Characterization of a cellulase-free xylanase producing Bacillus sp for biobleaching of kraft pulp

Application of the xylanase in the pulp bleaching process has been shown to be effective in decreasing the amount of chlorinating agents in the process and improving the brightness of the pulp. The use of thermostable cellulase-free xylanase might enhance both the technical and economic feasibility of the process. In this work an alkalophylic strain of Bacillus sp 77-2, was isolated which showed a high production of xylanase and free cellulases. The xylanase of Bacillus sp displayed an optimum pH of 6.0 (with 70% activity at pH 9.0), all optimum temperature of 60 degrees C, pH stability in the range 5-10 and thermal stability of 50 degrees C. These characteristics are important to the kraft pulp bleaching because they are similar to those found in the industrial paper environment.

Simultaneous Determination of Phenanthrene and Benzo(a)pyrene in Water Samples by Synchronous Fluorescence Spectroscopy

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

Efficacy of Endodontic Treatment for Endotoxin Reduction in Primarily Infected Root Canals and Evaluation of Cytotoxic Effects

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

Novel production method of porous surface Ti samples for biomedical application

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

Cytotoxicity and genotoxicity of pulp capping materials in two cell lines

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Peroxide penetration from the pulp chamber to the external root surface after internal bleaching

Purpose: To quantify the amount of peroxide penetration from the pulp chamber to the external surface of teeth during the walking bleaching technique. Methods: Seventy-two bovine lateral incisors were randomly divided over five experimental groups and one control (n = 12 per group): (1) 35% hydrogen peroxide (HP); (2) 35% carbamide peroxide (CP); (3) sodium perborate (SP); (4) (HP+SP); (5) (CP+SP) and (6) Control (CG), deionized water. All groups were treated according to the walking bleach technique. After 7 days at 37 degrees C in an acetate buffer solution, 100 mu l violet leukocrystal coloring and 50 mu l peroxidase was added, producing a blue stain that could be measured in a spectrophotometer and then converted into peroxide mu g/ml. Results: G5 exhibited the greatest penetration, while G2 and G3 produced the lowest values. All bleaching agents penetrated from the pulp chamber to the external root surface. There was a direct correlation between the presence of oxidative agents and penetration potential. Sodium perborate in distilled water was less oxidative and appeared to be the least aggressive bleaching agent. (Am J Dent 2010;23:171-174).

Ultrasonic versus high-speed cavity preparation: Analysis of increases in pulpal temperature and time to complete preparation

Statement of problem. The use of ultrasonic tips has become an alternative for cavity preparation. However, there are concerns about this type of device, particularly with respect to intrapulpal temperatures and cavity preparation time.Purpose. The purpose of this study was to analyze pulpal temperature increases generated by an ultrasonic cavity preparation with chemical vapor deposition (CVD) tips, in comparison to preparation with a high-speed handpiece with a diamond rotary cutting instrument. The time required to complete the cavity preparation with each system was also evaluated.Material and methods. Thermocouples were positioned in the pulp chamber of 20 extracted human third molars. Slot-type cavities (3 x 3 x 2 mm) were prepared on the buccal and the lingual surfaces of each tooth. The test groups were: high-speed cavity preparation with diamond rotary cutting instruments (n = 20) and ultrasonic cavity preparation with CVD points (n = 20). During cavity preparation, the increases In pulpal temperature, and the time required for the preparation, were recorded and analyzed by Student's t test for paired samples (alpha = .05).Results. The average pulpal temperature increases were 4.3 degrees C for the high-speed preparation and 3.8 degrees C for the ultrasonic preparation, which were statistically similar (P = .052). However, significant differences were found (P < .001) for the time expended (3.3 minutes for the high-speed bur and 13.77 minutes for the ultrasound device).Conclusions. The intrapulpal temperatures produced during cavity preparation by ultrasonic tips versus high-speed bur preparation were similar. However, the use of the ultrasonic device required 4 times longer for the completion of a cavity preparation.

The Effectiveness of Low-Intensity Red Laser for Activating a Bleaching Gel and Its Effect in Temperature of the Bleaching Gel and the Dental Pulp

Statement of the Problem: The effectiveness of low-intensity red laser for activating a bleaching gel and its effect in pulp temperature was not investigated in dental literature. Purpose: The objective of this study was to assess the effectiveness of low-intensity red laser for activating a bleaching gel, as well as its effect in temperature of the bleaching gel and the dental pulp. Materials and Methods: Forty extracted bovine teeth were immersed in a solution of coffee 14 days for darkening. The initial colors were recorded by spectrophotometric analysis. The specimens were randomly distributed into two groups (N = 20): the control, which did not receive light and the experimental group that received light from an appliance fitted with three red light-emitting laser diodes (? = 660 nm). A green-colored, 35% H2O2based bleaching gel was applied for 30 minutes, and changed three times. After bleaching, the colors were again measured to obtain the L*a*b* values. Color variation was calculated (?E) and the data submitted to the non-paired t-test (5%). To assess temperature, 10 human incisors were prepared, in which one thermocouple was placed on the bleaching gel applied on the surface of the teeth and another inside the pulp chamber. Results: There was a significant difference between the groups (p = 0.016), and the experimental group presented a significantly higher mean variation (7.21 +/- 2.76) in comparison with the control group (5.37 +/- 1.76). There was an increase in pulp temperature, but it was not sufficient to cause damage to the pulp. Conclusion: Bleaching gel activation with low-intensity red laser was capable of increasing the effectiveness of bleaching treatment and did not increase pulp temperature to levels deleterious to the pulp. CLINICAL SIGNIFICANCE The application of a low-intensity red laser was effective for activating a bleaching gel with green dye, without any deleterious increases in pulpal temperature. (J Esthet Restor Dent 24:126134, 2012)

Apoptosis in T lymphocytes from spleen tissue and peripheral blood of L. (L.) chagasi naturally infected dogs

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Direct and Simultaneous Determination of Cd Cu, and Se in Blood Samples by Graphite Furnace Atomic Absorption Spectrometry

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Chlorination treatment of aqueous samples reduces, but does not eliminate, the mutagenic effect of the azo dyes Disperse Red 1, Disperse Red 13 and Disperse Orange 1

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Copper determination in ethanol fuel samples by anodic stripping voltammetry at a gold microelectrode

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Determination of Glyphosate in Water Samples by Multi-pumping Flow System Coupled to a Liquid Waveguide Capillary Cell

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

MICROBIAL COUNTS of DARK RED LATOSOL SAMPLES STORED AT DIFFERENT TEMPERATURES

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Rabies laboratory diagnosis: peculiar features of samples from equine origin

O diagnóstico laboratorial da raiva é realizado através de métodos de pesquisa do corpúsculo de Negri, imunofluorescência direta e inoculação em camundongos. Na maioria dos casos, quando a amostra é bem coletada, bem conservada e o profissional responsável possui experiência, verifica-se concordância entre as técnicas utilizadas. A Seção de Raiva e Encefalomielite do Instituto Biológico ao comparar a sensibilidade das três técnicas diagnósticas, em 3713 amostras (córtex cerebral, cerebelo e hipocampo) recebidas no período de 1980-1994, sendo 3010 da espécie bovina (983 positivas) e 703 da espécie eqüina (111 positivas), observou que, no caso da raiva eqüina, esta concordância não é mantida. Verificou-se, nesta espécie, que somente em algumas oportunidades foi possível identificar, pelo método histopatológico, o corpúsculo de Negri. em relação à prova de imunofluorescência pode-se afirmar que a mesma detectou uma porcentagem menor de amostras positivas, provenientes da espécie equina, em compração com as da espécie bovina, sendo esta diferença estatisticamente significativa. A prova biológica foi a mais sensível, porém houve uma diferença, também significativa, entre o período de incubação em camundongos das amostras de origem bovina e das de origem eqüina. A presença pouco frequente de corpúsculos de Negri e o período de incubação em camundongos mais prolongado, das amostras de origem eqüina, sugerem que devem ser intensificados os estudos da patogenia da raiva nesta espécie.