Anderson Souza - Academia.edu (original) (raw)

Papers by Anderson Souza

In order to survive in a highly competitive environment, freshwater or marine algae have to devel... more In order to survive in a highly competitive environment, freshwater or marine algae have to develop defense strategies that result in a tremendous diversity of compounds from different metabolic pathways. Recent trends in drug research from natural sources have shown that algae are promising organisms to furnish novel biochemically active compounds. The current review describes the main substances biosynthesized by algae with potential economic impact in food science, pharmaceutical industry and public health. Emphasis is given to fatty acids, steroids, carotenoids, polysaccharides, lectins, mycosporine-like amino acids, halogenated compounds, polyketides and toxins.

Comparative Biochemistry and Physiology C-toxicology & Pharmacology, 2007

In order to survive in a highly competitive environment, freshwater or marine algae have to devel... more In order to survive in a highly competitive environment, freshwater or marine algae have to develop defense strategies that result in a tremendous diversity of compounds from different metabolic pathways. Recent trends in drug research from natural sources have shown that algae are promising organisms to furnish novel biochemically active compounds. The current review describes the main substances biosynthesized by algae with potential economic impact in food science, pharmaceutical industry and public health. Emphasis is given to fatty acids, steroids, carotenoids, polysaccharides, lectins, mycosporine-like amino acids, halogenated compounds, polyketides and toxins.

Fitopatologia Brasileira, 2004

In a survey carried out in the state of Mato Grosso, Brazil, the lesion nematode, Pratylenchus br... more In a survey carried out in the state of Mato Grosso, Brazil, the lesion nematode, Pratylenchus brachyurus, and the root-knot nematode, Meloidogyne incognita, were found, respectively, in 94% and 3.7% of a total of 623 root and soil samples representing 21,793 ha. No visible aboveground symptoms in cotton (Gossypium hirsutum) plants infected by P. brachyurus were observed, except for typical root lesions. In contrast, plants with M. incognita usually exhibited pronounced symptoms of damage. The high frequency (94%) of P. brachyurus was unexpected and is of concern considering the fact that soybean (Glycine max) and corn (Zea mays), are both susceptible to this nematode and are used in crop rotation programs.

This work proposes a localization system for mobile robots using the Extended Kalman Filter. The ... more This work proposes a localization system for mobile robots using the Extended Kalman Filter. The robot navigates in an known environment where the lines of the floor are used as natural landmarks and identifiqued by using the Hough transform.The prediction phase of the Kalman Filter is implemented using the odometry model of the robot. The update phase directly uses the parameters of the lines detected by the Hough algorithm to correct the robot's pose.

We propose a multimedia framework built on a flexible architecture designed for collaborative int... more We propose a multimedia framework built on a flexible architecture designed for collaborative interaction of people and robots through the Web. Users can communicate to each other exchanging text, audio and video messages. Besides, it provides a flexible interface for people to interact with robots, for robots with people, and among robots themselves, for example, allowing a robot to communicate to another one. One or several users can communicate with one or more robots and also receive information from them. Robots can be remotely controlled through the use of keyboard, joysticks, data glove, and voice commands. A user can perceive other users through a virtual environment and receive the video from an environment, in which the robot is

In this work we propose an enhanced model for mapping from sonar sensors and odometry that allows... more In this work we propose an enhanced model for mapping from sonar sensors and odometry that allows a robot to represent an environment map in a more suitable way to both the sonar sensory data and odometry system of the robot. We use a stochastic modelling of the errors that brings up reliable information. As a contribution, we obtain a final map that is more coherent with the reality of the original data provided by the robotic system. Practical experiments show the results obtained with the proposed modification to be trustable in such a way that this map can be used to provide previous knowledge to the mobile robot in order to perform its tasks in an easier and accurate way. Moreover, the map can help the robot to support unexpected situations inside of the environment

Spectrochimica Acta Part B-atomic Spectroscopy, 2005

The present paper proposes an on-line pre-concentration system for cadmium determination in drink... more The present paper proposes an on-line pre-concentration system for cadmium determination in drinking water using flame atomic absorption spectrometry (FAAS). Cadmium(II) ions are retained as 1-(2-pyridylazo)-2-naphthol (PAN) complex at the walls of a knotted reactor, followed of elution using hydrochloric acid solution. The optimization was performed in two steps using factorial design for preliminary evaluation and a Box-Behnken design for determination of the critical experimental conditions. The variables involved were: sampling flow-rate, reagent concentration, pH and buffer concentration, and as response the analytical signal (absorbance). The validation process was performed considering the parameters: linearity and other characteristics of the calibration curve, analytical features of on-line pre-concentration system, precision, effect of other ions in the pre-concentration system and accuracy. Using the optimized experimental conditions, the procedure allows cadmium determination with a detection limit (3 j / S) of 0.10 Ag L À 1 , a quantification limit (10 j / S) of 0.33 Ag L À1 , and a precision, calculated as relative standard deviation (RSD) of 2.7% (n = 7) and 2.4% (n = 7) for cadmium concentrations of 5 and 25 Ag L À 1 , respectively. A pre-concentration factor of 18 and a sampling frequency of 48 h À1 were obtained. The recovery for cadmium in the presence of several ions demonstrated that this procedure could be applied for the analysis of water samples. The method was applied for cadmium determination in drinking water samples collected in Salvador City, Brazil. The cadmium concentrations found in five samples were lower than the maximum permissible levels established by the World Health Organization. D

Journal of Hazardous Materials, 2007

An automatic on-line pre-concentration system is proposed for lead determination in drinking wate... more An automatic on-line pre-concentration system is proposed for lead determination in drinking water using flame atomic absorption spectrometry (FAAS). Lead(II) ions are retained as the 1-(2-pyridylazo)-2-naphthol (PAN) complex in the walls of a knotted reactor, followed by an elution step using 0.50 mol L −1 hydrochloric acid solution.

Journal of Hazardous Materials, 2007

The present paper describes the development of a microwave assisted digestion procedure for the d... more The present paper describes the development of a microwave assisted digestion procedure for the determination of zinc, copper and nickel in tea samples employing flame atomic absorption spectrometry (FAAS). The optimization step was performed using a full factorial design (2(3)) involving the factors: composition of the acid mixture (CMA), microwave power (MP) and radiation time (RT). The experiments of this factorial were carried out using a certified reference material of tea GBW 07605 furnished by National Research Centre for Certified Reference Materials, China, being the metal recoveries considered as response. The relative standard deviations of the method were found below 8% for the three elements. The procedure proposed was used for the determination of copper, zinc and nickel in several samples of tea from Turkey. For 10 tea samples analyzed, the concentration achieved for copper, zinc and nickel varied at 6.4-13.1, 7.0-16.5 and 3.1-5.7 (microg g(-1)), respectively.

Talanta, 2008

A method has been developed for the determination of lead in wine by electrothermal atomic absorp... more A method has been developed for the determination of lead in wine by electrothermal atomic absorption spectrometry without any sample preparation and calibration against aqueous standards, using 7.5 g Pd as a chemical modifier. The results obtained for seven wines using the proposed method and an acid digestion procedure did not show any significant difference using a Student's t-test. Atomization in a transversally heated filter atomizer (THFA) was compared with atomization in a conventional transversally heated platform furnace. The former provided a 2.6-fold higher sensitivity, improving the characteristic mass from 34 to 12 pg and a 1.6-fold better limit of detection (0.3 g L −1 compared to 0.5 g L −1 ) for aqueous solutions using the same injection volume of 20 L. However, the average precision, expressed as the relative standard deviation for the determination of lead in wine under routine conditions was improved from 4.6% with platform atomization to 0.6% in the THFA. The lead content found in seven arbitrarily chosen white and red wines, five from Brazil, one from Chile and one from Spain, ranged from 6 to 60 g L −1 Pb with an average content of 11.4 g L −1 Pb for the wines from South America.

Talanta, 2008

A procedure is proposed for the direct determination of manganese and iron in wine employing fast... more A procedure is proposed for the direct determination of manganese and iron in wine employing fast sequential flame atomic absorption spectrometry and the reference element technique to correct for matrix effects. Cobalt, silver, nickel and indium have been tested as reference elements. The results demonstrated that cobalt and indium at a concentration of 2 and 10 mg L −1 were efficient for quantification of manganese and iron, respectively. Under these conditions, manganese and iron could be determined with quantification limits of 27 and 40 g L −1 , respectively. The proposed method was applied to the determination of manganese and iron in 16 wine samples. The content of manganese varied from 0.78 to 2.89 mg L −1 and that of iron from 0.88 to 9.22 mg L −1 . The analytical results were compared with those obtained by inductively coupled plasma optical emission spectrometry after complete mineralization using acid digestion. The statistical comparison by a t-test (95% confidence level) showed no significant difference between the results.

Applied Spectroscopy Reviews, 2007

The present article describes fundamentals and applications of multivariate techniques used for t... more The present article describes fundamentals and applications of multivariate techniques used for the optimization of analytical procedures and systems involving spectroanalytical methods such as flame atomic absorption spectrometry (FAAS), electrothermal atomic absorption ...

Brain Research, 2006

In the present study, we investigated the role of 5-HT 3 and 5-HT 2C receptors located within the... more In the present study, we investigated the role of 5-HT 3 and 5-HT 2C receptors located within the medial amygdala (MeA) in the control of water and salt intake in sodium-depleted rats.

Talanta, 2006

Lead is recognized worldwide as a poisonous metal. Thus, the determination of this element is oft... more Lead is recognized worldwide as a poisonous metal. Thus, the determination of this element is often required in environmental, biological, food and geological samples. However, these analyses are difficult because such samples contain relatively low concentrations of lead, which fall below the detection limit of conventional analytical techniques such as flame atomic absorption spectrometry and inductively coupled plasma optical emission spectrometry. Several preconcentration procedures to determine lead have therefore been devised, involving separation techniques such as liquid-liquid extraction, solid phase extraction, coprecipitation and cloud point extraction. Citing 160 references, this paper offers a critical review of preconcentration procedures for determining lead using spectroanalytical techniques.

Analytica Chimica Acta, 2007

In this paper, we proposed a procedure for the determination of iron(II) and total iron in wine s... more In this paper, we proposed a procedure for the determination of iron(II) and total iron in wine samples employing molecular absorption spectrophotometry. The ligand used is 2-(5-bromo-2-pyridylazo)-5-(diethylamino)-phenol (Br-PADAP) and the chromogenic reaction in absence or presence of ascorbic acid (reducing agent) allows the determination of iron(II) or total iron, respectively. The optimization step was performed using a multivariate technique (Box Behnken design) involving the factors pH, acid ascorbic concentration and reaction time. The method allows the determination of iron(II) and iron(III) in wine samples, with limits of detection and quantification 0.22 and 0.72 microg L(-1), respectively. The precision expressed as relative standard deviation (R.S.D.) was 1.43 and 0.56% (both, n=11) for content of iron(II) in wine samples of 1.68 and 4.65 mg L(-1), and 1.66 and 0.87% (both, n=11) for content of total iron in wine samples of 1.72 and 5.48 mg L(-1). This method was applied for determination of iron(II) and total iron in six different wine samples. In these, the iron(II) content varied from 0.76 to 4.65 mg L(-1) and from 1.01 to 5.48 mg L(-1) for total iron. The results obtained in the determination of total iron by Br-PADAP method were compared with those that were performed after complete acid digestion in open system and determination of total iron employing FAAS. The method of regression linear was used for comparison of these results and demonstrated that there is no significant difference between the results obtained with these two procedures.

Microchemical Journal, 2010

In this work, the mineral composition of fresh bovine milk obtained from the milk-producing areas... more In this work, the mineral composition of fresh bovine milk obtained from the milk-producing areas of the Brazilian State of Sergipe was examined. A dry-ashed digestion method and the ICP OES technique were used for the quantification of mineral elements (e.g., Ca, Mg, K, Na, P, Sr and Zn) in 27 samples of milk collected from properties located in milk-producing areas around Nossa Senhora da Glória. The following ranges of values (% m/v) were obtained: 0.063 to 0.117 for Ca; 0.060 to 0.114 for P; 0.024 to 0.064 for Na; and 0.087 to 0.164 for K. The ranges of values (mg L − 1 ) for the other mineral elements were also found: 0.68 to 1.89 for Sr; 2.46 to 5.73 for Zn; and 54.2 to 109.9 for Mg. Additionally, the exploratory evaluation of the 27 milk samples was performed using principal component analysis (PCA) involving seven variables dealing with the effect of different management systems (conventional and organic) on milk composition. The results show that there are indeed differences between the mineral composition of milk from properties that use organic practices and those that use conventional management practices.

Journal of Hazardous Materials, 2007

Techniques -(FERREIRA, S. L. C.; DE ANDRADE, J. B.; KORN, M. D. G. A.; PEREIRA, M. D. G.; LEMOS, ... more Techniques -(FERREIRA, S. L. C.; DE ANDRADE, J. B.; KORN, M. D. G. A.; PEREIRA, M. D. G.; LEMOS, V. A.; DOS SANTOS, W. N. L.; RODRIGUES, F. D. M.; SOUZA, A. S.; FERREIRA, H. S.; DA SILVA, E. G. P.; J. Hazard. Mater. 145 (2007) 3, 358-367; Inst. Chem., Univ. Fed.

As propriedades físico-químicas da rizosfera têm elevada estabilidade, que, associadas ao forneci... more As propriedades físico-químicas da rizosfera têm elevada estabilidade, que, associadas ao fornecimento constante de substratos orgânicos e fatores de crescimento, favorecem intensa atividade metabólica das populações, influenciando diretamente e positivamente o tempo de geração microbiano. O solo é um local de grande número e variedade de interações biológicas, incluindo a competição, a predação, o parasitismo, o comensalismo, o mutualismo e a forésia. As interações biológicas possuem a capacidade de sustentar a vida tanto das plantas como dos animais e outros seres que vivem no solo. A comunidade microbiana na rizosfera é representada por populações diversificadas e numerosas em estado de equilíbrio dinâmico, refletindo o ambiente físico, químico, biológico e suas relações. Portanto, o objetivo dessa revisão foi demonstrar que há interação entre grupos de microorganismos com a rizosfera. As populações de microrganismos são importantes constituintes da microflora da rizosfera, seja pelos exsudados de raízes de plantas como fonte de carbono favorecidas pelo metabolismo destes microrganismos, seja pela capacidade de síntese de antibióticos, permitindo o uso de sua capacidade antagonista no biocontrole de fitopatógenos; seja pela influência que promove no estabelecimento de microrganismos benéficos, como diazotróficos e as micorrizas;. e ainda pela formação de actinorrizas, onde é capaz de fixar nitrogênio atmosférico.

In order to survive in a highly competitive environment, freshwater or marine algae have to devel... more In order to survive in a highly competitive environment, freshwater or marine algae have to develop defense strategies that result in a tremendous diversity of compounds from different metabolic pathways. Recent trends in drug research from natural sources have shown that algae are promising organisms to furnish novel biochemically active compounds. The current review describes the main substances biosynthesized by algae with potential economic impact in food science, pharmaceutical industry and public health. Emphasis is given to fatty acids, steroids, carotenoids, polysaccharides, lectins, mycosporine-like amino acids, halogenated compounds, polyketides and toxins.

Comparative Biochemistry and Physiology C-toxicology & Pharmacology, 2007

In order to survive in a highly competitive environment, freshwater or marine algae have to devel... more In order to survive in a highly competitive environment, freshwater or marine algae have to develop defense strategies that result in a tremendous diversity of compounds from different metabolic pathways. Recent trends in drug research from natural sources have shown that algae are promising organisms to furnish novel biochemically active compounds. The current review describes the main substances biosynthesized by algae with potential economic impact in food science, pharmaceutical industry and public health. Emphasis is given to fatty acids, steroids, carotenoids, polysaccharides, lectins, mycosporine-like amino acids, halogenated compounds, polyketides and toxins.

Fitopatologia Brasileira, 2004

In a survey carried out in the state of Mato Grosso, Brazil, the lesion nematode, Pratylenchus br... more In a survey carried out in the state of Mato Grosso, Brazil, the lesion nematode, Pratylenchus brachyurus, and the root-knot nematode, Meloidogyne incognita, were found, respectively, in 94% and 3.7% of a total of 623 root and soil samples representing 21,793 ha. No visible aboveground symptoms in cotton (Gossypium hirsutum) plants infected by P. brachyurus were observed, except for typical root lesions. In contrast, plants with M. incognita usually exhibited pronounced symptoms of damage. The high frequency (94%) of P. brachyurus was unexpected and is of concern considering the fact that soybean (Glycine max) and corn (Zea mays), are both susceptible to this nematode and are used in crop rotation programs.

This work proposes a localization system for mobile robots using the Extended Kalman Filter. The ... more This work proposes a localization system for mobile robots using the Extended Kalman Filter. The robot navigates in an known environment where the lines of the floor are used as natural landmarks and identifiqued by using the Hough transform.The prediction phase of the Kalman Filter is implemented using the odometry model of the robot. The update phase directly uses the parameters of the lines detected by the Hough algorithm to correct the robot's pose.

We propose a multimedia framework built on a flexible architecture designed for collaborative int... more We propose a multimedia framework built on a flexible architecture designed for collaborative interaction of people and robots through the Web. Users can communicate to each other exchanging text, audio and video messages. Besides, it provides a flexible interface for people to interact with robots, for robots with people, and among robots themselves, for example, allowing a robot to communicate to another one. One or several users can communicate with one or more robots and also receive information from them. Robots can be remotely controlled through the use of keyboard, joysticks, data glove, and voice commands. A user can perceive other users through a virtual environment and receive the video from an environment, in which the robot is

In this work we propose an enhanced model for mapping from sonar sensors and odometry that allows... more In this work we propose an enhanced model for mapping from sonar sensors and odometry that allows a robot to represent an environment map in a more suitable way to both the sonar sensory data and odometry system of the robot. We use a stochastic modelling of the errors that brings up reliable information. As a contribution, we obtain a final map that is more coherent with the reality of the original data provided by the robotic system. Practical experiments show the results obtained with the proposed modification to be trustable in such a way that this map can be used to provide previous knowledge to the mobile robot in order to perform its tasks in an easier and accurate way. Moreover, the map can help the robot to support unexpected situations inside of the environment

Spectrochimica Acta Part B-atomic Spectroscopy, 2005

The present paper proposes an on-line pre-concentration system for cadmium determination in drink... more The present paper proposes an on-line pre-concentration system for cadmium determination in drinking water using flame atomic absorption spectrometry (FAAS). Cadmium(II) ions are retained as 1-(2-pyridylazo)-2-naphthol (PAN) complex at the walls of a knotted reactor, followed of elution using hydrochloric acid solution. The optimization was performed in two steps using factorial design for preliminary evaluation and a Box-Behnken design for determination of the critical experimental conditions. The variables involved were: sampling flow-rate, reagent concentration, pH and buffer concentration, and as response the analytical signal (absorbance). The validation process was performed considering the parameters: linearity and other characteristics of the calibration curve, analytical features of on-line pre-concentration system, precision, effect of other ions in the pre-concentration system and accuracy. Using the optimized experimental conditions, the procedure allows cadmium determination with a detection limit (3 j / S) of 0.10 Ag L À 1 , a quantification limit (10 j / S) of 0.33 Ag L À1 , and a precision, calculated as relative standard deviation (RSD) of 2.7% (n = 7) and 2.4% (n = 7) for cadmium concentrations of 5 and 25 Ag L À 1 , respectively. A pre-concentration factor of 18 and a sampling frequency of 48 h À1 were obtained. The recovery for cadmium in the presence of several ions demonstrated that this procedure could be applied for the analysis of water samples. The method was applied for cadmium determination in drinking water samples collected in Salvador City, Brazil. The cadmium concentrations found in five samples were lower than the maximum permissible levels established by the World Health Organization. D

Journal of Hazardous Materials, 2007

An automatic on-line pre-concentration system is proposed for lead determination in drinking wate... more An automatic on-line pre-concentration system is proposed for lead determination in drinking water using flame atomic absorption spectrometry (FAAS). Lead(II) ions are retained as the 1-(2-pyridylazo)-2-naphthol (PAN) complex in the walls of a knotted reactor, followed by an elution step using 0.50 mol L −1 hydrochloric acid solution.

Journal of Hazardous Materials, 2007

The present paper describes the development of a microwave assisted digestion procedure for the d... more The present paper describes the development of a microwave assisted digestion procedure for the determination of zinc, copper and nickel in tea samples employing flame atomic absorption spectrometry (FAAS). The optimization step was performed using a full factorial design (2(3)) involving the factors: composition of the acid mixture (CMA), microwave power (MP) and radiation time (RT). The experiments of this factorial were carried out using a certified reference material of tea GBW 07605 furnished by National Research Centre for Certified Reference Materials, China, being the metal recoveries considered as response. The relative standard deviations of the method were found below 8% for the three elements. The procedure proposed was used for the determination of copper, zinc and nickel in several samples of tea from Turkey. For 10 tea samples analyzed, the concentration achieved for copper, zinc and nickel varied at 6.4-13.1, 7.0-16.5 and 3.1-5.7 (microg g(-1)), respectively.

Talanta, 2008

A method has been developed for the determination of lead in wine by electrothermal atomic absorp... more A method has been developed for the determination of lead in wine by electrothermal atomic absorption spectrometry without any sample preparation and calibration against aqueous standards, using 7.5 g Pd as a chemical modifier. The results obtained for seven wines using the proposed method and an acid digestion procedure did not show any significant difference using a Student's t-test. Atomization in a transversally heated filter atomizer (THFA) was compared with atomization in a conventional transversally heated platform furnace. The former provided a 2.6-fold higher sensitivity, improving the characteristic mass from 34 to 12 pg and a 1.6-fold better limit of detection (0.3 g L −1 compared to 0.5 g L −1 ) for aqueous solutions using the same injection volume of 20 L. However, the average precision, expressed as the relative standard deviation for the determination of lead in wine under routine conditions was improved from 4.6% with platform atomization to 0.6% in the THFA. The lead content found in seven arbitrarily chosen white and red wines, five from Brazil, one from Chile and one from Spain, ranged from 6 to 60 g L −1 Pb with an average content of 11.4 g L −1 Pb for the wines from South America.

Talanta, 2008

A procedure is proposed for the direct determination of manganese and iron in wine employing fast... more A procedure is proposed for the direct determination of manganese and iron in wine employing fast sequential flame atomic absorption spectrometry and the reference element technique to correct for matrix effects. Cobalt, silver, nickel and indium have been tested as reference elements. The results demonstrated that cobalt and indium at a concentration of 2 and 10 mg L −1 were efficient for quantification of manganese and iron, respectively. Under these conditions, manganese and iron could be determined with quantification limits of 27 and 40 g L −1 , respectively. The proposed method was applied to the determination of manganese and iron in 16 wine samples. The content of manganese varied from 0.78 to 2.89 mg L −1 and that of iron from 0.88 to 9.22 mg L −1 . The analytical results were compared with those obtained by inductively coupled plasma optical emission spectrometry after complete mineralization using acid digestion. The statistical comparison by a t-test (95% confidence level) showed no significant difference between the results.

Applied Spectroscopy Reviews, 2007

The present article describes fundamentals and applications of multivariate techniques used for t... more The present article describes fundamentals and applications of multivariate techniques used for the optimization of analytical procedures and systems involving spectroanalytical methods such as flame atomic absorption spectrometry (FAAS), electrothermal atomic absorption ...

Brain Research, 2006

In the present study, we investigated the role of 5-HT 3 and 5-HT 2C receptors located within the... more In the present study, we investigated the role of 5-HT 3 and 5-HT 2C receptors located within the medial amygdala (MeA) in the control of water and salt intake in sodium-depleted rats.

Talanta, 2006

Lead is recognized worldwide as a poisonous metal. Thus, the determination of this element is oft... more Lead is recognized worldwide as a poisonous metal. Thus, the determination of this element is often required in environmental, biological, food and geological samples. However, these analyses are difficult because such samples contain relatively low concentrations of lead, which fall below the detection limit of conventional analytical techniques such as flame atomic absorption spectrometry and inductively coupled plasma optical emission spectrometry. Several preconcentration procedures to determine lead have therefore been devised, involving separation techniques such as liquid-liquid extraction, solid phase extraction, coprecipitation and cloud point extraction. Citing 160 references, this paper offers a critical review of preconcentration procedures for determining lead using spectroanalytical techniques.

Analytica Chimica Acta, 2007

In this paper, we proposed a procedure for the determination of iron(II) and total iron in wine s... more In this paper, we proposed a procedure for the determination of iron(II) and total iron in wine samples employing molecular absorption spectrophotometry. The ligand used is 2-(5-bromo-2-pyridylazo)-5-(diethylamino)-phenol (Br-PADAP) and the chromogenic reaction in absence or presence of ascorbic acid (reducing agent) allows the determination of iron(II) or total iron, respectively. The optimization step was performed using a multivariate technique (Box Behnken design) involving the factors pH, acid ascorbic concentration and reaction time. The method allows the determination of iron(II) and iron(III) in wine samples, with limits of detection and quantification 0.22 and 0.72 microg L(-1), respectively. The precision expressed as relative standard deviation (R.S.D.) was 1.43 and 0.56% (both, n=11) for content of iron(II) in wine samples of 1.68 and 4.65 mg L(-1), and 1.66 and 0.87% (both, n=11) for content of total iron in wine samples of 1.72 and 5.48 mg L(-1). This method was applied for determination of iron(II) and total iron in six different wine samples. In these, the iron(II) content varied from 0.76 to 4.65 mg L(-1) and from 1.01 to 5.48 mg L(-1) for total iron. The results obtained in the determination of total iron by Br-PADAP method were compared with those that were performed after complete acid digestion in open system and determination of total iron employing FAAS. The method of regression linear was used for comparison of these results and demonstrated that there is no significant difference between the results obtained with these two procedures.

Microchemical Journal, 2010

In this work, the mineral composition of fresh bovine milk obtained from the milk-producing areas... more In this work, the mineral composition of fresh bovine milk obtained from the milk-producing areas of the Brazilian State of Sergipe was examined. A dry-ashed digestion method and the ICP OES technique were used for the quantification of mineral elements (e.g., Ca, Mg, K, Na, P, Sr and Zn) in 27 samples of milk collected from properties located in milk-producing areas around Nossa Senhora da Glória. The following ranges of values (% m/v) were obtained: 0.063 to 0.117 for Ca; 0.060 to 0.114 for P; 0.024 to 0.064 for Na; and 0.087 to 0.164 for K. The ranges of values (mg L − 1 ) for the other mineral elements were also found: 0.68 to 1.89 for Sr; 2.46 to 5.73 for Zn; and 54.2 to 109.9 for Mg. Additionally, the exploratory evaluation of the 27 milk samples was performed using principal component analysis (PCA) involving seven variables dealing with the effect of different management systems (conventional and organic) on milk composition. The results show that there are indeed differences between the mineral composition of milk from properties that use organic practices and those that use conventional management practices.

Journal of Hazardous Materials, 2007

Techniques -(FERREIRA, S. L. C.; DE ANDRADE, J. B.; KORN, M. D. G. A.; PEREIRA, M. D. G.; LEMOS, ... more Techniques -(FERREIRA, S. L. C.; DE ANDRADE, J. B.; KORN, M. D. G. A.; PEREIRA, M. D. G.; LEMOS, V. A.; DOS SANTOS, W. N. L.; RODRIGUES, F. D. M.; SOUZA, A. S.; FERREIRA, H. S.; DA SILVA, E. G. P.; J. Hazard. Mater. 145 (2007) 3, 358-367; Inst. Chem., Univ. Fed.

As propriedades físico-químicas da rizosfera têm elevada estabilidade, que, associadas ao forneci... more As propriedades físico-químicas da rizosfera têm elevada estabilidade, que, associadas ao fornecimento constante de substratos orgânicos e fatores de crescimento, favorecem intensa atividade metabólica das populações, influenciando diretamente e positivamente o tempo de geração microbiano. O solo é um local de grande número e variedade de interações biológicas, incluindo a competição, a predação, o parasitismo, o comensalismo, o mutualismo e a forésia. As interações biológicas possuem a capacidade de sustentar a vida tanto das plantas como dos animais e outros seres que vivem no solo. A comunidade microbiana na rizosfera é representada por populações diversificadas e numerosas em estado de equilíbrio dinâmico, refletindo o ambiente físico, químico, biológico e suas relações. Portanto, o objetivo dessa revisão foi demonstrar que há interação entre grupos de microorganismos com a rizosfera. As populações de microrganismos são importantes constituintes da microflora da rizosfera, seja pelos exsudados de raízes de plantas como fonte de carbono favorecidas pelo metabolismo destes microrganismos, seja pela capacidade de síntese de antibióticos, permitindo o uso de sua capacidade antagonista no biocontrole de fitopatógenos; seja pela influência que promove no estabelecimento de microrganismos benéficos, como diazotróficos e as micorrizas;. e ainda pela formação de actinorrizas, onde é capaz de fixar nitrogênio atmosférico.