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Comparison of Smear Layer Removal Using the Nd:YAG Laser, Ultrasound, ProTaper Universal System, and CanalBrush Methods: An In Vitro Study

INTRODUCTION The aim of this study was to compare the efficacy of the Nd:YAG laser, ultrasound, the ProTaper Universal system (Dentsply Maillefer, Ballaigues, Switzerland), and the CanalBrush (Coltene Whaledent, Langenau, Germany) methods for the removal of the smear layer from the apical third of root canals. METHODS Fifty distal root canals from extracted human mandibular first molars were instrumented up to ProTaper Universal F5 and divided randomly into 5 groups (n = 10) according to the following final irrigation agitation techniques: no agitation (control), ProTaper Universal file, ultrasound, CanalBrush, and Nd:YAG laser. Specimens were observed under a scanning electron microscope. The presence of the smear layer was evaluated using a 3-grade scoring system. The data were analyzed with Cohen kappa, Kruskal-Wallis, and Mann-Whitney U tests. A level of significance of .05 was adopted. RESULTS The ultrasound group performed significantly better than the rest of the groups; 56.6% of the specimens revealed no smear layer, 44.4% showed the presence of a moderate smear layer, and no heavy smear layers were observed. In the Nd:YAG laser group, 30% of the specimens presented with no smear layer, 70% showed the presence of a moderate smear layer, and no heavy smear layers were observed. In contrast, a heavy smear layer was observed on the surfaces of the root canals in the CanalBrush (23.4%), ProTaper Universal (13.4%), and control (86.6%) groups. Statistically significant differences were observed (P < .05). CONCLUSIONS None of the agitation methods completely removed the smear layer. However, the ultrasound method performed significantly better followed by the Nd:YAG laser, the CanalBrush, and the ProTaper Universal system. Agitation of the irrigant improved smear layer removal in the apical third of the canal.

Oxidation of dibenzothiophene (DBT) by Serratia marcescens UCP 1549 formed biphenyl as final product

BackgroundThe desulphurization of dibenzothiophene (DBT), a recalcitrant thiophenic fossil fuel component by Serratia marcescens (UCP 1549) in order for reducing the Sulphur content was investigated. The Study was carried out establishing the growth profile using Luria Bertani medium to different concentrations of DBT during 120 hours at 28°C, and orbital Shaker at 150 rpm.ResultsThe results indicated that concentrations of DBT 0.5, 1.0 and 2.0 mM do not affected the growth of the bacterium. The DBT showed similar Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MCB) (3.68 mM). The desulphurization of DBT by S. marcescens was used with 96 hours of growth on 2 mM of DBT, and was determined by gas chromatography (GC) and GC-mass spectrometry. In order to study the desulphurization process by S. marcescens was observed the presence of a sulfur-free product at 16 hours of cultivation.ConclusionsThe data suggests the use of metabolic pathway “4S” by S. marcescens (UCP 1549) and formed biphenyl. The microbial desulphurization process by Serratia can be suggest significant reducing sulphur content in DBT, and showed promising potential for reduction of the sulfur content in diesel oil.

Alcoolismo no Nordeste do Brasil: prevalência e perfil sociodemográfico dos afetados

Objective: The epidemiological survey was conducted to determine the prevalence of alcoholism and use of alcohol among the oldest and biggest families which make up the population of the island of Fernando de Noronha, state of Pernambuco, Brazil, as well as to identify a socio-demographic profile associated with this problem in that region. Methods: A representative sample of the population was composed by 119 individuals. The instrument of research included questions on demographic and social data of the sample, and characterization of alcohol consumption. To assess the prevalence of alcoholism among these people, we used an instrument for screening alcohol related disturbances – the CAGE – and in this analyses it was taken into consideration, one or more positive answers to define the alcoholics. Results: Results

Copper influence on polyphosphate metabolism of Cunninghamella elegans

The aim of this work was to evaluate the physiological aspects of polyphosphate metabolism of Cunninghamella elegans grown in presence of copper. The growth profile was obtained by means of biomass yields, orthophosphate consumption, polyphosphate accumulation and phosphatases activities. The results revealed the influence of copper on the growth, observed by biomass yields. Orthophosphate consumption was faster in cells grown in the presence of copper. The presence of copper in the culture medium induced polyphosphate accumulation. The polyphosphate level was almost constant in the beginning of control culture growth, and could be related to the exponential growth phase. On the other hand, the copper treated cultures exhibited a significant reduction in the polyphosphate levels, indicating an active metabolization of the polymer. Acid phosphatase activity was not detected in the conditions studied, but alkaline phosphatase activity was significantly lower in the treated cultures. The results suggest the potential use of Cunninghamella elegans isolate in bioremediation and biosorption applied to environments polluted by copper.

Evaluation of Moringa oleifera Seed Lectin as a Metal Remover in Aqueous Solutions.

The efficacy of Moringa oleifera seed lectin (WSMoL) as a metal remover in water and the effects of metals on its hemagglutinating and antibacterial activities were determined. Aqueous metal solutions were incubated with WSMoL for 8 h at 4°C and the concentrations of metals were determined using atomic absorption spectroscopy. Hemagglutination and antibacterial assays were conducted with WSMoL and lectin exposed or not to the metals. The removal efficiency of WSMoL was 49.00%, 53.21%, 71.45%, 55.42%, 69.88%, 62.14%, and 49.36% for Cd+2, Pb+2, Cu+2, Zn+2, Mg+2, Mn+2, and Al+3, respectively. WSMoL showed bacteriostatic and bactericidal activities against Escherichia coli and Salmonella enterica serovar Enteritidis. However, hemagglutinating and antibacterial activities were impaired after exposure to metals. In conclusion, WSMoL efficiently removed metals present in water but the interaction with metals impaired lectin carbohydrate-binding ability and antibacterial activity. This should be considered when properties of WSMoL other than metal removal are desired.

Hydraulic conductivity and soil-sewage sludge interactions

One of the main problems faced by humanity is pollution caused by residues resulting from the production and use of goods, e.g, sewage sludge. Among the various alternatives for its disposal, the agricultural use seems promising. The purpose of this study was to evaluate the hydraulic conductivity and interaction of soil with sandy-silty texture, classified as Spodosols, from the Experimental Station Itapirema - IPA, in Goiana, state of Pernambuco, in mixtures with sewage sludge from the Mangueira Sewage Treatment Station, in the city of Recife, Pernambuco at rates of 25, 50 and 75 Mg ha-1. Tests were conducted to let water percolate the natural saturated soil and soil-sludge mixtures to characterize their physical, chemical, and microstructural properties as well as hydraulic conductivity. Statistical data analysis showed that the presence of sewage sludge in soils leads to an increase of the < 0.005 mm fraction, reduction in real specific weight and variation in optimum moisture content from 11.60 to 12.90 % and apparent specific dry weight from 17.10 and 17.50 kN m-3. In the sludge-soil mixture, the quartz grains were covered by sludge and filling of the empty soil macropores between grains. There were changes in the chemical characteristics of soil and effluent due to sewage sludge addition and a small decrease in hydraulic conductivity. The results indicate the possibility that soil acidity influenced the concentrations of the elements found in the leachate, showing higher levels at higher sludge doses. It can be concluded that the leaching degree of potentially toxic elements from the sewage sludge treatments does not harm the environment.