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Condutividade iônica e eletrônica em vidros 0,50[xAg2O(1-x)V2O5].0,50P2O5
(Universidade Federal de São Carlos, 2016-10-27) Marin, Juan Jairo Diaz; Rodrigues, Ana Candida Martins; https://lattes.cnpq.br/4499231813051400; https://lattes.cnpq.br/3837298586123061
Mixed conductive glassy materials have in their composition, in addition to a glass former, a metallic element in two oxidation states and ions with high mobility, generally alkaline or Ag+ ions. These materials can be used in solid state batteries. However, from a scientific point of view, there are still some issues to be solved, such as the mechanism that best explains the behavior of electric conduction in these materials, and why there is a marked drop in conductivity as a function of composition, for equimolar compositions between the modifier that introduces the ionic conduction, and the transition metal oxide that introduces the electronic conduction. Therefore, to advance the frontier of knowledge about the conduction mechanisms present in mixed conductive glasses, the ternary system of the glass family 0.50[xAg2O(1-x)V2O5].0.50P2O5, (0 ≤ x ≤ 1) was chosen. Each vitreous composition was synthesized and characterized by X-ray diffraction, differential scanning calorimetry, Helium pycnometry, and impedance spectroscopy. The impedance spectroscopy measurements of the composition x=0.6 revealed a semicircle with a deformation at low frequency. This semicircle cannot be adjusted by a single RC circuit. The analysis of the pre-exponential factor and the activation energies of the glasses shows lower values for the glasses rich in vanadium, that is, in the "electronic" region, when compared to the pre-exponential factor of the glasses of the region richest in silver, or in the "ionic" region. This behavior is in accordance with the theoretical expressions for each of the conductivity mechanisms. In an attempt to quantify the ionic and electronic contributions, the electromotive force method (F.E.M) was applied. This method was selected because, theoretically, it allows a precise quantification of the electronic and ionic conductivities. However, the experimental results showed that the generated electrochemical cell did not correspond to the expected one, therefore it was not possible to quantify the ionic and electronic contributions to the total electrical conductivity.
Desenvolvimento de plataformas nanométricas híbridas baseadas em polímero/enzima visando aplicações em biossensores
(Universidade Federal de São Carlos, 2016-10-27) Rodrigues, Stanley Endrigo Bilatto; Corrêa, Daniel Souza; https://lattes.cnpq.br/0461451015026948; https://lattes.cnpq.br/2012719040203232
Foodborne illness cases are common in Brazil and in the world. However, in many cases the microorganism causing the illness cannot properly identified. In addition, traditional analyses usually employed for identifying such microorganisms are often expensive and time consuming. In this context, the development of novel methods capable of detecting such microorganism in a fast way, similarly to a pre-selection method to indicate the positive or negative presence of pathogenic, are highly pursued. In this work, two systems using a concept of Electronic Tongue were developed. The first system used the Layer-by-Layer (LbL) technique to immobilize lysozyme, trypsin and pepsin enzymes in nanostructured films. In the second system, the immobilization process was combined using the LbL technique and covalent bonding for lysozyme and trypsin enzymes. The trypsin and pepsin can react with bacterial sub-products released in the medium, while the lysozyme can react directly with the gram-positive bacteria cell wall. All parameters required to obtain stable films with preserved enzymatic activity were investigated and determined. In the first case, the detection of Escherichia coli using the Electrical Impedance Spectroscopy yielded detection of bacteria at 105 UFC (intermediate values). The second electronic tongue was composed by sensing units formed by lysozyme and trypsin immobilized by covalent and electrostatic (LbL) bonds, allowing the reaction with either by products or with the bacterial cell wall. Contamined solutions with the Gram-positive Staphylococcus aureus, Gram-negative Salmonella bacteria and a mixed solution with both were analyzed. The second system was able to detect small bacteria concentrations at 103 CFU. Finally, the solution re-suspension treatment showed to be beneficial for improving the detection results. The electronic tongue was capable of distinguishing solutions contaminated with bacteria, showing potential to aid in the prevention of foodbourne diseases.
Efeitos da exposição à nanopartícula de dióxido de titânio em hepatócitos de peixe zebra (Danio rerio, Hamilton, 1822). uma abordagem in vitro
(Universidade Federal de São Carlos, 2016-10-27) Siqueira, Priscila Rodrigues de; Fernandes, Marisa Narciso; https://lattes.cnpq.br/3021357484136942; https://lattes.cnpq.br/2052416811090234
Titanium dioxide nanoparticles (TiO2-NP) are commonly used in many industrial activities. Consequently, the daily consumption by humans is estimated in 5.4 mg day, with an input in the environment of 4.2 mg day per person, receiving or not appropriated treatment before disposure. The cytotoxicity, genotoxicity and mutagenicity of TiO2-NP were investigated using the established fish cell line derived from zebrafish (Danio rerio) liver (i. e. ZF-L cells). Prior to the evaluation of nanoparticle’s toxic potential, a careful characterization was realized in culture medium in the presence or not of fetal bovine serum (FBS). Regarding to the characterization in terms of size was accessed using a transmission electron microscope (TEM), the agglomeration potential and surface charge were accessed by diameter light scattering (DLS) and zeta potential measurements, respectively, using a spectrophotometer. TiO2-NP in environmentally relevant concentrations were tested for cytotoxicity, genotoxicity and mutagenicity. Cell viability was accessed by four different tests, the trypan blue assay (membrane integrity), MTT reduction assay (mitochondria), neutral red retention assay (lysosomes) and finally, induction of apoptosis and necrosis. Genotoxicity was determined by observing the fragmentation of DNA by the comet assay, while mutagenicity was determined by Cytokinesis-block micronucleus technique. The characterization showed that the FBS was effective in dispersing the nanoparticles and prevent the formation of large agglomerates allowing robust responses on the real toxicity of NP. After 24 hours of treatment, there was cell membranes rupture, decreasing cell viability to 35.33%, at the highest concentration (1.0 μg mL-1). Mitochondrial metabolic activity remained unchanged, but it was possible to detect the proliferation of lysosomes, which was mainly attributed to the NP endocytosis. The induction of apoptosis was 50.4%, and necrosis was 13.9%, both in the concentration 1.0 μg mL-1 TiO2-NP. In the case of necrosis, a result 10 times greater than that presented by the negative control. Added necrosis and apoptosis indicated a decrease in cell viability to 35.7%. The comet test showed the fragmentation of the DNA, it was also possible to observe the formation of micronuclei, bridges and shoots demonstrated by the micronucleus assay. In general, this study demonstrated that TiO2-NP, after 24 hours of exposure, significantly affect cell viability and cause DNA damage, which may become irreversible. In conclusion, this study showed the cytotoxic, genotoxic and mutagenic potential of TiO2-NP for ZF-L cells. Mitochondrial and lysosome responses require further studies on the effect of TiO2-NP on these organelles.
O uso de jogos e a mediação do professor na abordagem histórico-cultural : primeiras aproximações
(Universidade Federal de São Carlos, 2016-10-27) Pereira, Patrícia; Faria, Paulo Cezar de; https://lattes.cnpq.br/3630521378837174; https://lattes.cnpq.br/5172215720465911
The present study had as reference the Teaching Activity and Being Learning Situation aimed at internalizing of theoretical knowledge through the action and reflection (both the kids and the researcher) in the search for the solution of problem situations, with the intention to give children the need of appropriation of concepts, worrying about the "Genesis of the concept" (MOURA et al., 2010). The investigative procedure type taken as reference using a Teaching Guiding Activity (TGA) through Being Learning Situations (BLS). It sought to check if the game when used under the historical-cultural approach, triggers learning some own concepts to addition and subtraction operations. It to do so was considered the games CUBRA A SOMA and FECHE A CAIXA. The study consisted of five Teaching Activities with each game, totaling ten activities, during the months of October to December, in the year 2015, in a State school located in the city of São Carlos, in the State of São Paulo. The eight children were selected by the teacher of the class, four considered with more skills in calculus and four considered with less skills in calculus. The procedures included: a) request for authorization of School Unit for realization of this study; b) submission of the study to the Ethics Committee; c) filling a questionnaire for parents/guardians of the eight participating students of this study and the informed consent; d) use of the game CUBRA A SOMA, as activities for the appropriation of addition; e) using the FECHE A CAIXA how activities for the appropriation of addition and subtraction; f) resolution of problem situations involving addition and subtraction; g) footage of children in 10 classes in which were developed the teaching activities and some audio recordings; g) analysis and discuss of data obtained with the footage and audio recordings with the assumption the concepts of cultural-historical approach, the question of study and objectives. The results indicated that the mediations, associated with the motivation of children, during the Teaching Activity can provide the development. Whereas that the children do not generalize and do not internalize the concepts same way, though to be mediated by the same person (the researcher), we found that the knowledge related to the concepts of addition and subtraction were appropriate at different levels.
Ferramenta de apoio ao manejo de águas pluviais urbanas com base em indicadores de sustentabilidade - SAMSAP
(Universidade Federal de São Carlos, 2016-10-27) Silva, Sidnei Pereira da; Teixeira, Bernardo Arantes do Nascimento; https://lattes.cnpq.br/1166854416745527; https://lattes.cnpq.br/1773693912238195
Many municipalities have problems with the drainage system and the excess rainwater in certain periods of the year. The management of cities should take into account the sustainability and for this, the indicators are important tools in helping to making the use and land use decision and thus avoid risk situations related to urban water. The sustainability principles guided the development of this research for this, were developed 13 sustainability principles specific to the management of stormwater based on general principles in the literature. After surveying the literature of sustainability indicators, they were found 102 indicators and of those, 65 that could be used in the management of rainwater, one of the indicators selection criteria was the correlation with the specific principles and other direct relationship with problem. Then we sought in the literature, the problems faced by the government and the people related to rainwater, were 47 major found this total, 19 were considered direct problems and the remaining effects caused by these problems. These 19 problems were divided into five dimensions of sustainability: environmental, social, economic, political, cultural and technological or management. For each problem have been assigned their respective indicators, a total of 54, leaving at least 2 indicators of the problem. Using multi-criteria method, priority indicators were selected, that is, those that would be most suitable for the monitoring of problems, however, in the absence of information available to these priority indicators can be used side indicators. These indicators served for the preparation of SAMSAP tool - Support System for Water Management Stormwater, which will serve for the development of scenarios for monitoring and decision making of managers and responsible for the management of rainwater.