Thickness and Annealing Temperature Effects on the Optical Properties and Surface Morphology of Layer-by-Layer Poly(p-phenyline vinylene) plus Dodecylbenzenesulfonate Films

The fabrication of controlled molecular architectures is essential for organic devices, as is the case of emission of polarized light for the information industry. In this study, we show that optimized conditions can be established to allow layer-by-layer (LbL) films of poly(p-phenylene vinylene) (PPV)+dodecylbenzenesulfonate (DBS) to be obtained with anisotropic properties. Films with five layers and converted at 110 degrees C had a dichroic ratio delta = 2.3 and order parameter r = 34%, as indicated in optical spectroscopy and emission ellipsometry data. This anisotropy was decreased with the number of layers deposited, with delta = 1.0 for a 75-layer LbL PPV + DBS film. The analysis with atomic force microscopy showed the formation of polymer clusters in a random growth process with the normalized height distribution being represented by a Gaussian function. In spite of this randomness in film growth, the self-covariance function pointed to a correlation between clusters, especially for thick films. In summary, the LbL method may be exploited to obtain both anisotropic films with polarized emission and regular, nanostructured surfaces. (c) 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 206-213, 2011

Ruthenium(II) complexes containing N(4)-tolyl-2-acetylpyridine thiosemicarbazones and phosphine ligands: NMR and electrochemical studies of cis-trans isomerization

[Ru(HL)(PPh3)(2)Cl]Cl complexes have been obtained in which HL = N(4)-ortho (complex 1), N(4)-meta (complex 2) and N(4) pctratolyl 2-acetylpyridine thiosemicarbazone (complex 3). NMR and electrochemical studies indicate that both cis and trans isomers exist in solution, and that the cis isomers are converted into the trans isomers with time. Crystal structure determination of (1) reveals that the traps isomer is formed in the solid state. (c) 2007 Elsevier B.V. All rights reserved.

The mer-[RuCl(3)(dppb)(H(2)O)] complex: A versatile tool for synthesis of Ru(II) compounds

The complex mer-[RuCl(3)(dppb)(H(2)O)] [dppb = 1,4-bis(diphenylphosphino)butane] was used as a precursor in the synthesis of the complexes tc-[RuCl(2)(CO)(2)(dppb)], ct-[RuCl(2)(CO)(2)(dppb)]. cis-[RuCl(2)(dppb)(Cl-bipy)], [RuCl(2Ac4mT)(dppb)] (2Ac4mT = N(4)-meta-tolyl-2-acetylpyridine thiosemicarbazone ion) and trans-[RuCl(2)(dppb)(mang)] (mang = mangiferin or 1,3,6,7-tetrahydroxyxanthone-C2-beta-D-glucoside) complexes. For the synthesis of Run complexes, the Ru(III) atom in mer-[RuCl(3)(dppb)(H(2)O)] may be reduced by H(2)(g), forming the intermediate [Ru(2)Cl(4)(dppb)(2)], or by a ligand (such as H2Ac4mT or mangiferin). The X-ray structures of the cis-[RuCl(2)(dppb)(Cl-bipy)], tc-[RuCl(2)(CO)(2)(dppb)] and [RuCl(2Ac4mT)(dPpb)] complexes were determined. (C) 2010 Elsevier Ltd. All rights reserved.

Coordination of nitro-thiosemicarbazones to ruthenium(II) as a strategy for anti-trypanosomal activity improvement

Complexes [RuCl(H4NO(2)Fo4M)(bipy)(dppb)]PF(6) (1), [RuCl(H4NO(2)Fo4M)(Mebipy)(dppb)]PF(6) (2), [RuCl(H4NO(2)Fo4M)(phen)(dppb)]PF(6) (3), [RuCl(H4NO(2)Ac4M)(bipy)(dppb)]PF(6) (4), [RuCl(H4NO(2)Ac4M)(Mebipy)(dppb)]PF(6) (5) and [RuCl(H4NO(2)Ac4M)(phen)(dppb)]PF(6) (6) with N(4)-methyl-4-nitrobenzalde hyde thiosemicarbazone (H4NO(2)Fo4M) and N(4)-methyl-4-nitroacetophenone thiosemicarbazone (H4NO(2) Ac4M) were obtained from [RuCl(2)(bipy)(dppb)], [RuCl(2)(Mebipy)(dppb)], and [RuCl(2)(phen)(dppb)], (dppb = 1,4-bis(diphenylphospine)butane; bipy = 2,2`-bipyridine: Mebipy = 4,4`-dimethyl-2,2`-bipyridine: phen = 1,10-phenanthroline). In all cases the thiosemicarbazone is attached to the metal center through the sulfur atom. Complexes (1-6), together with the corresponding ligands and the Ru precursors were evaluated for their ability to in vitro suppress the growth of Trypanosoma cruzi. All complexes were more active than their corresponding ligands and precursors. Complexes (1-3) and (5) revealed to be the most active among all studied compounds with ID(50) = 0.6-0.8 mu M. In all cases the association of the thiosemicarbazone with ruthenium, dppb and bipyridine or phenanthroline in one same complex proved to be an excellent strategy for activity improvement. (C) 2010 Elsevier Masson SAS. All rights reserved.

THE SOUTHERN BRAZILIAN SHELF: GENERAL CHARACTERISTICS, QUATERNARY EVOLUTION AND SEDIMENT DISTRIBUTION

Extending from latitude 34 degrees S to 22 degrees S the Southern Brazilian shelf constitutes the only part of the Brazilian shelf with a subtropical to temperate environment. The studies on the different geological aspects of the area began in the 1960`s and have recently been reassessed after studies related to the determination of the Economic Exclusive Zone. In terms of morphology, the Southern Brazilian shelf may be divided into three sectors, the Sao Paulo Bight, the Florianopolis-Mostardas Sector and the Rio Grande Cone, characterized by conspicuous differences in terms of geological determining factors, bathymetry, declivities and the presence of canyons and channels. Despite the existence of hundreds of radiocarbon datings the sea level changes curve of southern Brazil during the Last Glacial Cycle is still a matter of debate. A recent controversy on the Middle and late Holocene sea level changes curve raised the question of the amplitude of the oscillations which occurred in the period. Also, a few but relatively consistent radiocarbon datings suggest the occurrence of a high sea level during Isotope Stage 3. In terms of sedimentary cover the Southern Brazilian shelf exhibits a very strong hydrodynamic control, both latitudinal and bathymetrical. The sector southward from 25 degrees S is characterized by the influence of the plume of water carrying sediments originating from the Rio de La Plata. Actually its presence is conspicuous up to 28 degrees S, with the area between this latitude and 25 degrees S constituting a transitional zone. In terms of bathymetry the outer shelf is marked by the ""floor-polisher"" effect of the Brazil Current, which is responsible for the maintenance of a relict facies in areas deeper than 100 meters.

Nd and Pb isotope signatures on the Southeastern South American upper margin: Implications for sediment transport and source rocks

Neodymium and lead isotope values in sediment samples were used to interpret sediment transport and source rocks on the Southeastern South American upper margin. The sediments of the Argentinian margin exhibit an average epsilon(Nd) value of -1.9, indicating the influence of the Andean rocks as sediment sources. Sediments from the Rio de La Plata estuary show an average epsilon(Nd) value of -9.6 which is similar to that of the Southern Brazilian Upper Margin. Finally, sediments of Southeastern Brazil, which are associated with the transport of the Brazil Current exhibit an average epsilon(Nd) of -13.0. The Pb isotope signatures also confirm the differentiation of source rocks in the sedimentation of the study area. In addition, Pb isotopes helped to establish the extent of the influence of the Rio de La Plata on the sedimentation of the Southern Brazilian margin. In terms of Pb isotopes the sediments from the Rio de La Plata estuary and Southern Brazil are more radiogenic than those of Southeastem Brazil and the Argentinian margin. (c) 2007 Elsevier B.V. All rights reserved.

Immobilization of primary cultures of insulin-releasing human pancreatic cells

Transplantation of pancreatic islets isolated from organ donors constitutes a promising alternative treatment for type 1 diabetes, however, it is severely limited by the shortage of organ donors. Ex vivo islet cell cultures appear as an attractive but still elusive approach for curing type 1 diabetes. It has recently been shown that, even in the absence of fibrotic over-growth, several factors, such as insufficient nutrition of the islet core, represent a major barrier for long-term survival of islets grafts. The use of immobilized dispersed cells may contribute to solve this problem due to conceivably easier nutritional and oxygen support to the cells. Therefore, we set out to establish an immobilization method for primary cultures of human pancreatic cells by adsorption onto microcarriers (MCs). Dispersed human islets cells were seeded onto Cytodex1 microcarriers and cultured in bioreactors for up to eight days. The cell number increased and islet cells maintained their insulin secretion levels throughout the time period studied. Moreover, the cells also presented a tendency to cluster upon five days culturing. Therefore, this procedure represents a useful tool for controlled studies on islet cells physiology and, also, for biotechnological applications.

Structure-Activity Relationship for Quaternary Ammonium Compounds Hybridized with Poly(methyl methacrylate)

Hybrid films from poly (methylmethacrylate) (PMMA) and dioctadecyldimethylammonium bromide (DODAB), cetyltrimethylammonium bromide (CTAB), or tetrapropylammonium bromide (TPAB) were characterized by determination of wettability, ellipsometry, atomic force microscopy, active compounds diffusion to water, X-ray photoelectron spectroscopy (XPS) with determination of atomic composition on the films surface, and biocidal activity against Pseudomonas aeruginosa or Staphylococcus aureus. QAC mobility in the films increased from DODAB to CTAB to TPAB. Diffusion and optimal hydrophobic hydrophilic balance imparted the highest bioactivity to CTAB. DODAB sustained immobilization at the film surface killed bacteria upon contact. TPAB ability to diffuse was useless because of its unfavorable hydrophobic hydrophilic balance for bioactivity.

Antimicrobial Particles from Cationic Lipid and Polyelectrolytes

Hybrid nanoparticles from cationic lipid and polymers were prepared and characterized regarding physical properties and antimicrobial activity. Carboxymethylcellulose (CMC) and polydiallyldimethylammonium chloride (PDDA) were sequentially added to cationic bilayer fragments (BF) prepared from ultrasonic dispersion in water of the synthetic and cationic lipid dioctadecyldimethylammonium bromide (DODAB). Particles thus obtained were characterized by dynamic light-scattering for determination of z-average diameter (Dz) and zeta-potential (zeta). Antimicrobial activity of the DODAB BF/CMC/PDDA particles against Pseudomonas aeruginosa or Staphylococcus aureus was determined by plating and CFU counting over a range of particle compositions. DODAB BF/CMC/PDDA particles exhibited sizes and zeta-potentials strictly dependent on DODAB, CM C, and PDDA concentrations. At 0.1 mM DODAB, 0.1 mg/mL CMC, and 0.1 mg/mL PDDA, small cationic particles with Dz = 100 nm and zeta = 30 mV were obtained. At 0.5 mM DODAB, 0.5 mg/mL CMC and 0.5 mg/mL PDDA, large cationic particles with Dz = 470 nm and zeta= 50 mV were obtained. Both particulates were highly reproducible regarding physical properties and yielded 0% of p. aeruginosa viability (10(7) CFU/mL) at 1 or 2 mu g/mL PDDA dissolved in solution or in form of particles, respectively. 99% of S. aureus cells died at 10 mu g/mL PDDA alone or in small or large DODAB BF/CMC/PDDA particles. The antimicrobial effect was dependent on the amount of positive charge on particles and independent of particle size. A high microbicide potency for PDDA over a range of nanomolar concentrations was disclosed. P. aeruginosa was more sensitive to all cationic assemblies than S. aureus.

Fast and reliable analyses of sulphite in fruit juices using a supramolecular amperometric detector encompassing in flow gas diffusion unit

A new compact system encompassing in flow gas diffusion unit and a wall-jet amperometric FIA detector, coated with a supramolecular porphyrin film, was specially designed as an alternative to the time-consuming Monier-Williams method, allowing fast, reproducible and accurate analyses of free sulphite species in fruit juices. In fact, a linear response between 0.64 and 6.4 ppm of sodium sulphite. LOD = 0.043 ppm, relative standard deviation of +/- 1.5% (n = 10) and analytical frequency of 85 analyses/h were obtained utilising optimised conditions. That superior analytical performance allows the precise evaluation of the amount of free sulphite present in foods, providing an important comparison between the standard addition and the standard injection methods. Although the first one is most frequently used, it was strongly influenced by matrix effects because of the unexpected reactivity of sulphite ions with the juice matrixes, leading to its partial consumption soon after addition. In contrast, the last method was not susceptible to matrix effects yielding accurate results, being more reliable for analytical purposes. (C) 2011 Elsevier Ltd. All rights reserved.

(+)- and (-)-Mutisianthol: First Total Synthesis, Absolute Configuration, and Antitumor Activity

The first synthesis of the natural product (+)-mutisianthol was accomplished in 11 steps and in 21% overall yield from 2-methylanisole. The synthesis of its enantiomer was also performed in a similar overall yield. The absolute configuration of the sesquiterpene (+)-mutisianthol was assigned as (1S,3R). Key steps in the route are the asymmetric hydrogenation of a nonfunctionalized olefin using chiral iridium catalysts and the ring contraction of 1,2-dihydronaphthalenes using thallium(III) or iodine(III). The target molecules show moderate activity against the human tumor cell lines SF-295, HCT-8, and MDA-MB-435.

Discovery of Phthalimides as Immunomodulatory and Antitumor Drug Prototypes

Brazilian National Council of Research (CNPq)[471834/2006-8]

Lectura de los textos de los libros del nivel 3 Alegría y El Sur : Un análisis de los textos y sus correspondientes ejercicios

El material didáctico para la enseñanza de español como lengua extranjera incluye textos cuya finalidad es favorecer la comprensión lectora. Los libros del nivel 3 de español Alegría y El Sur incluyen una variedad de textos cuya finalidad es, de acuerdo a Skolverket, la profundización de la capacidad de leer, comprender y reflexionar de forma crítica sobre los textos (n.t.) (Skolverket, 2011).El objetivo de este trabajo es hacer un análisis comparativo de los textos principales de lectura, incluyendo sus ejercicios correspondientes, de los libros de texto Alegría y El Sur del nivel 3 de español como lengua extranjera utilizados por alumnos de instituto. Para ello se realizó un análisis cualitativo describiendo las diferencias encontradas en los textos principales.El resultado de la investigación muestra que los textos de ambos libros, Alegría y El Sur, presentan temas similares. La mayoría de los ejercicios derivados de los textos se apegan literalmente a estos, no dando espacio a la reflexión ni a la interpretación personal. Además no se encontraron ejercicios donde se pongan en práctica estrategias de lectura, como la predicción o la inferencia, que propician la autonomía del alumno y además facilitan la comprensión del texto.

International collaborative project to compare and monitor the nutritional composition of processed foods

Background: Chronic diseases are the leading cause of premature death and disability in the world with overnutrition a primary cause of diet-related ill health. Excess energy intake, saturated fat, sugar, and salt derived from processed foods are a major cause of disease burden. Our objective is to compare the nutritional composition of processed foods between countries, between food companies, and over time.

Design: Surveys of processed foods will be done in each participating country using a standardized methodology. Information on the nutrient composition for each product will be sought either through direct chemical analysis, from the product label, or from the manufacturer. Foods will be categorized into 14 groups and 45 categories for the primary analyses which will compare mean levels of nutrients at baseline and over time. Initial commitments to collaboration have been obtained from 21 countries.

Conclusions: This collaborative approach to the collation and sharing of data will enable objective and transparent tracking of processed food composition around the world. The information collected will support government and food industry efforts to improve the nutrient composition of processed foods around the world.

Kruppel-like factor 15 regulates skeletal muscle lipid flux and exercise adaptation

The ability of skeletal muscle to enhance lipid utilization during exercise is a form of metabolic plasticity essential for survival. Conversely, metabolic inflexibility in muscle can cause organ dysfunction and disease. Although the transcription factor Kruppel-like factor 15 (KLF15) is an important regulator of glucose and amino acid metabolism, its endogenous role in lipid homeostasis and muscle physiology is unknown. Here we demonstrate that KLF15 is essential for skeletal muscle lipid utilization and physiologic performance. KLF15 directly regulates a broad transcriptional program spanning all major segments of the lipid-flux pathway in muscle. Consequently, Klf15-deficient mice have abnormal lipid and energy flux, excessive reliance on carbohydrate fuels, exaggerated muscle fatigue, and impaired endurance exercise capacity. Elucidation of this heretofore unrecognized role for KLF15 now implicates this factor as a central component of the transcriptional circuitry that coordinates physiologic flux of all three basic cellular nutrients: glucose, amino acids, and lipids.