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Mineral Liberation Analyzer (MLA) is an automated mineralogical system originally developed to characterize ore and mill feeds for the metallurgical processing industry. Its ability to quantitatively characterize solid and particulate material, including whole rock thin sections, waste rock, tailings, soil, and sediments, has led to increasing applications in other industries. The software uses back-scatter electron imagery and energy dispersive X-ray analysis to analyze each particle’s shape, size, and mineralogical information. Energy dispersive X-ray data are compared to a user-generated Mineral Reference Library consisting of known phases and corresponding EDS spectra to classify each particle. MLA is used in this study to provide quantitative assessments of mining-related environmental samples to answer questions regarding mineralogical controls on bioaccessibility, metal leaching/acid rock drainage potential, and anthropogenic influence. Six tailings samples from the New Calumet Mine in Quebec, Canada, were analyzed using MLA. Gastric Pb bioaccessibility testing and total metal content performed on these samples indicated that Pb bioaccessibility in the <250 micron size fraction was not directly correlated with the total Pb concentration. This suggested that there were mineralogical and/or physical controls on bioaccessibility. MLA was used to quantify the relative proportions of cerussite, a highly bioaccessible Pb carbonate, and galena, a lower bioaccessibility Pb sulfide. Liberation and particle size were also analyzed as controls on bioaccessibility. Sample GD-VEG1 (highest bioaccessibility) has the highest ratio of cerussite to galena, the smallest particle size, and the most liberated Pb-bearing particles. The New Calumet tailings were also analyzed using static testing, a suite of laboratory tests used by environmental scientists and mine operators to operationally define acid rock drainage and metal leaching potential. Modal mineralogy obtained from MLA analysis was used to calculate neutralization potential (NP) and acid potential (AP), taking into account the presence of iron carbonate minerals and iron-bearing sulfides other than pyrite. Results are within several units of those obtained by static testing. Two Ni-impacted soil samples collected from the region of Kalgoorlie, Australia were characterized using MLA. Previous studies had focused on bioaccessibility and sequential extraction testing and minor mineralogical work. Preliminary XANES characterization conflicted with mineralogy predicted from sequential extraction and EMPA and MLA were used to quantitatively characterize major Ni-bearing phases and resolve previous discrepancies. / Thesis (Master, Geological Sciences & Geological Engineering) -- Queen's University, 2013-08-24 08:13:18.722

The objective of this study was to evaluate the biofilm removal efficacy of three root canal treatment systems: ProUltra® PiezoFlow™, traditional needle irrigation, and the GentleWave® system in an ex-vivo benchtop study. Twenty-four extracted maxillary and mandibular molars were selected. Teeth were all instrumented to a master apical file size #25 with 4% taper. Teeth were then randomly divided into four experimental groups and two control groups. The root canals were inoculated with a culture of Enterococcus faecalis and incubated for five weeks to form a biofilm. Each group was then treated with one of the different root canal treatment systems using 6% sodium hypochlorite (NaOCl) as per the respective manufacturer’s recommendation followed by a rinse with water. Following treatment, teeth were decoronated and roots were sectioned longitudinally. Three scanning electron microscope images were taken at the apical level per root half at 5000x magnification. Images were scored by four calibrated examiners blind to group membership using a four-point scoring system (<5% coverage, 5-33%, 34-66%, and >66%). Results were analyzed using mixed model ANOVA. All the experimental groups were significantly better than the positive control group in removing biofilm. Among the experimental groups, the GentleWave® 15/04 group was significantly better than the other groups. There was no significant difference between the GentleWave® and the ProUltra® PiezoFlow™. Traditional needle irrigation scored the worst in reducing E. faecalis biofilm. The GentleWave™ system was as effective at intracanal biofilm removal as the ProUltra® PiezoFlow™ and better than traditional needle irrigation using 6% NaOCl as an irrigant.

Superalloys based on platinum-group metals (PGMs) are being developed for high temperature applications. Currently, the optimum alloy is Pt84:Al11:Ru2:Cr3, and work is ongoing. Niobium is a possible addition to increase the melting point, but limited phase diagram data are available. Although work has been done on the Pt-Al-Nb system, there are no reported data for Pt-Cr-Nb. This is a study of the Pt-Cr-Nb system. As-cast samples of the Pt-Cr-Nb ternary system were investigated using scanning electron microscopy with energy-dispersive X-ray spectroscopy, and X-ray diffraction. The results were used to plot a solidification projection and all binary phases extended into the ternary, except for α´Pt, which was not identified in this investigation. The extensions of the binary phases were: (Cr) ~2 at.% Nb; (Pt) ~24 at.% Nb and 65 at.% Cr; (Nb): ~12 at.% Pt and ~17 at.% Cr; ~NbPt2: ~20 at.% Cr; ~NbCr2: ~18 at.% Pt; ~Cr3Pt: ~10 at.% Nb; ~βNbPt3: ~4 at.% Cr and ~Nb1-XPt1+X: ~13 at.% Cr. Five ternary phases were identified: τ1:~Nb17:Cr64:Pt19; τ2:~Nb28:Cr55:Pt17; τ3:~Nb30:Cr30:Pt40; τ4:~Nb45:Cr27:Pt28 and τ5:~Nb40:Cr18:Pt42. The liquidus surface was derived using the binary phase diagrams, identified primary phases, solidification sequences and the solidification projection, together with the eutectic compositions. Nineteen ternary invariant reactions were identified. Hardness measurements were made on all samples, and also toughness and fracture toughness were deduced. Alloys with (Pt) and ~NbPt2 were ductile with reasonable hardness. Alloys containing (Cr), (Nb), ~Cr3Pt, ~NbCr2, ~Nb3Pt and ~Nb2Pt were extremely brittle with cracks, whereas alloys containing ~βNbPt3 and ~Nb1-XPt1+X phases were slightly brittle.

O gênero Aegla Leach, 1820 representa o único táxon dentro de Decapoda Anomura com representantes adaptados exclusivamente a ambientes de água doce. As eglas são endêmicas da América do Sul e vivem em ambientes lóticos com alto nível de oxigenação. Estudos comparativos da morfologia de jovens recém-eclodidos podem contribuir para estabelecer relações de afinidade entre as cerca de 70 espécies já descritas que compõem a família Aeglidae. Porém, o número de trabalhos que descrevem a morfologia em detalhe nesta fase de vida é ainda escasso. O objetivo do presente estudo foi descrever detalhadamente a morfologia externa dos jovens recém-eclodidos das espécies Aegla paulensis e Aegla perobae, com base em Microscopia Óptica e em Microscopia Eletrônica de Varredura (MEV). Fêmeas ovígeras foram coletadas e transferidas para o laboratório a fim de se obter os jovens recém-eclodidos dos ovos. A descrição detalhada da morfologia do jovem recém-eclodido incluiu a carapaça, o abdome, os apêndices cefalotorácicos (antênula, antena, mandíbula, maxílula, maxila, maxilípedes, pereópodes) e a região do télson juntamente com os urópodes. As cerdas foram analisadas em detalhe quanto ao número, localização e tipo morfológico com o auxílio da MEV. Os resultados obtidos foram analisados e comparados com os das espécies que já tiveram seus jovens recém-eclodidos descritos e também com os adultos. As principais descobertas do estudo foram: as lineae aeglicae, os pleópodes rudimentares, a riqueza de tipos de cerdas e os poros sensoriais / Genus Aegla Leach, 1820 represents the one taxon within Decapoda Anomura with representatives exclusively adapted to freshwater environments. Aeglids are endemic to South America and they live in lotic environments with high levels of dissolved oxygen. Comparative studies of the newly-hatched juvenile morphology may contribute to establish affinity relations among the 70 species of the Aeglidae family already described. However, the number of studies which describe the morphology at this life phase in detail is still scarce. The objective of this study was to describe the external morphology of the newly-hatched juvenile of Aegla paulensis and Aegla perobae in detail, using Light Microscopy and Scanning Electron Microscopy (SEM). Newly-hatched juveniles were obtained from ovigerous females kept under laboratory conditions. Detailed description of the newly-hatched juveniles included the carapace, the abdomen, the cephalothoracic appendages (antennule, antenna, mandible, maxillule, maxilla, maxillipeds, pereiopods), and the telson-uropods region. SEM was used to analyze setae number, location and type. The results were analyzed and compared with those from newly-hatched juveniles already described and with adults. The main findings in this study were: lineae aeglicae, rudimentary pleopods, setae morphology diversity, and pores sensilla.

Os sistemas de lima única constituem a mais recente tecnologia no que se refere ao preparo dos canais radiculares, e vem sendo objeto de estudo sob diversos aspectos. Uma das preocupações referentes aos sistemas automatizados é a manutenção da qualidade e segurança nos preparos quando da reutilização do instrumento. Este estudo teve como objetivo avaliar as alterações de superfície de dois sistemas de lima única - Wave One e One Shape - e seu desempenho através do tempo de preparo no decorrer dos usos. Duzentos condutos de molares inferiores humanos extraídos foram instrumentados com 10 limas Wave One e 10 limas One Shape, acompanhados de irrigação com 10 ml de Hipoclorito de Sódio 2.5%. Cada instrumento foi utilizado por 10 vezes. Os tempos para o preparo completo do canal foram registrados por um cronômetro digital e anotados em tabelas. Para avaliação em microscopia eletrônica de varredura as limas novas foram observadas assim que removidas da embalagem. Após as utilizações, os instrumentos foram limpos, esterilizados em autoclave e observados após 2, 6, 8 e 10 usos. Três avaliadores calibrados observaram as fotomicrografias e registraram de acordo com os scores propostos a presença ou ausência de alterações superficiais. O teste Kappa de concordância entre os avaliadores apresentou maioria de resultados ótimo a moderado (?=5%). Os dados referentes à avaliação das imagens foram submetidos ao teste Wilcoxon-Mann-Whitney com nível de significância de 5% (?=5%). As alterações mais observadas foram aplainamento e microcavidade. O crack foi observado nos dois instrumentos sendo significante a partir do sexto uso para Wave One e do décimo para One Shape. Os dados relativos aos tempos de preparo foram submetidos à análise estatística pelos testes Wilcoxon-Mann-Whitney, ANOVA e Mc-Nemar com nível de significância de 5% (?=5%). Os tempos de preparo registrados para One Shape foram inferiores aos tempos para Wave One. O uso influenciou os tempos de preparo sendo observado um aumento significativo para os dois instrumentos. Um instrumento One Shape fraturou mas a ocorrência não foi estatisticamente significante. / Single-file systems are the most recent technology in regard to the preparation of root canals and have been studied in several ways. One of the concerns related to automated systems is maintaining quality and safety in preparation when the instrument is reused. This study\'s aim was to evaluate the changes on the surface of two single-file systems - Wave One and One Shape - and their performance through preparation time over the uses. Two hundred root canals of extracted human molars were instrumented with 10 Wave One files and 10 One Shape files, followed by irrigation with 10 ml of sodium hypochlorite 2.5%. Each instrument was used 10 times. The time required to complete each root canal was measured by a digital stopwatch and recorded in tables. New unused files were analysed using a scanning electron microscope. After used, the instruments were cleaned and sterilized, then observed after 2, 6, 8 and 10 uses. Three calibrated evaluators observed these SEM images and listed according to the suggested scores the presence or absence of changes on the surface. The Kappa test showed mostly results from moderate to great (? = 5%). The data relating to evaluation of images was submitted to the Wilcoxon-Mann-Whitney test with a significance level of 5% (? = 5%). The most frequent changes were blunt edges and microcavities. Cracking was observed in both instruments being significant in Wave One after the sixth use and in One Shape after the tenth use. Data on preparation times were statistically analysed by the Wilcoxon-Mann-Whitney, ANOVA and Mc-Nemar tests with a significance level of 5% (? = 5%). Regarding the working time taken to shape the canals, One Shape was significantly faster than Wave One. The preparation time was affected by the number of file use increasing significantly on both instruments. A One Shape instrument fractured but the finding was not statistically significant.

A resistência de plantas daninhas é um grande problema que afeta a produtividade das culturas em nosso país, ao passo que quando é identificada, deve ser estudada visando desenvolver estratégias de manejo que evitem a expansão e seleção em novas áreas, além de seleção de resistência múltipla em áreas onde está presente. Nesta temática o objetivo desta pesquisa foi determinar manejo alternativo ao glyphosato para as espécies Chloris elata e Digitaria insularis no período de entressafra da cultura da soja e identificar características morfológicas da superfície foliar de Chloris elata que possam interferir sobre o controle com herbicidas. Foram estudadas alternativas ao glyphosate para manejo em áreas de sistema de produção soja/milho, em dois experimentos com as plantas daninhas Chloris elata e Digitaria insularis perenizadas e com duas condições de roçada (15 e 30 cm). Foram avaliados o controle visual das plantas daninhas, redução de matéria fresca e seca. Para morfologia das folhas da espécie Chloris elata foi realizada análise histológica com recursos de microscopia eletrônica de varredura, visando caracterizar a morfologia da folha, além de determinar o índice estomático, densidade estomática e densidade de tricomas para as superfícies adaxial e abaxial das folhas, nos estádios 4 e 6 folhas totalmente expandidas. Digitaria insularis se mostrou menos suscetível as técnicas de manejo empregadas para plantas perenizadas, necessitando duas aplicações sequenciais para conter a rebrota dos tratamentos. O uso da maior dose do herbicida haloxyfop associado aos herbicidas glyphosate ou amônio-glufosinato se mostrou eficaz no controle de C. elata e D. insularis. O manejo de roçagem potencializou a ação dos herbicidas, e a planta daninha D. insularis se mostrou mais suscetível a está técnica em relação ao C. elata. Para este manejo a associação da maior dose de haloxyfop ao glufosinato foi eficaz para as duas gramíneas. As alturas de roçagem somente se diferenciaram nas primeiras avaliações. O biótipo resistente de C. elata apresentou menor densidade estomática, no estádio de 4 folhas completamente expandidas e maior densidade de tricomas no estádios de 6 folhas completamente expandidas, o que pode contribuir para a resistência ao glyphosate. Está espécie apresentou formações de cristais de cera que circundam o ostíolo, no estádio de 6 folhas completamente expandidas, podendo estar relacionada a a menor suscetibilidade ao glyphosate desta planta daninha perenizada. / Weed resistance is a major problem that affects crop productivity in our country, whereas when it is identified, it must be studied in order to develop management strategies that avoid expansion and selection in new areas, as well as multiple resistance selection in areas where it is present. In this subject the objective of this research was to determine alternative management of glyphosate for the Chloris elata and Digitaria insularis species during the off - season of the soybean crop and to identify the morphological characteristics of the leaf surface of Chloris elata that could interfere the control with herbicides. It was studied alternatives to glyphosate for management in areas of soybean / maize production system in two experiments with weeds Chloris elata and Digitaria insularis perennial and with two mowing conditions (15 and 30 cm). The visual control of weeds, fresh and dry matter reduction were evaluated. For the morphology of the leaves of the Chloris elata species, a histological analysis was carried out using scanning electron microscopy to characterize the leaf morphology, as well as to determine the stomatal index, stomatal density and trichome density for the adaxial and abaxial surfaces of the leaves, stages 4 and 6 fully expanded leaves. Digitaria insularis was less susceptible to the management techniques used for perennial plants, requiring two sequential applications to contain the regrowth of treatments. The use of the highest dose of the herbicide haloxyfop associated with the herbicides glyphosate or ammonium glufosinate proved to be effective in the control of C. elata and D. insularis. Herbicide management potentiated herbicide action, and D. insularis weed was more susceptible to this technique than C. elata. For this management, the association of the highest dose of haloxyfop to glufosinate was effective for both grasses. The cutting heights differed only in the first evaluations. The resistant C. elata biotype showed lower stomatal density at the stage of 4 fully expanded leaves and greater density of trichomes in the stages of 6 fully expanded leaves, which may contribute to resistance to glyphosate. This species presented waxy crystal formations that surround the ostrich, in the stage of 6 fully expanded leaves, and may be related to the natural tolerance to the glyphosate of this perennial weed.

O objetivo desse estudo foi comparar o desempenho de ligaduras ortodônticas estéticas de 4 marcas comerciais, após 30 dias na cavidade bucal, com o uso de dentifrício clareador e convencional para avaliar: alteração de cor por meio da espectrofotometria; a ultraestrutura da superfície por meio da Microscopia Eletrônica de Varredura (MEV); propriedade elástica por meio do teste de tração. Foram avaliadas as ligaduras seguintes marcas comerciais: American Orthodontics, 3M Unitek, Orthotechnology e Morelli Ortodontia. Foram selecionados, após o cálculo amostral, 20 pacientes que atenderam aos critérios de inclusão. Os pacientes receberam, de forma aleatória, com o auxílio do acessório Shooter (TP Orthodontics, La Porte, IN, EUA) ligaduras nos elementos 13, 23, 33 e 43; 32, 31, 41 e 42. No mesmo dia receberam dentifrício clareador Colgate Luminous White (Colgate-Palmolive Indústria e Comércio, São Bernardo do Campo, SP, Brasil) que foi usado por 30 dias (grupo experimental). Após esse período as ligaduras foram removidas, armazenadas (em saliva artificial) e, imediatamente submetidas aos testes. Os pacientes receberam, então, dentifrício convencional Colgate Máxima Proteção Anti-cáries (Colgate-Palmolive Indústria e Comércio, São Bernardo do Campo, SP, Brasil) (grupo controle). Após 30 dias, foram removidas, armazenadas e submetidas aos ensaios. As ligaduras inseridas nos bráquetes dos caninos foram avaliadas para alteração de cor pelo espectrofotômetro (Vita Easyshade Zahnfabrik, Bad Säckingen, Alemanha). Em seguida, as ligaduras, de cada marca, que apresentaram maior e menor variação de cor com o dentifrício clareador e convencional, bem como ligaduras novas, foram submetidas à avaliação qualitativa com a visualização pelo Microscópio Eletrônico de Varredura (EVO 50, Carl Zeiss, Cambridge, Inglaterra). As ligaduras que estavam inseridas nos bráquetes incisivos inferiores foram submetidas ao teste de tração pela Máquina de Ensaio Mecânico Universal (EMIC DL 2000, São José dos Pinhais, PR, Brasil). Os achados foram submetidos à análise estatística ANOVA e ao teste complementar de Duncan em um nível de significância de 5%. Os resultados mostraram que o dentifrício clareador não conseguiu efetivamente manter a estabilidade de cor das ligaduras ortodônticas estéticas. O valor final para o &Delta;E (variação total de cor) para todas as marcas foi > 3,3 o que indica uma alteração clinicamente perceptível pelo olho humano e que sinaliza a reposição do material por razões estéticas. Em relação à MEV as imagens obtidas foram heterogêneas e não permitiram caracterizar um padrão para um ou outro dentifrício. No que se refere ao teste de tração, houve melhor desempenho para as marcas 3M Unitek e American Orthodontics. O tipo de dentifrício, clareador ou convencional, não alterou a propriedade elástica entre as marcas estudadas. Pode-se concluir, pela presente pesquisa, que o dentifrício clareador não foi capaz de alterar a estabilidade de cor nas 4 marcas avaliadas por um período de 30 dias. A avaliação qualitativa pela MEV não permitiu concluir se a abrasividade do dentifrício clareador trouxe danos ou injurias à superfície das ligaduras. Apesar disso, o seu uso não alterou a propriedade elástica das mesmas. / The objective of this study was to compare the performance of aesthetic orthodontic ligatures/modules of 4 commercial brands, after 30 days in the oral cavity, with the use of conventional and whitening dentifrice to evaluate: color change by spectrophotometry; the ultrastructure of the surface by Scanning Electron Microscopy (SEM); elastic property by the tensile test. The following brands were evaluated: American Orthodontics, 3M Unitek, Orthotechnology and Morelli Orthodontics. Twenty patients who were included in the inclusion criteria were selected after sample calculation. Patients received, at random, with the aid of the Shooter accessory (TP Orthodontics, La Porte, IN, USA) ligatures on elements 13, 23, 33, 43, 32, 31, 41 e 42 and whitening dentifrice Colgate Luminous White (Colgate-Palmolive Indústria e Comércio, São Bernardo do Campo, SP, Brazil), which was used for 30 days (test group). After this period, the ligatures were removed, stored (in artificial saliva) and immediately submitted to the tests. Patients were then given conventional toothpaste Colgate Maximum Anti-caries Protection (Colgate-Palmolive Indústria e Comércio, São Bernardo do Campo, SP, Brazil). This was the control group. Once again, after 30 days, the modules were removed, stored and submitted to assays. Ligatures inserted into the canine brackets were evaluated by the spectrophotometer (Vita Easyshade Zahnfabrik, Bad Säckingen, Germany) to evaluate the color change. After this step, the ligatures of each brand, which presented greater and lesser color variation, both with the whitening dentifrice as well as the conventional one, and new ligatures, were selected for qualitative evaluation with the visualization by the Scanning Electron Microscope (EVO 50, Carl Zeiss, Cambridge, England). The ligatures that were inserted in the lower incisor brackets were subjected to the tensile test by the Universal Mechanical Testing Machine (EMIC DL 2000, São José dos Pinhais, PR, Brazil). The findings were submitted to ANOVA statistical analysis and Duncan\'s complementary test at a significance level of 5%. The results showed that the whitening dentifrice failed to effectively improve the color stability of aesthetic orthodontic ligatures. The final value for &Delta;E (total color change) for all brands was > 3.3 which indicates a change clinically perceptible by the human eye and signaling the replacement of the material for aesthetic reasons. In relation to the SEM the images obtained were heterogeneous and did not allow to characterize a standard for one or the other dentifrice. Regarding the tensile test, there was better performance for the brands 3M Unitek and American Orthodontics. The type of dentifrice, whitening or conventional did not alter the elastic property between the brands studied. It can be concluded from the present research that the whitening dentifrice was not able to change the color stability in the 4 brands evaluated for a period of 30 days. The qualitative evaluation by SEM did not allow the conclusion that the abrasiveness of the whitening dentifrice caused damage to the surface of the ligatures. Despite this, their use did not alter their elastic property.

Diferentes técnicas e metodologias foram utilizadas no estudo do desenvolvimento do sistema nervoso, analisando como modelos experimentais, entre outros, o embrião do \"Gallus domesticus\" e embriões de diferentes anfíbios. Com o advento do microscópio eletrônico de varredura (M.E.V.) pode-se, com certas limitações, efetuar uma análise tridimensional de estruturas biológicas. Portanto, utilizando o M.E.V., neste trabalho apresentamos nossas observações sobre o desenvolvimento inicial do tecto óptico do embrião de \"Gallus domesticus. / Different techniques and methods were used in the study of the development of the nervous system, analyzing how experimental models, among others, the embryo of \"Gallus domesticus\" and embryos of different amphibians. With the advent of the scanning electron microscope (SEM) can be, with certain limitations, make an analysis of three-dimensional structures. Therefore, using the SEM, in this paper we present our observations on the initial development of the embryo optical roof of \"Gallus domesticus.