Sorption of aspartic and glutamic aminoacids on calcined hydrotalcite

Sorption of aspartic and glutamic aminoacids by regeneration of calcined hydrotalcite is reported. Hydrotalcite was synthesized by coprecipitation and calcined at 773 K. Sorption experiments were performed at 298 K and 310 K, and the results reveal that at low aminoacids equilibrium concentrations, intercalation of hydroxyl anions takes place while at high equilibrium concentrations, the sorption process occur by means re-hydration and aminoacids intercalation of hydrotalcite. The results also suggested that Asp and Glu sorption is a temperature dependent process. The amount of sorbed amino acid decreases as the temperature increase. The effect is more pronounced for Glu sorption probably due to its higher hydrophobic character, which makes the sorption more difficult in comparison with sorption of Asp at higher temperature.The authors thank the Brazilian agencies CAPES and CNPq for financial support

Temperature effect on the sorption of cholate anions on calcined LDH

Layered Double Hydroxides are a class of materials that can be described as positively charged layers of divalent and trivalent cations in the centre of edge-sharing octahedra. Cholesterol derivatives such as cholic acid are substances that play an important role in the digestion of fat components by the organism. This work presents a study on the intercalation of cholate anions in calcined MgAl-CO(3)-HDL. Isotherm experiments were performed at three different temperatures to evaluate the capacity of anion removal by sorption in the calcined LDH. The plateau was reached in all conditions. Increasing temperature results in decreasing cholate sorption. Characteristic peaks of LDH regenerated with OH(-) anions were observed at lower cholate concentrations. A peak in 2 theta equals to 7.5 degrees and peaks between 15 degrees and 20 degrees are observed. Those peaks are the same as the ones observed in the pure sodium cholate PXRD. At higher cholate concentrations the sorbed solids present PXRD related to an additional layered phase, which is related to intercalation of cholate anions with basal spacing equal to 34.3 angstrom. Thus, the cholate anions are also intercalated with a bilayer molecular arrangement at equilibrium concentrations at the isotherms plateau. (C) 2009 Elsevier Ltd. All rights reserved

Percolated non-Newtonian flow for silicone obtained from exfoliated bioinorganic layered double hydroxide intercalated with amino acid

A simple and scalable procedure was used to obtain thin, stable, homogeneous, and easy-to-handle films composed of silicone derived from dimethicones containing dispersed hydrotalcite-type materials previously organo-modified with amino acids. The absence of the typical X-ray pattern of the bioinorganic LDH filler suggested an exfoliation process that was further indirectly evidenced by a drastic change in the rheological behavior, which turned from a quasi-Newtonian behavior for the silicone free of LDH filler to an extensive developed gel-like structure for the nanocomposite derivatives. Visualized by the shear-thinning exponent of the complex viscosity in the low-frequency range, the percolation threshold was evident for filler loading as low as <5 w/W%, suggesting the presence of a largely developed interface between the filler and the polymer. The increase of more than one order of magnitude in viscosity was explained by the rather strong attrition phenomenon between the tethered amino acid anions and the silicone chains. UVB radiation absorption profiles make such bioinorganic polymer nanocomposites potentially applicable in skin protection. Thermo-gravimetric analysis revealed significant improvement in the thermal stability, especially in the final step of the polymer combustion, thus underlining the role of the hybrid material as a thermal retardant agent. (C) 2011 Elsevier B.V. All rights reserved.CAPES/CNPqCAPES/CNPqCOFECUBCOFECU

A natureza e fins das contraordenações fiscais

Mestrado em FiscalidadeDesde os registos mais antigos que os tributos surgem como uma fonte de receita, cujo contributo se destinava à proteção e progressão dos povos. Na Idade Média, os vassalos pagavam altos tributos aos senhores feudais, com o intuito de ver garantida a sua segurança e subsistência em caso de guerra, bem como a possibilidade da progressão do feudo onde todos habitavam. Numa perspetiva pessoal, o atual Estado Português pode ser considerado um Puro Estado Fiscal, dado que se encontra cada vez mais dependente da receita fiscal para garantir a subsistência do seu circuito económico. Deste modo, e tendo em consideração esta dependência, a Autoridade Tributária não deve deixar impune quem, na sua perfeita idoneidade cívica, moral ou profissional, seja incumpridor das suas obrigações para com o Fisco Português, ou ainda quem, por recurso a atos menos lícitos, procure induzir a redução do seu dever contributivo, através do não pagamento dos tributos devidos aos cofres do Estado. Tendo como horizonte de atuação a Constituição da República Portuguesa, todos os cidadãos de um Estado livre, sejam eles contribuintes ou não, dispõem de direitos e deveres. Salienta-se o dever de contribuir, através do pagamento dos respetivos tributos. O incumprimento dos deveres fiscais, previstos nos códigos tributários, originará infrações fiscais que, consoante a sua natureza, e tipologias quantitativas, serão consideradas contraordenacionais ou criminais, estando todos sujeitas a punições diversas: multas, coimas, sanções acessórias ou penas de prisão.Since the begining of the civilazations, taxes always presented a source of revenue intended for the protection and progression of the peoples. In the Middle Ages, the vassals paid taxes to their feudal lords, with the intention that they would guarantee their security and subsistence in case of war, together, with the responsability of the progression of the land where all of them lived. Currently, the Portuguese State, in my opinion, could be considerate, a pure Tax State, given that, it´s increasingly dependent of the Tax Revenue to guarantee the subsistence of it´s economic circuit. In this way, and taking account the financial Fiscal State dependence, the Tax Authority can´t leave unpunished those who, in their perfect suitability, breach their fiscal obligations towards the Portuguese Tax Authority, or who, through recourse to acts less legals, try to induce the reduction of their tax liability, through non-payment of taxes due to the state coffers. Taking into account the Constitution of the Portuguese Republic, all people of a Free State, whether as citizens or taxpayers, have rights and duties, being one of the most important constitutional duty, the contribution through the payment of their taxes. Failure with tax obligations, provided in the tax law codes, should result in tax offenses which, depending of the nature of their acts, and their typologies, will be considered as non-criminal or criminal, being all subject to punishment from fines, ancillary sanctions or even imprisonment.info:eu-repo/semantics/publishedVersio

Adsorption of phenylalanine on layered double hydroxides: effect of temperature and ionic strength

In this work we report the adsorption of phenylalanine (Phe) on Magnesium Aluminum Layered Double Hydroxides (Mg-Al-CO(3)-LDH) at two different temperatures (298 and 310 K) and under two distinct ionic strength conditions (with and without the addition 0.1 M of NaCl). The adsorption isotherms exhibit the same profile in all conditions, and they only differ in the amount of removed Phe. At lower ionic strength, the isotherms are almost identical at both temperatures, except for the last points, where the increase in temperature causes a decrease in the amount of adsorbed Phe. An increase in ionic strength results in a decrease in Phe adsorption. The electrokinetic potential decreases as the amount of adsorbed Phe increases, and only positive values are observed. This indicates that the surface of the adsorbent is not totally neutralized and suggests that more Phe could be removed by adsorption. The presence of Phe on the solid is confirmed by FTIR spectra, which present the specific bands assigned to Phe. The hydrophobicity of the amino acid probably contributes to its extraction, thus enabling the removal of a great amount of Phe. In conclusion, LDH is potentially applicable in the removal of Phe from wastewater

Hyperfine interaction in Zn-Al layered double hydroxides intercalated with conducting polymers

Organic-inorganic hybrid materials based on the assembly between inorganic 2D host structure and polymer have received considerable attention in the last few years. This emerging class of materials presents several applications according to their structural and functional properties. Particularly, among others, layered double hydroxides (LDHs) provide the opportunity of preparing new organically modified 2D nanocomposites. Pyrrole carboxylic acid derivatives, namely 4-(lH-pyrrol-1-yl)benzoate, 3-(pyrrol-i-yl)-propanoate,7-(pyrrol-1-yl)-heptanoate, and aniline carboxylic acid derivative, namely 3-aminobenzoic acid, have been intercalated in LDHs of intralamellar composition Zn2Al(OH)(6). The LDHs were synthesized by the co-precipitation method at constant pH followed by hydrothermal treatment for 72 h. The materials were characterized by powder X-ray diffraction patterns (PXRD), transmission electron microscopy (TEM) thermogravimetric analysis (TGA), and electron spin resonance (ESR). The basal spacing found by the PXRD technique gives evidence of the formation of bilayers of the intercalated anions. ESR spectra present a typical signal with a superhyperfine structure with 6 + 1 lines (g = 2.005 +/- 0.0004), which is assigned to the interaction between a carboxylate radical from the guest molecules and a nearby aluminium nucleus (I = 5/2) from the host structure. Additionally, the ESR data suggest that the monomers are connected to each other in limited number after thermal treatment. (c) 2007 Elsevier Ltd. All rights reserved

New layered double hydroxides intercalated with substituted pyrroles. 1. In situ polymerization of 4-(1H-pyrrol-1-yl)benzoate

The two-dimensional hybrid organic-inorganic materials Zn-2-Cr and Zn-2-Al-LDHs (Layered Double Hydroxides) containing 4-(1H-pyrrol-1yl)benzoate anions as the interlayer anions were synthesized by the co-precipitation method at constant pH followed by subsequent hydrothermal treatment for 72 h. The materials were characterized by PXRD, C-13 CP-MAS NMR, ESR, TGA, and TEM. The basal spacing found by the X-ray diffraction technique is coincident with the formation of bilayers of the intercalated anions. Solid-state C-13 NMR and ESR data strongly suggest the partial in situ polymerization of the 4-(1H-pyrrol-1yl)benzoate anions during coprecipitation. (c) 2006 Elsevier Ltd. All rights reserved

Unusual Incorporation of Neutral and Low Water-Soluble Guest Molecules into Layered Double Hydroxides: The Case of Cucurbit [6 and 7]uril Inclusion Hosts

CNPqCAPESFAPESPCOFECUB through a Brazilian French cooperation[Ph 557/07

Patients With Systemic Sclerosis Present Increased Dna Damage Differentially Associated With Dna Repair Gene Polymorphisms.

Patients with systemic sclerosis (SSc) exhibit increased toxicity when exposed to genotoxic agents. In our study, we evaluated DNA damage and polymorphic sites in 2 DNA repair genes (XRCC1 Arg399Gln and XRCC4 Ile401Thr) in patients with SSc. A total of 177 patients were studied for DNA repair gene polymorphisms. Fifty-six of them were also evaluated for DNA damage in peripheral blood cells using the comet assay. Compared to controls, the patients as a whole or stratified into major clinical variants (limited or diffuse skin involvement), irrespective of the underlying treatment schedule, exhibited increased DNA damage. XRCC1 (rs: 25487) and XRCC4 (rs: 28360135) allele and genotype frequencies observed in patients with SSc were not significantly different from those observed in controls; however, the XRCC1 Arg399Gln allele was associated with increased DNA damage only in healthy controls and the XRCC4 Ile401Thr allele was associated with increased DNA damage in both patients and controls. Further, the XRCC1 Arg399Gln allele was associated with the presence of antinuclear antibody and anticentromere antibody. No association was observed between these DNA repair gene polymorphic sites and clinical features of patients with SSc. These results corroborate the presence of genomic instability in SSc peripheral blood cells, as evaluated by increased DNA damage, and show that polymorphic sites of the XRCC1 and XRCC4 DNA repair genes may differentially influence DNA damage and the development of autoantibodies.41458-6