Identification of bacteria in endodontic infections by sequence analysis of 16S rDNA clone libraries

A significant proportion of oral bacteria are unable to undergo cultivation by existing techniques. In this regard, the microbiota from root canals still requires complementary characterization. The present study aimed at the identification of bacteria by sequence analysis of 16S rDNA clone libraries from seven endodontically infected teeth. Samples were collected from the root canals, subjected to the PCR with universal 16S rDNA primers, cloned and partially sequenced. Clones were clustered into groups of closely related sequences (phylotypes) and identification to the species level was performed by comparative analysis with the GenBank, EMBL and DDBJ databases, according to a 98 % minimum identity. All samples were positive for bacteria and the number of phylotypes detected per subject varied from two to 14. The majority of taxa (65(.)2 %) belonged to the phylum Firmicutes of the Gram-positive bacteria, followed by Proteobacteria (10(.)9 %), Spirochaetes (4(.)3 %), Bacteroidetes (6(.)5 %), Actinobacteria (2(.)2 %) and Deferribacteres (2(.)2 %). A total of 46 distinct taxonomic units was identified. Four clones with low similarity to sequences previously deposited in the databases were sequenced to nearly full extent and were classified taxonomically as novel representatives of the order Clostridiales, including a putative novel species of Mogibacterium. The identification of novel phylotypes associated with endodontic infections suggests that the endodontium may still harbour a relevant proportion of uncharacterized taxa.

The significance and determination by image analysis of microcrack density in hard chromium plating

It is well known that the microcrack density is a fundamental parameter in hard chromium electroplating. The chemical and mechanical properties of this coating are widely dependent on its microcrack density. In this paper a simple image analysis procedure to determine microcrack density is presented in order to demonstrate it as a fundamental tool to estimate the fatigue, corrosion and wear behavior, as well as the residual stress field of a coated component. For this purpose, the image analysis procedure was carried out on two kinds of hard chromium plating - one called accelerated (high velocity of deposition and fluoride-free) and the other conventional (with fluoride). The coatings were applied on samples of AISI 4340 aeronautical steel, which is widely used in aircraft landing gear components. To characterize the practical significance of this study, the microcrack density results were related to the fatigue, wear and corrosion behavior from previous study and to the residual stress field in the coatings.

Small-area census data services by microcomputer applications of the REDATAM system in Latin America and the Caribbean

Analiza las facilidades que ofrece el sistema REDATAM (recuperación de datos de áreas pequeñas por computador) para los censos de 1990 en América Latina y el Caribe.

Degree of conversion of polymer-matrix composite assessed by FTIR analysis

Aims and objectives: The behavior of polymer-matrix composite is dependent on the degree of conversion. The aim of this study was to evaluate the degree of conversion of two resin cements following storage at 37°C immediately, 24 and 48 hours, and 7 days after light-curing by FTIR analysis. Materials and methods: The specimens were made in a metallic mold and cured with blue LED with power density of 500 mW/cm2 for 30 seconds. The specimens were pulverized, pressed with KBr and analyzed with FTIR following storage times. Statistical analysis used: ANOVA (two-way) and Tukey's post hoc. Results: To the polymer-matrix composites between 24 and 48 hours does not show a significant increase (p > 0.05), however, the highest values were found after 7 days. Conclusion: The polymer-matrix composites used in this study showed similarity on the degree of conversion and increased of according to the time of storage.

Are fertility estimates from retrospective data biased by maternal mortality?: an assessment based on parametric models of family size distribution

Includes bibliography

Influência da técnica cirúrgica guiada para implantes sobre o aquecimento ósseo, a viabilidade celular imediata e a deformação de fresas após osteotomia para implantes

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Percepção e atitudes de estudantes de odontologia sobre a pobreza

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Associação dos padrões alimentares com variáveis sócio-demográficas e componentes da síndrome metabólica de adultos de uma unidade de estratégia de saúde da família (Rubião Junior, Botucatu)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Genetic differentiation of Macrodon ancylodon (Sciaenidae, Perciformes) populations in Atlantic coastal waters of South America as revealed by mtDNA analysis

The king weakfish (pescada-gó in Portuguese - Macrodon ancylodon (Sciaenidae), a demersal (bottom-feeding) species found in South America Atlantic coastal waters from the Gulf of Paria in Venezuela to Baia Blanca in Argentina, is an economically important species because of its abundance and wide acceptance by consumers. Because of its wide distribution this fish may be subject to geographic isolation and this may have resulted in distinct populations along its coastal range. Considering that this species represents an important economic resource, confirmation of whether M. ancylodon is a single species or there are different genetic stocks spread over its wide distribution would be an important contribution to conservation policies and population management of the king weakfish. To investigate differences between king weakfish populations we used the cytochrome b and 16S rRNA genes to characterize M. ancylodon specimens caught throughout its South American range from Venezuela to Argentina. Our results clearly distinguished two genetically different groups which show nucleotide divergence and genetic structuring patterns that strongly suggest they may be different species, disagreeing with the widely accepted traditional taxonomy that accepts only one species of Macrodon in the western Atlantic.

Puberty in male collared peccary (Pecari tajacu) determined by quantitative analysis of spermatogenic cells

Estudos biológicos são necessários para o manejo da vida silvestre em cativeiro, e o conhecimento da reprodução é um dos aspectos importantes para o aumento da produção. Esta pesquisa teve como objetivo determinar a idade da puberdade do cateto macho. Foram utilizadas amostras testiculares de 15 animais, entre 7 a 16 meses, distribuídos em cinco grupos (G1, G2, G3, G4 e G5). Os testículos aumentaram no peso, comprimento e largura consideravelmente (p < 0,05) do G1 ao G3, enquanto que, a partir deste grupo, o desenvolvimento desse órgão foi mais lento. Houve correlação positiva (p < 0,001) entre os seguintes parâmetros testiculares: peso e comprimento (r = 0,97), peso e largura (r = 0,88), comprimento e largura (r = 0,92). Com relação ao diâmetro tubular, observou-se um aumento (p < 0,05) do G1 ao G4. A quantidade total de células espermatogênicas aumentou significativamente (p < 0,05) até o G3, e se estabilizou a partir deste grupo. Houve correlação positiva entre o peso testicular e o diâmetro tubular (r = 0,99, p < 0,001), bem como o peso testicular e as células espermatogênicas (r = 0,98, p < 0,001). A quantidade de células de Sertoli reduziu significativamente (p < 0,05) do G1, onde se encontravam indiferenciadas como células de suporte, até G5, onde foram observadas juntamente com todas as células da linhagem espermática. Estes resultados demonstraram que as fases do desenvolvimento reprodutivo de catetos podem ser classificadas em: impúbere (G1, 7-8 meses), pré-púbere (G2, 9-10 meses), púbere (G3, 11-12 meses), pós-púbere 1 (G4, 13-14 meses) e pós-púbere 2 (G5, 15-16 meses). Com base na análise histológica, a puberdade dos catetos machos ocorre entre 11 e 12 meses de idade.

Evaluation of Decomposition Kinetics of Poly (Ether-Ether-Ketone) by Thermogravimetric Analysis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)