Estudo da mistura comercial dolomita-quartzo, dopada com Hg(I), Cd(II) e Cr(III), para adsorção de H2S

The present work was to carry out a study on the adsorption of hydrogen sulfide (H2S) in arrays synthesized from a commercial clay mineral formed by a mixture of dolomite and quartz. To produce the ion exchange matrix were made using aqueous solutions of salts of cobalt II chloride hexahydrate (CoCl2.6H2O) II cadmium nitrate tetrahydrate (Cd (NO3)2.4H2O) I mercuric chloride (HgCl) nitrate and chromium III pentahydrate (Cr (NO3)3.5H2O). The arrays were subjected to hydrogen sulphide gas passage for one hour. To check the amount of gas adsorbed was used gravimetric process. The best result was in the adsorption matrix doped with cadmium and the solution retained for a longer time than the largest amount of H2S was the cobalt matrix. The matrix unmodified exhibited poor adsorption capacity. The characterization of the matrices were used XRD, XRF and IV. Mother with cadmium showed a high capacity in ion exchange, because the percentage of cadmium increased from 0% to 81.38% by replacing atoms of calcium and silicon which increased from 96.54% to 17.56% and 15, 72% to 0.32%, respectively, but also the best performance in adsorption of H2S adsorbing 11.89507 mg per gram of matrix

Adsorção dos gases NH3, NO e H2S em fosfato de vanadila, hidrogeno fosfato de vanadila e fosfatos de vanadila dopados por Al, Co, Mn e Cr

In this work were synthesized the materials called vanadyl phosphate, hydrogen vanadyl phosphate and vanadyl phosphate doped by transition metals with the aim in adsorption the following compounds: ammonia, hydrogen sulfide and nitrogen oxide. To characterize the starting compounds was used DRX, FTIR, FRX and TG analysis. After the characterization of substrates, proceeded de adsorption of NH3 and H2S gases in reactor, passing the gases with continuous flow for 30 min and room temperature. Gravimetric data indicate that the matrices of higher performance in adsorption of ammonia was those doped by aluminum and manganese, obtaining results of 216,77 mgNH3/g and 200,40 mgNH3/g of matrix, respectively. The matrice of higher performance in adsorption of hydrogen sulfide was that doped by manganese, obtaining results of 86,94 mgH2S/g of matrix. The synthesis of substrates VOPO4.2H2O and MnVOPO4.2H2O with nitrogen oxide was made in solution, aiming the final products VOPO4.G.nH2O and MnVOPO4.G.nH2O (G = NO and n = number of water molecules). The thermo analytical behavior and the infrared spectroscopy are indicative of formation of VOPO4.2,5NO.3H2O compound. Results of scanning electron microscopy (SEM) and Energy dispersive spectroscopy (EDS) of materials vanadyl phosphate and vanadyl phosphate modified after reaction in solid state or in solution with the gases show morphology changes in substrates, beyond the formation of orthorhombic sulfur crystals over their respective hosts when these adsorb hydrogen sulfide

The central repeat domain 1 of Kaposi's sarcoma-associated herpesvirus (KSHV) latency associated-nuclear antigen 1 (LANA1) prevents cis MHC class I peptide presentation

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effect of Er : YAG and diode lasers on the adhesion of blood components and on the morphology of irradiated root surfaces

Objectives: the aim of this study was to evaluate in vitro, by scanning electron microscopy (SEM), the adhesion of blood components on root surfaces irradiated with Er:YAG (2.94 mu m) and GaAlAs Diode (808 nm) lasers and the effects on the morphology of irradiated root surfaces.Methods: One hundred samples of human teeth were obtained. They were previously planed and scaled with manual instruments and divided into five groups of 20 samples each: G1 (control group) - absence of treatment; G2 - Er:YAG laser (7.6 J/cm(2)); G3 - Er:YAG laser (12.9 J/cm(2)); G4 - Diode laser (90 J/cm(2)) and G5 - Diode laser (108 J/cm(2)). After these treatments, 10 samples of each group received a blood tissue but the remaining 10 did not. After laboratory treatments, the samples were obtained by SEM, the photomicrographs were analysed by the score of adhesion of blood components and the results were statistically analysed (Kruskall-Wallis and Mann-Whitney test).Results: In relation to the adhesion of blood components, the study showed no significant differences between the control group and the groups treated with Er:YAG laser (p = 0.9633 and 0.6229). Diode laser radiation was less effective than control group and Er:YAG laser radiation (p < 0.01).Conclusion: None of the proposed treatments increased the adhesion of blood components in a significant way when compared to the control group. Although the Er:YAG laser did not interfere in the adhesion of blood components, it caused more changes on the root surface, whereas the Diode laser inhibited the adhesion.

Effect of Er : YAG and diode laser irradiation on the root surface: Morphological and thermal analysis

Background: the aim of the present study was to compare the effects of Er:YAG and diode laser treatments of the root surface on intrapulpal temperature after scaling and root planing with hand instruments.Methods: Fifteen extracted single-rooted teeth were scaled and root planed with hand instruments. The teeth were divided into 3 groups of 5 each and irradiated on their buccal and lingual surfaces: group A: Er:YAG laser, 2.94 mum/100 mJ/10 Hz/ 30 seconds; group B: diode laser, 810 nm/1.0 W/0.05 ms/30 seconds; group C: diode laser, 810 nm/1.4 W/0.05 ms/30 seconds. The temperature was monitored by means of a type T thermocouple (copper-constantan) positioned in the pulp chamber to assess pulpal temperature during and before irradiation. Afterwards, the specimens were longitudinally sectioned, and the buccal and lingual surfaces of each root were analyzed by scanning electron microscopy.Results: In the Er:YAG laser group, the thermal analysis revealed an average temperature of -2.2 +/- 1.5degreesC, while in the diode laser groups, temperatures were 1.6 +/- 0.8degreesC at 1.0 W and 3.3 +/- 1.0degreesC at 1.4 W. Electronic micrographs revealed that there were no significant morphological changes, such as charring, melting, or fusion, in any group, although the specimens were found to be more irregular in the Er:YAG laser group.Conclusions: the application of Er:YAG and diode lasers at the utilized parameters did not induce high pulpal temperatures. Root surface irregularities were more pronounced after irradiation with an Er:YAG laser than with a diode laser.

Short-term clinical and immunologic effects of scaling and root planing with Er : YAG laser in chronic periodontitis

Background: Recently, the erbium-doped:yttrium, aluminum, and garnet (Er:YAG) laser has been used for periodontal therapy. This study compared Er:YAG laser irradiation (100 mJ/pulse, 10 Hz, 12.9 J/cm(2)) with or without conventional scaling and root planing (SRP) to SRP only for the treatment of periodontal pockets affected with chronic periodontitis.Methods: Twenty-one subjects with pockets from 5 to 9 mm in non-adjacent sites were studied. In a split-mouth design, each site was randomly allocated to a treatment group: SRP and laser (SRPL), laser only (L), SRP only (SRP), or no treatment (C). The plaque index (PI), gingival index (GI), bleeding on probing (BOP), and interleukin (IL)-1 beta levels in crevicular fluid were evaluated at baseline and at 12 and 30 days postoperatively, whereas probing depth (PD), gingival recession (GR), and clinical attachment level (CAL) were evaluated at baseline and 30 days after treatment. A statistical analysis was conducted (P<0.05).Results: Twelve days postoperatively, the PI decreased for SRPL and SRP groups (P<0.05); the GI increased for L, SRP, and C groups but decreased for the SRPL group (P<0.05); and BOP decreased for SRPL, L, and SRP groups (P<0.01). Thirty days postoperatively, BOP decreased for treated groups and was lower than the C group (P<0.05). PD decreased in treated groups (P<0.001), and differences were found between SRPL and C groups (P<0.05). CAL gain was significant only for the SRP group (P<0.01). GR increased for SRPL and L groups (P<0.05). No difference in IL-1 beta was detected among groups and periods.Conclusion: Er:YAG laser irradiation may be used as an adjunctive aid for the treatment of periodontal pockets, although a significant CAL gain was observed with SRP alone and not with laser treatment.

Comparative Histopathological Analysis of Human Pulps after Class I Cavity Preparation with a High-Speed Air-Turbine Handpiece or Er:YAG Laser

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Shear bond strength of aesthetic materials bonded to Ni-Cr alloy

Objectives. This study was undertaken to evaluate the shear bond strength of four materials used as aesthetic material bonded to Ni-Cr alloy.Methods. Sixty-eight alloy discs were prepared and divided equally into four groups, and received four treatments for veneering: conventional feldspathic porcelain (Noritake EX-3) and three light-cured prosthodontic composite resins (Artglass, Solidex and Targis). The aesthetic materials were applied after metal structure conditioning in accordance with the manufacturers' recommendations. The specimens were stored in distilled water at 37 degreesC for 7 days. A universal testing machine was used to measure the shear bond strength of the specimens at a cross head speed of 0.5 mm/min. Fractured specimens were examined by using both optical and scanning electron microscope.Results. The analysis of variance and Tukey's test showed that the strongest mean shear bond was obtained with Noritake EX-3 (mean shear bond strength 42.90 +/- 7.82 MPa). For composites, the highest mean shear bond strength was observed for Targis (12.30 +/- 1.57 MPa); followed by Solidex (11.94 +/- 1.04 MPa) and Artglass (10.04 +/- 0.75 MPa). Optical analysis of the fractured surf aces indicated that for Targis and Noritake EX-3 all failures were a mixture of both cohesive and adhesive patterns. As for Artglass and Solidex, the fractures were mainly adhesive in nature.Conclusions. The Solidex system was equivalent to the Targis system in bond strength and exhibited greater strength than the Artglass system. The porcelain fused-to-metal showed considerably higher shear bond strength than the three metal-resin bonding techniques. (C) 2003 Elsevier B.V. Ltd. Ali rights reserved.

Adhesive Bonding of Resin Composite to Various Ni-Cr Alloy Surfaces Using Different Metal Conditioners and a Surface Modification System

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

Er : YAG laser: Antimicrobial effects in the root canals of dogs' teeth with pulp necrosis and chronic periapical lesions

Objective: Our goal in this study was to evaluate the antimicrobial effect of Er:YAG laser applied after biomechanical preparation of the root canals of dog's teeth with apical periodontitis. Background Data: Various in vitro studies have reported effective bacterial reduction in infected root canals using Er:YAG laser. However, there is no in vivo research to support these results. Methods: Forty root canals of dogs' premolar teeth with pulp necrosis and chronic periapical lesions were used. An initial microbiological sample was taken, and after biomechanical preparation was carried out, a second microbiological sample was taken. The teeth were divided into two groups: Group I-biomechanical preparation was taken of root canals without Er:YAG laser application; Group II-biomechanical preparation was taken of root canals with Er:YAG laser application using 140-mj input, 63-mJ output/15 Hz. After coronal sealing, the root canals were left empty for 7 days at which time a third microbiological sample was taken. The collected material was removed from the root canal with a #40 K file and placed in transport media. It was serially diluted and seeded on culture dishes selective for anaerobes, aerobes, and total streptococci. Colony-forming units per milliliter (CFU/mL) were counted. Results: Groups I and II showed an increase of CFU/mL for all microorganisms 7 days after treatment, being statistically significant for anaerobes in Group I and for anaerobes and total streptococci in Group II. When comparing CFU/mL of Groups I and II, there was a statistically significant increase after 7 d for total streptococci in Group II. Conclusion: Er:YAG laser applied after biomechanical preparation did not reduce microorganisms in the root canal system.

Microtensile bond strength of different adhesive systems in dentin irradiated with Er : YAG laser

The objective this study was to evaluate in vitro the bond strength of two etch-and-rise and one self-etching adhesive system after dentin irradiation with Er:YAG (erbium: yttrium aluminum garnet) laser using microtensile test. The results revealed that the groups treated with laser Er:YAG presented less tensile bond strength, independently to the adhesive system used. The prompt L-pop adhesive presented less microtensile bond strength compared to the other adhesives evaluated. There was no difference between single bond and excite groups. The adhesive failures were predominant in all the experimental groups. The Er:YAG laser influenced negatively bond strength values of adhesive systems tested in dental substrate.

Influence of Er:YAG laser on surface treatment of aged composite resin to repair restoration

The purpose of this study was to investigate the effect of Er:YAG laser on surface treatment to the bond strength of repaired composite resin after aged. Sixty specimens (n = 10) were made with composite resin (Z250, 3M) and thermocycled with 500 cycles, oscillating between 5 to 55A degrees C. The specimens were randomly separated in six groups which suffered the following superficial treatments: no treatment (GI, control), wearing with diamond bur (GII), sandblasted with aluminum oxide with 27.5 A mu m particles (GIII) for 10 s, 200 mJ Er:YAG laser (GIV), 300 mJ Er:YAG laser (GV), and 400 mJ Er:YAG laser (GVI), with the last 3 groups under a 10 Hz frequency for 10 s. Restoration repair was done using the same composite. The shear test was done into the Universal testing machine MTS-810. Analyzing the results through ANOVA and Tukey test, no significant differences were found (p-value is 0.5120). Average values analysis showed that superficial treatment with aluminum oxide presented the highest resistance to shear repair interface (8.91MPa) while 400 mJ Er:YAG laser presented the lowest (6.76 MPa). Fracture types analysis revealed that 90% suffered cohesive fractures to GIII. The Er:YAG laser used as superficial treatment of the aged composite resin before the repair showed similar results when used diamond bur and sandblasting with aluminum oxide particles.

Evaluation of Ultrasonic and ErCr:YSGG Laser Retrograde Cavity Preparation

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