Petrologia aplicada da formação Corumbataí (região de Rio Claro - SP) e produtos cerâmicos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Influence of parity on concentrations of enzymes, proteins, and minerals in the milk of cows

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Platinum-Group Minerals in Chromitites of the Niquelandia Layered Intrusion (Central Goias, Brazil): Their Magmatic Origin and Low-Temperature Reworking during Serpentinization and Lateritic Weathering

A variety of platinum-group-minerals (PGM) have been found to occur associated with the chromitite and dunite layers in the Niquelandia igneous complex. Two genetically distinct populations of PGM have been identified corresponding to phases crystallized at high temperatures (primary), and others formed or modified during post-magmatic serpentinization and lateritic weathering (secondary). Primary PGM have been found in moderately serpentinized chromitite and dunite, usually included in fresh chromite grains or partially oxidized interstitial sulfides. Due to topographically controlled lateritic weathering, the silicate rocks are totally transformed to a smectite-kaolinite-garnierite-amorphous silica assemblage, while the chromite is changed into a massive aggregate of a spinel phase having low-Mg and a low Fe3+/Fe2+ ratio, intimately associated with Ti-minerals, amorphous Fe-hydroxides, goethite, hematite and magnetite. The PGM in part survive alteration, and in part are corroded as a result of deep chemical weathering. Laurite is altered to Ru-oxides or re-crystallizes together with secondary Mg-ilmenite. Other PGM, especially the Pt-Fe alloys, re-precipitate within the altered chromite together with kaolinite and Fe-hydroxides. Textural evidence suggests that re-deposition of secondary PGM took place during chromite alteration, controlled by variation of the redox conditions on a microscopic scale.

Caracterização hidroquímica dos sistemas aquíferos Serra Geral e Guarani da sub-bacia do Rio Pardo e municípios adjacentes, no sudoeste do estado de São Paulo

The main purpose of this work is to evaluate the chemical composition of the groundwaters from Guarani Aquifer System and Serra Geral Aquifer System in the Rio Pardo basin, located at the southwestern of São Paulo state. To the hydrochemical characterization, physicalchemical analyses from 32 sampled wells were used. These results were plotted in Piper diagrams allowing the classification of groundwater as calcium or calcium-magnesium bicarbonate type and sodium bicarbonate type for both aquifer systems. Distribution of hydrochemical facies over the study area was obtained using Stiff diagrams. The groundwater can be classified, representing in this sequence its hydrochemical evolution. The recognized mechanisms responsible for groundwater evolution are dissolution of minerals magnesium, such as olivine, present in the basalt, dissolution of feldspars and removal of the carbonate cement of the sandstones mineral framework. Ionic exchange may represent an important processes in the groundwater evolution, responsible for the increase in the sodium concentration and decrease of calcium

Preventive effect of a high fluoride toothpaste and arginine-carbonate toothpaste on dentinal tubules exposure followed by acid challenge: a dentine permeability evaluation

Coordenação de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)

Effect of organic sources of minerals on fat-corrected milk yield of dairy cows in confinement

This study evaluated the effects of organic and inorganic sources of minerals in diets for mid-lactation dairy cows on milk yield and composition, intake and total apparent digestibility of dry matter and nutrients, blood parameters, microbial protein synthesis, and energy and protein balances. Twenty Holstein cows averaging 146.83 +/- 67.34 days in milk and weighing 625.30 +/- 80.37 kg were used. The experimental design was a crossover. Diets were composed of corn silage (50%), ground grain corn, and soybean meal, differing with regard to the sources of trace minerals, plus an organic and inorganic mix. The organic mineral source increased milk fat and fat-corrected milk yield without changing milk yield, intake, or total apparent digestibility. Blood parameters, microbial protein synthesis, and energy and protein balances were not affected by the sources of minerals. Organic sources of minerals improve milk fat yield without affecting other parameters.

The ultra-sonication of minerals in swine feed

A sample preparation method based on ultrasound assisted-extraction (UAE) of Ca, Mg and P from swine feed has been described. The experiment was performed to cover the variables influencing the sonication process and, the method validation using standard reference material. Final solutions obtained upon sonication were analyzed by flame atomic absorption spectrometry (for Ca and Mg) and by UV-vis spectrophotometry (for P). The best conditions for metal extraction were as follows: sample mass: 100 mg in 20 mL 0.10 mol/L HCl, a particle size: <60 μm, sonication time: 5 cycles of 10 s and ultrasound power: 102 W. The UAE method was applied in digestibility assays in different piglet feeds and their results showed that it is highly comparable (P > 0.05) to the other methods used for such purposes, as block digestion, and offered a Ca, Mg and P method of quantification limit of 10.6, 12.4 and 14 mg/kg, respectively. The major advantages of the UAE method compared to other methods are the high treatment rate, low reagent usage in the extracts and, it does not generate toxic residues that might negatively affect human health and the environment, accompanied by good precision and accuracy.