1444 research outputs found
Sort by
Wood typification by Venturi easy ambient sonic spray ionization mass spectrometry: the case of the endangered Mahogany tree
No full text6 p. : il.Venturi easy ambient sonic spray ionization mass spectrometry in both its liquid (VL-EASI-MS) and solid samplemodes (VS-EASI-MS)
is shown to provide nearly immediate and secure typification of woods, as demonstrated for Mahogany, an endangered and
most valuable type of tropical wood. This reddish wood displays unique phytochemical markers (phragmalin-type limonoids)
which are rapidly detected from the wood surface by VS-EASI-MS or from a simple methanol extract of a tiny wood chip by
VL-EASI-MS. Unique profiles were obtained for Mahogany (Swietenia macrophylla) whereas genuine samples of six other
similar types of woods, which are commonly falsified by artificial coloring and commercialized as Mahogany, display also
typical but dissimilar pythochemical profiles as compared to that of the authentic wood. Variable and atypical chemical
profiles were observed for artificially colored woods. Secure chemical characterization via VS-EASI-MS or Vs-EASI-MS
fingerprints of Mahogany and other types of woods with similar appearance should help to control the illegal logging and
trade of this and other endangered woods and their falsification, and to create certified standards. Copyright © 2012 John
Wiley & Sons, Ltd
Inorganic polyphosphates are stored in spherites within the midgut of Anticarsia gemmatalis and play a role in copper detoxification
No full text9 p. : il.Inorganic polyphosphates (PolyP) are widespread molecules that have been shown to play a role in metal detoxification and heavy-metal tolerance. In the present report, we investigated the functional role of spherites as PolyP-metal binding stores in epithelial cells of the midgut of Anticarsia gemmatalis, a lepidopteran pest of soybean. PolyP stores were detected by DAPI staining and indirect immunohistochemistry as vesicles distributed in columnar cells and around goblet cell cavities. These PolyP vesicles were identified as spherites by their elemental profile in cell lysates that were partially modulated by P- or VATPases.
PolyP levels along the midgut were detected using a recombinant exopolyphosphatase assay.
When copper was added in the diet of larva, copper detection in spherites by X-ray microanalysis correlated with an increase in the relative phosphorous X-ray signal and with an increase in PolyP levels in
epithelia cell lysate. Transmission electron microscopy of chemically fixed or cryofixed and freeze substituted tissues confirmed a preferential localization of spherites around the goblet cell cavity. Taken together, these results suggest that spherites store high levels of PolyP that are modulated during metal uptake and detoxification. The similarity between PolyP granules and spherites herein described also suggest that PolyP is one of the main phosphorous source of spherites found in different biological models. This suggests physiological roles played by spherites in the midgut of arthropods and mechanisms
involved in heavy metal resistance among different insect genera
Bayesian inference in waveform metrology
No full text12 p. : il.A Bayesian approach to spectrum analysis is here applied to waveform metrology. The
objective is the analysis of deterministic signals contaminated by additive noise that are
generated and measured for instrument calibration purposes. The method uses
approximations based on the normal distribution and posterior mode which are valid for
large sample sizes and/or high signal-to-noise ratios. It can be easily implemented with
those commercial laboratory software packages routinely used by metrologists for
controlling instrumentation and reporting measurement results. Its performance is
confirmed here through several computer simulated examples
Traceability & uncertainty
No full text1 pôster : il.O pôster RASTREABILIDADE E INCERTEZA ressalta a existência de incertezas associadas a todo processo de medição e a importância de conhecê-las para determinar quão exato é o valor medido. Identifica os fatores que podem causar a incerteza (fatores ambientais, instrumentos de medição inferiores, técnicas de medição inadequadas) e que asseguram medições bem sucedidas (instrumentos calibrados, rastreabilidade a padrões nacionais, compreensão da incerteza, aplicação de boas práticas para medição). O cartaz esclarece a forma de expressar a incerteza e sua relação com o conceito de erro de medição. O conceito de rastreabilidade é relacionado à manutenção do SI e à atuação dos Institutos Nacionais de Metrologia. A diferença entre exatidão e precisão é tratada com ilustrações das quatro possíveis situações – inexato e impreciso; preciso e inexato; exato e impreciso; exato e preciso
Metagenomics in polluted aquatic environments
No full text16 p. : il.Metagenomics is defined as the culture-independent genomic analysis of biological
assemblages providing access to the whole set of genes and genomes from a sample. It
encompasses a variety of techniques that are based on (i) total DNA extraction from samples followed by PCR amplification of specific genes, (ii) library construction or amplification and sequencing of the whole genetic material. These methodologies have successfully been applied in studies of composition, dynamics, and functions of microbial communities in a variety of ecosystems including those subjected to anthropogenic modifications (Gilbert & Dupont, 2011).
Culture independent methods allow the analysis of a set of metabolic genes from microbial communities, which can be used to determine how environmental conditions such as pollution can shape community composition and the diversity of genes associated with
biogeochemical cycles such as those of carbon, nitrogen, and phosphorus (Singh et al., 2009).
This approach is also useful for the discovery of novel environmental microorganisms and genes, with important applications for biotechnology, medicine, and bioremediation (Cardoso et al., 2011).
This applicability has resulted in a recent sharp increase in studies focusing in the
metagenomic analysis of polluted sites. Their aim is to characterize microbial communities from a diverse set of environments such as freshwater, marine sediments, open ocean, pelagic ecosystems, soil, and host-associated communities. An example of these initiatives is the Global Ocean Sampling Expedition (GOS), which assessed the genetic diversity of marine microbial communities around the Earth. Since 2003, an enormous amount of data has been generated by GOS helping scientists to reveal the microbial diversity and also allowing them to better understand microbial phylogeny and ecology (Gilbert & Dupont, 2011)
In vivo and in vitro biocompatibility study of nanostructured carbonateapatite
No full text5 p. : il., tab.The objective of this study was to investigate the in vitro and in vivo biological responses to carbonate apatite (cHA) in comparison to hydroxyapatite (HA). Spheres (400500 μm) of both materials were synthesized under 5ºC (cHA) and 90ºC (HA) and not sintered. The in vitro cytocompatibility was determined by the XTT assay, according to ISO 10993-5:2009, after
exposure of MC3T3-E1 cells to the materials extracts. Ethics Commission on Teaching and
Research in Animals approved this project (CEPA/NAL 193/10) and, subsequently, the
biomaterials were grafted in the subcutaneous tissues of mice (n=15). After 1 and 3 weeks, five animals of each group were killed for samples removal containing biomaterials and surrounding tissues for histological examination. Semi-serial (5-μm thick) sections were cut and stained with
Hematoxylin and Eosin (HE) and the presence of inflammatory infiltrates and biomaterials
resorption were evaluated. The experimental group of 3 weeks didn’t show the presence of spheres of both biomaterials and few spheres were observed after 1 week. Histological analysis showed the granulation tissue around the biomaterials with the presence of multinucleated giant cells. After 3 weeks it was observed the presence of fibrous tissue around biomaterials and few inflammatory
cells. No signals of tissue necrosis were observed in both groups in all experimental studied periods.
Nanostructured carbonate apatite spheres are cytocompatible, biocompatible and present initial biosorption on the subcutaneous comparable to stoichiometric HA, indicating its suitability for further studies on regenerative medicine
Standardized study of carbonate apatite as bone substitute in rabbit’s tibia
No full text5 p. : il., tab.The objective of this study was to investigate the bone repair of carbonate apatite (cHA)in comparison to hydroxyapatite (HA, control group) on osseous repair of rabbit’s tibia. Spheres (400-500 μm) of both materials were synthesized under 37ºC (cHA) and 90ºC (HA) and were not sinterized. Ethics Commission on Teaching and Research in Animals approved this project (CEPA/NAL 208/10). Six White New Zealand rabbits were submitted to general anesthesia and one
perforation (2mm) was made in each tibia for implantation of cHA (left tibia) and HA spheres (right tibia). After 4 weeks all animals were killed and one fragment of each tibia with the biomaterial was collected with a total of 6 bone blocks for each group. Five bone blocks of each group were
demineralized and 5-μm thick semi-serial sections were stain with Hematoxillin and Eosin and Trichromic of Masson for histological analysis and two fragments were collected and embedded in a methacrylate-based resin and cut into slices with ~30 μm and were analyzed by light microscopy (bright field and polarized microscopy). Both groups didn’t show the spheres after 4 weeks, newformed bone was observed from the periphery toward to the center of the surgical defect, which was even filled with connective tissue. Both materials are biocompatible, promote osteoconduction and
showed to be resorbable
Programa de análise de produtos : relatório da análise em fontes de alimentação para computadores do tipo desktop
No full text33 f.: il.Há muitos anos, graças a aspectos como a globalização, a importância da comunicação com rapidez e segurança, a informatização de serviços fundamentais à sociedade e a inclusão digital, os computadores tornaram-se bens imprescindíveis nas empresas e residências. Estudo recente, divulgado pela Fundação Getúlio Vargas – FGV, mostrou que o uso de computadores no Brasil continua crescendo exponencialmente, chegando ao impressionante número de 85 milhões em 2011, com uma projeção de 140 (cento e quarenta) milhões para 2014. Um dos componentes internos de um computador que merece mais atenção, embora na maioria das vezes seja negligenciado por quem o utiliza, é a fonte de alimentação, dispositivo de vital importância por ser responsável pelo fornecimento de energia para que os demais
dispositivos do computador funcionem corretamente. A fonte de alimentação tem o papel de converter a corrente alternada, fornecida pela Concessionária de Energia Elétrica, em corrente contínua, mais apropriada ao funcionamento de equipamentos eletrônicos, como o computador. Essa conversão é necessária porque a corrente
alternada possui oscilações em seu curso, além de uma alta voltagem, propriedades que embora permitam o percurso de longos trajetos das usinas às residências sem grandes perdas, não são indicadas para a alimentação de equipamentos eletrônicos, mais sensíveis a variações de tensão e
curtos-circuitos. Embora fundamental para o bom funcionamento do computador e de seus demais componentes internos, a fonte de alimentação, tradicionalmente, não é levada em consideração no momento da compra ou na montagem de um computador. Isso ocorre porque outros componentes como a frequência do processador, a quantidade de memória, o volume de armazenamento do disco rígido e a capacidade da placa de vídeo, além de serem mais transparentes ao usuário final, tem maior apelo comercial, enquanto a fonte de alimentação, o “combustível” para que todos esses outros componentes funcionem corretamente, atua praticamente imperceptível
Methodological implications on quantitative studies of cytocompatibility in direct contact with bioceramic surfaces
No full text6 p. : il., tabCell adhesion, proliferation and differentiation are important specific parameters to be evaluated on biocompatibility studies of candidate biomaterials for clinical applications. Several different methodologies have been employed to study, both qualitative and quantitatively, the direct interactions of ceramic materials with cultured mammal and human cells. However, while quantitatively evaluating cell density, viability and metabolic responses to test materials, several methodological challenges may arise, either by impairing the use of some widely applied techniques, or by generating false or conflicting results. In this work, we tested the inherent interference of different representative calcium phosphate ceramic surfaces (stoichiometric dense
and porous hydroxyapatite (HA) and cation-substituted apatite tablets) on different tests for quantitative evaluation of osteoblast adhesion and metabolism, either based on direct cell counting after trypsinization, colorimetric assays (XTT, Neutral Red and Crystal Violet) and fluorescence microscopy. Cell adhesion estimation after trypsinization was highly dependent on the time of treatment, and the group with the highest level of estimated adhesion was inverted from 5 to 20 minutes of exposition to trypsin. Both dense and porous HA samples presented high levels of
background adsorption of the Crystal Violet dye, impairing cell detection. HA surfaces also were able to adsorb high levels of fluorescent dyes (DAPI and phalloidin-TRITC), generating backgrounds which, in the case of porous HA, impaired cell detection and counting by image processing software (Image Pro Plus 6.0). We conclude that the choice for the most suitable method for cell detection and estimation is highly dependent on very specific characteristics of the studied material, and methodological adaptations on well established protocols must always be carefully taken on consideration
Uncertainty and UncertaintyGUM mathematica functions
No full text15 p. : il.Two functions from the authors Mathematica package are demonstrated. UncertaintyGUM is based on the Guide to
the Expression of Uncertainty in Measurement (GUM) [1]. The more powerful Uncertainty use the propagation of
distributions to find analytically, numerically, or statistically the expectation ± standard deviation for expression of
random variables with prescribed statistical distributions. These two functions gives the same results for the linear
expression c1*x1+c2*x2+c3*x3 with normal or multinormal statistical distributions of variables x1, x2, and x3.
The approximate results of UncertaintyGUM and exact one of Uncertainty, for the nonlinear expressions
Sin[x] and x^n of the normally distributed random variable x, are compared in three interactive demonstrations. This
paper is a Mathematica notebook transformed to the new CDF (Computable Document Format) supported by the free
CDF Player distributed by the Wolfram Research [3]