In vitro efficacy of plant extracts and synthesized substances on Rhipicephalus (Boophilus) Microplus (Acari: Ixodidae)

Herbal drugs have been widely evaluated as an alternative method of parasite control, aiming to slow development of resistance and obtain low-cost biodegradable parasiticides. This study evaluated the in vitro efficacy on Rhipicephalus (Boophilus) microplus of extracts from Carapa guianensis seed oil, Cymbopogon martinii and Cymbopogon schoenanthus leaf essential oil, and Piper tuberculatum leaf crude extract and similar synthesized substances. In the immersion test, engorged females were evaluated in five dilutions ranging from 10% to 0.030625% concentration. In the larval test on impregnated filter paper, the concentration ranged from 10% to 0.02%. The treatments and controls were done in three replicates. Chemical analysis of the oils was performed by gas chromatography. The main compounds were oleic acid (46.8%) for C. guianensis and geraniol for C. martinii (81.4%), and C. schoenanthus (62.5%). The isolated and synthesized substances showed no significant effect on larvae and adult. C. martinii and P. tuberculatum showed the best efficacy on the engorged females. The LC50 and LC90 were 2.93% and 6.66% and 3.76% and 25.03%, respectively. In the larval test, the LC50 and LC90 obtained for C. martinii, P. tuberculatum, and C. schoenanthus were 0.47% and 0.63%, 0.41% and 0.79%, 0.57% and 0.96%, respectively. The fact that geraniol is present in greater quantities in C. martinii explains its higher activity in relation to C. shoenanthus. It is necessary to validate the in vivo use of safe and effective phytoparasiticidal substances. Efforts should be focused on developing formulations that enhance the efficacy in vivo and lengthen the residual period.

Development and validation of a HPLC method for standardization of herbal and commercial extracts of Myrcia uniflora

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

The influence of internal surface treatments on tensile bond strength for two ceramic systems

Statement of the Problem: the ceramic composition and surface microstructure of all-ceramic restorations are important components of an effective bonding substrate. Hydrofluoric acid and sandblasting are well-known procedures for surface treatment; however, surface treatment for high alumina-containing and lithium disilicate ceramics have not been fully investigated.Purpose: This in vitro study evaluated the tensile bond strength of resin cement to two types of ceramic systems with different surface treatments.Methods and Materials: Thirty specimens of each ceramic system were made according to the manufacturer's instructions and embedded in polyester resin. Specimens of In-Ceram Alumina [1] and IPS Empress 2 [E] were distributed to three groups with differing surface treatments (n=10): sandblasting with 50 jam aluminum oxide (APA); sandblasting with 110 pm aluminum oxide modified with silica particles (ROCATEC System-RS); a combination of sandblasting with APA and 10% hydrofluoric acid etching (HA) for two minutes on In-Ceram and for 20 seconds for IPS Empress 2. After the respective surface treatments, all the specimens were silanated, and Rely-X resin cement was injected onto the ceramic surface and light polymerized. The specimens were stored in distilled water at 37 degrees C for 24 hours and thermally cycled 1,100 times (5 degrees C/55 degrees C). The tensile bond strength test was performed in a universal testing machine at a 0.5 mm/minute crosshead speed.Results: the mean bond strength values (AWa) for IPS Empress 2 were 12.01 +/- 5.93 (EAPA), 10.34 +/- 1.77 (ERS) and 14.49 +/- 3.04 (EHA). The mean bond strength values for In-Ceram Alumina were 9.87 +/- 2.40 JAPA) and 20.40 +/- 6.27 (IRS). All In-Ceram specimens treated with 10% hydrofluoric acid failed during thermal cycling.Conclusion: the Rocatec system was the most effective surface treatment for In-Ceram Alumina ceramics; whereas, the combination of aluminum oxide sandblasting and hydrofluoric acid etching for 20 seconds worked more effectively for Empress 2 ceramics.

Biocompatibility of denture base acrylic resins evaluated M culture of L929 cells. Effect of polymerisation cycle and postpoymerisation treatments

Objective: the purpose of this study was to evaluate the effect of two post-polymerisation treatments and different cycles of polymerisation on the cytotoxicity of two denture base resins.Materials and methods: the resins tested were Lucitone 550 and QC 20. Discs of resins were fabricated following the manufacturer's instructions. Lucitone 550 was processed by long cycle or short cycle. The resin QC 20 was processed by reverse cycle or normal cycle. The specimens were divided into groups: (i) post-polymerised in microwave for 3 min at 500 W; (ii) post-polymerised in water-bath at 55 degrees C for 60 min and (iii) without post-polymerisation. Eluates were prepared by placing three discs into a sterile glass vial with 9 ml of Eagle's medium and incubated at 37 degrees C for 24 hours. L929 cells were seeded into 96 3 well culture plates and DNA synthesis was assessed by H-thymidine incorporation assay.Results: the results were submitted to two-way ANOVA and Tukey HSD test. QC 20 specimens polymerised by the normal cycle and submitted to microwave post-polymerisation were graded as moderately cytotoxic. Similar results were observed for Lucitone 550 processed by long cycle without post-polymerisation. The other experimental groups were graded as not cytotoxic. After water-bath post-polymerisation, specimens of Lucitone 550 processed by long cycle produced significantly lower inhibition of DNA synthesis than the other groups.Conclusion: the long cycle increased the cytotoxicity of Lucitone 550 and water-bath post-polymerisation reduced the cytotoxicity of Lucitone 550 processed by long cycle.

Residual monomer of reline acrylic resins - Effect of water-bath and microwave post-polymerization treatments

Objectives. This study compared the residual monomer (RM) in four hard chair-side reline resins (Duraliner II-D, Kooliner-K, Tokuso Rebase Fast-TRF and Ufi Gel hard-UGH) and one heat-polymerized denture base resin (Lucitone 550-L), which was processed using two polymerization cycles (short-LS and long-LL). It was also investigated the effect of two after polymerization treatments on this RM content.Methods. Specimens (n = 18) of each material were produced following the manufacturers' instructions and then divided into three groups. Group I specimens were left untreated (GI-control). Specimens of group II (GII) were given post-polymerization treatment by microwave irradiation. In group III (GIII), specimens were submitted to immersion in water at 55 degrees C (reline resins-10 min; denture base resin L-60min). The RM was analyzed using high performance liquid chromatography (HPLC) and expressed as a percentage of RM. Data were analyzed by two-way ANOVA followed by Tukey's test (alpha = 0.05).Results. Comparing control specimens, statistical differences were found among all materials (p < 0.05), and the results can be arranged as K (1.52%) > D (0.85%) > UGH (0.45%) > LL (0.24%) > TRF (0.14%) > LS (0.08%). Immersion in hot water (GIII) promoted a significant (p < 0.05) reduction in the RM for all materials evaluated compared to control (GI), with the exception of LL specimens. Materials K, UGH and TRF exhibited significantly (p < 0.05) lower values of RM after microwave irradiation (GII) than in the control specimens.Significance. The reduction in RM promoted by water-bath and microwave post-polymerization treatments could improve the mechanical properties and biocompatibility of the relining and denture base materials. (c) 2006 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Comparison of hexamethyidisilazane and critical point drying treatments for SEM analysis of anaerobic biofilms and granular sludge

We present a fast procedure for scanning electron microscopy (SEM) analysis in which hexamethyldisilazane (HMDS) solvent, instead of the critical point drying, is used to remove liquids from a microbiological specimen. The results indicate that the HMDS solvent is suitable for drying samples of anaerobic cells for examination by SEM and does not cause cell structure disruption.

Effects of different treatments on purity of silica from soluble sodium silicate

Noncrystalline silica was obtained with low iron, sodium, and nitrate ions concentrations from soluble sodium silicate (water glass) and nitric acid solution. Extractions with nitric acid solution and/or deionized water and/or dialysis were carried out to eliminate soluble metal ions. Products were dried in a microwave oven and characterized by chemical analysis, XRD, and IR. Dialysis seems to be the best treatment for the elimination of sodium and nitrate ions. Silica purified by nitric acid and water extractions followed by dialysis yields the purest silica sample.