Tripolyphosphate as precursor for REPO4: Eu3+ (RE = Y, La, Gd) by a polymeric method

A modification of the Pechini method was applied to obtain luminescent rare earth orthophosphates. The developed synthetic route is based on the ability of the tripolyphosphate anion (P3O105-) to act both as a complexing agent and as an orthophosphate precursor. Heating of aqueous solutions containing RE3+, Eu3+, P3O105-, citric acid, and ethylene glycol led to polymeric resins. The ignition of these resins at different temperatures yielded luminescent orthophosphates. The produced nanosized phosphors (YPO4:Eu3+, (Y,Gd)PO4:Eu3+, and LaPO4:Eu3+) were analyzed by infrared and luminescence spectroscopies, X-ray diffractometry, and scanning electron microscopy.

Reverse Microemulsion Synthesis, Structure, and Luminescence of Nanosized REPO(4):Ln(3+) (RE = La, Y, Gd, or Yb, and Ln = Eu, Tm, or Er)

A surfactant-mediated solution route for the obtainment of nanosized rare-earth orthophosphates of different compositions (LaPO(4):Eu(3+), (Y,Gd)PO(4):Eu(3+),LaPO(4):Tm(3+), YPO(4):Tm(3+), and YbPO(4):Er(3+)) is presented, and the implications of the morphology control on the solids properties are discussed. The solids are prepared in water-in-heptane microemulsions, using cetyltrimethylammonium bromide and 1-butanol as the surfactant and cosurfactant; the alteration of the starting microemulsion composition allows the obtainment of similar to 30 nm thick nanorods with variable length. The morphology and the structure of the solids were evaluated through scanning electron microscopy and through powder X-ray diffractometry; dynamic light scattering and thermal analyses were also performed. The obtained materials were also characterized through vibrational (FTIR) and luminescence spectroscopy (emission/excitation, luminescence lifetimes, chromaticity, and quantum efficiency), where the red, blue, and upconversion emissions of the prepared phosphors were evaluated.

Synthesis of YAP nanopowder by a soft chemistry route

Polycrystalline fine powder of YAlO(3) (YAP) was synthesized by the modified polymeric precursor method. A preliminary gradual pyrolytic decomposition under nitrogen flux was crucial in the removal process of organic residues to avoid the formation of molecular level inhomogeneities. YAP single phase was crystallized at temperatures between 950 degrees C and 1000 degrees C using chemically homogeneous ball-milled amorphous particles and very fast heating rates, corresponding to the lowest synthesis temperature of pure YAP nanopowder by soft chemistry routes. (C) 2009 Elsevier Ltd. All rights reserved.

Propiedades termodinámicas de sorción de agua de la pulpa de lulo en polvo con encapsulantes

Datos de humedad de equilibrio de polvo de pulpa de lulo (PL) con y sin aditivos - 58% de maltodextrina (MD) o 58% de goma Arábiga (GA) - fueran determinados en las temperaturas de 20, 30, 40 y 50 °C utilizando el método estático gravimétrico para un rango de actividades de agua entre 0.06 y 0.90. Las isotermas presentaran formato sigmoidal del tipo III, y el modelo de Guggenhein-Anderson-de Boer (GAB) fue ajustado satisfactoriamente a los datos experimentales de humedad de equilibrio en función de la actividad de agua. La adición de encapsulantes afecto las isotermas de tal manera que en la misma actividad de agua, las muestras PL + GA y PL + MD presentaron un menor contenido de humedad de equilibrio y no fueron afectadas por la variación de temperatura. Los calores isostéricos de sorción de las pulpas en polvo con encapsulantes fueron mayores (menos negativos) con relación a las pulpas de lulo en polvo, sugiriendo la existencia de sitios polares más activos en el producto sin adición de GA o MD. Una relación exponencial empírica fue utilizada para describir la dependencia del calor de sorción con el contenido de humedad del material.

A new species of Pimelodus La Cépède, 1803 (Siluriformes: Pimelodidae) from rio Ribeira de Iguape basin, Brazil

Pimelodus multicratifer, a new species, is described from the rio Ribeira de Iguape basin. The new species differs from the other Pimelodus species by the following features: 26 to 30 gill rakers on the first branchial arch; a combination of three to six rows of dark spots regularly or irregularly scattered on the flanks and several small dark spots irregularly scattered on the dorsal surface of head, supraoccipital process, and sometimes on the dorsal and caudal fins; striated lips; maxillary barbels reaching between posterior tip of the pelvic-fin rays and posterior tip of the middle caudal-fin rays.

Haciendo hologramas en la escuela y en la casa

La comunidad científica que se ocupa de los problemas relacionados con el proceso de enseñanza-aprendizaje de la físicas, ha dedicado muchos esfuerzos en los ultimos años al perfeccionamiento del mismo, motivado en primera instancia, por las demandas de renovación que el impetuoso desarrollo científico-técnico le impone en la actualidad a la enseñanza de las ciencias. En los últimos años se ha producido un desarrollo vertiginoso en la fabricación de diodos láser que emiten en el espectro visible, esto ha permitido su utilización creciente en múltiples aplicaciones y hace factible su utilización en la enseñanza aprendizaje de la física universitaria y en particular de la holografía, por sus grandes ventajas frente a los láseres convencionales de gran costo y difícil manipulación. En el trabajo se describen la instalación experimental portátil diseñada para la obtención de hologramas en la escuela y en la casa con la utilización de diodos láser, la metodología de trabajo a seguir, los métodos de procesamiento utilizados para diferentes tipos de emulsiones holográficas y un análisis de los defectos que pueden presentar los hologramas producidos y la forma de detectarlos y erradicarlos

Transmissão psíquica transgeracional e construção de subjetividade: relato de uma psicoterapia psicanalítica vincular

O presente artigo tem como objetivo refletir acerca do conceito de transmissão psíquica entre gerações, especificamente de uma modalidade - a transmissão psíquica transgeracional - e sua influência na construção das subjetividades individuais e dos vínculos familiares, enfatizando-se aqui o vínculo mãe-filha como gerador de sintomas na criança e conflitos no âmbito familiar, através de um relato clínico de uma psicoterapia psicanalítica vincular, segundo os referenciais de Eiguer (2006) e Berenstein e Puget (1997, 2005). A apresentação do caso clínico permite discutir, ainda, a relação entre a transmissão psíquica transgeracional e o estabelecimento da “maternagem”, bem como os resultados obtidos ao longo de todo o processo psicoterápico. A finalidade desse espaço terapêutico familiar é a de propiciar transformações frente ao legado geracional, promovendo o surgimento de uma subjetividade nova, impulsionadora de vida.

Genetic-morphometric variation in Culex quinquefasciatus from Brazil and La Plata, Argentina

Variation among natural populations of Culex (Culex) quinquefasciatus Say is associated with different vectorial capacities. The species Cx. quinquefasciatus is present in the equatorial, tropical and subtropical zones in the Brazilian territory, with intermediate forms between Cx. quinquefasciatus and Culex pipiens occurring in regions of latitudes around 33°-35°S. Herein, we studied geographically distinct populations of Cx. quinquefasciatus by genetic characterization and analysis of intra-specific wing morphometrics. After morphological analysis, molecular characterization of Cx. quinquefasciatus and intermediate forms was performed by polymerase chain reaction of the polymorphic nuclear region of the second intron of the acetylcholinesterase locus. Additionally, the morphology of adult female wings collected from six locations was analyzed. Wing centroid sizes were significantly different between some geographical pairs. Mean values of R2/R2+3 differed significantly after pairwise comparisons. The overall wing shape represented by morphometric characters could be divided into two main groupings. Our data suggest that Brazilian samples are morphologically and genetically distinct from the Argentinean samples and also indicated a morphological distinction between northern and southern populations of Brazilian Cx. quinquefasciatus. We suggest that wing morphology may be used for preliminary assessment of population structure of Cx. quinquefasciatusin Brazil

Prediction of good glass formers in the Al-Ni-La and Al-Ni-Gd systems using topological instability and electronegativity

A new criterion has been recently proposed combining the topological instability (lambda criterion) and the average electronegativity difference (Delta e) among the elements of an alloy to predict and select new glass-forming compositions. In the present work, this criterion (lambda.Delta e) is applied to the Al-Ni-La and Al-Ni-Gd ternary systems and its predictability is validated using literature data for both systems and additionally, using own experimental data for the Al-La-Ni system. The compositions with a high lambda.Delta e value found in each ternary system exhibit a very good correlation with the glass-forming ability of different alloys as indicated by their supercooled liquid regions (Delta T(x)) and their critical casting thicknesses. In the case of the Al-La-Ni system, the alloy with the largest lambda.Delta e value, La(56)Al(26.5)Ni(17.5), exhibits the highest glass-forming ability verified for this system. Therefore, the combined lambda.Delta e criterion is a simple and efficient tool to select new glass-forming compositions in Al-Ni-RE systems. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3563099]

Protection against tuberculosis by a single intranasal administration of DNA-hsp65 vaccine complexed with cationic liposomes

Background: The greatest challenges in vaccine development include optimization of DNA vaccines for use in humans, creation of effective single-dose vaccines, development of delivery systems that do not involve live viruses, and the identification of effective new adjuvants. Herein, we describe a novel, simple technique for efficiently vaccinating mice against tuberculosis (TB). Our technique consists of a single-dose, genetic vaccine formulation of DNA-hsp65 complexed with cationic liposomes and administered intranasally. Results: We developed a novel and non-toxic formulation of cationic liposomes, in which the DNA-hsp65 vaccine was entrapped (ENTR-hsp65) or complexed (COMP-hsp65), and used to immunize mice by intramuscular or intranasal routes. Although both liposome formulations induced a typical Th1 pattern of immune response, the intramuscular route of delivery did not reduce the number of bacilli. However, a single intranasal immunization with COMP-hsp65, carrying as few as 25 mu g of plasmid DNA, leads to a remarkable reduction of the amount of bacilli in lungs. These effects were accompanied by increasing levels of IFN-gamma and lung parenchyma preservation, results similar to those found in mice vaccinated intramuscularly four times with naked DNA-hsp65 (total of 400 mu g). Conclusion: Our objective was to overcome the significant obstacles currently facing DNA vaccine development. Our results in the mouse TB model showed that a single intranasal dose of COMP-hsp65 elicited a cellular immune response that was as strong as that induced by four intramuscular doses of naked-DNA. This formulation allowed a 16-fold reduction in the amount of DNA administered. Moreover, we demonstrated that this vaccine is safe, biocompatible, stable, and easily manufactured at a low cost. We believe that this strategy can be applied to human vaccines to TB in a single dose or in prime-boost protocols, leading to a tremendous impact on the control of this infectious disease.

A Simple and Fast Method for the Production and Characterization of Methylic and Ethylic Biodiesels from Tucum Oil via an Alkaline Route

A simple, fast, and complete route for the production of methylic and ethylic biodiesel from tucum oil is described. Aliquots of the oil obtained directly from pressed tucum (pulp and almonds) were treated with potassium methoxide or ethoxide at 40 degrees C for 40 min. The biodiesel form was removed from the reactor and washed with 0.1 M HCl aqueous solution. A simple distillation at 100 degrees C was carried out in order to remove water and alcohol species from the biodiesel. The oxidative stability index was obtained for the tucum oil as well as the methylic and ethylic biodiesel at 6.13, 2.90, and 2.80 h, for storage times higher than 8 days. Quality control of the original oil and of the methylic and ethylic biodiesels, such as the amount of glycerin produced during the transesterification process, was accomplished by the TLC, GC-MS, and FT-IR techniques. The results obtained in this study indicate a potential biofuel production by simple treatment of tucum, an important Amazonian fruit.

Um modo de ler um livro-biblioteca: a reescritura perecquiana na composição de La vie mode d'emploi

This article presents and analyses some aspects of Georges Perec's composition as shown in his book Life: a user's manual (1978). Starting with the image of a ""book-library"", composed by some of Perec's literary 'models', and discussing the theory of intextertuality and rewriting, we propose to analyse some possible approximations between Perec and Flaubert, especially in the latter's Bouvard and Pecuchet (1881).

Spontaneous long and short-range ferroelectric ordering in Pb(0.55)La(0.30)TiO(3) ceramics

In this work, we investigated the temperature dependence of short and long-range ferroelectric ordering in Pb(0.55)La(0.30)TiO(3) relaxor composition. High-resolution x-ray powder diffraction measurements revealed a clear spontaneous macroscopic cubic-to-tetragonal phase transition in the PLT relaxor sample at similar to 60 K below the maximum of the dielectric constant peak (T(m)). Indeed, the x-ray diffraction (XRD) data showed that at 300 K (above T(m) but below the Burns temperature, T(B)) the long-range order structure corresponds to a macroscopic cubic symmetry, space group number 221 (Pm-3m), whereas the data collected at 20 K revealed a macroscopic tetragonal symmetry, space group number 99 (P4mm) with c/a=1.0078, that is comparable to that of a normal ferroelectric. These results show that for samples with tetragonal composition, the long-range ferroelectric order may be recovered spontaneously at cryogenics temperatures, in contrast to ferroelectric samples with rhombohedral symmetry. On the other hand, x-ray absorption spectroscopy investigations intriguingly revealed the existence of local tetragonal disorder around Ti atoms for temperatures far below T(m) and above T(B), for which the sample presents macroscopic tetragonal and cubic symmetries, respectively. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3431024]

Iridium(III)-surfactant complex immobilized in mesoporous silica via templated synthesis: a new route to optical materials

In this work we report the preparation of a new blue-emitting material based on the templated synthesis of mesoporous silica (MCM-41) using micellar solutions of the newly synthesized monocationic metallosurfactant complex bis[1-benzyl-4-(2,4-difluorophenyl)-1H-1,2,3-triazole](4,4'-diheptadecyl-2,2'- bipyridine)-iridium(III) chloride in hexadecyl-trimethyl-ammonium bromide (CTAB). Under ambient conditions, significant increases in excited state lifetime and quantum yield values (up to 45%), were obtained for the solid materials in comparison to the corresponding micellar solutions. Solid state (1)H and (19)F NMR spectroscopies were successfully employed for quantifying the luminophore content in terms of Ir-surfactant to CTAB and Ir-surfactant to silica ratios.

Analysis of foraminifera assemblages and sediment geochemical properties to characterise the environment near Araca and Saco da Cape la domestic sewage submarine outfalls of Sao Sebastiao Channel, Sao Paulo State, Brazil

Superficial bottom samples were collected near diffusers of domestic sewage submarine outfalls at Araca and Saco da Capela, Sao Sebastiao Channel, Brazil. The goal of this study was to investigate the distribution and composition of live benthic foraminifera assemblages and integrate the results obtained with geochemical analyses to assess human-induced changes. According to the results obtained no environmental stress was observed near the Saco da Capela submarine outfall diffusers. The foraminifera assemblage is characterised by species typical of highly hydrodynamic environments, with well-oxygenated bottom waters and low nutrient contents. In contrast, near Araca submarine outfall, organic enrichment was denoted by high phosphorus, sulphur and, to a lesser extent, total organic carbon content. Harmful influences on foraminifera could be identified by low richness and specific diversity, as well as the predominance of detritivore feeder species, which are associated with higher organic matter flux and low oxygen in the interstitial pore water. (C) 2009 Elsevier Ltd. All rights reserved.