Synthesis and luminescence properties of water dispersible Eu3+-doped boehmite nanoparticles

Nanocrystallized boehmite gamma-AlOOH center dot nH(2)O had been synthesized by spray-drying (SD) of a solution of aluminium tri-sec-butoxide peptized by nitric acid. The sub-micronic spherical particles obtained had an average diameter of 500 nm and were built of 100 nm or less platelet-like sub-particles. The average crystallite size calculated from XRD was 1.6 nm following the b axis (i.e. one unit cell) and 3-4 nm perpendicular to b. As a result of the nanometric sizes of crystallites, there was a large surface free for water adsorption and it was found to be n = 1.18 +/- 0.24H(2)O per AlOOH. The SD spheres spontaneously dispersed in water at room temperature and formed stable-over months-suspensions with nanometre-size particles (25-85 nm). Luminescent europium-doped nanocrystallized boehmites AlOOH: Eu (Al0.98Eu0.02OOH center dot nH(2)O) were synthesized the same way by SD and demonstrated the same crystallization properties and morphologies as the undoped powders. It is inferred from the Eu3+ luminescence spectroscopy that partly hydrated europium species are immobilized on the boehmite nanocrystals where they are directly bonded to alpha(OH) groups of the AlOOH surface. The europium coordination is schematically written [Eu3+(OH)(alpha)(H2O)(7-alpha/2)]. The europium-doped boehmite from SD spontaneously dispersed in water: the luminescence spectroscopy proves that most of the Eu3+ ions were detached from the NPs during water dispersion. The AlOOH: Eu nanoparticles were modified by the amine acid asparagine (ASN). The modification aimed to render the NPs compatible for further bio-functionalization. After surface modification, the NPs easily dispersed in water; the luminescence spectra after dispersion prove that the Eu3+ ions were held at the boehmite surface.

Biometric relationship analysis of the wet weight by carapace width to the swimming crab Arenaeus-cribrarius (Lamarck, 1818) (Crustacea, Brachyura, Portunidae)

The biometric relationship between the weigth and the carapace width in the swimming crab A. cribrarius was compared with the results from other portunid crabs studied previously. During November/1988 to October/1989, a total of 403 specimens (189 males and 214 females) were collected with otter-trawl nets in north coast of the São Paulo State, Brazil. The animals were measured (carapace width excluding lateral spines = LC! and weighed (wet weight = PE). The empiric points of this relation were fit according to the power function (Y = a.X(b)) for each sex, maturation phases and total of individuals. The relation PE x LC indicates that the mole's growth changes during the ontogenesys from isometric (in juvenile phase) to allometric positive (in adult phase). For the females the growth is isometric in the two phases. The weight grows in a higher proportion than the carapace width variable (allometric positive growth). The data can be grouped in a single equation (PE = 7.85.10(-5).LC(3.14)) for the convertion between the variables there was a greater similarity between the equations obtained far each sex. In spite of this, the males present the fattening grade value (''a'') slightly higher than that of the females, possibly because of the greater size reached in its devellopment. The mean weight of the males is greater than the females one (p < 0.01). In the range 80 proves 90mm the males were more abundant, probably due to the females terminal ecdysis is near this size. The females only have the mean weight greater than the males in the 60 proves 70mm range (p < 0.01) when the puberty molt occurs and they present morphological changes in their reproductive system.

UVC emitting phosphors obtained by spray pyrolysis

The broadband inter-configurational (4f(1)5d(1)-->4f(2)) emission of Pr(3+) doped in lanthanum orthophosphate (LaPO(4)) and in calcium pyrophosphate (Ca(2)P(2)O(7)) has been investigated under plasma excitation. The synthesis by spray pyrolysis at moderate temperature followed by a controlled annealing proves to be a very efficient way to produce good quality UVC emitting phosphor Ca(1.92)Pr(0.04)Na(0.04)P(2)O(7) (alpha phase). The emission of this phosphor in the wavelength range 200-350 nm has been measured with a prototype device, which can be employed for anti-microbial testing. (C) 2010 Elsevier B.V. All rights reserved.

Bone mineralization among male adolescents: Critical years for bone mass gain

Objective: To verify the behavior of the mineral bone content and density in male adolescents according to age and secondary sexual characters. Methods: 47 healthy adolescents between 10 and 19 years old were assessed according to weight, height, body mass index, puberty stage, calcium intake, bone mineral density and content in the lumbar spine and in the proximal femur. The bone mass was measured through bone densitometries. The intake of calcium was calculated through a 3-day diet. The BMI (body mass index) was calculated with the Quetelet Index and the puberty stage was defined according to Tanner's criteria. The analysis used descriptive statistics such as average and standard deviation, and variance estimates to compare the different age groups. Moreover, the Tukey test was used to determine the significant differences. Results: It was evident that the calcium intake in the different ages assessed has not reached the minimum value of 800 mg. The bone mineral density and content showed an increase after the age of 14, as well as when the teenagers reached the sexual maturation stage G4. The mineralization parameters showed a high level when the teenagers were in the G3 stage, however, without statistical significance. Conclusion: The results indicate an important level of bone mineralization during adolescence. Maturation levels superior to G3 have shown more mineralization. This study proves that the critical years for bone mass gain start after the 14-15 years old or older. Copyright © 2004 by Sociedade Brasileira de Pediatria.

Women's contribution to equality in Latin America and the Caribbean

Includes bibliography

Trade, investment and fragmentation of the global market: is Latin America lagging behind?

Includes bibliography

Auto-avaliação dos Discentes do Curso de Ciências Biológicas da Unemat, Campus de Nova Xavantina: um modelo para avaliação das disciplinas curriculares, segundo a percepção do corpo discente e docente

This paper presents an evaluation of the curriculum subjects of the Biological Sciences course in the University of the State of Mato Grosso (UNEMAT), Nova Xavantina campus, Brazil. The research was carried out by means of a self-assessment instrument, aimed at searching learners' and educators' points of view. The questionnaires were given in the first, third and seventh semesters, in which students were asked to assess pedagogical aspects regarding professors and their didacticism, as well as the subject matters being taught; in addition, they were invited to evaluate themselves as learners. The data was analyzed using statistical parameters, in order to measure teaching performance, and, subsequently, professors were given the opportunity to express their concepts about the students' assessment. The average value of the overall Cronbach's alpha coefficient was 0.923±0.001, a significant value considering that alpha varies between 0 and 1, which proves the questionnaire to be reliable. The hierarchical cluster analysis (HCA) does not permit teaching performance to be associated with professors' qualification or workload.

A proteção dos direitos autorais a partir da realidade Internet: a perspectiva brasileira

Pós-graduação em Ciência da Informação - FFC

Poe diante do espelho: uma nova leitura da literatura fantástica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Análise da variabilidade genética e do padrão de atividade esterásica no hepatopâncreas de camarões palemonídeos expostos a diferentes pesticidas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A mão oculta: Estevam Marcolino : política e modernidade no interior paulista (1889-1914)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

XML na ciência da informação: uma análise do MARC21

Pós-graduação em Ciência da Informação - FFC

O sistema vocálico do português arcaico visto a partir das Cantigas de Santa Maria

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Extração de contornos de telhados usando princípios de Snake Balloon

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Determinação da atividade antimicrobiana in vitro de extratos, frações e compostos isolados de Arrabidaea brachypoda

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)