Estrutura de galáxias HII

Galáxias HII são galáxias do universo local, selecionadas a partir de placas de prisma objetivo, e estão sofrendo formação estelar violenta. Justamente devido a esta propriedade observacional, essa classe de galáxias foi alvo de extensos trabalhos espectroscópicos para caracterizar as condições físicas de seu meio interestelar. A alta taxa de formação estelar combinada com a baixa abundância de elementos pesados deduzida de seus espectros levanta a questão sobre se algumas delas poderiam ser galáxias verdadeiramente “jovens”. De qualquer forma, aparentemente essas são as galáxias próximas mais jovens, que podem ser estudadas em detalhe e suas propriedades estruturais oferecem uma indicação importante sobre a relação evolutiva e a origem das galáxias anãs no universo. Para podermos inferir a história de formação estelar em galáxias HII, necessitamos de informações em uma faixa espectral ampla. Para este projeto obtivemos imagens no visível nos telescópios de 0.60 m B&C e de 1.60 m do Laboratório Nacional de Astrofísica, para uma amostra de 42 objetos em quatro bandas fotométricas (B, V, R e I), que, combinadas com modelos recentes de síntese evolutiva, possibilitaram restringir a natureza da população e sua distribuição espacial. Com essa amostra construímos um catálogo morfológico com fotometria em banda larga. A análise inicial das propriedades morfológicas sugeriu que as galáxias podem ser classificadas em duas classes segregadas pela regularidade das isofotas externas e pela presença de perturbações, em consonância com o que já havia sido proposto na literatura: Tipo I são luminosas e têm envelopes irregulares ou perturbados, enquanto que galáxias do Tipo II são menos luminosas e tem isofotas externas regulares. Nosso trabalho também permitiu analisar o comportamento das galáxias HII na relação metalicidade-luminosidade para galáxias anãs. Essa relação é interpretada como uma relação entre a massa e a metalicidade para galáxias anãs de baixo brilho superficial (dSph e dIrr) e tem implicações diretas sobre sua formação e evolução e sobre as possíveis conexões evolutivas entre as galáxias HII e os outros tipos de galáxias anãs

NGC 55: a disc galaxy with flat abundance gradients

We present new spectroscopic observations obtained with Gemini Multi-Object Spectrographs at Gemini-South of a sample of 25 H II regions located in NGC 55, a late-type galaxy in the nearby Sculptor group. We derive physical conditions and chemical composition through the Te method for 18 H II regions, and strong-line abundances for 22 H II regions. We provide abundances of He, O, N, Ne, S and Ar, finding a substantially homogeneous composition in the ionized gas of the disc of NGC 55, with no trace of radial gradients. The oxygen abundances, both derived with Te and strong-line methods, have similar mean values and similarly small dispersions: 12+log (O/H) = 8.13 ± 0.18 dex with the former and 12+log (O/H) = 8.17 ± 0.13 dex with the latter. The average metallicities and the flat gradients agree with previous studies of smaller samples of H II regions and there is a qualitative agreement with the blue supergiant radial gradient as well. We investigate the origin of such flat gradients comparing NGC 55 with NGC 300, its companion galaxy, which is also twin of NGC 55 in terms of mass and luminosity. We suggest that the differences in the metal distributions in the two galaxies might be related to the differences in their K-band surface density profile. The flatter profile of NGC 55 probably causes in this galaxy higher infall/outflow rates than in similar galaxies. This likely provokes a strong mixing of gas and a re-distribution of metals

Evaluation of Oral Hygiene in Patients with Visual Disabilities

Introduction: Patients with visual impairment present greater difficulty in achieving adequate oral hygiene due to restricted eyesight. Therefore, oral hygiene motivation and instruction methods should be adapted to these patients to understand the importance of bacterial plaque control, both for the health of dental tissues and periodontal tissues Objective: The objective of the present study was to compare the plaque index (PI) of patients with and without visual impairment before and after the institution of oral hygiene instructions through a Randomized Clinical Trial. Twenty patients with visual impairment (Group 1) from the Instituto dos Cegos and 20 without visual impairment (Group 2) from the ASCES Periodontia Clinic were selected. Data were collected through the IP of O'Leary and reevaluated every 21 days for four sessions. Results: in both groups, the mean of PI decreased with the time of evaluation, with a significant difference between the evaluations (p <0.001). Group 1 had a mean PI higher than group 2 only in the fourth evaluation, but there was no significant difference (p> 0.05). As for the mean of the PI assessments, group 2 presented a mean higher than group 1, but without significant difference (p> 0.05). Conclusion: The study therefore suggests that there is no difference in PI in patients with or without visual impairment, and that the guidelines stimulate and motivate an improvement in oral hygiene conditions

Evaluation of DEFB1 polymorphisms in individuals with chronic periodontitis and diabetes mellitus type 2 in a population of northeastern Brazil

Aims: The role of genetic variations in genes related to innate response, as \u3b2-defensin-1 (DEFB1), in the context of chronic periodontitis (CP) and diabetes mellitus type 2 (DM2), is still not clear. The present study evaluates the distribution of DEFB1 single nucleotide polymorphisms (SNPs) 5\u2032-untranslated (5\u2032UTR) region and its relation with the CP in DM2 individuals in northeastern Brazilians. Methods: Two hundred and eighty individuals participated in the study, being 116 DM2+CP, 95 CP, and 69 healthy individuals. Three known DEFB1 functional SNPs [-52 G\ua0>\ua0A (rs1799946), -44 C\ua0>\ua0G (rs1800972), -20 G\ua0>\ua0A (rs11362)] were genotyped with allele-specific assays. Results: Association was found for the DEFB1 -20 G\ua0>\ua0A SNP. The G allele, the GA and GG genotypes were significantly (P\ua0<\ua00.05) more frequent in the DM2+CP (59.5%, 50%, and 34.5%, respectively) and CP (61%, 44.2%, and 38.9%, respectively) than in healthy individuals (26.8%, 36.2%, and 8.7%, respectively). The GCG and ACG combinations (-52, -44, -20) were significantly more frequent among DM2+CP and CP than in the healthy individuals. Conclusion: The results indicate that genetic variations of DEFB1 gene (SNP-20: G allele and GA and GG genotypes) and the DEFB1 5\u2032UTR haplotypes (GCG and ACG) may be associated with a susceptibility to CP in DM2 individuals as well as CP individuals without DM2

Are there differences between partial and total periodontal examination of the mouth?

Background: Diagnosis of periodontal disease for epidemiologic survey is difficult due to complexity of periodontal exam. The aim of this study was &nbsp;to compare data from a full-mouth examination and a partial-mouth examination, observing the agreement between both methods of presenting the Community Periodontal Index (CPI). Methods and Findings: The population comprised of male and female subjects, aged 18 years and over, attending public health centers in the city of Recife, Brazil. A total of 505 patients participated in this study. Each participant completed a form and underwent periodontal examination. Firstly, for each tooth present one of the periodontal conditions was determined: periodontal health, gingival bleeding, dental calculus, shallow periodontal pockets and deep periodontal pockets, according to CPI. Finally, partial data (10 index teeth) was recorded derived from the total version of CPI. Bivariate analysis of frequencies and means was performed. Mc Nemar test was used to calculate the level of statistical significance of the association tested. There are significant statistical differences between partial and full-mouth examination (p&lt;0.001). According to gender, men classified as score 1 presented the same prevalence in both methods; partial recording overestimated 0.2% of women classified as score 1; percentile difference among men was higher for subjects classified as score 0. Among subjects with at least one tooth with deep periodontal pocket, percentile difference between different approaches was higher among elders (60 years and over). Conclusions: Considering the variable age, the smaller amount of lost information refers to periodontal pockets in individuals aged 18 to 30 years of age. In older individuals classified as periodontally healthy and with gingival bleeding no loss of information was observed. Partial examination of the mouth underestimated the presence of periodontal pockets and overestimated the presence of calculus and bleeding. A high concordance between the partial and total examination was observed

Tratamento da superfície de zircônia para cimentação: uma revisão da literatura/Zirconia surface treatment for cementation: a literature review

As cerâmicas de zircônia tetragonal policristalina estabilizada por ítrio (Y-TZP) apresentam propriedades mecânicas como alta resistência e tenacidade à fratura superiores às das demais cerâmicas odontológicas. Entretanto, o aumento do conteúdo cristalino modificou suas características de adesão a cimentos resinosos, tornando necessário o desenvolvimento de métodos mais efetivos de união a estes materiais. Estudos têm sugerido técnicas de cimentação específicas para cerâmicas Y-TZP que incluem métodos de tratamento da superfície para alcançar uma condição satisfatória de adesão da zircônia aos cimentos resinosos. O presente trabalho traz uma revisão da literatura acerca das diferentes técnicas de tratamento de superfície de coroas protéticas de cerâmicas de zircônia tetragonal policristalina estabilizada por ítrio (Y-TZP). As pesquisas mostram que ainda não há um protocolo definido de cimentação, contudo os resultados apontam para uma associação de métodos para que a união adesiva seja obtida e que a silicatização e o jateamento com óxido de alumina foram os métodos mais investigados apresentando bons resultados quando associados com um agente químico de união