic biomass formation capable of treating vinasse from the production of sugar cane alcohol, which was evolved within an anaerobic sequencing batch biofilm reactor (ASBBR) as immobilized biomass on cubes of polyurethane foam at the temperature of 55ºC. The reactor was inoculated with mesophilic granular sludge originally treating poultry slaughterhouse wastewater. The evolution of the biofilm in the polyurethane foam matrices was assessed during seven experimental phases which were thus characterized by the changes in the organic matter concentrations as COD (1.0 to 20.0 g/L). Biomass characterization proceeded with the examination of sludge samples under optical and scanning electron microscopy. The reactor showed high microbial morphological diversity along the trial. The predominance of Methanosaeta-like cells was observed up to the organic load of 2.5 gCOD/L.d. On the other hand, Methanosarcinalike microorganisms were the predomi...

The anaerobic single-stage reactor was evaluated to treat vinasse and to evaluate its stability. ... more The anaerobic single-stage reactor was evaluated to treat vinasse and to evaluate its stability. This bench reactor was filled with dolomitic limestone with a horizontal plug flow to simulate a drainage channel. The experiment lasted 129 days while the reactor was submitted to different applied organic concentrations (chronologically applied: 3.0; 5.0; 12.0; 9.0 and 7.5 g L-1 as COD, chemical oxygen demand). COD removals were 50% and 9% with 3.0 and 7.5 g L-1 , respectively. With 12.0 g L-1 , reactor efficiency increased to 33%, with an abrupt drop to 3% on the 84 th day. Therefore, in order to avoid reactor collapse, a remedial measure was necessary. The system remained in batch without feeding for 19 days (from the 85 th to the 104 th day) with 9.0 g L-1. Afterwards, it was observed that the performance of the system tended to stabilize, reaching 47% with 7.5 g L-1 in the 118 th day. At the end of the experiment, the potassium content of the wastewater decreased from 800 mg L-1 to 594 mg L-1 (on an average 25%) and calcium and magnesium increased within the reactor liquor. The dissolution of the limestone inside the liquor reactor probably caused this result. After the treatment with limestone, the average pH value of the effluent increased from 4.9 to over 6.0 in all organic concentrations. It could be concluded that the reactor filled with dolomitic limestone in these operational conditions assured a low efficiency in COD removal, potassium reduction, increasing values of pH, alkalinity, calcium and magnesium. The instability was observed when there was increase in organic load to 12 g L-1 with subsequent recovery.

Histology and histopathology, 2003

Widespread genetic alterations are a common feature of most colorectal cancers. While specific re... more Widespread genetic alterations are a common feature of most colorectal cancers. While specific recurrent alterations may reveal the involvement of a gene or set of genes in the biology of the disease, the cumulated genomic damage is likely to reflect the biological history of the neoplastic cells. Furthermore, the functional implications behind many of these genetic changes may show the evolutionary potential of the neoplastic cells. Different approaches, ranging from the gross determination of total nuclear DNA content to cytogenetic and molecular approaches, reveal different types of chromosomal and subchromosomal alterations and have been applied to measure generalized genomic damage in colorectal carcinomas. High levels of genomic damage usually appear associated with increased aggressiveness in colorectal cancer, and the use of different assessments of genomic damage as independent prognostic factors has been proposed. Therefore, appropriate definition of the extent of cumulate...

Scientia Agricola, 2003

Manipueira, wastewater of cassava (Manihot esculenta) processing, can be treated by anaerobic bio... more Manipueira, wastewater of cassava (Manihot esculenta) processing, can be treated by anaerobic biodigestion. To study the start-up process of a plug-flow digester for manipueira treatment, this work consisted of two stages: gradual decrease of the hydraulic retention time (HRT) to the preset time of 4 days or maintaining a fixed HRT of 4 days with gradual increase of the substrate concentration. A digester of 1980 mL capacity was opperated, at constant temperature (32 ± 1º C), with substrate pH corrected between 5.5 and 6.0. The first stage had durations of 16.6; 13.6; 11.6; and 9.6 days and the organic loads were 3.1; 2.0; 2.3; and 2.9 COD L-1 d-1, (chemical oxigen demand) respectively. The second stage was characterized by a fixed HRT (4 days) and organic loads of 0.48; 0.86; 1.65; and 2.46 g COD L-1 d-1. Total solids (TS), volatile solids (VS), COD, alkalinity and volatile acidity were determined in the substrate and in the effluent. During the first stage, the HRT of 9.6 days and...

Brazilian Archives of Biology and Technology, 2010

The wastewater of the processing of cassava's flour (manipueira) was submitted to the anaerobic t... more The wastewater of the processing of cassava's flour (manipueira) was submitted to the anaerobic treatment in two phases: acidogenic and methanogenic. In the acidogenic phase, the wastewater was stabilized with NaOH (ASH) and with limestone (ASL). After that, both stabilized effluents were treated by a methanogenic reactor. Then, the effluent of the methanogenic reactor was used as fertilizer on maize in the initial growth stage (30 days), cultivated in pots in a greenhouse. The treatments were T1: control without urea addition (only N from soil); T2: NPK (2.2 g of urea with 45% of N); T3: ASH (84 mL.kg soil-1); T4: ASL (102 mL.kg soil-1); T5: double dose ASH (168 mL.kg soil-1) and T6: double dose ASL (204 mL.kg soil-1). Each treatment was composed by 4 plants/pot in five repetitions. It was observed that all the treatments with stabilized wastewater had favorable effect to the soil pH (> than 7.5) and basis saturation (V%) in the soil around to 90%. The performances of nitrogen absorption by the maize plants were 64, 54, 80 and 78% for T3, T4, T5 and T6, respectively.

Scientia Agricola, 2003

Manipueira, wastewater of cassava (Manihot esculenta) processing, can be treated by anaerobic bio... more Manipueira, wastewater of cassava (Manihot esculenta) processing, can be treated by anaerobic biodigestion. To study the start-up process of a plug-flow digester for manipueira treatment, this work consisted of two stages: gradual decrease of the hydraulic retention time (HRT) to the preset time of 4 days or maintaining a fixed HRT of 4 days with gradual increase of the substrate concentration. A digester of 1980 mL capacity was opperated, at constant temperature (32 ± 1 o C), with substrate pH corrected between 5.5 and 6.0. The first stage had durations of 16.6; 13.6; 11.6; and 9.6 days and the organic loads were 3.1; 2.0; 2.3; and 2.9 COD L -1 d -1 , (chemical oxigen demand) respectively. The second stage was characterized by a fixed HRT (4 days) and organic loads of 0.48; 0.86; 1.65; and 2.46 g COD L -1 d -1 . Total solids (TS), volatile solids (VS), COD, alkalinity and volatile acidity were determined in the substrate and in the effluent. During the first stage, the HRT of 9.6 days and organic load of 2.9 g COD L -1 d -1 resulted in the best performence; reductions in COD, total and volatile solids were 60, 44 and 60%, respectively. During the second stage, with a 4-day HRT, the best results were achieved with the 0.86 g COD L -1 d -1 organic load, which provided reductions in COD, total and volatile solids of 71, 58 and 79%, respectively. The start-up of the plug-flow digester for manipueira treatment can be made by gradually by decreasing the HRT, or fixing HRT and increasing substrate concentration.

Engenharia Sanitaria e Ambiental, 2007

Sistemas de tratamento anaeróbios são sensíveis às mudanças de condições ambientais que influenci... more Sistemas de tratamento anaeróbios são sensíveis às mudanças de condições ambientais que influenciam no metabolismo dos microrganismos responsáveis pela estabilidade do processo. Os objetivos deste trabalho foram (i) avaliar a acurácia de métodos que determinam os parâmetros de controle ácidos graxos voláteis (AGV) e alcalinidade a bicarbonato (AB) em amostras preparadas com concentrações de 50 a 1000 mg/L e, (ii) verificar diferentes procedimentos de remoção de CO2 formado durante titulação ácida das amostras. A partir do teste estatístico de Tukey aplicado aos resultados obtidos, observou-se que os métodos Kapp e DiLallo & Albertson com utilização de ultra-som para a remoção de CO2 do meio líquido apresentaram os melhores resultados para AGV. Os métodos da Condutividade, Kapp e Jenkins se destacaram na determinação de AB.

Brazilian Archives of Biology and Technology, 2009

The aim of this work was to investigate the anaerobic biomass formation capable of treating vinas... more The aim of this work was to investigate the anaerobic biomass formation capable of treating vinasse from the production of sugar cane alcohol, which was evolved within an anaerobic sequencing batch biofilm reactor (ASBBR) as immobilized biomass on cubes of polyurethane foam at the temperature of 55ºC. The reactor was inoculated with mesophilic granular sludge originally treating poultry slaughterhouse wastewater. The evolution of the biofilm in the polyurethane foam matrices was assessed during seven experimental phases which were thus characterized by the changes in the organic matter concentrations as COD (1.0 to 20.0 g/L). Biomass characterization proceeded with the examination of sludge samples under optical and scanning electron microscopy. The reactor showed high microbial morphological diversity along the trial. The predominance of Methanosaeta-like cells was observed up to the organic load of 2.5 gCOD/L.d. On the other hand, Methanosarcinalike microorganisms were the predomi...

The anaerobic single-stage reactor was evaluated to treat vinasse and to evaluate its stability. ... more The anaerobic single-stage reactor was evaluated to treat vinasse and to evaluate its stability. This bench reactor was filled with dolomitic limestone with a horizontal plug flow to simulate a drainage channel. The experiment lasted 129 days while the reactor was submitted to different applied organic concentrations (chronologically applied: 3.0; 5.0; 12.0; 9.0 and 7.5 g L-1 as COD, chemical oxygen demand). COD removals were 50% and 9% with 3.0 and 7.5 g L-1 , respectively. With 12.0 g L-1 , reactor efficiency increased to 33%, with an abrupt drop to 3% on the 84 th day. Therefore, in order to avoid reactor collapse, a remedial measure was necessary. The system remained in batch without feeding for 19 days (from the 85 th to the 104 th day) with 9.0 g L-1. Afterwards, it was observed that the performance of the system tended to stabilize, reaching 47% with 7.5 g L-1 in the 118 th day. At the end of the experiment, the potassium content of the wastewater decreased from 800 mg L-1 to 594 mg L-1 (on an average 25%) and calcium and magnesium increased within the reactor liquor. The dissolution of the limestone inside the liquor reactor probably caused this result. After the treatment with limestone, the average pH value of the effluent increased from 4.9 to over 6.0 in all organic concentrations. It could be concluded that the reactor filled with dolomitic limestone in these operational conditions assured a low efficiency in COD removal, potassium reduction, increasing values of pH, alkalinity, calcium and magnesium. The instability was observed when there was increase in organic load to 12 g L-1 with subsequent recovery.