A New Indirect Electrochemical Method for Determination of Ozone in Water Using Multiwalled Carbon Nanotubes

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Morphological assessment of dentine and cementum following apicectomy with Zekrya burs and Er:YAG laser associated with direct and indirect Nd:YAG laser irradiation

Objectives. This study aimed to assess the apical surface morphology of maxillary central incisors resected 3.0 mm from the tooth apex using Zekrya burs or Er:YAG laser, with or without subsequent direct Nd:YAG laser irradiation (apical and buccal surfaces) and indirect irradiation (palatal surface).Study design. Forty maxillary central incisors were instrumented and obturated. The roots were divided into 4 groups according to the root resection method (Zekrya bur or Er: YAG laser -1.8 W, 450 mJ, 4 Hz, 113 J/cm(2)) and further surface treatment (none or Nd: YAG laser -2.0 W, 100 mJ, 20 Hz, 124 J/cm(2)). The teeth were prepared for SEM analysis. Scores ranging from 1 to 4 were attributed to cut quality and morphological changes. The data were analyzed by the Kruskal-Wallis test and by Dunn's test.Results. SEM images showed irregular surfaces on the apical portions resected with Zekrya burs, with smear layer and grooves in the resected dentine and slight gutta-percha displacement and plasticization. on the other hand, apicectomies carried out with Er: YAG laser showed morphological changes compatible with ablated dentine, with rough surfaces and craters. In spite of the presence of plasticized gutta-percha, with the presence of bubbles, an irregular adaptation of the filling material to the root walls was also observed. Direct Nd: YAG laser irradiation of the apical and buccal surfaces of the resected roots resulted in areas of resolidification and fusion in the dentine and cementum, with a vitrified aspect; indirect Nd: YAG laser irradiation of the palatal surfaces yielded a lower number of changes in the cementum, with irregular resolidification areas.Conclusions. There were no differences in terms of cut quality between the use of burs and Er: YAG laser or between the 2 surfaces (apical and buccal) treated with Nd: YAG laser with direct irradiation. However, morphological changes were significantly less frequent on surfaces submitted to indirect irradiation (palatal) when compared with those directly irradiated. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010; 109: e77-e82)

Numeric evaluation of the stiffness of log-concrete composite beams submitted the cyclical load

In this paper was evaluated, using the software ANSYS, the stiffness (El) of the log-concrete composite beams, of section T, with connectors formed by bonded-in steel rods, type CA-50, disposed in X, with application of cyclical load. The stiffness of the system was evaluated through the simulation of bending tests, considered 1/2 beam, with cyclical shipment varying among 40 % and 5 % of the strength of the connection with the load relationship R=0,125, for a total of 10 load cycles applied. The numeric results show a good agreement with experimental tests.

The reliability of experts' opinions in constructing a composite environmental index: The case of ESI 2005

The complexity of the environment demands a well-constructed composite environmental index (CEI) to provide a useful tool to draw attention to environmental conditions and trends for policy purposes. Among the common difficulties in constructing a proper CEI are uncertainties due to the selection of the most representative underlying variables or indicators. A degree of uncertainty accompanies experts' judgments, and to deal with vague, subjective or inconsistent information, logic other than classic is required. This study analyzes a procedure that uses different experts' opinions in constructing a CEI. with the use of paraconsistent annotated logic. For this, a sensitivity analysis of the Environmental Sustainability Index (ESI 2005) was used as an example to assess the reliability of experts' opinions. The uncertainty due to the disagreement in experts' opinions clearly indicates that the forms we presently use to measure and monitor the actual environment are insufficient, that is, there is a lack of a "science of sustainability". (C) 2009 Elsevier Ltd. All rights reserved.

Development, characterization and clinical use of a biodegradable composite scaffold for bone engineering in oro-maxillo-facial surgery

We have developed a biodegradable composite scaffold for bone tissue engineering applications with a pore size and interconnecting macroporosity similar to those of human trabecular bone. The scaffold is fabricated by a process of particle leaching and phase inversion from poly(lactide-co-glycolide) (PLGA) and two calcium phosphate (CaP) phases both of which are resorbable by osteoclasts; the first a particulate within the polymer structure and the second a thin ubiquitous coating. The 3-5 mu m thick osteoconductive surface CaP abrogates the putative foreign body giant cell response to the underlying polymer, while the internal CaP phase provides dimensional stability in an otherwise highly compliant structure. The scaffold may be used as a biomaterial alone, as a carrier for cells or a three-phase drug delivery device. Due to the highly interconnected macroporosity ranging from 81% to 91%, with macropores of 0.8 similar to 1.8 mm, and an ability to wick up blood, the scaffold acts as both a clot-retention device and an osteoconductive support for host bone growth. As a cell delivery vehicle, the scaffold can be first seeded with human mesenchymal cells which can then contribute to bone formation in orthotopic implantation sites, as we show in immune-compromised animal hosts. We have also employed this scaffold in both lithomorph and particulate forms in human patients to maintain alveolar bone height following tooth extraction, and augment alveolar bone height through standard sinus lift approaches. We provide a clinical case report of both of these applications; and we show that the scaffold served to regenerate sufficient bone tissue in the wound site to provide a sound foundation for dental implant placement. At the time of writing, such implants have been in occlusal function for periods of up to 3 years in sites regenerated through the use of the scaffold.

Indirect fluorescent test for detection of anti-Paracoccidioides brasiliensis antibodies using coated bentonite particles as antigen

An indirect fluorescent test was developed for detecting antibodies to Paracoccidioides brasiliensis using bentonite particles as antigen (Bent-IF). The bentonite particles were coated with P. brasiliensis polysaccharide antigen and tested with sera from paracoccidioidomycosis patients (36 sera), normal blood donors (32 sera) and patients with non-mycotic diseases (29 sera). The titres given by the positive sera were compared with those of complement fixation (CF), immunodiffusion (ID) and immunofluorescent test using yeast forms of the fungus as antigen (conventional-IF). All normal blood donors' sera gave a negative Bent-IF, conventional-IF, ID and CF tests. All paracoccidioidomycosis sera were reactive in conventional-IF and gave concordant results in Bent-IF. There was no correlation between CF and Bent-IF titres. 27·6% of sera from patients with non-mycotic diseases gave weak titres in both IF-tests. The present data indicate that the Bent-IF is a sensitive and simple serodiagnostic technique comparable with the conventional P. brasiliensis antibody test. © 1983.

Serology of paracoccidioidomycosis - I. Evaluation of the indirect immunofluorescent test

The purposes of the present work were: i) to study the positivity indices and compare titers obtained with the indirect immunofluorescence (II), tube precipitation (TP), complement fixation (CF) and double immunodiffusion on agar gel (ID) tests in the sera of 196 patients with paracoccidioidomycosis before treatment, and ii) to compare the initial titers of II with those obtained 1 year or more after treatment. II was the most sensitive serologic reaction (85.2%), and the positivity indices for CF, ID and TP were 67.7%, 66.0% and 50.0%, respectively. The sera tended to show parallel mean titers in II, CF and TP tests. One year after treatment there was a fall in titers of II in 66.2% of patients. The data, taken as a whole, demonstrate the usefulness of the indirect immunofluorescent test and the importance of using 2 or more serologic tests for the diagnosis and monitoring of patients with paracoccidioidomycosis. © 1985 Martinus Nijhoff/Dr W. Junk Publishers.

Evaluation of an indirect ELISA method for the detection of chicken antibodies against infectious bronchitis virus

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Second quantization approach to composite hadron interactions in quark models

Starting from the Fock space representation of hadron bound states in a quark model, a change of representation is implemented by a unitary transformation such that the composite hadrons are redescribed by elementary-particle field operators. Application of the unitary transformation to the microscopic quark Hamiltonian gives rise to effective hadron-hadron, hadron-quark, and quark-quark Hamiltonians. An effective baryon Hamiltonian is derived using a simple quark model. The baryon Hamiltonian is free of the post-prior discrepancy which usually plagues composite-particle effective interactions.

Light and thermal excitation of depolarization current in indirect bandgap Alx Ga1-xAs

Monochromatic light excitation in conjunction with thermally stimulated depolarization current measurements are applied to indirect bandgap AlxGa1-xAs. The obtained average activation energy for dipole relaxation is in very close agreement with the DX center binding energy. Monochromatic light induces state transition in the defect and makes possible the identification of dipoles observed in the dark. Charge relaxation currents are destroyed by photoionization of Al0.5Ga0.5As using either 647 nm Kr+ or 488 nm Ar+ laser lines, which are above the DX center threshold photoionization energy. It suggests that correlation may exist among charged donor states DX--d+. Sample resistance as a function of temperature is also measured in the dark and under illumination and shows the probable X valley effective mass state participation in the electron trapping. Ionization with energies of 0.8 eV and 1.24 eV leads to striking current peak shifts in the thermally stimulated depolarization bands. Since vacancies are present in this material, they may be responsible for the secondary band observed in the dark as well as participation in the light induced recombination process.

Anaerobic microorganisms in root canals of human teeth with chronic apical periodontitis detected by indirect immunofluorescence

Aiming to assess the presence of selected anaerobic microorganisms in root canals of human teeth with chronic apical periodontitis, 25 central and lateral upper incisors presenting with radiographic evidence of chronic apical periodontitis were studied. The pulp chamber was opened under aseptic conditions and samples of the root canal content were collected with sterile absorbent paper points, which were placed and dispersed in test tubes containing reduced transport medium (RTF). Aliquots were dried on glass slides and stained by indirect immunofluorcscencc for detection of Actinomyces viscosus, Fusobacterium nucleatum, Porphyromonas gingivalis and Prevotella intermedia. The results showed a positive indirect immunofluorescence reaction in 24 of the 25 samples. Fourteen were positive for the specie Actinomyces viscosus, 12 for Prevotella intermedia, 10 for Fusobacterium nucleatum and 4 for Porphyromonas gingivalis. A semiquantitative assay was easily implemented for assessment of degree of infection by the organisms in individual cases. © Munksgaard, 1996.

Field-theoretic approach for systems of composite hadrons

Systems containing simultaneously hadrons and their constituents are most easily described by treating composite hadron field operators on the same kinematical footing as the constituent ones. Introduction of a unitary transformation allows redescription of hadrons by elementary-particle field operators. Transformation of the microscopic Hamiltonian leads to effective Hamiltonians describing all possible processes involving hadrons and their constituents.

Two-Way Selection for Daily Gain and Feed Conversion in a Composite Rabbit Population

We conducted a two-way selection experiment in a composite rabbit population to investigate the responses to selection for postweaning ADG and feed conversion (FC). Two generations of crossing, followed by four generations of random pair matings, preceded three generations of selection. Selection was practiced within four lines: high-feed conversion (HFC), low-feed conversion (LFC), high gain (HG), and low gain (LG). Data on 1,446 rabbits from the random mating and selection generations were fitted to an animal model to estimate heritabilities of and the genetic correlation between ADG and FC. The two-trait model included rabbit and common litter random effects and line, generation, and sex fixed effects. Estimates of heritability of ADG and FC were .48 and .29, respectively, and the genetic correlation between them was -.82. Common litter environmental effects accounted for a proportion of .11 and . 13 of the phenotypic variation of the two traits, respectively. For ADG (in g/d) the regressions of mean breeding values on generation number during the selection period were 1.23 ± .12 (P < .01) in the HG line and -.86 ± .12 (P < .01) in the LG line; the regressions for FC (in g feed/g gain) were -.07 ± .01 (P < .01) in the HFC line and .03 ± .01 (P < .05) in the LFC line. Selection for ADG was effective in improving ADG and FC.

Anatomical changes induced by selection for plant architecture in maize (Zea mays L.)

The original brachytic population 'Dent Single Cross Composite' (DSCC-br2br2) and a selection-derived sub-population with modified plant architecture (DSCC-br2br2-Lg3Lg3, selected for erect leaves), were evaluated for the following characteristics number of vascular bundles of greater and smaller size, total vascular tissue area (phloem and xylem), sustaining tissue area (vascular tissue plus sclerenchyma), phloem and sclerenchyma areas in apical, medial and basal portions from midclub and in apical and basal sheath regions (from second leaf above and first below ear insertion). These variables had different values for the five different sections studied in each leaf and these differences did not have the same pattern in the two DSCC populations (brachytic and with modified architecture). Selection for architectural modification caused some indirect foliar anatomical modifications. With the exception of the phloem and the vascular tissue areas in apical leaf and sheath base regions, the modified plant architecture population showed smaller values of sustaining tissue area, sclerenchyma area, vascular tissue area and number of smaller vascular bundles than the original one. In the ligule region the modified maize leaves had smaller vascular and sustaining tissue areas, reducing transportation area, which could reduce gram yield.

Electrical properties of a composite of Polyurethane and ferroelectric ceramics

Ferroelectric ceramic particles based on lead titanate zirconate (PZT) were dispersed in a polymer matrix based on castor oil. After the poling process, the pyroelectric activity of this composite was measured using a direct method in which a linear heating rate was applied to the pre-poled samples. The pyroelectric coefficient at 343 K is comparable with that of a PZT-poly(vinylidene fluoride) (PVDF) composite and significantly higher than that of PVDF. © 1998 Kluwer Academic Publishers.