Comment on "Prediction of lattice constant in cubic perovskites"

In a recent work by Jiang et al. [J. Phys. Chem. Solids 67 (2006) 1531-1536], the interrelationship between lattice constant, ionic radii and tolerance factor of cubic perovskites has been established and an empirical equation was obtained. However, the assumption of incorrect ionic coordination led to an incorrect mathematical expression even though the average relative errors between predicted and observed lattice constants of 132 materials were below 1%. Here, corrected coefficients for that empirical expression are obtained, which would likely be useful for investigation of general perovskite materials

Specialized odorant receptors in social insects that detect cuticular hydrocarbon cues and candidate pheromones.

Eusocial insects use cuticular hydrocarbons as components of pheromones that mediate social behaviours, such as caste and nestmate recognition, and regulation of reproduction. In ants such as Harpegnathos saltator, the queen produces a pheromone which suppresses the development of workers' ovaries and if she is removed, workers can transition to a reproductive state known as gamergate. Here we functionally characterize a subfamily of odorant receptors (Ors) with a nine-exon gene structure that have undergone a massive expansion in ants and other eusocial insects. We deorphanize 22 representative members and find they can detect cuticular hydrocarbons from different ant castes, with one (HsOr263) that responds strongly to gamergate extract and a candidate queen pheromone component. After systematic testing with a diverse panel of hydrocarbons, we find that most Harpegnathos saltator Ors are narrowly tuned, suggesting that several receptors must contribute to detection and discrimination of different cuticular hydrocarbons important in mediating eusocial behaviour.Cuticular hydrocarbons (CHC) mediate the interactions between individuals in eusocial insects, but the sensory receptors for CHCs are unclear. Here the authors show that in ants such as H. saltator, the 9-exon subfamily of odorant receptors (HsOrs) responds to CHCs, and ectopic expression of HsOrs in Drosophila neurons imparts responsiveness to CHCs

On the reversed crystal growth of BaZrO3 decaoctahedron: shape evolution and mechanism

BaZrO3 (BZO) nanoparticles were nucleated, grown and subsequently self-assembled into a 3D decaoctahedronal architecture via a microwave-assisted hydrothermal (MAH) method. X-Ray diffraction (XRD), field emission scanning microscopy (FE-SEM), X-ray absorption spectroscopy (XAFS) as well as both photoluminescence (PL) and radioluminescence (RL) emission studies have provided fundamental insight into the nature of the anisotropic crystal growth mechanism of BZO nanocrystals into their final decaoctahedral shape. The growth mechanism of the assembled nanoparticles via mesoscale transformations to form BZO decaoctahedrons occurs from the surface to the core along a reversed crystallization route. This pathway is accompanied by a large enhancement of RL emissions while the intensity of PL emissions is enhanced and worsened along the process. The analysis of the results reveals a relationship between the decaoctahedrons obtained and their optical\ud properties.FAPESP / CEPID (98/14324-8)CNPqINCTMNMinisterio de Educación y Cultura y Deporte (MECD) (CTQ2009-14541-C02)Generalitat Valenciana (PROMETEO/2009/053)CYTEDMinisterio de Educación (PHB2009-0065-PC

A Cellular Automata Model for Citrus Variagated Chlorosis

A cellular automata model is proposed to analyze the progress of Citrus Variegated Chlorosis epidemics in S\~ao Paulo oranges plantation. In this model epidemiological and environmental features, such as motility of sharpshooter vectors which perform L\'evy flights, hydric and nutritional level of plant stress and seasonal climatic effects, are included. The observed epidemics data were quantitatively reproduced by the proposed model varying the parameters controlling vectors motility, plant stress and initial population of diseased plants.Comment: 10 pages, 10 figures, Scheduled tentatively for the issue of: 01Nov0

Análise de Perigos e Pontos Críticos de Controle em Processamento de Abate de Bovinos

Em um mundo globalizado onde a competência marca a subsistência das empresas, a busca da qualidade assume um papel preponderante, convertendo-se na ferramenta básica para a competitividade. Os princípios para a melhoria da qualidade aplicam-se tanto a pequenas empresas como a grandes corporações, tanto à s indústrias de serviços como à s de fabricação, e tanto ao setor público como à s empresas privadas. Desta forma, o HACCP surge como elemento essencial (Hazard Analysis Critical Control Point)

Novel SrTi1-xFexO3 nanocubes synthesized by microwave-assisted hydrothermal method

We report herein for the first time a facile synthesis method to obtain SrTi1-xFexO3 nanocubes by means by a microwave-assisted hydrothermal (MAH) method at 140 degrees C. The effect of iron addition on the structural and morphological properties of SrTiO3 was investigated. X-ray diffraction measurements show that all STFO samples present a cubic perovskite structure. X-ray absorption spectroscopy at Fe absorption K-edge measurements revealed that iron ions are in a mixed Fe2+/Fe3+ oxidation state and preferentially occupy the Ti4+-site. UV-visible spectra reveal a reduction in the optical gap (E-gap) of STFO samples as the amount of iron is increased. An analysis of the data obtained by field emission scanning electron microscopy points out that the nanoparticles present a cubic morphology independently of iron content. According to high-resolution transmission electron microscopy results, these nanocubes are formed by a self-assembly process of small primary nanocrystals.CNPqCNPq [70/2008]Generalitat Valenciana [Prometeo/2009/053]Generalitat ValencianaMinisterio de Ciencia e Innovacion, [CTQ2009-14541-Co2]Ministerio de Ciencia e InnovacionMinisterio de EducacionMinisterio de Educacion [PHB2009-0065-PC

Clinical evaluation, biochemistry and genetic polymorphism analysis for the diagnosis of lactose intolerance in a population from northeastern Brazil

OBJECTIVE: This work aimed to evaluate and correlate symptoms, biochemical blood test results and single nucleotide polymorphisms for lactose intolerance diagnosis. METHOD: A cross-sectional study was conducted in Fortaleza, Ceará, Brazil, with a total of 119 patients, 54 of whom were lactose intolerant. Clinical evaluation and biochemical blood tests were conducted after lactose ingestion and blood samples were collected for genotyping evaluation. In particular, the single nucleotide polymorphisms C>;T-13910 and G>;A-22018 were analyzed by restriction fragment length polymorphism/polymerase chain reaction and validated by DNA sequencing. RESULTS: Lactose-intolerant patients presented with more symptoms of flatulence (81.4%), bloating (68.5%), borborygmus (59.3%) and diarrhea (46.3%) compared with non-lactose-intolerant patients (

Structural and optical properties of CaTi'O IND.3' perovskite-based materials obtained by microwave-assisted hydrothermal synthesis: an experimental and theoretical insight

CaTiO3 powders were synthesized using both a polymeric precursor method (CTref) and a microwave-assisted hydrothermal (CTHTMW) method in order to compare the chemical and physical properties of the perovskite-based material as a function of the synthesis method. To this end, X-ray diffraction, Raman spectroscopy, inductively coupled plasma atomic emission spectroscopy and experimental Ti and Ca K-edge X-ray absorption near-edge structure spectroscopy, as well as measurements of photoluminescence (PL) emission, were used to characterize the typical bottom-up process of the CaTiO3 perovskite phase at different times. Detailed Rietveld refinements show a random polycrystalline distortion in the powder structure, which can be associated with the tilting (α angle < O–Ti–O) between adjacent TiO6 octahedra (intermediate range) for CTHTMW samples and an intrinsic TiO6 distortion (short range) in relation to the polymeric precursor CTref sample. These properties were further investigated by first-principles calculations based on the density functional theory at the B3LYP level. The relationship between this tilting on the PL profile is highlighted and discussed. Thus, a structural model derived from both experimental results and theoretical simulations reveals a close relationship between this tilting and the presence of intermediate energy states within the band gap which are mainly responsible for PL emissionsCAPESCNPQFAPESP/CEPID 98/14324-