EXAFS of the superconducting oxide BaPb1−xBixO3

The two-valence state Bi³⁺ and Bi⁵⁺ of Bi in the semiconductor BaBiO₃ and in the BaPb_1?xBi_xO₃ (x = 0, 0.25, 0.6 and 1) system has been determined from the EXAFS spectra above the L_III-edges of Ba, Pb and Bi. Peaks in the radial distribution function up to 5 Å from the absorber have been identified through a model calculation using theoretical amplitudes and phase shifts and the interatomic distances from neutron diffraction measurements. We found indication of local disorder in the Pb-Bi sublattice for the mixed compound.     

Selective high-performance liquid chromatographic method for the determination of glycyrrhizin and glycyrrhetic acid-3-O-glucuronide in biological fluids: application of ion-pair extraction and fluorescence labelling agent

A selective high-performance liquid chromatographic method has been developed for the simultaneous determination of glycyrrhizin and glycyrrhetic acid-3-O-glucuronide in biological fluids of the rat. The procedure is based on the ion-pair formation using tetra-n-amylammonium bromide, extraction with ethyl acetate-n-heptane from the salt-saturated aqueous phase, labelling with 4-bromomethyl-7-methoxycoumarin, followed by chromatographic separation with fluorescence detection. Glycyrrhizin in plasma, bile and urine could be precisely determined in concentrations as low as 1, 1 and 2.5 micrograms/ml, respectively, in a 0.1-ml sample. The equivalent values for the glucuronide were 1, 2.5 and 2.5 micrograms/ml, respectively. The method is applicable in pharmacokinetic studies of glycyrrhizin in small animals.     

Recent progress in the development of derivatization reagents having a benzofurazan structure

Chemical derivatization is often used to enhance the detectability of the target compounds and to improve the separation efficiency in high-performance liquid chromatography (HPLC). In this review, we describe the recent progress in the development of derivatization reagents having a benzofurazan structure, namely, the fluorogenic reagents, water-soluble reagents, reagents for the analysis of peptides and proteins, and reagents for mass spectrometric detection. The application of these reagents to bio-samples is also briefly described.     

Synthesis of 4-[2-(N,N-dimethylamino)ethylaminosulfonyl]-7-N-methylhydrazino-2,1,3-benzoxadiazole (DAABD-MHz) as a derivatization reagent for aldehydes in liquid chromatography/electrospray ionization-tandem mass spectrometry

Benzofurazan derivatization reagent, 4-[2-(N,N-dimethylamino)ethylaminosulfonyl]-7-N-methylhydrazino-2,1,3-benzoxadiazole (DAABD-MHz), for aldehydes in liquid chromatography/electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS), was synthesized. DAABD-MHz reacted with aliphatic aldehydes under mild conditions. The generated derivatives were separated on a reversed-phase column and detected by ESI-MS/MS with detection limits of 30-60 fmol on-column. Upon collision-induced dissociation, a single and intense fragment ion at m/z 151 was observed. These results suggested that DAABD-MHz was suitable as a derivatization reagent in LC/ESI-MS/MS.     

Study of variables for optimization of the dye indosol adsorption process using red mud and clay as adsorbents

The effluents from the textile industry, which not properly treated or discharged directly into water bodies, are a serious environmental problem. In order to find options to solve this problem, in this study, it was evaluate two alternative adsorbents: red mud and smectite clay, to remove the dye Indosol dark-blue SF-BL SGR 240. Assays were performed in batch using the experimental design to optimize the process and evaluate the influence of pH, mass and agitation speed on the adsorption capacity of dye by each material. The results showed that the adsorption process was influenced by the amount of mass of the adsorbent, by the pH and the by interaction between pH and mass, thereby obtaining a removal of approximately 0.110 and 0.119 mg g^?1 with red mud and smectite clay respectively.     

DC(13)PC bilayers from anomalous swelling to main transition: an X-ray scattering investigation

We have performed small-angle (SAXS) and wide-angle X-ray scattering (WAXS) measurements on the lamellar phase and on large unilamellar vesicles (LUVs) of DC(13)PC in the temperature range corresponding to the anomalous swelling regime of multibilayer systems, adjacent to the chain melting transition, and across the transition. Our SAXS measurements indicate that on cooling from the L(alpha) phase, a uniform progressive swelling of the lamellar system to anomalous distances, starting approximately 2 degrees C above the main transition, is followed by a region of coexistence, covering the width of the transition ( approximately 0.6 degrees C). Across the transition region, a progressively increasing volume fraction of gel phase with a constant P (beta') interlamellar distance coexists with a decreasing amount of nongel phase that keeps on swelling to longer distances. Along both the swelling and the transition regions, anomalies in the specific heat are observed revealing a two-step process. Simultaneous WAXS experiments show a progressive "density" increase along the swelling region, constituting a direct spectroscopic evidence of an "evolving membrane" approaching the transition in a bulk real system. Calorimetric and densitometric measurements on LUVs are also presented, together with WAXS results, that show the existence of a double step main transition in a single component nanosized closed bilayer.     

A White Grape Juice Extract Reduces Fat Accumulation through the Modulation of Ghrelin and Leptin Expression in an In Vivo Model of Overfed Zebrafish

A caloric surplus and a sedentary lifestyle are undoubtedly known to be the leading causes of obesity. Natural products represent valuable allies to face this problematic issue. This study was planned to assess the effect of a white grape (Vitis vinifera) juice extract (WGJe) in diet-induced obese zebrafish (Danio rerio). Fish were divided into four different diet groups: (i) normally fed (NF); (ii) overfed (OF); (iii) WGJe-supplemented NF (5 mL/L in fish water); (iv) WGJe-supplemented OF. Body mass index (BMI) was extrapolated each week. After the fourth week, euthanized zebrafish were processed for both microscopic evaluations and gene expression analyses. OF zebrafish showed higher BMI values with respect to NF counterparts, an effect that was hindered by WGJe treatment. Moreover, histological analyses showed that the area of the adipose tissue, as well as the number, size, and density of adipocytes was significantly higher in OF fish. On the other hand, WGJe was able to avoid these outcomes both at the subcutaneous and visceral levels, albeit to different extents. At the gene level, WGJe restored the altered levels of ghrelin and leptin of OF fish both in gut and brain. Overall, our results support the anti-obesity property of WGJe, suggesting its potential role in weight management.     

The chick embryo: an animal model for detection of the effects of hormonal compounds

Hormonal compounds are a class of pharmaceutical product that disrupt the endocrine system of animals and humans. Exposure to these molecules, even at low concentrations, can have severely damaging effects on the environment, to organisms, and to humans. The cumulative presence of these compounds is also characterized by synergistic effects which are difficult to estimate. They are an underestimated danger to the environment and to the human population. This paper presents an in-vivo model enabling to assessment of the real impact of exposure to hormonal compounds and the synergistic effect which can be involved. The anatomical effects of in-ovo exposure to two natural estrogen compounds (estrone and estriol, at 600 ng g(-1)) and a synthetic estrogen (ethynylestradiol, at 20 ng g(-1)) have been investigated. Estrone and estriol lead to morphological defects, mainly in the urogenital system of the developing chick embryo, whereas ethynylestradiol has fewer effects. Estriol caused persistence of Müllerian ducts in 50% of male embryos and hypertrophic oviducts in 71% of females. Estrone had the same effects but at the percentages were lower. Kidney dysfunction was also observed, but only with estrone, in both males and females. We also tested estrogenic compounds in two types of cell line which are estrogen sensitive (BG1 and MCF7) then completed and confirmed our previous in-vivo results. Seven pharmaceutical-like compounds--estrone (E1), estradiol (E2), estriol (E3), ethynylestradiol (EE(2)), carbamazepine (C), genistein (G), and bisphenol-A (BPA)--were tested alone or in mixtures. Different effects on the two cell lines were observed, indicating that endocrine compounds can act differently on this organism. Experiments also showed that these molecules have synergistic action and induce more severe effects when they are in mixtures.