Composition and particle size of mineral trioxide aggregate, portland cement and synthetic geopolymers

Objective: To describe the composition and particle size of Portland cement (PC) and geopolymers in comparison to mineral trioxide aggregate (MTA).Design: A quantitative, laboratory-based exploratory study.Setting: Schools of Dental Sciences and Physical Sciences, University of Nairobi; World Agroforestry Centre (ICRAF); Ministry of Mining, all in Nairobi, Kenya.Study population: Grey PC clinker, Kaolin, Fly ash (FA) and blast furnace (BF) slag, together with alkaline-activated aluminosilicates (AS) or geopolymers derived from them, were evaluated in comparison to two brands of MTA (MTA Cem and ProRoot MTA).Methods: The materials were characterized by x-ray diffraction (XRD), energy dispersive X-ray fluorescence (EDXRF), graphite furnace atomic absorption spectroscopy (GFAAS) and fluoride ion selective electrode (FISE) for compositional analysis, and laser diffraction for particle size distribution analysis. Continuous data was subjected to analysis of variance (ANOVA) and Tukey’s post hoc test for hypothesis testing at α level of 0.05.Results: While MTA and PC comprised mainly of dicalcium and tricalcium silicate phases, geopolymers contained aluminosilicate phases such as quartz and mullite. Only FA contained fluoride (43.33μg/g, sd 5.77). There was no statistically significant difference in the composition of MTA and PC as determined by EDXRF except in the Bi (F-statistic=44.29, df=2, adjusted p<0.0001, difference=2.47, 95% CI 16.30, 33.14%wt) and Pb content (F-statistic=164.40, df=2, adjusted p=0.000, difference=1.74, 95% CI 1.43, 2.05%wt). There was no statistically significant difference in the mean particle size distribution of MTA, PC and geopolymers (D50 for PC = 12.46μm, sd 3.18, MTA = 7.23μm, sd 3.43, aluminosilicates = 12.74μm, sd 3.79, p>0.05).Conclusion: Composition of PC was similar to MTA while particle size of PC and geopolymers was similar to MTA

Representação de células vegetais em duas dimensões.

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Substitution of strontium for calcium in glass ionomer cements (Part 1): Glass synthesis and characterisation, and the effects on the cement handling variables and setting reaction

Objectives: To investigate the effects of substituting strontium for calcium in fluoroaluminosilicate glass on the handling variables and setting reaction of high-viscosity glass ionomer cements.Design: An exploratory, laboratory-based study.Setting: Dental biomaterials research laboratory, Dental Physical Sciences Unit, Barts and the London School of Medicine and Dentistry, Queen Mary, University of London.Subjects: A series of five glasses in which strontium substitutes for calcium and based on the general formula: 4.5SiO2 - 3Al2O3 – 1.25P2O5 – xSrO - ySrF,sub>2 – zCaO - yCaF2, where x = 0, 0.5, 1.5 or 3; y = 0, 1 or 2; and, z = 0, 1.5, 2.5 or 3 were synthesized, ground, sieved and the powders characterised by X-Ray Diffraction (XRD), particle size analysis and thermal analysis. Thereafter, they were mixed with poly (acrylic acid) (PAA) and aqueous tartaric acid to form glass ionomer cements, whose properties were investigated at different time points: working and setting times were determined by rheometry;  and, the setting reaction was studied by Fourier transform infra-red (FT-IR) spectroscopy. Results: XRD confirmed the amorphous nature of the glasses, while thermal analysis showed a mixed alkaline/entropic effect on the glass transition temperature. Working and setting times did not vary significantly with strontium content but the shortest times were recorded for the cement with the smallest particle size.Conclusion: The results suggest that substitution of strontium for calcium has insignificant effects on the manipulation and setting reaction of the cement; therefore, substitution can be optimised to produce restorative materials with beneficial anticariogenic properties

Perception of patients attending a tertiary hospital in Nigeria about good dental practice: A pilot study

Background: Criteria for a good dental practice as expressed by patients have influence on their behavior in terms of compliance with clinical advice, less pain and anxiety and more utilization of dental care.Objective: To assess the opinion of patients attending the dental clinic of a tertiary hospital Southwestern, Nigeria about their perception of a good dental practice.Materials and Methods: A 16 item semi‑structured bi‑lingual interviewer‑administered questionnaire comprising socio‑demographic characteristics and 24 criteria of a good dental practice generated by clinicians and patients was administered to 156 patients who were blinded from knowing which criteria were clinicians’ or patients’ criteria. Patients were then asked to pick 12 criteria out of the 24 criteria that they considered of greater priority. Frequency of the most picked criteria in a descending order was determined. Student’s t‑test was used to compare mean scores at P < 0.05.Results: The mean age of study participants was 36.7 ± 13.8 years. The majority 139 (89.1%) of the study participants ranked ‘‘clinician’s procedure should be as painless as possible’’ as the most important clinician determined criteria of a good dental practice while 31 (19.9%) of them ranked hotlines available for emergencies as the least. The majority 133 (85.2%) of the study participants ranked ‘‘sterile procedure and proper handling of equipment’’ as the most important patient determined criteria of a good dental practice while 30 (19.2%) of them ranked patients being attended by just one clinician as the least. There was a statistically significant difference between mean scores of clinicians’ criteria and patients’ criteria (P = 0.00001), participants ranked more patients’ criteria than clinicians’ criteria.Conclusion: In determining the criteria for a good dental practice, clinicians’ perspective as well as patients’ perspective should be considered.Keywords: Clinicians, dental house officers, good dental practice, patientsNigerian Journal of Clinical Practice • Oct-Dec 2013 • Vol 16 • Issue

Preparação de amostras de bactérias para realização de imagens de microscopia de força atômica.

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Selection of impression materials and techniques employed by dentists in Kenya

Objectives: The aim of the study was to determine the preferred impression material and impression recording technique employed by the dentists in Kenya for specific clinical procedures.Design: A descriptive cross sectional study.Setting: Dental clinics/institutions within Kenya.Participants: Dentists registered by the Medical Practitioners and Dentists Board as at 2015.Methods: A sample n=322 was randomly selected among the 1000 dentists registered in 2015. Data was collected using a pre-tested self-administered questionnaire that was distributed via online web-based survey monkey softwareand off-line by data collection assistants. Data was analysed using SPSS version 20 and Microsoft Excel 2013. Results were presented in tables, pie and bar charts.Results: Ninety seven dentists (30.1%) returned the questionnaires, 57 (58.8%) completed the hard copy version while 40 (41.2%) responded via the on-line tool. Majority of the respondents were males 52 (53.6%), 44 (45.4%) females while one dentist (1%) did not respond. Nearly half of the dentists 44 (46.4%) had 0-5 years clinical experience and a sizeable number 72 (74.2%) were general practitioners. Majority 56 (57.7%) considered availability, cost, ease of use and degree of accuracy in selecting impression materials (IM’s). The most commonly used (IM) was alginate whereas the least applied were polysulphide and vinyl siloxanether. Alginate was used in primary and final impressions of all procedures except border moulding, mostly in study model 88 (90.7%) and least in complete denture final impression 4 (4.1%). Addition and condensation cured silicones were preferred for fixed restoration impressions with majority 40 (41.1%) using single mix impression technique. One dentist used digital impression recording technique.Conclusion: Selection of (IM’s) is influenced by availability, cost, ease of use and degree of accuracy. Alginate and silicone impression materials were most utilised. The single mix impression technique was more popular while digital impression technique is yet to be widely embraced by dentists in Kenya

Acurácia da qPCR associada ao cultivo no meio Novy-MacNeal-Nicolle no diagnóstico da leishmaniose tegumentar americana

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Medicina, Programa de Pós-Graduação em Ciências Médicas, 2019.FUNDAMENTOS: A sensibilidade dos métodos de cultura em meio sólido para o diagnóstico da leishmaniose tegumentar americana (LTA) é limitada pela capacidade visual do avaliador. OBJETIVO: Neste trabalho, foi testada a acurácia da reação em cadeia da polimerase em tempo real (qPCR) baseada em ensaios com sonda de hidrólise TaqMan acoplada à cultura em meio Novy-MacNeal-Nicolle (NNN) modificado para o diagnóstico de LTA. MÉTODOS: Pacientes com apresentação clínica compatível com LTA foram alocados nos grupos controle e grupo LTA. Foram comparadas a acurácia da avaliação microscópica da cultura e da qPCR de aspirados de lesões cultivados. Os ensaios quantitativos e qualitativos foram realizados utilizando uma sonda de hidrólise específica e primers que amplificam o kDNA de Leishmania braziliensis. RESULTADOS: Cinquenta e oito pacientes foram incluídos no estudo, sendo 38 no grupo LTA e 20 no grupo controle. A análise combinada da qPCR + cultura melhorou significativamente a acurácia do diagnóstico em comparação com a análise visual microscópica (p = 0,006). Ao comparar a avaliação microscópica e a qPCR + cultura, foi observado um ganho de sensibilidade de 44.7% (17 de 38 pacientes com LTA; IC 95% = 28,6 - 61.7) para 68.4% (26 de 38 pacientes com LTA; IC 95% = 51.3 - 82.5), com uma pequena redução de especificidade de 100% (20 de 20 controles; 95% IC = 83.2 - 100) para 95% (19 de 20 controles; 95% IC = 75.1 - 99.9), respectivamente. A quantidade mínima de parasitos por tubo de cultura detectada por microscopia foi de 15. Entretanto, a sensibilidade foi de apenas 30% quando menos de 1.000 parasitos foram quantificados. CONCLUSÃO: A avaliação microscópica das amostras de cultura na LTA pode ter sua sensibilidade limitada pela não visualização de parasitos escassos ou pela não diferenciação de parasitos amastigotas em formas promastigotas.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES).BACKGROUND: The sensitivity of culture methods in solid medium for the diagnosis of American tegumentary leishmaniasis (ATL) is limited by the visual capacity of the evaluator. OBJECTIVE: It was tested the accuracy of a TaqMan-based real-time polymerase chain reaction (qPCR) coupled to culture in Novy-MacNeal-Nicolle (NNN) medium modified for the diagnosis of ATL. METHOD: Patients with a clinical presentation compatible with ATL were allocated into ATL and control groups. The accuracy of microscopic and qPCR processing of cultured lesion aspirates were compared. Quantitative and qualitative assays were performed using a specific hydrolysis probe and primers amplifying the kDNA minicircle of Leishmania braziliensis. RESULTS: Fifty-eight patients were included in the study, with 38 in the ATL group and 20 in the control group. The combined qPCR + culture analysis significantly improved the accuracy of diagnosis compared to the microscopic analysis (p=0.006). When comparing microscopic and qPCR + culture processing, we observed a sensitivity gain from 44.7% (17 of 38 ATL patients; 95% CI = 28.6 - 61.7) to 68.4% (26 of 38 ATL patients; 95% CI = 51.3 - 82.5), with a small specificity reduction from 100% (20 of 20 controls; 95% CI = 83.2 - 100) to 95% (19 of 20 controls; 95% CI = 75.1 - 99.9), respectively. The minimum quantity of parasites per culture tubes detected by microscopic evaluation was 15, but the sensitivity was only 30% when fewer than 1,000 parasites were quantified. CONCLUSION: The microscopic evaluation of culture samples in ATL may have its sensitivity limited by the non-visualization of scarce parasites or by the non-differentiation of amastigote parasites into promastigote forms

A mulher japonesa no mercado de trabalho no século 21

Monografia (graduação)—Universidade de Brasília, Instituto de Letras, Departamento de Línguas Estrangeiras e Tradução, Licenciatura em Língua e Literatura Japonesa, 2015.O presente trabalho tem como finalidade compreender a situação da mulher japonesa no mercado de trabalho, levando em consideração as mudanças que ocorreram na sociedade japonesa no que diz respeito às políticas públicas de igualdade de gênero e tomando por base a Constituição Japonesa e as leis trabalhistas, assim como as influências/pressões internas e externas que o governo japonês tem sofrido para melhorar a situação das mulheres no mercado de trabalho. Estatísticas oficiais e pesquisas de agências internacionais são utilizadas com intuito de averiguar a eficácia das leis, que tem como objetivo a igualdade de gêneros na sociedade e no mercado de trabalho japonês. Os dados indicaram que o país está muito bem em questão de educação e de saúde, enquanto ainda apresenta indicadores muito baixos no que tange à participação e às oportunidades das mulheres na força de trabalho e política. Frente à combinação de envelhecimento da população e declínio da taxa de natalidade na sociedade japonesa, o governo tem estimulado a maior participação da mulher em cargos de responsabilidade, embora tal iniciativa esbarre em práticas tradicionais de discriminação social e trabalhista. ____________________________________________________________________________________ ABSTRACTThis work has the scope of understanding the situation of the Japanese woman in the labor market, taking into consideration changes that occurred in Japanese society in regards to public policies of gender equality. Also, it takes into account the Japanese Constitution and the labor laws, as well as internal and external influences on the government to advance the situation of women in the labor market. Official statistics and surveys done by international agencies are used to determine the efficiency of the legislation related to the promotion of gender equity in society and the labor market. Data shows that the country is doing well in regards to education and health, while still presents very low indicators regarding the participation of and opportunities for women in the workforce and politics. Vis-à-vis the combination of the aging of the population and the declining birthrate in Japanese society, the government has encouraged greater participation of women in positions of responsibility, although such an initiative comes up against traditional practices of discrimination in society and labor market

NARRATIVAS FRONTEIRIÇAS: UMA RECONFIGURAÇÃO DO UNIVERSALISMO ABSTRATO

Este artigo propõe abordar narrativas que emergem de loci fronteiriços e que reconfiguram valores originados através de uma concepção “universal” do mundo. Para tanto, tomarei a fronteira como espaço enunciativo que privilegia os sujeitos que foram silenciados pelo sistema mundial colonial/moderno. Pretendo assim, trazer a luz do debate narrativas e/ou formas de se narrar “histórias locais” que, como uma resistência da margem, servem de mecanismos para ressignificar os preceitos impostos pela razão ocidental. Contudo, estas “histórias locais” serão abordadas com a finalidade de constatar um pensamento outro, que busca novas dimensões epistêmicas a partir de “pluriversalidades” que foram ignoradas em nome de um “universalismo abstrato”.