Nanoencapsulation of quercetin and resveratrol into elastic liposomes.

Based on the fact that quercetin (QUE) and resveratrol (RES) induce a synergic inhibition of the adipogenesis and increase apoptosis in adipocytes, and that sodium deoxycholate (SDC) has necrotic effects, the nanoencapsulation of QUE and RES into SDC-elastic liposomes is proposed as a new approach for dissolving the subcutaneous fat. The concentration of constituents and the effect of the drug incorporation into cyclodextrin inclusion complexes on the stability of QUE/RES-loaded liposomes were studied. The best liposomal formulation reduced the use of phosphatidylcholine and cholesterol in 17.

Fermentation medium for collagenase production by Penicillium aurantiogriseum URM4622.

Medium composition and culture conditions for maximal collagenase production by Penicillium aurantiogriseum URM4622 were optimized using a response surface approach. A full two-level design on three factors (initial medium pH, soybean flour concentration, and temperature) was employed to identify the most significant fermentation parameters for collagenase production, and a subsequent central composite design (CCD) was used to find the optimal levels of the two most significant factors (initial medium pH and soybean flour concentration). The design results indicated that the initial medium pH and the temperature had significant negative main effects, whereas the substrate concentration had a positive effect on the collagenase production.

Chitosan effect on dental enamel de-remineralization: an in vitro evaluation.

Objectives: The aim of this work was to evaluate the in vitro effect of chitosan (concentration and time of action) treatment on enamel de-remineralization behavior upon a pH cycling assay.

Methods: Different group of human tooth samples were exposed to de-remineralizing solutions of controlled pH using a random experimental design. Microhardness and phosphorus chemical analysis were employed to evaluate the loss of phosphorus from the samples.

The patterns of base sequences in the nucleic acids of prokaryotes and eukaryotes reflect features of their abiotic past.

The base sequences of the nucleic acids corresponding to ten proteins (aconitase, alcohol dehydrogenase, enolase, fumarase, isocitrate dehydrogenase, lactate dehydrogenase, phosphofructokinase, phosphoglycerate mutase, pyruvate kinase and succinate dehydrogenase) belonging to a total of 154 species, ranging from prokaryotes to vertebrates, were compared with the base sequences of oligoribotides whose growth rates were calculated by a chemical kinetics model. It was shown that oligoribotides grown according to the kinetics model have a fraction of repetitive bases larger than expected from random processes. The base sequences of nucleic acids of prokaryotes and eukaryotes retain, in decreasing proportions, this feature of their abiotic past.

Nutrient and phytoplankton biomass in the Amazon River shelf waters.

The Amazon River estuary is notable at the Amazon Continental Shelf, where the presence of the large amount of water originating from the Amazon during the river's falling discharge period was made evident by the low salinity values and high nutrient levels. Even so, the presence of oceanic waters in the shelf area was significant. Dissolved organic nitrogen was the predominant species of the nitrogen cycle phases, followed by total particulate nitrogen, nitrate, ammonium and nitrite.

Do older taxa have older proteins?

We have confirmed through an enlarged set of 728 species with 10,000 or more compiled codons, and a subset of 237 species with at least 50,000 compiled codons, that the mean values of a previously described index phi [the mean value of the ratio between the relative (G, C) content of Class II and Class I codons, where G and C are guanine and cytosine] decrease monotonically across five large taxa, viz archaea, bacteria, eukaryotes (excluding metazoa), metazoa (excluding vertebrates) and vertebrates. It is proposed that these main taxa diverge successively from an ancestral progenome along lines which have persisted over long periods of time, leading to a primordial non-symmetrical phylogenetic tree. Further divergence, i.

Behaviour of chemical modifiers in the determination of arsenic by electrothermal atomic absorption spectrometry in petroleum products.

Most comparative studies on the efficiency of chemical modifiers have been conducted in aqueous media. In the present work, we proposed a detailed study of the use of different chemical modifiers for direct determination of arsenic in complex organic matrices by electrothermal atomic absorption spectrometry (ETAAS). Palladium, rhodium, tungsten, silver, lanthanum and a mixture of palladium and magnesium were tested.

Removal of proteases from Clostridium perfringens fermented broth by aqueous two-phase systems (PEG/citrate).

In order to reduce the toxicity of Clostridium perfringens fermentation broths used in vaccine preparation, we developed two-phase aqueous systems for removal of toxin-activating proteases. Removal of the proteases inhibits the conversion of protoxin to active toxin. In order to establish the conditions under which the phase separation occurs, binodal curves, formed by poly(ethylene glycol) (PEG) and sodium citrate, were investigated at different values of pH and PEG molar mass.

Statistical designs and response surface techniques for the optimization of chromatographic systems.

This paper describes fundamentals and applications of multivariate statistical techniques for the optimization of chromatographic systems. The surface response methodologies: central composite design, Doehlert matrix and Box-Behnken design are discussed and applications of these techniques for optimization of sample preparation steps (extractions) and determination of experimental conditions for chromatographic separations are presented. The use of mixture design for optimization of mobile phases is also related.

Aqueous two-phase systems extraction of alpha-toxin from Clostridium perfringens type A.

Two sequential half-fraction designs were applied to studying the alpha-toxin partition produced by Clostridium perfringens type A in aqueous two phase systems (ATPS), as a function of four factors: PEG molar mass and concentration, phosphate concentration and pH. The highest purification factor, yield and partition coefficient results were obtained with PEG 8000 (15%, w/w), phosphate at 20% (w/w) and pH 8.0.

Extraction and recovery of chromium from electroplating sludge.

This work reports a study of the extraction and recovery of chromium from the wastes (class I dangerous) generated by a galvanic manufacturer. Commercial HCl at room temperature was employed, and the conditions of the extraction process were optimized according to a sequential experimental design, which also included the acid concentration and contact time as variables. The best extraction conditions (80% v/v; 30 min; 97.

Extractive cultivation of xylanase by Penicillium janthinellum in a poly(ethylene glycol)/cashew-nut tree gum aqueous two-phase system.

Cultivation of the fungus Penicillium janthinellum for xylanase production was studied in a poly(ethylene glycol)/cashew-nut tree gum aqueous two-phase system, using a two-level fractional factorial design. The parameters studied were initial pH, cultivation time, type of agro-industrial residue (oat husk or corn cob), agitation, temperature, and phase-forming polymers. The xylanase produced during fermentation partitioned into the top phase.

Effect of medium components and time of cultivation on chitin production by Mucor circinelloides (Mucor javanicus IFO 4570) -- a factorial study.

Chitin production of mycelia from Mucor circinelloides (Mucor javanicus) was studied with a two-level factorial design in all combinations of the following factors in the culture medium: time of cultivation, concentration of D-glucose, L-asparagine and thiamine. Chitin was characterised by infrared and nuclear magnetic resonance spectroscopy. The four factors showed statistically significant (95%) positive main effects on chitin production, without interactions between them.