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Evaluación in vitro del potencial de hidrógeno y grado abrasivo de las pastas dentales post- blanqueamiento / In vitro evaluation of the hydrogen potential and abrasive degree of post-whitening toothpastesCanelo Muñante, Amir Gianella, Mendoza Mansilla, Rosa Angela 04 January 2022 (has links)
Objetivo: Evaluar in vitro el potencial de hidrógeno y el grado abrasivo de las pastas dentales post-blanqueamiento.
Materiales y métodos: El diseño del estudio fue experimental in vitro. La unidad de análisis estuvo constituida por un fragmento de pasta dental indicada post-blanqueamiento. La muestra fue conformada por 28 fragmentos de pastas dentales dividida en 7 grupos (n=4), a los cuales se evaluó el potencial de hidrógeno a través de un pH metro electrónico (Hanna® HI2221-01, USA) durante 10 minutos. Para ello, se depositaron 20gr de pasta dental en su estado original en un vaso beacker. Asimismo, para determinar el grado abrasivo se empleó la clasificación de la relatividad abrasiva de la dentina (RDA) obtenido de la ficha técnica del producto de las pastas dentales indicadas post-blanqueamiento. Para comparar los valores de pH se utilizó la prueba de Kruskal Wallis (p<0,05).
Resultados: Las medias registradas para la pasta dental con el pH más alcalino fue 8.315 ±0.05 (Sensodyne® blanqueadora) y 5.86 ±0.02 el más ácido (Vitis® Sensible). En relación al grado abrasivo, la pasta Oral B® Pro Salud obtuvo el valor más alto (140), y la pasta Vitis® sensible el más bajo (40).
Conclusiones: En la evaluación, la pasta dental con pH más ácido resultó ser la Vitis sensible con 5.86; mientras que la pasta con valor de grado abrasivo alto fue la Oral B Pro salud con un RDA de 140. / Objective: To evaluate in vitro the potential of hydrogen and the abrasive degree of post-whitening toothpastes.
Materials and methods: The study design was experimental in vitro. The analysis unit consisted of a fragment of toothpaste indicated post-whitening. The sample was made up of 28 toothpaste fragments divided into 7 groups (n = 4), to which the hydrogen potential was evaluated through an electronic pH meter (Hanna® HI2221-01, USA) for 10 minutes. To do this, 20gr of toothpaste in its original state was placed in a beacker glass. Likewise, to determine the abrasive degree, the classification of the abrasive relativity of dentin (RDA) obtained from the technical data sheet of the toothpaste product indicated after bleaching was used. To compare the pH values, check the Kruskal Wallis test (p <0.05).
Results: The means registered for toothpaste with the most alkaline pH were 8,315 ± 0.05 (Sensodyne® whitening) and 5.86 ± 0.02 at the most acidic (Vitis® Sensitive). A statistically significant difference (p <0.05) was considered in the comparison of these. In the evaluation of abrasive degree, the Oral B® Pro Salud paste obtained the highest value (140), and the sensitive Vitis® paste the lowest (40).
Conclusions: In the evaluation, the toothpaste with the most acidic pH proved to be sensitive Vitis with 5.86; while the paste with a high abrasive grade value was Oral B Pro health with 140 RDA. / Tesis
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Heat Stress Inhibits Chloroplast Development in Ivy GeraniumHorton, Anna McLaurin 04 May 2018 (has links)
Pelargonium peltatum, ivy geranium, experiences foliar bleaching at temperatures exceeding 30° C. Contessa™ Red (heat tolerant) and Temprano™ Lavender (heat susceptible) were compared. Established plants underwent temperature treatments of 15/20° C or 25/30° C night/day with moisture treatments of 80% or 30% substrate volumetric water content (VWC). Photosynthesis, leaf greenness and growth data were collected at days 0, 7 and 11. No differences in photosynthetic rate nor a decrease in greenness in developed leaves occured in either cultivar due to high temperature or drought. Contessa™ Red had overall greater growth and leaf greenness than Temprano™ Lavender. Greenness and growth increased similarly for both cultivars at 80% VWC. Any decrease in foliar bleaching due to drought was likely due to a decrease in growth. A second study using Temprano™ Lavender indicated foliar bleaching occurs in newly emerging, developing leaves.
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Effectiveness and mechanisms of action of whitening dentifrices on enamel extrinsic stainsAlshara, Salem A. January 2012 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Whitening dentifrices use different mechanisms for stain removal and prevention. These approaches are abrasives, oxidizing agents, and chemical cleaning agents. The objectives of this in-vitro study were: 1) To compare the whitening effect of commercial whitening and non-whitening dentifrices; 2) To verify the mechanism of action of whitening dentifrices by contrasting two experimental models: chemical model (toothpaste exposure only) and chemo-mechanical (toothpaste exposure with tooth-brushing abrasion). The 256 bovine enamel specimens (10 mm x10 mm) were prepared and partially stained. They were assigned to 8 groups: 6 whitening dentifrices, 1 non-whitening reference dentifrice and deionized water (control); and they were further divided in 2 subgroups (n = 16), chemical and chemo-mechanical. Specimens were exposed to dentifrice slurries 2X/day for 1 min and brushed or not, according to each model. In between dentifrice treatments, specimens were exposed to the staining solution for 5 h. This protocol was repeated for 5 consecutive days and enamel color changes (∆E, ∆L) were measured by spectrophotometry after each day. The abrasivity of the toothpastes was determined using a standard test (ISO 11609). Significantly higher ∆E values (whitening effect) were observed for all groups (p < 0.05), except for the control, when tested in the chemo-mechanical model. In this model, the whitening ability of the toothpastes was mainly determined by their abrasive levels. For the chemical model, no significant differences were observed among groups (p > 0.05). Whitening dentifrices can be effective in preventing and removing enamel surface staining, when associated with tooth-brushing abrasion. This was modulated by the abrasive level of the tested toothpastes, with no chemical action attributed to the chemical agents. / indefinitely
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Gradient Conditioning in Deep Neural NetworksNelson, Michael Vernon 04 August 2022 (has links)
When using Stochastic Gradient Descent (SGD) to train Artificial Neural Networks, gradient variance comes from two sources: differences in the weights of the network when each batch gradient is estimated and differences between the input values in each batch. Some architectural traits, like skip-connections and batch-normalization, allow much deeper networks to be trained by reducing each type of variance and improving the conditioning of the network gradient with respect to both the weights and the input. It is still unclear to which degree each property is responsible for these dramatic stability improvements when training deep networks. This thesis summarizes previous findings related to gradient conditioning in each case, demonstrates efficient methods by which each can be measured independently, and investigates the contribution each makes to the stability and speed of SGD in various architectures as network depth increases.
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Toothwhit"eu"ningBengtsson, Fredrik, Svanberg, Martin January 2016 (has links)
SyfteAtt utvärdera effekterna och bieffekterna av tandblekningsprodukter innehållande eller utsöndrande av väteperoxid på permanenta tänder hos personer under 18 år. Studien gjordes med tanke på barn som drabbats av missfärgade tänder med ett objektivt och subjektivt behandlingsbehov. Detta i syfte att insamla all nuvarande forskning på området samt ställa detta mot EU-direktiven utfärdade 2012. SökstrategierEn systematisk sökning av litteraturen gjordes i databaserna Medline, Cochrane, Embase och Scopus. Inkluderade artiklar skulle vara på antingen Engelska, Svenska, Danska eller Norska. SelektionskriterierStudierna skulle vara gjorda på personer under 18 år med produkter som innehöll eller utsöndrande väteperoxid. Enbart studier på permanenta tänder inkluderades. Studierna var tvungna att utvärdera positiva och/eller negativa effekter av behandlingen. Blekningen skulle utföras in vivo. Fallrapporter inkluderades enbart i syfte att finna eventuella allvarliga bieffekter. ResultatTotalt identifierades 214 artiklar varav 13 stycken uppfyllde inkluderings- och exkluderings-kriterierna. Fyra studier bedömdes ha låg risk av bias, åtta av medelhög samt en som hög risk av bias. Syftet och studiedesignen varierade mellan de inkluderade studierna. De flesta studierna var utförda på mildare missfärgningar samtidigt som de saknade erforderliga uppföljningstider. SlutsatsDet finns inte tillräckligt med studier gjorda på personer under 18 år som utvärderar effekterna av bleking med väteperoxid på fall med mer omfattande missfärgningar. Ett begränsat antal studier med medelhög risk av bias ger ett visst stöd för blekning med väteperoxid på mildare fall av missfärgningar. Samtidigt rapporterades ett stort antal milda, övergående bieffekter. Tills motsatsen bevisats finns ett etiskt stöd för EU-direktiven etablerade 2012. / AimTo investigate the effects and adverse events of tooth whitening performed on children with permanent teeth by the use of products containing or releasing hydrogen peroxide. This was made considering children affected by objectively and subjectively observed tooth discolorations in purpose to consolidate existing research and compare it to the EU directives established 2012.Search strategiesA systematic search of the literature was conducted using the databases Medline, Cochrane, Embase and Scopus. Only studies published in English, Swedish, Danish and Norwegian were included. Selection criteriaThe selection criteria aimed to include studies performed on patients under the age of 18, using whitening products containing or releasing hydrogen peroxide. The bleaching process had to be performed in vivo on permanent teeth. Case reports were included only to be separately reviewed looking for severe side effects and adverse events.ResultsA total of 214 articles were identified and 13 met the inclusion criteria. Four papers were judged to have a low risk of bias, eight a moderate risk and one a high risk of bias. Most studies were performed on mild discolorations while they lacked in necessary follow-up times.ConclusionThere are not enough studies evaluating the effect of using hydrogen peroxide to bleach more severe discolorations on individuals under 18 years old. A limited number of studies showed some support for bleaching with hydrogen peroxide on mild tooth discolorations. Parallel to this, the included studies demonstrated a high number of mild and transient adverse events. Until proven otherwise, the lack of studies gives some ethical support to the EU-directives established 2012.
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[en] METROLOGICAL AND INSTRUMENTAL EVALUATION CONTROL OF WHITE SAMPLES TREATED WITH FLUORESCENT WHITENING AGENTS / [pt] CONTROLE METROLÓGICO E INSTRUMENTAL DA AVALIAÇÃO DE AMOSTRAS BRANCAS TRATADAS COM ALVEJANTE ÓTICOJENNIFER KATHRIN GAY 21 June 2004 (has links)
[pt] A avaliação de artigos brancos tratados com alvejantes
ópticos, como eles são comuns em substratos têxteis,
plásticos e de papel, é uma tarefa que tradicionalmente
resulta em muitas divergências entre avaliações visuais
realizadas em uma cabine padronizada e avaliações
instrumentais realizadas com espectrofotômetros de
refletância. Mesmo entre as avaliações visuais ou entre as
avaliações instrumentais são encontradas diferenças muito
além do aceitável. Uma das principais causas é a
fluorescência dos alvejantes ópticos que é influenciada
pela quantidade de radiação UV em relação com a radiação
na faixa visível do espectro. O trabalho apresentado
analisa as diferentes formas de avaliação, principalmente
do ponto de vista da qualidade da distribuição espectral de
potência do simulador de luz do dia. No caso das avaliações
visuais, são testadas diferentes lâmpadas fluorescentes.
Para as avaliações instrumentais, a calibração e o ajuste
de UV em conjunto com as diferentes aberturas de medição
são analisados. O objetivo é aprimorar os aspectos
metrológicos da avaliação e contribuir para a sua
padronização a fim de garantir a maior reprodutibilidade de
resultados, um procedimento importante e almejado por todos
os segmentos industriais que utilizam os alvejantes ópticos. / [en] The evaluation of white objects treated with fluorescent
whitening agents, such as they are commonly found on
substrates like textiles, plastics and paper, is a task
that traditionally leads to frequent controversy between
the visual evaluations performed in a standardized light
booth and the instrumental evaluations performed on
reflectance spectrophotometers. Even between visual
or instrumental evaluations the differences encountered are
far beyond the acceptable. One of the main reasons is the
fluorescence of the optical brightening agents that is
influenced by the amount of UV radiation in relation to
the amount of radiation in the visible range of the
spectrum. The work presented analyses the different forms
of evaluation, mainly from the point of view of the
quality of the daylight simulators´ spectral power
distribution. In the case of the visual evaluations,
different fluorescent lamps are tested. For the instrumental
evaluations, the UV calibration and adjustment are analyzed
together with the different measurement apertures. The
objective is to improve the metrological aspects of the
evaluation and contribute to its standardization with the
aim to guarantee better reproducibility of results, an
important procedure that is desired by all the industrial
segments that use optical brighteners.
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O desafio das relações étnico-raciais em região de colonização italiana : estudo no município de Carlos Barbosa - RSBertuzzi, Damaris 22 March 2018 (has links)
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Previous issue date: 2018-03-22 / Nenhuma / A presente Dissertação de Mestrado tem por objeto a análise da historicidade das desigualdades nas relações étnico-raciais da sociedade brasileira, notadamente entre brancos e negros, tomando como dimensão empírica para o estudo o município de Carlos Barbosa – RS. A escolha do tema decorre da inserção da autora com atividades docentes e de pesquisa, da preocupação com os processos de discriminação pelos quais sofre o negro e pelo desafio de pensar em uma sociedade de maior igualdade. Na dimensão metodológica o estudo foi realizado mediante pesquisas bibliográficas e documentais na composição dos dois primeiros capítulos. E por meio de coleta de depoimentos de negros e brancos, no município em estudo, a partir de roteiro-base de entrevista, foram elaboradas as exposições e as análises que constituem o terceiro capítulo. As informações e representações dos sujeitos sociais foram catalogadas e, posteriormente, analisadas mediante a técnica da análise de discurso. A reflexão em torno das manifestações discursivas coletadas e dos dados levantados nas pesquisas históricas, demonstra a permanência do preconceito étnico-racial nas práticas cotidianas na comunidade estudada, apontando para os desafios que cidadãos e cidadãs precisam enfrentar para a construção de uma sociedade de igualdade, respeito às diferenças e reconhecimento do outro. / The purpose of this Master's Dissertation is to analyze the historicity of the inequalities in the ethnic-racial relations of Brazilian society, especially among whites and blacks, taking as an empirical dimension to the study the municipality of Carlos Barbosa - RS. The choice of theme stems from the author's insertion in teaching and research activities, concern with the processes of discrimination suffered by black people and the challenge of thinking about a more equal society. In the methodological dimension, the study was carried out through bibliographical and documentary researches in the composition of the first two chapters. Through the collection of testimonies of blacks and whites, in the city under study, based on the interview script, the expositions and analyzes that constitute the third chapter were elaborated. The information and representations of social subjects were cataloged and later analyzed through the technique of discourse analysis. The reflection on the collected discursive manifestations and the data collected in historical research shows the continuation of ethnic-racial prejudice in everyday practices in the community studied, pointing to the challenges that citizens have to face in order to build a society of equality, respect for differences and recognition of the other.
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Les Libres de couleur face au préjugé : franchir la barrière à la Martinique aux XVIIe-XVIIIe siècles / Free colored people confronted with prejudice : crossing lines in Martinique in the seventeenth and eighteenth centuriesPierre-Louis, Jessica 20 June 2015 (has links)
À la Martinique au XVIIIe siècle, les « libres de couleur », qu’ils soient nés libres ou affranchis, noirs ou métis, forment une catégorie juridique distincte des Blancs et des esclaves. L’étude comparée, avec les territoires espagnols ou anglais, montre qu’aucune réglementation légale n’a officialisé un passage de la catégorie Libre de couleur à celle de Blanc dans les colonies françaises de la fin du XVIIe siècle à la Révolution française. Aussi, cette thèse se propose de montrer les processus officieux qui ont permis à certaines personnes – les « assimilés » – de franchir la barrière de couleur. Une réflexion a été menée sur le préjugé de couleur, système raciste dont l’idéologie, soutenue par la réglementation locale, a légitimé la construction collective d’un ordre public et social. Puis, on a examiné l’élaboration de la barrière de couleur. Les libres de couleur ont été les premiers à faire les frais de l’imperméabilisation de la ligne de démarcation et des problèmes posés par la pureté de sang ; mais les Blancs mésalliés, dans le cadre d’unions interraciales, et les Amérindiens ont aussi été visés. Enfin nous avons réfléchi à ce qui faisait la blancheur et aux stratégies adoptées pour réussir ce changement de statut. Le notariat et les 33 000 actes des registres paroissiaux traités ont donné lieu à la reconstitution de généalogies pour examiner des individus et des familles sur plusieurs générations ; on a ainsi observé l’importance du phénotype, le blanchiment, la légitimité des relations, les conjoints privilégiés, le choix des réseaux, les niveaux de fortune et l’usage de l’espace. / In Martinique in the eighteenth century, the "free people of color", both those free by birth and freedmen, black or mixed race, form a legal category, which was distinct from those of whites and slaves. Comparative studies with Spanish or English territories show that no legal regulation formalized a shift - from the category of free colored people to that of White - in the French colonies between the late seventeenth century and the French Revolution. Also, this thesis proposes to show the informal process that enabled some people - the "assimilated" - to cross the color barrier. I analysed the color prejudice, a racist system, whose ideology, supported by local regulations, legitimized the collective construction of a public and social order. In a second step, I examined the development of the color bar. The free colored people were the first to bear the brunt of the impermeability of the demarcation line and of the problems posed by the purity of blood; but some whites, through interracial unions, and Native Americans have also been targeted. Finally I thought about what made the whiteness, and the strategies to achieve whiteness, change in status. Notarial acts and 33,000 acts of parish registers treaties led to the reconstitution of genealogies, in order to examine individuals and families over generations; I observed the importance of the phenotype, whitening, legitimacy relations, privileged partners, choice of networks, wealth levels and the use of space.
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Amperometric biosensor systems prepared on poly(aniline-ferrocenium hexafluorophosphate) composites doped with poly(vinyl sulfonic acid sodium salt).Ndangili, Peter Munyao. January 2008 (has links)
<p>The main hypothesis in this study is the development of a nanocomposite mediated amperometric biosensor for detection of hydrogen peroxide. The aim is to combine the electrochemical properties of both polyaniline and ferrocenium hexafluorophosphate into highly conductive nano composites capable of exhibiting electrochemistry in non acidic media / shuttling electrons between HRP and GCE for biosensor applications.</p>
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Non-iterative joint decoding and signal processing: universal coding approach for channels with memoryNangare, Nitin Ashok 16 August 2006 (has links)
A non-iterative receiver is proposed to achieve near capacity performance on intersymbol
interference (ISI) channels. There are two main ingredients in the proposed
design. i) The use of a novel BCJR-DFE equalizer which produces optimal soft
estimates of the inputs to the ISI channel given all the observations from the channel
and L past symbols exactly, where L is the memory of the ISI channel. ii) The
use of an encoder structure that ensures that L past symbols can be used in the
DFE in an error free manner through the use of a capacity achieving code for a
memoryless channel. Computational complexity of the proposed receiver structure
is less than that of one iteration of the turbo receiver. We also provide the proof
showing that the proposed receiver achieves the i.i.d. capacity of any constrained
input ISI channel. This DFE-based receiver has several advantages over an iterative
(turbo) receiver, such as low complexity, the fact that codes that are optimized for
memoryless channels can be used with channels with memory, and finally that the
channel does not need to be known at the transmitter. The proposed coding scheme
is universal in the sense that a single code of rate r; optimized for a memoryless
channel, provides small error probability uniformly across all AWGN-ISI channels of
i.i.d. capacity less than r:
This general principle of a proposed non-iterative receiver also applies to other
signal processing functions, such as timing recovery, pattern-dependent noise whiten ing, joint demodulation and decoding etc. This makes the proposed encoder and
receiver structure a viable alternative to iterative signal processing. The results show
significant complexity reduction and performance gain for the case of timing recovery
and patter-dependent noise whitening for magnetic recording channels.
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