ABSTRACT
Abstract Objective: To evaluate the efficacy of desensitizing agents for the obliteration of dentinal tubules subjected or not to a simulated oral environment. Material and Methods: Dentinal discs (n=8) treated with Riva-Star (RS) or PRG-Barrier-Coat (PRG) were submitted (cycled) or not submitted (control) to erosive-abrasive-thermal cycles and evaluated using scanning electron microscopy/energy dispersive spectroscopic analysis. The variables analyzed were tubule obliteration and dentin surface chemical composition. Data were analyzed by non-parametric tests (p<0.05). Results: The cycled and control groups did not differ significantly for the responses in each material. The PRG control and cycled groups had fewer visible tubules and a higher proportion of totally obliterated tubules than the RS groups. The percentages of silver coverage were higher in the RS-control than in the RS-cycled. There was a significant inverse correlation between the presence of silver and non-obliterated tubules (R=-0.791; p<0.001). The percentages of carbon, aluminum, strontium, and potassium were significantly higher in the PRG-control and PRG-cycled compared to the RS control. The percentages of calcium, phosphorus, and silver were significantly higher in the RS compared to the PRG groups. PRG-control showed a higher percentage of boron than RS-control. Conclusion: PRG promoted greater tubule obliteration than SR. Simulated stress did not affect the obliterating effect of each agent. Greater silver coverage corresponded to a lower proportion of non-obliterated tubules in RS. Carbon, aluminum, strontium, boron, and potassium predominated in the dentin surface treated with PRG, while calcium, phosphorus, and silver prevailed in RS groups (AU).
Subject(s)
Potassium Iodide , Microscopy, Electron, Scanning/instrumentation , Dentin Sensitivity/drug therapy , Dentin Desensitizing Agents/therapeutic use , In Vitro Techniques , Statistics, NonparametricABSTRACT
The use of multivariate techniques for factor analysis is an efficient alternative for coffee breeding programs. This study aimed to evaluate the genetic diversity of 60 genotypes of conilon coffee based on agronomic performance in the northern state of Espírito Santo and to estimate the relative contribution of different agronomic characteristics towards the diversity of the species. The data were collected in an experiment conducted on the Experimental Farm of Bananal do Norte (Instituto Capixaba de Pesquisa, Assistência Técnica e Extenção Rural INCAPER) in the southern state of Espírito Santo, and 12 agronomic characteristics were evaluated over four sequential harvests (4 years). Significant differences between the genotypes were observed for all of the characteristics, indicating the possibility of exploiting the high genetic variability to classify the genotypes into different groups based on their similarities. Of the agronomic characteristics, the duration of the ripening cycle was the variable that contributed the most to the variability among the 60 genotypes, with a relative contribution of 70.02%.
A utilização de técnicas multivariadas de análise de fatores é uma alternativa eficiente utilizada no melhoramento genético do cafeeiro. O presente trabalho objetivou avaliar a divergência genética de 60 clones de café conilon, selecionados pelo seu desempenho no norte do Estado do Espírito Santo, e estimar a contribuição relativa de diferentes características agronômicas para a diversidade da espécie. Os dados foram coletados em experimento conduzido na Fazenda Experimental Bananal do Norte (INCAPER), considerando 12 características agronômicas, avaliadas através de médias de quatro safras. Diferenças significativas entre os genótipos foram observadas para todas as características avaliadas, indicando a possibilidade de exploração da alta variabilidade genética para a classificação dos genótipos em diferentes grupos homogêneos, baseado em suas similaridades. Dentre as características agronômicas, a duração do ciclo de maturação foi a variável que mais contribuiu para a variabilidade entre os 60 genótipos, com contribuição relativa de 70,02%.
Subject(s)
Breeding , Clone Cells , Coffee , Genetic Enhancement , Coffea , GenotypeABSTRACT
Os óleos essenciais constituem um tipo de metabólito secundário de grande importância econômica e estão sendo cada vez mais estudados e utilizados como potentes inibidores de sementes e do crescimento de diversas plantas. O presente trabalho teve por objetivo a análise química qualitativa e quantitativa bem como a avaliação da atividade alelopática do óleo essencial extraído das folhas frescas de eucalipto (Eucalyptus citriodora) sobre a germinação e o desenvolvimento radicular das sementes de sorgo (Sorghum bicolor L.) e pepino (Cucumis sativus L.), cultivados em placa de Petri. O óleo essencial foi obtido por hidrodestilação, utilizando um aparelho tipo Clevenger, e analisado por cromatografia em fase gasosa com detector de ionização de chama e espectrometria de massas. Foi possível identificar doze constituintes químicos correspondendo a 97,69%, com predominância dos monoterpenos oxigenados citronelal (64,92%) e iso-isopulegol (10,20%) e do citronelol (8,25%). Os ensaios biológicos utilizando o óleo essencial mostraram que o mesmo apresenta efeito alelopático, prejudicando a germinação e o desenvolvimento da radícula das sementes de sorgo e pepino, sendo a redução da germinação mais pronunciada no sorgo, e que o aumento da concentração do óleo leva a uma redução linear na capacidade germinativa e no desenvolvimento da radícula.
Essential oils consist of a type of secondary metabolite that holds great economic importance, they have been increasingly studied and used as potent inhibitors of seeds and growth of various plants. The present work aimed at the qualitative and quantitative chemical analysis and evaluation of the allelopathic activity of the essential oil extracted from fresh leaves of eucalyptus (Eucalyptus citriodora) over the germination and root development of seeds of sorghum (Sorghum bicolor L.) and cucumber (Cucumis sativus L.), grown in a Petri dish. The essential oil was obtained by steam distillation, using a Clevenger apparatus, and analyzed by chromatography in gas phase with flame ionization detector and mass spectrometry. It was possible to identify twelve chemical constituents corresponding to 97.69%, with predominance of oxygenated monoterpenes citronellal (64.92%) and iso-isopulegol (10.20%) and citronellol (8.25%). The biological essays using the essential oil showed the presence of an allelopathic effect, affecting the germination and radicule length of sorghum and cucumber seeds, the germination reduction being more pronounced in sorghum, also the increase of the oil concentration leads to a linear decrease in the germination and in the radicule length.