Leonardo Almeida

The interaction of four phenolic acids, representative of three chemical groups present in human diet, with peroxyl radicals was studied in vitro in a low density lipoprotein (LDL) oxidation model. The controlled oxidation of LDL was initiated by free radicals generated from a hydrophilic azo initiator and followed by monitoring the oxygen consumption and the fluorescence quenching of cis-parinaric acid previously incorporated into LDL. The hydroxycinnamic acid derivatives, chlorogenic and caffeic acids, have high stoichiometric numbers and reactivity with peroxyl radicals as compared with trolox, the water-soluble analogue of vitamin E, whereas ellagic acid (a tannic compound) compares with trolox effects. Protocatechuic acid (a hydroxybenzoic acid derivative) exhibits a complex reaction with peroxyl radicals, as indicated by UV spectroscopy, resulting in undefined inhibition periods of LDL oxidation and low reactivity with peroxyl radicals. Presumably, secondary radicals of these compounds are unable to initiate LDL oxidation. The antioxidant activity of the various phenolic compounds is discussed in terms of structure-activity relationships.

A comprehensive investigation of anhydrous form of 3,4,5-Triacetoxybenzoic acid (TABA) is reported. Single crystal X-ray diffraction, Thermal analysis, Fourier Transform Infrared spectroscopy (FTIR) and DFT calculations were applied for TABA characterization. This anhydrous phase crystallizes in the triclinic [Formula: see text] space group (Z' = 1) and its packing shows a supramolecular motif in a classical [Formula: see text] ring formed by acid-acid groups association. The phase stability is accounted in terms of supramolecular architecture and its thermal behaviour. Conformation search at B3LYP/6-311++G(2d,p) level of theory shows the existence of three stable conformers and the most stable conformation was found experimentally. The reactivity of TABA was investigated using the molecular orbital theory and molecular electrostatic potential. The calculation results were used to simulate the infrared spectrum. There is a good agreement between calculated and experimental IR spectrum, which allowed the assignment of the normal vibrational modes.

We present an astrometric analysis of the triple system LHS 1070. The public data from NIRI/GEMINI, NACO/VLT, and CIAO/SUBARU were used to improve the orbital solutions for the LHS 1070 B/C and LHS 1070 A/BC binaries. Consider-ing LHS 1070 as an hierarchical triple system, the two orbits can be simultaneously fitted and the individual masses of the three components obtained. The best solution gives M A = 0.132 ± 0.016 M , M B = 0.085 ± 0.005 M , and M C = 0.066 ± 0.004 M . Therefore, LHS 1070 is a triple system composed by two low-mass stars and a brown dwarf.

In this work, we present a study regarding the phenomena associated with the stains and eruptions ('∞ares') that happen in the atmosphere of the Sun. Experimental results are obtained with the instruments on board of the satellite SOHO. From the data of the Monitor of Protons of the in- strument CELIAS, we make an analysis of the loaded particles emitted by the Sun which allows to get the speed of propagation of the accelerated particles on '∞ares'. The use of cinematic measures of the speeds stem from the images of the eruptions observed by the instrument LASCO and these measures allow a comparison with the one of the Monitor of Protons. In six events observed by the Monitor of Protons the speeds show a great dispersion, in contrast with those observed by Moni- tor of Protons. Such a fact indicates that the '∞ares' take place in an isolated way so they don't contribute in an efiective way to the global production of the particles detected by the Monitor ...

We present an analysis of eclipse timings of the post-common envelope binary NSVS 14256825, which is composed of an sdOB star and a dM star in a close orbit (P_{orb} = 0.110374 days). High-speed photometry of this system was performed between July, 2010 and August, 2012. Ten new mid-eclipse times were analyzed together with all available eclipse times in the literature. We revisited the (O-C) diagram using a linear ephemeris and verified a clear orbital period variation. On the assumption that these orbital period variations are caused by light travel time effects, the (O-C) diagram can be explained by the presence of two circumbinary bodies, even though this explanation requires a longer baseline of observations to be fully tested. The orbital periods of the best solution would be P_c ~ 3.5 years and P_d ~ 6.9 years. The corresponding projected semi-major axes would be a_c i_c ~ 1.9 AU and a_d i_d ~ 2.9 AU. The masses of the external bodies would be M_c ~ 2.9 M_{Jupiter} and M_d ~ ...

We present an analysis of UBVR$_{\rm C}$I$_{\rm C}$JH photometry and phase-resolved optical spectroscopy of NSVS 14256825, an HW Vir type binary. The members of this class consist of a hot subdwarf and a main-sequence low-mass star in a close orbit ($P_{\rm orb} ~ 0.1$ d). Using the primary-eclipse timings, we refine the ephemeris for the system, which has an orbital period of 0.11037 d. From the spectroscopic data analysis, we derive the effective temperature, $T_1 = 40000 \pm 500$ K, the surface gravity, $\log g_1 = 5.50\pm0.05$, and the helium abundance, $n(\rm He)/n(\rm H)=0.003\pm0.001$, for the hot component. Simultaneously modelling the photometric and spectroscopic data using the Wilson-Devinney code, we obtain the geometrical and physical parameters of NSVS 14256825. Using the fitted orbital inclination and mass ratio ($i = 82\fdg5\pm0\fdg3$ and $q = M_2/M_1 = 0.260\pm0.012$, respectively), the components of the system have $M_1 = 0.419 \pm 0.070 M_{\odot}$, $R_1 = 0.188 \p...

Page 1. Two bodies with high-eccentricity around the cataclysmic variable QS Vir LA Almeida & F. Jablonski Instituto Nacional de Pesquisas Espaciais, Brasil email: leonardo@das.inpe.br Abstract QS Vir is an eclipsing cataclysmic variable with 3.618 hrs or-bital period. ...

Page 1. Journal of Psychoeducational Assessment 29(2) 150 –159 © 2011 SAGE Publications Reprints and permission: http://www. sagepub.com/journalsPermissions.nav DOI: 10.1177/0734282910374707 http://jpa.sagepub.com Trait Emotional Intelligence and Academic ...

Tamoxifen (TAM) is the antiestrogen most widely used in the chemotherapy and chemoprevention of breast cancer. It has been reported that TAM and its more active metabolite 4-hydroxytamoxifen (OHTAM) induce multiple cellular effects, including antioxidant actions. Here sarcoplasmic reticulum membranes (SR) were used as a simple model of oxidation to clarify the antioxidant action type and mechanisms of these anticancer drugs on lipid peroxidation induced by Fe2+/ascorbate and peroxyl radicals generated by the water-soluble 2,2'-azobis(2-amidinopropane)dihydrochloride (AAPH) and by the lipid-soluble 2,2'-azobis(2,4-dimethylvaleronitrile) (AMVN). Peroxidation was monitored by different assay systems, namely cis-parinaric acid (PnA) fluorescence quenching, production of thiobarbituric acid-reactive substances, polyunsaturated fatty acids (PUFA) degradation and oxygen consumption. TAM and OHTAM are efficient inhibitors of lipid peroxidation induced by Fe2+/ascorbate and strong intramembraneous scavengers of peroxyl radicals generated either in the water or lipid phases by AAPH and AMVN, respectively. However, these drugs are not typical chain-breaking antioxidant compounds as compared with vitamin E. Additionally, their antioxidant effectiveness enhances the protective capacity of vitamin E against lipid peroxidation induced by AMVN. OHTAM is a more powerful intramembraneous inhibitor of lipid peroxidation as compared with TAM; this effectiveness not correlating with alterations on membrane fluidity may be due to the presence of a hydrogen-donating HO-group in the OHTAM molecule and its preferential location in the outer bilayer regions where it can donate the hydrogen atom to quench free radicals capable of initiating the membrane oxidative degradation. The stronger OHTAM intramembraneous scavenger capacity over TAM also correlates with its higher partition in biomembranes. Therefore, the strong peroxyl radical scavenger activity of OHTAM in the hydrophobic membrane phase may putatively contribute to the mechanisms of cytostatic and chemopreventive action of its promoter TAM on development of breast cancer.

... LIPIDS MONITORED BY INTRAMOLECULAR EXCIMERIZATION OF 1,3DI(2PYRENYL)PROPANE Amalia SJurado, Leonor M.Almeida and Vitor MCMadeira ... Liquid paraffin 10C MONOMER Liquid paraffin 30C MONOMER EXCIMER EXCIMER .....it NZW I. ZWUZ lu UN uJ O ...