Determination of oligoelements in parenteral formulations by planar chromatography and spectrophotometry

The authors have studied the chromatographic behavior of parenteral preparations for pediatric use containing inorganic cations. After separation and identification by thin-layer chromatography, Mn2+, Zn2+, and Cu2+ were analyzed by a method based on reaction with an appropriate reagent and extraction with an organic solvent which yielded elution and preconcentration, resulting in an appropriate solution for colorimetric quantitation. Cr3+ cation was determined by atomic absorption spectrophotometry after appropriate chromatographic separation, using microcrystalline cellulose (adsorbent) and an acetone:water:hydrochloric acid mixture (80:5:8) as the mobile phase.

Cross linked Poly (4-Vinylpyridine-Ethylene Glycol Dimethacrylate) Used for Preconcentration of Cd(II) and its Determination by Flow Injection Flame Atomic Absorption Spectrometry

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Organic and inorganic sources of zinc, copper and selenium in diets for dairy cows: intake, blood metabolic profile, milk yield and composition

The present study was carried out with the objective of evaluating the effects of feeding dairy cows with organic or inorganic sources of zinc (Zn), copper (Cu) and selenium (Se) on blood concentrations of these minerals, blood metabolic profiles, nutrient intake and milk yield and composition. Nineteen Holstein cows were selected and randomly assigned to two groups for receiving organic (n = 9) or inorganic (n = 10) sources of Zn, Cu and Se from 60 days before the expected date of calving to 80 days of lactation. Samples of feed, orts and milk were collected for analysis. Body condition score (BCS) was determined and blood samples were collected for analysis of Zn, Cu and Se concentrations, as well as for metabolic profile. Supplying organic or inorganic sources of Zn, Cu, and Se did not affect dry matter and nutrient intake, blood metabolic profile, milk yield and composition, plasma concentration of these minerals, and BCS or change the BCS in cows from 60 days before the expected date of calving to 80 days of lactation. An effect of time was observed on all feed intake variables, plasma concentrations of Zn and Se, milk yield, milk protein content, BCS and change in BCS.

Inorganic pyrophosphate-phosphohydrolytic activity associated with rat osseous plate alkaline phosphatase

Purified membrane-bound alkaline phosphatase from rat osseous plate hydrolyzed pyrophosphate in the presence of magnesium ions, with a specific activity of 92.7 U/mg. Optimal apparent pH for pyrophosphatase activity was 8.0 and it remained unchanged on increasing the pyrophosphate concentration. In the absence of magnesium ions the enzyme had a K-m = 88 mu M and V = 36.7 U/mg for pyrophosphate and no inhibition by excess substrate was observed. Pyrophosphatase activity was rapidly destroyed at temperatures above 40 degrees C, but magnesium ions apparently protected the enzyme against danaturation. Sodium metavanadate (Ki = 1.0 mM) was a competitive inhibitor of pyrophosphatase activity, while levamisole (Ki = 8.2 mM) and theophylline (Ki = 7.4 mM) were uncompetitive inhibitors. Magnesium ions (K-0.5 = 1.7 mu M) stimulated pyrophosphatase activity, while cobalt (Ki = 48.5 mu M) and zinc (Ki = 22.0 mu M) ions were non-competitive inhibitors. Manganese and calcium ions had no effect on pyrophosphatase activity. The M-w of the pyrophosphatase: protein was 130 kDa by gel filtration, but a value of 65 kDa was obtained by dissociative gel electrophoresis, suggesting that it was a dimer of apparently identical subunits. These results suggested that pyrophosphatase activity stems from the membrane-bound osseous plate alkaline phosphatase and not from a different protein.

Exchangeable basic cations and nitrogen distribution in soil as affected by crop residues and nitrogen

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

Ruthenium(II) phosphine/diimine/picolinate complexes: Inorganic compounds as agents against tuberculosis

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

DFT study of the water-assisted tautomerization process between hydrated oxide, MO(H2O)(+), and dihydroxide, M(OH)(2)(+) cations (M = V, Nb and Ta)

Density functional theory (DFT) calculations point out that the participation of water can effectively lower the barrier height for the isomerization process between hydrated oxide cation, MO(H2O)(+), and dihydroxide cation, M(OH)(2)(+), (M = V, Nb and Ta). The catalytic effect is achieved by a water-assisted mechanism in which water acts as proton donor and acceptor, via a transition structure corresponding to a six-membered ring. In the case of vanadium atom, the presence of two water molecules has been taken into account and the tautomerization becomes nearly barrierless, decreasing both the stability of the transition structures relative to intermediates and the depths of wells associated with the intermediates. (C) 2003 Elsevier B.V. All rights reserved.

Synthesis and thermal studies of solid state 2-chloro-benzylidenepyruvic acid and its compounds with sodium, aluminium (III), gallium (III) and indium (III) cations

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

Bacterial cellulose-silica organic-inorganic hybrids

Bacterial cellulose (BC) hydrated membranes present nanometric reticulated structure that can be used as a template in the preparation of new organic-inorganic hybrids. BC-silica hybrids were prepared from BC membranes and tetraethoxysilane, (TEOS) at neutral pH conditions at room temperature. Macroscopically homogeneous membranes were obtained containing up to 66 wt.% of silica spheres, 20-30 nm diameter. Scanning electron micrographs clearly show the silica spheres attached to cellulose microfibrils. By removing the cellulose, the silica spheres can be easily recovered. The new hybrids are stable up to 300 degrees C and display a broad emission band under UV excitation assigned to oxygen-related defects at the silica particles surface. Emission color can be tuned by changing the excitation wavelength.

The volumetric fraction of inorganic particles and the flexural strength of composites for posterior teeth

Objective. To evaluate the content of inorganic particles and the flexural strength of new condensable composites for posterior teeth in comparison to hybrid conventional composites.Method. The determination of the content of inorganic particles was performed by mass weighing of a polymerized composite before and after the elimination of the organic phase. The volumetric particle content was determined by a practical method based on Archimedes' principle, which calculates the volume of the composite and their particles by differential mass measured in the air and in water. The flexural. strength of three points was evaluated according to the norm ISO 4049:1988.Results. The results showed the following filter content: Alert, 67.26%; Z-100, 65.27%; Filtek P 60, 62.34%; Ariston pHc, 64.07%; Tetric Ceram, 57.22%; Definite, 54.42%; Solitaire, 47.76%. In the flexural strength test, the materials presented the following decreasing order of resistance: Filtek P 60 (170.02 MPa) > Z-100 (151.34 MPa) > Tetric Ceram (126.14 MPa) = Alert (124.89 MPa) > Ariston pHc (102.00 MPa) = Definite (93.63 MPa) > Solitaire (56.71 MPa).Conclusion. New condensable composites for posterior teeth present a concentration of inorganic particles similar to those of hybrid composites but do not necessarily present higher flexural strength. (C) 2003 Elsevier B.V. Ltd. Alt rights reserved.

A systematic study of transfection efficiency and cytotoxicity in HeLa cells using iron oxide nanoparticles prepared with organic and inorganic bases

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

Electrical conductivity of silicate glasses with tetravalent cations substituting Si

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

Weathering rates at Alto Sorocaba basin, Brazil, using U-isotopes and major cations

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

A homovalent doping in PMN ceramics by using lithium and scandium cations

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

Effects of organic and inorganic additives on flotation recovery of washed cells of Saccharomyces cerevisiae resuspended in water

Separation of microbial cells by flotation recovery is usually carried out in industrial reactors or wastewater treatment systems, which contain a complex mixture of microbial nutrients and excretion products. In the present study, the separation of yeast cells by flotation recovery was carried out using a simple flotation recovery systems containing washed yeast cells resuspended in water in order to elucidate the effects of additives (defined amounts of organic and inorganic acids, ethanol, surfactants and sodium chloride) on the cellular interactions at interfaces (cell/aqueous phase and cell/air bubble). When sodium chloride, organic acids (notably propionic, succinic and acetic acids) and organic surfactants (sodium dodecyl sulphate (SDS), cetyltrimethylammonium bromide (CTAB) and Nonidet P40) were added to the flotation recovery system, significant increases in the cell recovery of yeast hydrophobic cells (Saccharomyces cerevisiae, strain FLT-01) were observed. The association of ethanol to acetic acid solution (a minor by-product of alcoholic fermentation) in the flotation recovery system, containing washed cells of strain FLT-01 resuspended in water, leading to an increased flotation recovery at pH 5.5. Thus, the association among products of the cellular metabolism (e.g., ethanol and acetic acid) can improve yeast cell recovery by flotation recovery. (c) 2006 Elsevier B.V. All rights reserved.