BFFT quantization and dynamical solutions of a fluid field theory

We study a field theory formulation of a fluid mechanical model. We implement the Hamiltonian formalism by using the BFFT conjecture in order to build a gauge invariant fluid field theory. We also generalize previous known classical dynamical field solutions for the fluid model. ©2000 The American Physical Society.

Treatment of gingival recession: Comparative study between subepithelial connective tissue graft and guided tissue regeneration

Background: Various procedures have been proposed to treat gingival recession, but few studies compare these procedures to each other. The purpose of this study was to evaluate a clinical comparison of subepithelial connective tissue graft (SCTG) and guided tissue regeneration (GTR) with a collagen membrane in the treatment of gingival recessions in humans. Methods: Twenty-four defects were treated in 12 patients who presented canine or pre-molar Miller Class I and/or II bilateral gingival recessions. Both treatments were performed in all patients, and clinical measurements were obtained at baseline and 18 months after surgery. These clinical measurements included gingival recession height (GR), root coverage (RC), probing depth (PD), keratinized tissue width (KT), and final esthetic result. Results: Both SCTG and GTR with a bioabsorbable membrane and bone graft demonstrated significant clinical and esthetic improvement for gingival recession coverage. The SCTG group was statistically significantly better than GTR for height of GR (SCTG = 0.2 mm, GTR = 1.12 mm, P = 0.02) and KT (SCTG = 4.58 mm, GTR = 2.5 mm, P <0.0001). However, PD was statistically significantly better for GTR than SCTG treatment (GTR = 1.66 mm, SCTG = 1.00, P = 0.01). The 2 procedures were statistically similar in root coverage (SCTG = 95.6%, GTR = 84.2%, P = 0.073). The esthetic condition after both treatments was satisfactory (P = 0.024). Conclusions: It was concluded that the gingival recessions treated with the SCTG group were superior for GR, RC, and KT clinical parameters, while GTR demonstrated better PD reduction. The final esthetic results were similar using both techniques.

The improvement in grinding of inlet engine valves by the adoption of the most effective cuting fluid type

In this paper is presented an experimental research in which the grinding of seating surfaces of inlet engine valves was improved by the adoption of the most effective cutting fluid type, matching the new requirements of cutting fluid application. Four different types of cutting fluids (straight oil and three different types of soluble oils) were analyzed. As qualitative and quantitative evaluation parameters of the performance of the cutting fluids, the roughness, the grinding wheel wear, the cutting force and the workpiece residual stress were determined. As a conclusion, the straight oil was the cutting fluid that presented the best results in all of the parameters analyzed. Copyright © 2000 Society of Automotive Engineers, Inc.

Morphometric evaluation of gingival overgrowth and regression caused by cyclosporin in rats

Cyclosporin A is a selective immunosuppressant, used in organ transplants to prevent graft rejection. Cyclosporin A can cause various side effects including gingival overgrowth. The aim of this work was to evaluate gingival overgrowth of rats treated daily with 10 mg/kg body weight of Cyclosporin A for 60 days, as well as the regression after the interruption of treatment. All rats treated with Cyclosporin A developed gingival overgrowth, with increased thickness of the epithelium, height and width of the connective tissue. The density of fibroblasts and collagen fibers also increased. Five to 90 days after the interruption of treatment with Cyclosporin A, there was a progressive reduction of the gingival volume and of collagen fibers and fibroblast densities. The reduction was more pronounced in the initial periods and after 90 days did not return to the normal values.

Morphological evaluation of combined effects of cyclosporin and nifedipine on gingival overgrowth in rats

It has previously been shown that, while cyclosporin A (CsA) and nifedipine both cause gingival overgrowth in the rat. the combined use of these drugs increases the severity of overgrowth. The aim of this study was to describe the histometry and densities of fibroblasts, collagen fibers and vessels in the gingival tissue of rats that were treated with CsA and nifedipine, either alone or in combination. Rats were treated for 60 days with a daily subcutaneous injection of 10 mg/kg body weight of CsA and/or with 50 mg/kg body weight of nifedipine added to the chow. The results confirmed that CsA causes a more severe overgrowth than nifedipine, and that the combined use of these drugs increases the overgrowth severity. All the rat groups that were studied showed that, as the severity of overgrowth increased, there was a parallel increase in fibroblasts and collagen, and a decrease in vessel content. Therefore, independently of whether the gingival overgrowth was caused by CsA alone, nifedipine alone, or both treatments in combination, the fibroblast and collagen density increased in parallel with the severity of the overgrowth. © Blackwell Munksgaard, 2002.

Combined effects of cyclosporin and nifedipine on gingival overgrowth in rats is not age dependent

Background: Cyclosporin A and nifedipine cause gingival overgrowth in rat, and the combined use of these drugs increases the overgrowth severity. Objective: The purpose of this study was to compare gingival overgrowth of rats of differents ages treated with cyclosporin A and nifedipine alone or given concurrently. Materials and methods: Rats 15, 30, 60 and 90 d old were treated with 10 mg/kg body weight of cyclosporin A and/or 50 mg/kg body weight of nifedipine in the chow. Results: Young rats showed evident gingival overgrowth with nifedipine, cyclosporin A, and cyclosporin A and nifedipine given concurrently. Adult rats did not show significant gingival alterations when treated with cyclosporin A and nifedipine alone. Nevertheless evident gingival overgrowth with alterations of the epithelium and connective tissue were observed when treated simultaneously with cyclosporin A and nifedipine. Conclusion: These results suggest that the combined effects of cyclosporin A and nifedipine on gingival overgrowth in rat is not age dependent.

The influence of fluid ingestion on performance of soccer players during a match

The purpose of this study was to verify the effects of a carbohydrate-electrolyte drink on soccer performance. Twenty soccer players volunteered to participate in the study. Players were allocated to two assigned trials according to their positional roles in the team: CHO group (ingesting a 6% carbohydrate-electrolyte solution at regular 15 minutes intervals) and NCHO (ingesting no fluid) during 75 min on-field soccer game. During the trials, body mass loss, heart rate, time spent running, number of sprints and core temperature were measured. There were statistically significant changes (p < 0.05) in body mass loss (CHO: 1.14 ± 0.37 kg vs. NCHO: 1.75 ± 0.47 kg) and number of sprints performed (CHO: 14.70 ± 4.38 vs. NCHO: 10.70 ± 5.80) between groups. The main finding of the present study indicates that supplementation with a carbohydrate-electrolyte drink during a soccer match is beneficial in helping to prevent deterioration in performance. © Journal of Sports Science and Medicine (2004).

Use of the paired samples (cerebrospinal fluid and serum) in immunodiagnostic of active and inactive human neurocysticercosis

Paired samples of cerebrospinal fluid (CSF) and serum of 30 patients - 10 with active, 10 with inactive neurocysticercosis (NCC), and 10 control subjects - were evaluated by enzyme-linked immunosorbent assay (ELISA) using two Taenia crassiceps metacestode extracts as antigen in order to detect IgG antibodies. In active NCC, high levels of IgG were detected (p < 0.05). The CSF samples showed 80% (CI 72-88) of reactivity in the saline extract (S) and 90% (CI 84-95) in sodium dodecyl sulphate (SDS) and the serum samples were reactive in 90% (CI 84-95) and 100% (CI 98-100) in the S and SDS antigenic extracts, respectively. The use of the paired samples of CSF and serum in active NCC showed equivalent results suggesting that the serum samples could be used as a screening in those patients whose CSF puncture is counter-indicated.

Simulations of incompressible fluid flows by a least squares finite element method

In this work simulations of incompressible fluid flows have been done by a Least Squares Finite Element Method (LSFEM) using velocity-pressure-vorticity and velocity-pressure-stress formulations, named u-p-ω) and u-p-τ formulations respectively. These formulations are preferred because the resulting equations are partial differential equations of first order, which is convenient for implementation by LSFEM. The main purposes of this work are the numerical computation of laminar, transitional and turbulent fluid flows through the application of large eddy simulation (LES) methodology using the LSFEM. The Navier-Stokes equations in u-p-ω and u-p-τ formulations are filtered and the eddy viscosity model of Smagorinsky is used for modeling the sub-grid-scale stresses. Some benchmark problems are solved for validate the numerical code and the preliminary results are presented and compared with available results from the literature. Copyright © 2005 by ABCM.

Development of a supercritical fluid extraction method for simultaneous determination of organophosphorus, organohalogen, organonitrogen and pyretroids pesticides in fruit and vegetables and its comparison with a conventional method by GC-ECD and GC-MS

The aim of this paper was to apply a multiresidue method using Supercritical Fluid Extraction (SFE) and capillary gas chromatography with electron capture and mass spectrometry detections in the analysis of the levels of pesticide residues in fruits and vegetables. Single laboratory validation of both solid-liquid and supercritical fluid extraction methods was carried out for 32 compounds selected from four pesticide classes (organochlorine, organonitrogen, organophosphorus and pyretroid) in blank and fortified samples of fresh lettuce, potato, apple and tomato. Recoveries for the majority of pesticides from fortified samples at fortification level of 0.04-0.10 mg kg -1 ranged 74-96% for both methods and confirmation of pesticide identity was performed by gas-chromatography-mass spectrometry in a selected-ion monitoring mode. Both methods showed good limits of detection (less 0.01 mg kg-1, depending on the pesticide and matrix) and the SFE method minimized environmental concerns, time, and laboratory work. ©2005 Sociedade Brasileira de Química.

Periodontal plastic surgery associated with treatment for the removal of gingival overgrowth

Background: Excisional biopsies of gingival overgrowths, performed with safety margins, frequently result in mucogingival defects. These defects may produce esthetic problems and increase the chances of dentin hyperesthesia and its possibility of hindering oral hygiene. Methods: Two clinical cases are reported in which gingival overgrowths were removed by excisional biopsy, resulting in unsightly defects. The first clinical case presents an invasive approach for the treatment of a recurrent pyogenic granuloma in the anterior maxilla, and the second depicts a complete removal of a peripheral odontogenic fibroma in the posterior maxilla. In both situations, the soft-tissue defects were repaired by periodontal plastic surgery, including a laterally positioned flap and a coronally positioned flap, respectively. Results: Periodontal plastic surgery successfully restored the defects that resulted from biopsies, and no recurrence has been noticed in the 5-year postoperative follow-up period. Conclusions: The combination of biopsy and periodontal plastic surgery in a one-step procedure seems to be suitable to remove gingival overgrowths in most areas of the mouth, regardless of esthetic significance. Such procedures seem to restore gingival health, encourage healing, and create both esthetics and function in the excised area.

Relationship between gingival clinical parameters and the reactivity of the BANA test in subgingival samples from children.

Gingivitis is the first manifestation of periodontal disease, and is characterized by painless and slow evolution. Early diagnosis and intervention must be done to avoid the possibility of precocious periodontitis during the childhood or teenage years. The enzymatic BANA test (N-benzoyl-DL-arginine-naphthylamide) was used to evaluate subgingival samples from 54 children between 6 and 9 years of age. Plaque index (PI) and gingival index (GI) were assessed according to the criteria recommended by Löe (1967). Subgingival plaque was collected from the region that featured the greatest periodontal alteration, represented by a higher gingival index. Resulting data were grouped individually according to visible and non-visible plaque and bleeding and non-bleeding gingiva. Results showed that there was no statistically significant correlation between the presence of visible plaque and the positivity of the BANA test, nor was there a statistically significant correlation between the presence of bleeding and the positivity of the BANA test in subgingival samples obtained from children. This study concluded that the BANA test is not an ideal diagnostic test to be applied to children.

Gingival margin alterations and the pre-orthodontic treatment amount of keratinized gingiva

The purpose of this retrospective study was to associate the amount of keratinized gingiva present in adolescents prior to orthodontic treatment to the development of gingival recessions after the end of treatment. The sample consisted of the intra-oral photographs and orthodontic study models from 209 Caucasian patients with a mean age of 11.20 ± 1.83 years on their initial records and 14.7 ± 1.8 years on their final records. Patients were either Angle Class I or II and were submitted to non-extraction orthodontic treatment. Gingival recession was evaluated by visual inspection of the lower incisors and canines as seen in the initial and final study models and intra-oral photographs. The amount of recession was quantified using a digital caliper and the observed post-treatment gingival margin alterations were classified as unaltered, coronal migration of the gingival margin or apical migration of the gingival margin. The width of the keratinized gingiva was measured from the mucogingival line to the gingival margin on the pre-treatment photographs. The teeth that developed gingival recession and those that did not have their gingival margin position changed did not differ in relation to the initial amount of keratinized gingiva (3.00 ± 0.61 and 3.5 ± 0.86 mm, respectively). Paradoxically, teeth that presented a coronal migration of the gingival margin had a smaller initial amount of keratinized gingiva (2.26 ± 0.31 mm). The mean amount of initial keratinized gingiva did not predispose lower incisors and canines to gingival recession.

Lower intercanine width and gingival margin changes. A retrospective study.

OBJECTIVE: To determine if changes in the lower intercanine widths during orthodontic treatment with fixed appliances result in gingival margin changes around the lower canines and incisors. METHOD: Pre- and post-treatment intra-oral photographs and orthodontic study models of 178 Caucasian adolescents (101 female, 77 male) were used. All subjects were treated with fixed appliances. The subjects had mean ages of 11.41 (SD: 1.83) years and 14.91 (SD: 1.78) years on their initial and final records respectively. The latter were taken 28 days or more after the appliances had been removed. The inclusion criteria were: Angle Class I or Class II malocclusion (with or without transverse and/or vertical discrepancies); nonextraction treatment; less than 4 mm crowding or spacing; fully erupted lower incisors and good periodontal health. The intercanine widths and the positions of the gingival margins relative to the maximum curvatures of the labial surfaces of the lower canines and incisors were measured with digital calipers. RESULTS: A significant association was found between unaltered intercanine widths and coronal migration of the gingival margins (p = 0.045). There were no significant associations between either increased or reduced intercanine widths and changes in the gingival margins. CONCLUSIONS: Following orthodontic treatment coronal migration of the gingival margins around the lower incisors and canines is more likely to be associated with an unaltered intercanine width.