Lec��ons sur les applications du calcul infinite��simal a�� la ge��ometrie,

Mode of access: Internet.

La religion des Gaulois : les Druides et la druidisme : lec��ons professe��es a�� l'E��cole du Louvre en 1896 /

Includes bibliographical references.

S��ntese e caracteriza����o de compostos de coordena����o do ��cido 4-cloro-2-(2- furilmetilamino)-5- sulfamoil-benz��ico com os ��ons n��quel, cobalto e zinco

This work aimed to promote the synthesis, characterization and propose a plausible molecular structure for coordination compounds involving furosemide (4-Chloro-2-(2- furylmethylamino)-5-sulfamoyl-benzoic acid) with the metal ions Ni+2, Zn+2 and Co+2. The compounds were obtained in methanoic medium by evaporation of the solvent after the synthesis procedure. For characterization of coordination compounds determining the levels of metals by EDTA complexometry, infrared spectroscopy (FTIR), solubility of compounds in various solvents, thermogravimetry (TG), differential scanning calorimetry (DSC), differential thermal analysis were made (DTA), determination of the carbon , hydrogen and nitrogen (CHN). The results of infrared spectroscopy in the region suggest that the organic ligand is coordinated in a bidentate fashion to the metal ions, the metal center interactions to occur by the coordination of the nitrogen atom of the amino group and the oxygen atom of the carboxylic acid of the structure of furosemide. With the results of the levels of metal, elemental analysis (CHN) and thermal analysis has been possible to propose the structure of the ligand. The values of the molar conductivity of the complex in acetonitrile behavior suggest the non acetonitrile electrolyte solution. With the solubility tests it was found that the compounds have high solubility in methanol and acetonitrile, as are partially insoluble in water. From the results of thermal analysis (TG, DSC, DTA), it was possible to obtain the thermal behavior of the compounds as stages of dehydration, thermal stability, decomposition and the energies involved.

S��ntese, estrutura e propriedades de pol��meros de coordena����o �� base de ��ons lantan��deos e ��cidos benzenodicarbox��licos

Metal Organic Frameworks (MOFs) are hybrids materials, often crystalline, consisting of metal or metal clusters, connected by polytopic organic ligands repetitively, leading to structures, usually porous. In this work, MOFs based on lanthanide ions (La3+ and Gd3+) and dicarboxylate type of ligands (isophthalic and terephthalic acids), were synthesized by hydrothermal, solvothermal and hydro(solvo)thermal methods. The effects of the synthetic route as well as the type of heating, conventional or by microwave, on the structure and properties of MOFs were studied. The powder samples obtained were characterized by X-ray diffraction, infrared spectroscopy, thermal analysis and scanning electron microscopy. The results suggest that the addition of an organic or inorganic base is needed to promote the deprotonation of the ligand, since in the samples prepared by the hydrothermal method, without the use of a base, no formation of the metalorganic framework was observed. On the other hand, the presence of DMF as solvent or cosolvent, afforded the deprotonation of the ligand with the consequent formation of MOFs. At least two different crystalline structures were identified for the samples prepared with terephthalic acid. These samples are isostructural with those reported for phases Eu(1,3-BDC)DMF, Eu2(1,4-BDC)3 (DMF)2 and Tb(1,4-BDC)H2O. The presence of water in the reaction medium in the hydro(solvo)thermal method, provoked the growth of the structure different from that observed in the absence of water. This can be explained by the difference in the coordination mode of water and DMF to lanthanide ions. Although not identified by XRD, the samples prepared with isophthalic acid, also present metalorganic structures, which was confirmed by the presence of the characteristic displacement of the carbonyl group band in their infrared spectra, compared to the spectrum of the pure ligand. This shift was also observed in the samples prepared with terephthalic acid. Thermal analisys shows that the metal organic frameworks do not collapse occurs at a temperature below 430��C.The analysis of scanning electron microscopy suggests that the morphology of powders is highly dependent on the type of heating used, conventional or by microwave.

Investiga����o da rota biohidrometal��rgica com Acidithiobacillus ferrooxidans/thiooxidans para recupera����o do cobalto de baterias de ��ons l��tio descartadas

The recycling of metals from secondary sources can be advantageous. Among the metals of interest, we have cobalt, a metal used for various purposes. As regards the secondary sources of cobalt, the lithium-ion batteries can be considered, since they contain cobalt oxide in their composition (LiCoO2). This way, the objective of this work was to use the microorganism strains (Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans) to bioleach the LiCoO2 extracted from discarded lithium ion batteries with emphasis on the recovery of cobalt for synthesis of new materials of interest. The lineage growth occurred in T&K medium and the growth investigation was made by observing the media, by platelet growth and microscope analysis. Then, the inoculum was standardized on 5 x 106 cells mL-1 and used in bioleaching tests. The bioleaching was investigated: the microorganism nature: separate strains and A. ferrooxidans and A. thiooxidans consortium, bioleaching time (0 to 40 days), inoculum proportion (5 to 50% v/v), energy source (iron and sulfur) and residue concentration (1063 to 8500 mg L-1 of cobalt). The cobalt concentration in the media was found by atomic absorption spectrometry and the medium pH was monitored during the bioleaching. The results show that the amount of bioleached cobalt increases with time and the iron concentration. The bioleaching with A. thiooxidans was not influenced by the addition of sulfur. The use of the two lineages together did not improve the bioleaching rates. Among the lineages, the A. thiooxidans presented better results and was able to bioleach cobalt amounts above 50% in most of the experiments. A. thiooxidans presented lower bioleaching rates, with a maximum of 50% after 24 days of experiment. After reprocessing by bioleaching, the cobalt in solution was used for synthesis of new materials: such as LiCoO2 cathode and as adsorbent pesticide double lamellar hydroxide (HDL Co-Al-Cl) by the Pechini and co-precipitation methods. The reprocessed LiCoO2 presented a unique stoichiometric phase relative to the HT-LiCoO2 structure similar to the JCPDS 44-0145, presenting electrochemical activity when tested as a cathode material. The double lamellar hydroxide Co-Al-Cl was tested as pesticide adsorbent, being possible to adsorb around 100% of the pesticide. The bioleaching was efficient in the recovery of cobalt present in lithium-ion batteries and microorganisms presented high tolerance to the residue, being able to bioleach even at higher LiCoO2 concentrations. The cobalt bioleaching medium did not impair the synthesis phases and the obtained materials presented structure and activity similar to the sintered materials from the reagents containing cobalt.

Utiliza����o de quitosana obtida de res��duos de camar��o para avaliar a capacidade de adsor����o de ��ons Fe3+

A quitosana �� produzida atrav��s de uma desacetila����o alcalina da quitina, a qual �� encontrada em exoesqueleto de crust��ceos, parede celular de fungos e materiais biol��gicos. Calcula-se que os res��duos de camar��o apresentam de 5 a 7% do seu peso total na forma de quitina, sugerindo que estes sejam utilizados para obten����o do biopol��mero. Os processos para obten����o destes biopol��meros consiste nas seguintes etapas: desmineraliza����o, desproteiniza����o e desodoriza����o, obtendo-se assim, a quitina ��mida. Ap��s seca, passa por uma desacetila����o qu��mica para a convers��o em quitosana ��mida, sendo purificada e posteriormente seca. A quitosana, por apresentar grupamentos amino livres em sua estrutura, �� uma mol��cula capaz de formar complexos est��veis com c��tions met��licos. O objetivo geral deste trabalho foi obter quitina a partir de res��duos de camar��o (Penaeus brasiliensis) com posterior produ����o de quitosana, e avaliar sua capacidade de complexa����o com ��ons Fe3+, em solu����o. A quitosana produzida foi caracterizada atrav��s do grau de desacetilia����o e da massa molecular viscosim��trica, Para caracteriza����o estrutural das amostras de quitosana, utilizaram-se espectrometria de infravermelho e espectrofotometria UV-Vis��vel, bem como para o complexo formado de quitosana e ferro. Para analisar a efici��ncia da remo����o deste ��on, foram feitas an��lises em espectrometria de absor����o at��mica em chama e em espectrofotometria UV-Vis��vel. Uma an��lise estat��stica foi realizada para avaliar a percentagem de remo����o do ��on ferro das solu����es, sendo utilizado um planejamento fatorial em dois n��veis, tendo como vari��veis independentes o pH do meio, a quantidade de quitosana adicionada, a granulometria da mesma e o tempo de rea����o. A quitosana apresentou grau de desacetila����o de 87��2% e massa molecular viscosim��trica de 196��4kDa, sendo esses valores, compar��veis �� quitosana dispon��vel comercialmente. Na melhor regi��o de trabalho definida pela an��lise estat��stica, obteve-se uma remo����o m��xima de 85 % do ��on ferro das solu����es.

Estudo da adsor����o de ��ons met��licos em caulinita para ��gua de reuso

Disserta����o (Mestrado em Tecnologia Nuclear)

Determina����o de res��duos de glifosato em plantas de soja utilizando cromatografia de ��ons.

O glifosato (N-(fosfonometil) glicina, C3H8NO5P) �� um herbicida sist��mico n��o seletivo (mata qualquer tipo de planta) desenvolvido para matar ervas, principalmente as perenes. �� amplamente empregado na cultura de soja transg��nica, a qual �� resistente ao glifosato e cujas sementes s��o comercializadas pela Monsanto. A determina����o de res��duos de glifosato em amostras ambientais, plantas e alimentos normalmente �� realizada por meio de cromatografia l��quida de alta efici��ncia com detec����o por fluoresc��ncia e rea����o p��s coluna. Este m��todo vem sendo utilizado rotineiramente no Laborat��rio de Res��duos e Contaminantes da Embrapa Meio Ambiente (LRC). Entretanto o mesmo �� muito trabalhoso e consome grandes quantidades de reagentes. Assim neste trabalho est�� sendo apresentado um m��todo cromatogr��fico alternativo, por cromatografia de ��ons, o qual possui as vantagens de ser mais simples e r��pido que o m��todo convencional.

Calibra����o da Reflectometria no Dom��nio do Tempo (TDR) para a estimativa da concentra����o da solu����o no solo

Time Domain Reflectometry (TDR) is a reliable method for in-situ measurements of the humidity and the solution concentration at the same soil volume. Accurate interpretation of electrical conductivity (and soil humidity) measurements may require a specific calibration curve. The primary goal of this work was to establish a calibration procedure for using TDR to estimate potassium nitrate concentrations (KNO3) in soil solution. An equation relating the electrical conductivity measured by TDR and KNO3 concentration was established enabling the use of TDR technique to estimate soil water content and nitrate concentration for efficient fertigation management.

Efeito cariost��tico de restaura����es adesivas em superf��cies radiculares: estudo in vitro

Dental materials that release fluoride have been shown to be effective in caries inhibition around restorations. Adhesive materials would also be effective in caries inhibition by sealing and protecting cavity margins from acidic demineralization. This in vitro study tested the hypothesis that composite restorations with a dentin adhesive system have a caries preventive effect similar to that of an adhesive material with fluoride - glass-ionomer cement - on root surfaces. Twenty roots from extracted sound third molars were embedded in polystyrene resin and ground flat. Standardized cavities were prepared in leveled root surfaces and randomly restored with (a) Chelon-Fil (Espe) or (b) Z100/SingleBond (3M). Baseline indentations were measured at 100, 200 and 300 mum from the occlusal margins of each restoration and the surface microhardness values were obtained using a Knoop diamond indenter. A 2.0 mm wide margin around the restorations was submitted to a pH-cycling model, at 37��C. After that, surface microhardness was measured again, as it was before. The differences between baseline and final surface microhardness were considered for statistical analysis. The median values of differences were (a): -3.8; -0.3; -1.0; and (b): 3.3; 2.5; 1.7, for the distances of 100, 200 and 300 mum, respectively. The Kruskal-Wallis test did not show statistically significant difference between 100, 200 and 300 mum distances in each tested group. There was no difference between the studied materials at the distances of 200 and 300 mum. Chelon-Fil was statistically different from Z100/SingleBond, at 100 mum (p<0.05). Under the studied conditions, the glass-ionomer cement had a higher caries preventive effect than the composite/dentin adhesive restorations.

Dentin permeability of the apical third in different groups of teeth

This ex vivo study evaluated dentin permeability of the root canal in the apical third of different human groups of teeth. Eighty teeth were used, 8 from each dental group: maxillary and mandibular central incisors, lateral incisors and canines, maxillary first premolars (buccal and palatal roots), mandibular first premolars, and maxillary and mandibular second premolars, totalizing 88 roots that were distributed in 11 groups. The root canals were instrumented, irrigated with 1% NaOCl and 15% EDTA. Roots were immersed in 10% copper sulfate for 30 min and then in 1% rubeanic acid alcohol solution for the same period; this chemical reaction reveals dentin permeability by the formation of copper rubeanate, which is a dark-colored compound. Semi-serial 100-��m-thick cross-sections were obtained from the apical third of the roots. Five sections of each apical third were washed, dehydrated, cleared and mounted on glass slides for examination under optical microscopy. The percentage of copper ion infiltration and the amount of tubular dentin were quantified by morphometric analysis. The penetration of copper ions in the apical third ranged from 4.60 to 16.66%. The mandibular central and lateral incisors presented the highest dentin permeability (16.66%), while the maxillary canines and mandibular second and first premolars presented the lowest dentin permeability (4.60%, 4.80% and 5.71%, respectively; p<0.001). The other teeth presented intermediate permeability. In conclusion, dye penetration into dentin tubules at the apical region is strongly dependent on the group of teeth evaluated.

Enhanced response of the fricke solution doped with hematoporphyrin under X-rays irradiation

The vials filled with Fricke solutions were doped with increasing concentrations of Photogem��, used in photodynamic therapy. These vials were then irradiated with low-energy X-rays with doses ranging from 5 to 20 Gy. The conventional Fricke solution was also irradiated with the same doses. The concentration of ferric ions for the Fricke and doped-Fricke irradiated solutions were measured in a spectrophotometer at 220 to 340 nm. The results showed that there was an enhancement in the response of the doped-Fricke solution, which was proportional to the concentration of the photosensitizer. The use of such procedure for studying the radiosensitizing property of photosensitizers based on the production of free radicals is also discussed.