Effect of Sub-Stoichiometric Fe(III) Amounts on LCFA Degradation by Methanogenic Communities.

Long-chain fatty acids (LCFA) are common contaminants in municipal and industrial wastewater that can be converted anaerobically to methane. A low hydrogen partial pressure is required for LCFA degradation by anaerobic bacteria, requiring the establishment of syntrophic relationships with hydrogenotrophic methanogens. However, high LCFA loads can inhibit methanogens, hindering biodegradation.

Co-cultivation of Thermoanaerobacter strains with a methanogenic partner enhances glycerol conversion.

Glycerol-rich waste streams produced by the biodiesel, bioethanol and oleochemical industries can be treated and valorized by anaerobic microbial communities to produce methane. As current knowledge of the microorganisms involved in thermophilic glycerol conversion to methane is scarce, thermophilic glycerol-degrading methanogenic communities were enriched. A co-culture of Thermoanaerobacter and Methanothermobacter species was obtained, pointing to a non-obligately syntrophic glycerol degradation.

Sealing the Screw Access Channel with Polytetrafluoroethylene Tape: Advantages of the Technique.

The aim of this article is to describe the procedure for sealing the screw access channel using plastic tape, polytetrafluoroethylene, in screw- or cement-retained implant-supported prostheses. This technique is viable and easily performed, and the functional and esthetic results are satisfactory.

Effect of Fluoride-Releasing Adhesive Systems on the Mechanical Properties of Eroded Dentin.

The aim of the study was to evaluate the effect of erosive pH cycling with solutions that simulate dental erosion on Martens hardness (HMV) and elastic modulus (Eit) of dentin restored with fluoride-releasing adhesive systems. Twenty-seven bovine dentin slabs were restored with three adhesive systems: Adper Single Bond 2 total-etch adhesive system, One Up Bond F and Clearfil SE Protect fluoride-containing self-etching adhesive systems. The restorations were made with Filtek Z250.

Conversion of Cn-Unsaturated into Cn-2-Saturated LCFA Can Occur Uncoupled from Methanogenesis in Anaerobic Bioreactors.

Fat, oils, and grease present in complex wastewater can be readily converted to methane, but the energy potential of these compounds is not always recyclable, due to incomplete degradation of long chain fatty acids (LCFA) released during lipids hydrolysis. Oleate (C18:1) is generally the dominant LCFA in lipid-containing wastewater, and its conversion in anaerobic bioreactors results in palmitate (C16:0) accumulation. The reason why oleate is continuously converted to palmitate without further degradation via β-oxidation is still unknown.

Fluorescence intensity of composite layering combined with surface sealant submitted to staining solutions.

Purpose: The aim of this study was to evaluate the fluorescence intensity of a composite in different layering techniques combined to a surface sealant submitted to staining solutions.

Methods And Materials: One surface sealant and one composite resin (shades A2-0, A2, and YE) were tested. Specimens were carried out using layering with different shades of composite, and dental blocks (dentin/enamel) were obtained of human molars.

Microtensile bond strength of resin cements to caries-affected dentin.

Statement Of Problem: The bonding of resin materials to caries-affected dentin, especially self-adhesive cements, remains a challenge in dentistry.

Purpose: The purpose of this study was to evaluate the bond strength of different resin cements to sound or caries-affected dentin at 24 hours and 6 months after the bonding procedure.

Material And Methods: Thirty-six human molars were used, 18 sound and 18 affected by caries.

Activity and viability of methanogens in anaerobic digestion of unsaturated and saturated long-chain fatty acids.

Lipids can be anaerobically digested to methane, but methanogens are often considered to be highly sensitive to the long-chain fatty acids (LCFA) deriving from lipids hydrolysis. In this study, the effect of unsaturated (oleate [C18:1]) and saturated (stearate [C18:0] and palmitate [C16:0]) LCFA toward methanogenic archaea was studied in batch enrichments and in pure cultures. Overall, oleate had a more stringent effect on methanogens than saturated LCFA, and the degree of tolerance to LCFA was different among distinct species of methanogens.

Effect of whitening and desensitizing dentifrices on composite surfaces treated with surface sealants.

Objective: This study evaluated the effect of different dentifrices on the microhardness and surface roughness of composite surfaces covered by surface sealants.

Methods: Samples of Filtek P60 were made and divided into groups, in accordance with surface treatments: G1 - Fortify; G2 - Fortify Plus; G3 - control (none). For Knoop microhardness evaluation, the specimens were placed in a microdurometer, under a load of 50 g for 15 sec.

Effect of postpolymerization method on the color stability of composite resins submitted to ultraviolet aging.

The aim of this research was to evaluate the effect of postpolymerization method on the color stability of resin-based composites. Samples of direct and indirect restorative materials were polymerized with two photo-curing units (Visio photo-curing oven system and LED Elipar Freelight 2). All samples were submitted to an initial chromatic analysis using a spectrometer and submitted to ultraviolet-accelerated artificial aging.

Influence of desensitizing agents on the microshear bond strength of adhesive systems to dentin.

The aim of this study was to evaluate the effect of desensitizing agents on the micro-shear bond strength of adhesive systems to dentin. Forty bovine teeth were divided into 8 groups (n=5): G1--Single Bond (SB); G2--GH.F + SB; G3-- Desensibilize + SB; G4--essensiv + SB; G5 --ingle Bond 2 (SB2); G6--H.

Variation of the essential oil content and composition in leaves from cultivated plants of Hypericum androsaemum L.

The amount and composition of the essential oil from leaves of Hypericum androsaemum L. cultivated in Arouca (Portugal) were determined in six samples harvested during 1 year at intervals of 2 months. The seasonally dependent essential oil content ranged from 0.

Antibodies to Schistosoma mansoni in human cerebrospinal fluid.

Cerebrospinal fluid (CSF) and serum samples from patients suspected of having neuroschistosomiasis (NS) were evaluated by an enzyme-linked immunosorbent assay. Monoclonal antibodies of various immunoglobulin isotypes (IgM, IgA, IgE, total IgG, IgG1, IgG2, IgG3, and IgG4) were used to detect antibodies against Schistosoma mansoni soluble egg antigen (SEA) and soluble worm adult preparation (SWAP). Of the 83 CSF samples tested, 55% were reactive to SEA (26% were reactive only to SEA and 29% to both SEA and SWAP), 34% were reactive to SWAP (5% only to SWAP and 29% to both SEA and SWAP), and 40% were not reactive with any antigen.

Essential oils from plants and in vitro shoots of Hypericum androsaemum L.

The essential oil yields obtained by hydrodistillation of the aerial parts of Hypericum androsaemum cultivated plants varied from 0.94 to 4.09 mg/g of biomass dry weight, depending of the harvest time.