In this work we present a review of main statistical properties of speckle patterns and accomplis... more In this work we present a review of main statistical properties of speckle patterns and accomplish a comparative study of the more used methods for analysis and extraction of information from optical grainy. The first and second order space-time statistics are dicussed in an overview perspective. The biospeckle phenomenon has detailed attention, specially in its application on monitoring of activity in tissues. The main techniques used to obtain information from speckle patterns are presented, with special prominence to autocorrelation function, co-occurrence matrices, Fujii's method, Briers' contrast and spatial and temporal contrast analisys (LASCA and LASTCA). An incipient method for analysis, based on the study of sucessive correlations contrast, is introduced. Numerical simulations, using diferent probability density functions for velocities of scatterers, were made with two objectives: to test the analysis methods and to give subsidies for interpretation of in vivo results. Vegetable and animal tissues are investigated, achieving the monitoring of senescence process and vascularization maps on leaves, the accompaniment of fungi contamined fruits, the mapping of activity in flowers and the analisys of healing in rats subjected to abdominal surgery. Experiments using the biospeckle phenomenon in microscopy are carried out. At last, it is evaluated the potentiality of biospeckle as diagnosis tool in chronic vein ulcer cared with low intensity laser therapy and the better analysis methods for each kind of tissue are pointed.
In this work, we propose the contrast of sucessive correlations as a valid estimator for activity... more In this work, we propose the contrast of sucessive correlations as a valid estimator for activity on dynamic speckles. We call ``sucessive correlations'' the correlation coeficients between two sucessive instants recorded on a Time History Speckle Pattern (THSP). In following, by dividing the standard deviation of these coeficients by their mean value, we get the corresponding contrast of sucessive correlations.
Since the sixties, dynamic speckles have found a wide number of applications, covering fields fro... more Since the sixties, dynamic speckles have found a wide number of applications, covering fields from engineering to biomedicine. However, despite of this potential, its utilisation in food manufacture control is still incipient. In this work, our objective was to use the biospeckle phenomenon to monitoring the expansion of the dough during the leavening process. Our experiments consisted in the temporal
The self-assembly of peptide nanotubes formed by anl-glutamic acid-based bolaamphiphile is shown ... more The self-assembly of peptide nanotubes formed by anl-glutamic acid-based bolaamphiphile is shown to proceedviaa remarkable mechanism where the peptide conformation changes from β-sheet to unordered.
ABSTRACT We provide a panorama on the utilization of microscopy for investigating peptide-based s... more ABSTRACT We provide a panorama on the utilization of microscopy for investigating peptide-based self-assemblies. Specifically, we present results from researches around the self-assembly of L-diphenylalanine. Recent advances obtained in our group are presented and the paramount role of microscopy on these developments is hightlighted. We begin by presenting a brief overview of self-ordered structures built from peptidic building blocks. In following, we present the use of microscopy tools within a multiscale perspective. First, we analyze the assemblies at the micrometre length reporting on the use of optical approaches. In following, we focuse on electron microscopy to discuss the morphology of nanostructures at mesoscopic scale. Finer topological details are discussed through the presentation of atomic force microscopy studies. The different techniques are discussed within a comparative context emphasizing the complementarity among different analytical tools. Aspects related to the applications of these structures are also presented, specially their utilization as biosensors, where the morphological characterization via microscopy appears together with electrochemical analyses.
Neste trabalho apresentamos a medida do coeficiente linear de dilatação térmica do alumínio, usan... more Neste trabalho apresentamos a medida do coeficiente linear de dilatação térmica do alumínio, usando o interferograma obtido a partir da transformada de Fourier sobre a soma de duas imagens de speckle deslocadas. O resultado alcançado está em bom acordo com o tabelado e os equipamentos necessários têm custo acessível, tornando o experimento uma alternativa interessante para introdução da metrologia óptica no laboratório didático ou um projeto a ser desenvolvido em disciplinas experimentais.
ABSTRACT Solid-phase approach was used to build peptidic assemblies at normal pressure. Different... more ABSTRACT Solid-phase approach was used to build peptidic assemblies at normal pressure. Different vapors, peptide concen-trations and incubation times were investigated. Water leads to nanoforests and aniline, to micrometer horizontally-oriented fibers. Distinct vibrational modes are found according to the solvent used in the growth. PAni was used to functionalize the structures. a b s t r a c t The short aromatic dipeptide L-diphenylalanine (FF) was used to build supramolecular assemblies from amorphous films that were deposited onto Si substrates using an adapted form of the solid-vapor method [Adv. Mater. 20 (2008) 3754e3758]. The morphological and spectroscopic behaviors of the resulting micro-and nano-sized 1-D arrays were investigated. The formation of the structures was examined under different preparation conditions; specifically, the nature of the solvent (water or aniline), the concentration of peptides in the precursor solution and the incubation time were varied. Our results indicate that changes in preparation have dramatic consequences on the final morphology of the assemblies. Particularly, our data suggest that the solvent vapor pressure and a reduction of the hydrophobic capabilities of the substrate play a relevant role on structuration since they presumably increase heat and mass transport, respectively. Spectroscopic data reveal that the use of different vapors promotes the emergence of new vibrational modes, which is interpreted as a change in the symmetry of the molecular arrangement that is accompanied by an increase in the number of degrees of freedom. These findings strongly indicate that different symmetries-presumably orthorhombic and hexagonal symmetries-can be obtained depending on the type of solvent used during the preparation. To assess the interaction between our structures and a functionalizing agent, aniline was polymerized onto the structured films and then their morphological and spectroscopic behaviors were also investigated.
O crescimento de plantas em substrato em cultivo protegido requer conhecimento técnico apropriado... more O crescimento de plantas em substrato em cultivo protegido requer conhecimento técnico apropriado para uso racional e eficientede água e de nutrientes. O objetivo deste trabalho foi avaliar o efeito de seis freqüências de irrigação no desenvolvimento e na produção do tomateiro cultivado em ambiente protegido. O experimento foi conduzido em Campinas, de novembro de 2003 a abril de 2004. O delineamento experimental foi de blocos ao acaso com seis tratamentos e quatro repetições. Os tratamentos consistiram em seis freqüências de irrigação: cinco, quatro, três, duas, uma vez por dia e irrigação em dias alternados. A irrigação foi aplicada por gotejamento. O substrato utilizado foi o composto de fibra de coco. As freqüências de irrigação de uma, três, quatro e cinco vezes por dia resultaram nas maiores produções de frutos comerciáveis de tomateiro. O maior número e peso médio dos frutos foram obtidos nos tratamentos com freqüência de irrigação de uma, duas, três, quatro e cinco vezes por...
Langmuir : the ACS journal of surfaces and colloids, Jan 30, 2014
We have developed a nonenzymatic biosensor for the detection of ammonia and urea oxidation based ... more We have developed a nonenzymatic biosensor for the detection of ammonia and urea oxidation based on the deposition of peptide microstructures onto thiolated gold electrodes. FF-MNSs/MCP/Au assemblies were obtained by modifying gold substrates with 4-mercaptopyridine (MCP), followed by coating with l,l-diphenylalanine micro/nanostructures (FF-MNSs) grown in the solid-vapor phase. Benzene rings and amide groups with peptide micro/nanostructures interact with synthetic NH4(+) receptors through cation-π and hydrogen bonding. AuOH clusters on the Au surface provided the catalytic sites. The application of a predetermined concentration of analytes at the peptide interfaces activated the catalytic sites. We observed a relationship between the stability of films and the crystal structure of peptides, and we organized the FF-MNSs into an orthorhombic symmetry that was the most suitable assembly for creation of our biosensors. At 0.1 mol L(-1) NaOH, these FF-MNSs/MCP/Au electrodes have electr...
Hybrid associates formed between peptide assemblies and fluorophores are attractive mainly becaus... more Hybrid associates formed between peptide assemblies and fluorophores are attractive mainly because of their unique properties for biomedical applications. Recently, we demonstrated that the production of reactive oxygen species (ROS) by hypericin and their stability in excited states are enhanced upon conjugation with l,l‐diphenylalanine microtubes (FF‐MNTs). Although the detailed mechanisms responsible for improving the photophysical properties of ROS remain unclear, tentative hypotheses have suggested that the driving force is the growth of overall dipolar moments ascribed either to coupling between aligned H2O dipoles within the ordered structures or to the organization of hypericin molecules on peptide interfaces. To provide new insights on ROS activity in hypericin/FF‐MNTs hybrids and further explore the role of water in this respect, we present results obtained from investigations on the behavior of these complexes organized into different crystalline arrangements. Specificall...
ABSTRACTBecause of the economical relevance of sugarcane and its high potential as a source of bi... more ABSTRACTBecause of the economical relevance of sugarcane and its high potential as a source of biofuel, it is important to understand how this crop will respond to the foreseen increase in atmospheric [CO2]. The effects of increased [CO2] on photosynthesis, development and carbohydrate metabolism were studied in sugarcane (Saccharum ssp.). Plants were grown at ambient (∼370 ppm) and elevated (∼720 ppm) [CO2] during 50 weeks in open‐top chambers. The plants grown under elevated CO2 showed, at the end of such period, an increase of about 30% in photosynthesis and 17% in height, and accumulated 40% more biomass in comparison with the plants grown at ambient [CO2]. These plants also had lower stomatal conductance and transpiration rates (−37 and −32%, respectively), and higher water‐use efficiency (c.a. 62%). cDNA microarray analyses revealed a differential expression of 35 genes on the leaves (14 repressed and 22 induced) by elevated CO2. The latter are mainly related to photosynthesis...
A new method for analysis of scattering data from lamellar bilayer systems is presented. The meth... more A new method for analysis of scattering data from lamellar bilayer systems is presented. The method employs a form-free description of the cross-section structure of the bilayer and the fit is performed directly to the scattering data, introducing also a structure factor when required. The cross-section structure (electron density profile in the case of X-ray scattering) is described by a set of Gaussian functions and the technique is termed Gaussian deconvolution. The coefficients of the Gaussians are optimized using a constrained least-squares routine that induces smoothness of the electron density profile. The optimization is coupled with the point-of-inflection method for determining the optimal weight of the smoothness. With the new approach, it is possible to optimize simultaneously the form factor, structure factor and several other parameters in the model. The applicability of this method is demonstrated by using it in a study of a multilamellar system composed of lecithin b...
In this work we present a review of main statistical properties of speckle patterns and accomplis... more In this work we present a review of main statistical properties of speckle patterns and accomplish a comparative study of the more used methods for analysis and extraction of information from optical grainy. The first and second order space-time statistics are dicussed in an overview perspective. The biospeckle phenomenon has detailed attention, specially in its application on monitoring of activity in tissues. The main techniques used to obtain information from speckle patterns are presented, with special prominence to autocorrelation function, co-occurrence matrices, Fujii's method, Briers' contrast and spatial and temporal contrast analisys (LASCA and LASTCA). An incipient method for analysis, based on the study of sucessive correlations contrast, is introduced. Numerical simulations, using diferent probability density functions for velocities of scatterers, were made with two objectives: to test the analysis methods and to give subsidies for interpretation of in vivo results. Vegetable and animal tissues are investigated, achieving the monitoring of senescence process and vascularization maps on leaves, the accompaniment of fungi contamined fruits, the mapping of activity in flowers and the analisys of healing in rats subjected to abdominal surgery. Experiments using the biospeckle phenomenon in microscopy are carried out. At last, it is evaluated the potentiality of biospeckle as diagnosis tool in chronic vein ulcer cared with low intensity laser therapy and the better analysis methods for each kind of tissue are pointed.
In this work, we propose the contrast of sucessive correlations as a valid estimator for activity... more In this work, we propose the contrast of sucessive correlations as a valid estimator for activity on dynamic speckles. We call ``sucessive correlations'' the correlation coeficients between two sucessive instants recorded on a Time History Speckle Pattern (THSP). In following, by dividing the standard deviation of these coeficients by their mean value, we get the corresponding contrast of sucessive correlations.
Since the sixties, dynamic speckles have found a wide number of applications, covering fields fro... more Since the sixties, dynamic speckles have found a wide number of applications, covering fields from engineering to biomedicine. However, despite of this potential, its utilisation in food manufacture control is still incipient. In this work, our objective was to use the biospeckle phenomenon to monitoring the expansion of the dough during the leavening process. Our experiments consisted in the temporal
The self-assembly of peptide nanotubes formed by anl-glutamic acid-based bolaamphiphile is shown ... more The self-assembly of peptide nanotubes formed by anl-glutamic acid-based bolaamphiphile is shown to proceedviaa remarkable mechanism where the peptide conformation changes from β-sheet to unordered.
ABSTRACT We provide a panorama on the utilization of microscopy for investigating peptide-based s... more ABSTRACT We provide a panorama on the utilization of microscopy for investigating peptide-based self-assemblies. Specifically, we present results from researches around the self-assembly of L-diphenylalanine. Recent advances obtained in our group are presented and the paramount role of microscopy on these developments is hightlighted. We begin by presenting a brief overview of self-ordered structures built from peptidic building blocks. In following, we present the use of microscopy tools within a multiscale perspective. First, we analyze the assemblies at the micrometre length reporting on the use of optical approaches. In following, we focuse on electron microscopy to discuss the morphology of nanostructures at mesoscopic scale. Finer topological details are discussed through the presentation of atomic force microscopy studies. The different techniques are discussed within a comparative context emphasizing the complementarity among different analytical tools. Aspects related to the applications of these structures are also presented, specially their utilization as biosensors, where the morphological characterization via microscopy appears together with electrochemical analyses.
Neste trabalho apresentamos a medida do coeficiente linear de dilatação térmica do alumínio, usan... more Neste trabalho apresentamos a medida do coeficiente linear de dilatação térmica do alumínio, usando o interferograma obtido a partir da transformada de Fourier sobre a soma de duas imagens de speckle deslocadas. O resultado alcançado está em bom acordo com o tabelado e os equipamentos necessários têm custo acessível, tornando o experimento uma alternativa interessante para introdução da metrologia óptica no laboratório didático ou um projeto a ser desenvolvido em disciplinas experimentais.
ABSTRACT Solid-phase approach was used to build peptidic assemblies at normal pressure. Different... more ABSTRACT Solid-phase approach was used to build peptidic assemblies at normal pressure. Different vapors, peptide concen-trations and incubation times were investigated. Water leads to nanoforests and aniline, to micrometer horizontally-oriented fibers. Distinct vibrational modes are found according to the solvent used in the growth. PAni was used to functionalize the structures. a b s t r a c t The short aromatic dipeptide L-diphenylalanine (FF) was used to build supramolecular assemblies from amorphous films that were deposited onto Si substrates using an adapted form of the solid-vapor method [Adv. Mater. 20 (2008) 3754e3758]. The morphological and spectroscopic behaviors of the resulting micro-and nano-sized 1-D arrays were investigated. The formation of the structures was examined under different preparation conditions; specifically, the nature of the solvent (water or aniline), the concentration of peptides in the precursor solution and the incubation time were varied. Our results indicate that changes in preparation have dramatic consequences on the final morphology of the assemblies. Particularly, our data suggest that the solvent vapor pressure and a reduction of the hydrophobic capabilities of the substrate play a relevant role on structuration since they presumably increase heat and mass transport, respectively. Spectroscopic data reveal that the use of different vapors promotes the emergence of new vibrational modes, which is interpreted as a change in the symmetry of the molecular arrangement that is accompanied by an increase in the number of degrees of freedom. These findings strongly indicate that different symmetries-presumably orthorhombic and hexagonal symmetries-can be obtained depending on the type of solvent used during the preparation. To assess the interaction between our structures and a functionalizing agent, aniline was polymerized onto the structured films and then their morphological and spectroscopic behaviors were also investigated.
O crescimento de plantas em substrato em cultivo protegido requer conhecimento técnico apropriado... more O crescimento de plantas em substrato em cultivo protegido requer conhecimento técnico apropriado para uso racional e eficientede água e de nutrientes. O objetivo deste trabalho foi avaliar o efeito de seis freqüências de irrigação no desenvolvimento e na produção do tomateiro cultivado em ambiente protegido. O experimento foi conduzido em Campinas, de novembro de 2003 a abril de 2004. O delineamento experimental foi de blocos ao acaso com seis tratamentos e quatro repetições. Os tratamentos consistiram em seis freqüências de irrigação: cinco, quatro, três, duas, uma vez por dia e irrigação em dias alternados. A irrigação foi aplicada por gotejamento. O substrato utilizado foi o composto de fibra de coco. As freqüências de irrigação de uma, três, quatro e cinco vezes por dia resultaram nas maiores produções de frutos comerciáveis de tomateiro. O maior número e peso médio dos frutos foram obtidos nos tratamentos com freqüência de irrigação de uma, duas, três, quatro e cinco vezes por...
Langmuir : the ACS journal of surfaces and colloids, Jan 30, 2014
We have developed a nonenzymatic biosensor for the detection of ammonia and urea oxidation based ... more We have developed a nonenzymatic biosensor for the detection of ammonia and urea oxidation based on the deposition of peptide microstructures onto thiolated gold electrodes. FF-MNSs/MCP/Au assemblies were obtained by modifying gold substrates with 4-mercaptopyridine (MCP), followed by coating with l,l-diphenylalanine micro/nanostructures (FF-MNSs) grown in the solid-vapor phase. Benzene rings and amide groups with peptide micro/nanostructures interact with synthetic NH4(+) receptors through cation-π and hydrogen bonding. AuOH clusters on the Au surface provided the catalytic sites. The application of a predetermined concentration of analytes at the peptide interfaces activated the catalytic sites. We observed a relationship between the stability of films and the crystal structure of peptides, and we organized the FF-MNSs into an orthorhombic symmetry that was the most suitable assembly for creation of our biosensors. At 0.1 mol L(-1) NaOH, these FF-MNSs/MCP/Au electrodes have electr...
Hybrid associates formed between peptide assemblies and fluorophores are attractive mainly becaus... more Hybrid associates formed between peptide assemblies and fluorophores are attractive mainly because of their unique properties for biomedical applications. Recently, we demonstrated that the production of reactive oxygen species (ROS) by hypericin and their stability in excited states are enhanced upon conjugation with l,l‐diphenylalanine microtubes (FF‐MNTs). Although the detailed mechanisms responsible for improving the photophysical properties of ROS remain unclear, tentative hypotheses have suggested that the driving force is the growth of overall dipolar moments ascribed either to coupling between aligned H2O dipoles within the ordered structures or to the organization of hypericin molecules on peptide interfaces. To provide new insights on ROS activity in hypericin/FF‐MNTs hybrids and further explore the role of water in this respect, we present results obtained from investigations on the behavior of these complexes organized into different crystalline arrangements. Specificall...
ABSTRACTBecause of the economical relevance of sugarcane and its high potential as a source of bi... more ABSTRACTBecause of the economical relevance of sugarcane and its high potential as a source of biofuel, it is important to understand how this crop will respond to the foreseen increase in atmospheric [CO2]. The effects of increased [CO2] on photosynthesis, development and carbohydrate metabolism were studied in sugarcane (Saccharum ssp.). Plants were grown at ambient (∼370 ppm) and elevated (∼720 ppm) [CO2] during 50 weeks in open‐top chambers. The plants grown under elevated CO2 showed, at the end of such period, an increase of about 30% in photosynthesis and 17% in height, and accumulated 40% more biomass in comparison with the plants grown at ambient [CO2]. These plants also had lower stomatal conductance and transpiration rates (−37 and −32%, respectively), and higher water‐use efficiency (c.a. 62%). cDNA microarray analyses revealed a differential expression of 35 genes on the leaves (14 repressed and 22 induced) by elevated CO2. The latter are mainly related to photosynthesis...
A new method for analysis of scattering data from lamellar bilayer systems is presented. The meth... more A new method for analysis of scattering data from lamellar bilayer systems is presented. The method employs a form-free description of the cross-section structure of the bilayer and the fit is performed directly to the scattering data, introducing also a structure factor when required. The cross-section structure (electron density profile in the case of X-ray scattering) is described by a set of Gaussian functions and the technique is termed Gaussian deconvolution. The coefficients of the Gaussians are optimized using a constrained least-squares routine that induces smoothness of the electron density profile. The optimization is coupled with the point-of-inflection method for determining the optimal weight of the smoothness. With the new approach, it is possible to optimize simultaneously the form factor, structure factor and several other parameters in the model. The applicability of this method is demonstrated by using it in a study of a multilamellar system composed of lecithin b...
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