Float-polishing process and analysis of float-polished quartz

A fluid-mechanical model is developed for the float-polishing process. In this model laminar flow between the sample and the lap results in pressure gradients at the grooves that support the sample on a fluid layer. The laminar fluid motion also produces supersmooth, damage-free surfaces. Quartz substrates for applications in high-stress environments were float polished, and their surfaces were analyzed by optical scatterometry, photoacoustic spectroscopy, and atomic force microscopy. The removal of 100 µm of material by a lapping-polishing process, with final float polishing, left low levels of subsurface damage, with a surface roughness of approximately 0.2-nm rms

Mapeamento da variabilidade genética espontânea das cepas vacinais B19 E RB51 contra Brucella abortus, comercializadas no Brasil.

A brucelose é uma zoonose causada por bactérias intracelulares do gênero Brucella, que infectam humanos, animais domésticos e silvestres. Esta doença apresenta grande impacto econômico, devido à ocorrência de distúrbios reprodutivos nos animais. A prevenção contra infecções causadas por Brucella abortus em bovinos é feita por meio da administração das cepas vacinais B19 e RB51 de B. abortus. Existem relatos de que estas vacinas podem causar aborto às fêmeas vacinadas. Devido a isso, a vacinação de fêmeas jovens é preconizada. Entretanto, há diversos relatos na literatura de persistência da B19 no úbere, proporcionando a eliminação da bactéria pelo leite. Portanto, toda a ocorrência de aborto em animais vacinados, seja por B19 ou por RB51, merece um estudo aprofundado sobre a sua causa. Técnicas moleculares capazes de diferenciar cepas vacinais de cepas selvagens têm sido descritas. O gene ery, ligado ao catabolismo do eritritol, foi caracterizado como um importante marcador nessa diferenciação, por apresentar uma deleção espontânea de 702 pares de base na cepa B19. Como esta cepa é comercializada por diferentes empresas, estudos descreveram que algumas destas cepas comercializadas na Índia não apresentam essa deleção. No Brasil, não há registro sobre a origem das amostras B19 e RB51 utilizadas na confecção das vacinas comerciais, logo um estudo no sentido da verificação de possíveis mutações em relação à amostra padrão se faz necessário, devido a estas poderem reverter a sua virulência. Objetiva-se com este estudo caracterizar genotipicamente as cepas vacinais B19 e RB51 comercializadas no Brasil contra a brucelose bovina. A metodologia utilizada será a genotipagem de genes marcadores de virulência destas cepas vacinais, através da amplificação, sequenciamento e análises in silico das sequências obtidas. Os resultados obtidos permitirão a identificação do genótipo de todas as vacinas comerciais B19 e RB51 utilizadas para a imunização de bovinos no Brasil

Emprego de zeólitas naturais como absorventes de Cd.

O cádio (Cd) é um elemento relativamente raro (0,2 mg/kg na crosta terrestre) e não e encontrado em estado puro na natureza, entretanto passou a ser produzido comercialmente no séculoXX para utilização industrial. São atribuídos à longaexposição ao CD alguns efeitos nocivos àsaúde dentre ele bronquites, distúrbios nosulmões enfseas e efeito renais. A busca ppor materiais naturais que estejam disponíveis em grandes quantidades na natureza e que possam ser empregados como adsorventes para o tratamento de efluentes vem sedo alvo de inúmeras pesquisa

Holonomy corrected Schwarzschild black hole lensing

In the present work, we theoretically investigate gravitational lensing in the spacetime of a holonomy corrected Schwarzschild black hole. Analytical expressions for the light deflection angle are obtained in both the weak field limit and the strong field limit. Furthermore, we analyze observables, such as relativistic images and magnifications, and compare the results with those expected in a Schwarzschild spacetime. We discuss the possibilities and difficulties of investigating such a solution in practice

Characterization of three natural zeolites.

In recent years, great attention has been paid to the application of nano structure materials. Since zeolites have primary particles with at least one dimension in the nanometer scale, they may be regarded as nanomaterials of geological and pedological origins. Zeolites are hydrated aluminosilicates, crystalline, with a wide variety of technological applications. Its structure consists of a skeleton with three-dimensional tetrahedral of AlO4 and SiO4, linked via oxygen atoms, and having channels and cavities in which it is possible to settle ions, water molecules or other adsorbates and salts. The Si and Al are at the center of the tetrahedron, the structural frame includes cavities occupied by relatively large sizes cations (Na+, K+, Ca2+, Mg2+) and water molecules, both having considerable freedom of movement, allowing ion exchange and reversible dehydration. High degree of hydration, low density, stability of the crystal structure, cation exchange properties, electrical conductivity, adsorption of gases and catalytic properties are the main properties of zeolites. About forty species of natural zeolites have been identified and over one hundred and fifty species have been synthesized. The synthetic zeolites have a high degree of purity and are widely used as catalysts for the petrochemical industry. In contrast, natural zeolites, have lower purity, and are easily found on the market, being used for a wide range of purposes. Treatment of industrial effluents, waste water purification, treatment of saline soils and supplementation in the diet of animals are examples of applications of commercial products made from natural zeolites derived from mines located in different regions of the world. Due to their technological applications and physicochemical properties, zeolites have been investigated owing their mineral identification and characterization. Aiming to obtaining the physical and chemical properties, three samples of natural zeolites were evaluated. Their main composition were respectively heulandites/clinoptilolite; clinoptilolite; and stilbite. For this purpose, we determined the particle size distribution, degree of hydration, the superficial area, by BET method, the assessment of the crystalline state by using micrography, the analysis of mineralogical composition by X-rays diffraction technique, and the chemical composition of natural zeolites by using inductively coupled plasma optical spectrometry

Avaliação dos genes gap, virB9 e virB12 de Brucella abortus como potenciais marcadores em teste sorológico para brucelose.

Objetiva-se, com este estudo, analisar as proteínas virB9, virB12 e GAPDH, como potenciais antígenos para diagnóstico da brucelose bovina. Para isto, as proteínas recombinantes serão produzidas via sistema de expressão heteróloga e testadas frente aos parâmetros de qualidade em ensaios de ELISA

Reaction of banana cultivars to the Meloidogyne javanica X Fusarium oxysporum f. sp. cubense complex.

The interaction Fusarium oxysporum f. sp. cubense (Foc) x nematode and the genetic variability of Foc are the main problems with potential to affect the use of resistant varieties in the management of the Panama disease. The objective of this work was to evaluate the interaction between Foc and Meloidogyne javanica on the banana of the Prata Anã, Grande Naine and BRS Princesa cultivars. The experiment was conducted in a randomized block design, with six treatments and ten replications, which differed in the inoculation time of each pathogen. Simultaneous inoculation with Foc and M. javanica, inoculation with Foc one week before inoculation with M. javanica, and inoculation with M. javanica one week before inoculation with Foc. In addition to the controls, Foc isolated, M. javanica isolated, and cultivars without the pathogens. The seedlings were transplanted in 3-liter pots with sterile soil infested with 40 grams of Foc inoculum at the concentration of 1x106CFU/gram and 1000 eggs and J2 of M. javanica. At the end of 56 days, the treatments with 'Grande Naine' presented the highest reproduction factors of M. javanica. In the 'Prata Anã' no interaction was observed between Foc x M. javanica. The treatments with simultaneous inoculation of the two pathogens, and with Foc a week before, in the 'BRS Princesa', presented the highest external disease indices (DI), which promoted the highest AUDPC. The highest internal DI were observed in the treatments Foc+Mj+Grande Naine, Foc+Mj+BRS Princesa, Mj+Grande Naine+Foc and Foc+BRS Princesa+Mj. The simultaneous presence of M. javanica and Foc increases the severity of the Panama disease in Grande Naine and BRS Princesa cultivars

Enamel and dentin mineralization in familial hypophosphatemic rickets: a micro-CT study

Objectives: The aim of the present study was to analyse the mineralization pattern of enamel and dentin in patients affected by X-linked hypophosphatemic rickets (XLHR) using micro-CT (µCT), and to associate enamel and dentin mineralization in primary and permanent teeth with tooth position, gender and the presence/absence of this disease. Methods: 19 teeth were collected from 5 individuals from the same family, 1 non-affected by XLHR and 4 affected by XLHR. Gender, age, tooth position (anterior/posterior) and tooth type (deciduous/permanent) were recorded for each patient. Following collection, teeth were placed in 0.1% thymol solution until µCT scan. Projection images were reconstructed and analysed. A plot profile describing the greyscale distance relationship in µCT images was achieved through a line bisecting each tooth in a region with the presence of enamel and dentin. The enamel and dentin mineralization densities were measured and compared. Univariate ANOVA and post hoc Tukey tests were used for all comparisons. Results: Teeth of all affected patients presented dentin with a different mineralization pattern compared with the teeth of healthy patients with dentin defects observed next to the pulp chambers. Highly significant differences were found for gray values between anterior and posterior teeth (p < 0.05), affected and non-affected (p < 0.05), as well as when position and disease status were considered (p < 0.05). Conclusions: In conclusion, the mineralization patterns of dentin differed when comparing teeth from patients with and without FHR, mainly next to pulp chambers where areas with porosity and consequently lower mineral density and dentin defects were found