Comparison of the fracture torque of different Brazilian mini-implants

This study evaluated fracture torque by torsion, in relation to the length and diameter of orthodontic mini-implants, to demonstrate their viability for clinical and experimental use based on the torque recommended by the manufacturers. The fractures at the moment of insertion, whose incidence in the literature is around 4%, are principally due to excessive force and the inability of the implant to resist rotational forces. Thirty orthodontic mini-implants of three commercial brands available in Brazil (Neodent 1.6 x 9 mm, Dentoflex 1.6 x 9 mm and Kopp 1.6 x 9 mm) were attached to a device made specifically for this research, leaving the mini-implants with sufficient stability. The miniimplants were submitted to torsion torque, using a digital torque wrench, until their breaking point. The values obtained with the test were submitted to analysis of variance and the Tukey test. The mean values of mini-implant ruptures were 26 N.cm for group A (Dentoflex), 25.4 N. cm for group B (Kopp) and 32.8 N.cm for group C (Neodent). From the Tukey test we could observe that the relationships between the means of the Dentoflex and Neodent groups, and between the Kopp and Neodent groups, were significant. Between the Dentoflex and Kopp groups, significance was nonexistent. All the values found in our research for fracture torque were higher than the limits recommended by the manufacturers for clinical use in orthodontics. The highest values were found in the Neodent group.

Influence of specimens' design and manufacturing process on microtensile bond strength to enamel: laboratory and FEA comparison

This study evaluated the effect of specimens' design and manufacturing process on microtensile bond strength, internal stress distributions (Finite Element Analysis - FEA) and specimens' integrity by means of Scanning Electron Microscopy (SEM) and Laser Scanning Confocal Microscopy (LCM). Excite was applied to flat enamel surface and a resin composite build-ups were made incrementally with 1-mm increments of Tetric Ceram. Teeth were cut using a diamond disc or a diamond wire, obtaining 0.8 mm² stick-shaped specimens, or were shaped with a Micro Specimen Former, obtaining dumbbell-shaped specimens (n = 10). Samples were randomly selected for SEM and LCM analysis. Remaining samples underwent microtensile test, and results were analyzed with ANOVA and Tukey test. FEA dumbbell-shaped model resulted in a more homogeneous stress distribution. Nonetheless, they failed under lower bond strengths (21.83 ± 5.44 MPa)c than stick-shaped specimens (sectioned with wire: 42.93 ± 4.77 MPaª; sectioned with disc: 36.62 ± 3.63 MPa b), due to geometric irregularities related to manufacturing process, as noted in microscopic analyzes. It could be concluded that stick-shaped, nontrimmed specimens, sectioned with diamond wire, are preferred for enamel specimens as they can be prepared in a less destructive, easier, and more precise way.

Tendência e diferenciais socioeconômicos da mortalidade por câncer de colo de útero no Estado do Paraná (Brasil), 1980-2000

O objetivo deste artigo é discutir a evolução da mortalidade por câncer de colo de útero no Estado do Paraná entre 1980 e 2000 e analisar seus diferenciais socioeconômicos em cada região. Taxas de mortalidade ajustadas por idade foram calculadas para as 22 regionais de saúde do Estado a cada ano. Análises comparativas avaliaram indicadores socioeconômicos associados com regiões que apresentaram tendência estacionária e crescente de mortalidade. A mortalidade por câncer de colo uterino cresceu no Estado como um todo a uma taxa de 1,68% (IC 1,20-2,17) ao ano. A maior parte das regiões apresentou tendência estacionária de mortalidade por câncer de colo de útero. As regionais com tendência de aumento na mortalidade apresentaram proporção significativamente mais elevada de analfabetismo (p<0,001) e de adultos (15 anos ou mais) com menos de 4 anos de estudo (p=0,001), e renda per capita (p=0,025) e IDH (p=0,023) inferiores. Houve tendência de aumento na mortalidade em todo o Estado; as regiões que contribuíram para o aumento experimentaram piores indicadores socioeconômicos.

An in vitro comparison of nickel and chromium release from brackets

This study aimed at comparing amounts of nickel (Ni) and chromium (Cr) released from brackets from different manufacturers in simulated oral environments. 280 brackets were equally divided into 7 groups according to manufacturer. 6 groups of brackets were stainless steel, and 1 group of brackets was made of a cobalt-chromium alloy with low Ni content (0.5%). International standard ISO 10271/2001 was applied to provide test methods. Each bracket was immersed in 0.5 ml of synthetic saliva (SS) or artificial plaque fluid (PF) over a period of 28 days at 37ºC. Solutions were replaced every 7 days, and were analyzed by spectrometry. The Kruskal-Wallis test was applied. Amounts of Ni release in SS (µg L-1 per week) varied between groups from "bellow detection limits" to 694, and from 49 to 5,948.5 in PF. The group of brackets made of cobalt-chromium alloy, with the least nickel content, did not release the least amounts of Ni. Amounts of Cr detected in SS and in PF (µg L-1 per week) were from 1 to 10.4 and from 50.5 to 8,225, respectively. It was therefore concluded that brackets from different manufacturers present different corrosion behavior. Further studies are necessary to determine clinical implications of the findings.

Inclusão da epistasia em modelo de avaliação genética de bovinos de corte compostos

Dados de bovinos compostos foram analisados para avaliar o efeito da epistasia nos modelos de avaliação genética. As características analisadas foram os pesos aos 205 (P205) e 390 dias (P390) e perímetro escrotal aos 390 dias (PE390). As análises foram realizadas pela metodologia de máxima verossimilhança considerando-se dois modelos: o modelo 1 incluiu como covariáveis os efeitos aditivos diretos e maternos, e os não aditivos das heterozigoses para os efeitos diretos e para o materno total, e o modelo 2 considerou também o efeito direto de epistasia. Para comparação dos modelos, foram utilizados o critério de informação de Akaike (AIC) e o critério de informação Bayesiano de Schwartz (BIC), e o teste de razão de verossimilhança. A inclusão da epistasia no modelo de avaliação genética pouco alterou as estimativas de componentes de (co)variâncias genéticas aditivas e, consequentemente, as herdabilidades. O teste de verossimilhança e o critério de Akaike sugeriram que o modelo 2, que inclui a epistasia, apresentou maior aderência aos dados para todas as características analisadas. O critério BIC indicou este modelo como o melhor apenas para P205. Para análise genética dessa população, o modelo que considerou o efeito de epistasia foi o mais adequado.

Vancomycin use in a brazilian teaching hospital: comparison with the Hospital Infection Controlpractices Advisory Committee Guidelines (HICPAC)

This study describes vancomycin prescribing patterns in an average complexity hospital and compare the guidelines proposed by the Hospital Infection Control Practices Advisory Committee (HICPAC). The study was conducted in a 256-bed secondary-care hospital. Data were collected of all patients given vancomycin from March 2003 to February 2004, using a standardized chart-extraction form designed. Appropriate and inappropriate use was reviewed according to the Hospital Infection Control Practices Advisory Committee (HICPAC) guidelines on prudent vancomycin use. Out of 118 prescriptions, 95 (80.5%) were considered appropriate. Out of these 95 orders, 77 (81.1%) were administered for empiric treatment of suspected Gram-positive infections, 17 (17.9%) were administered for treatment of proven Gram-positive infections (76.5% identified as Staphyloccocus aureus-like agents) and 1 (1.0%) for beta-lactam allergy. The majority of the patients (96.6%) had recently used an antimicrobial medication (3 months). The mean pre-treatment hospitalization period was 11±10 days. Out of the 118 treatments, 67 (56.8%) were for nosocomial infections. The more frequent indications for vancomycin use were pneumonia (48.3%) and primary sepsis (18.6%), accounting for more than 66% of all treatments. No restriction policy was suggested because vancomycin use was considered adequate in the majority of the treatment cases. The broad empiric use of this antimicrobial was greater than expected in the institution and its use should be revised.

Time evolution of the South Atlantic Magnetic Anomaly

The South Atlantic Magnetic Anomaly (SAMA) is one of the most outstanding anomalies of the geomagnetic field. The SAMA secular variation was obtained and compared to the evolution of other anomalies using spherical harmonic field models for the 1590-2005 period. An analysis of data from four South American observatories shows how this large scale anomaly affected their measurements. Since SAMA is a low total field anomaly, the field was separated into its nondipolar, quadrupolar and octupolar parts. The time evolution of the non-dipole/total, quadrupolar/total and octupolar/total field ratios yielded increasingly high values for the South Atlantic since 1750. The SAMA evolution is compared to the evolution of other large scale surface geomagnetic features like the North and the South Pole and the Siberia High, and this comparison shows the intensity equilibrium between these anomalies in both hemispheres. The analysis of non-dipole fields in historical period suggests that SAMA is governed by (i) quadrupolar field for drift, and (ii) quadrupolar and octupolar fields for intensity and area of influence. Furthermore, our study reinforces the possibility that SAMA may be related to reverse fluxes in the outer core under the South Atlantic region.

Comparison of radial growth rate of the mutualistic fungus of Atta sexdens rubropilosa forel in two culture media

In vitro culture of the mutualistic fungus of leaf-cutting ants is troublesome due to its low growth rate, which leads to storage problems and contaminants accumulation. This paper aims at comparing the radial growth rate of the mutualistic fungus of Atta sexdens rubropilosa Forel in two different culture media (Pagnocca B and MEA LP). Although total MEA LP radial growth was greater all along the bioassay, no significant difference was detected between growth efficiencies of the two media. Previous evidences of low growth rate for this fungus were confirmed. Since these data cannot point greater efficiency of one culture medium over the other, MEA LP medium is indicated for in vitro studies with this mutualistic fungus due its simpler composition and translucent color, making the analysis easier.

Allometric models for estimating the phytomass of a secondary Atlantic Forest area of southeastern Brazil

The purpose of this study was to develop and validate equations to estimate the aboveground phytomass of a 30 years old plot of Atlantic Forest. In two plots of 100 m², a total of 82 trees were cut down at ground level. For each tree, height and diameter were measured. Leaves and woody material were separated in order to determine their fresh weights in field conditions. Samples of each fraction were oven dried at 80 °C to constant weight to determine their dry weight. Tree data were divided into two random samples. One sample was used for the development of the regression equations, and the other for validation. The models were developed using single linear regression analysis, where the dependent variable was the dry mass, and the independent variables were height (h), diameter (d) and d²h. The validation was carried out using Pearson correlation coefficient, paired t-Student test and standard error of estimation. The best equations to estimate aboveground phytomass were: lnDW = -3.068+2.522lnd (r² = 0.91; s y/x = 0.67) and lnDW = -3.676+0.951ln d²h (r² = 0.94; s y/x = 0.56).

Influence of spawning procedure on gametes fertilization success in Salminus hilarii Valenciennes, 1850 (Teleostei: Characidae): Implications for the conservation of this species

Artificial reproduction and gamete fertilization were evaluated in Salminus hilarii wild and domesticated broodstocks. Wild and domesticated broodstocks were artificially induced to reproduction using a carp pituitary treatment. Four groups were considered: Group 1 (G1), fish caught in the wild maintained for three years in the same conditions as the domesticated broodstocks and spawned naturally; Group 2 (G2), broodstock born and raised in captivity and spawned naturally; Group 3 (G3), wild broodstocks, which were manually stripped for gamete collection and dry fertilization; and Group 4 (G4), domesticated males and females, also manually stripped. Oocytes, eggs, and larvae were sampled at different time intervals throughout embryonic development. Yolk sac absorption occurred approximately 24-29 h after hatching. Twenty-six h after hatching, the larvae mouths opened. Cannibalism was identified just 28-30 h after hatching. There was no morphological difference in embryonic development among all groups. The number of released eggs per gram of female was: G1: 83.3 ± 24.5 and G2: 103.8 ± 37.4; however, the fertilization success was lower in G2 (42.0 ± 6.37 %) compared with G1 (54.7 ± 3.02%) (P = 0.011). Hand-stripping of oocytes was not successful and the fertilization rate was zero. The reproduction of this species in captivity is viable, but it is necessary to improve broodstock management to enhance fertilization rates and obtain better fingerling production for restocking programs.

A comparison of the leaf-litter ant fauna in a secondary atlantic forest with an adjacent pine plantation in southeastern Brazil

We investigated the influence of Pinus afforestation on the structure of leaf-litter ant communities in the southeastern Brazilian Atlantic Forest, studying an old secondary forest and a nearly 30 year-old never managed Pinus elliottii reforested area. A total of 12,826 individual ants distributed among 95 species and 32 genera were obtained from 50 1 m² samples/ habitat. Of these, 60 species were recorded in the pine plantation and 82 in the area of Atlantic forest; almost 50% of the species found in the secondary forest area were also present in the pine plantation. The number of species per sample was significantly higher in the secondary forest than in the pine plantation. Forest-adapted taxa are the most responsible for ant species richness differences between areas, and the pine plantation is richer in species classified as soil or litter omnivorous-dominants. The specialized ant predators registered in the pine plantation, as seven Dacetini, two Basiceros, two Attini and two Discothyrea, belong to widely distributed species. The NMDS (non-metric multidimensional scaling) ordination also suggested strong differences in similarity among samples of the two areas. Furthermore, this analysis indicated higher sample heterogeneity in the secondary forest, with two clusters of species, while in the pine plantation the species belong to a single cluster. We applied the ant mosaic hypothesis to explain the distribution of the leaf-litter fauna and spatial autocorrelation tests among samples. We argue that the results are likely related to differences in quality and distribution of the leaf-litter between the pine plantation and the secondary area.

Perspectives of vaccination in Chagas disease revisited

The perspectives for a Chagas Disease vaccine 30 years ago and today are compared. Antigens and adjuvants have improved, but logistic problems remain the same. Sterilizing vaccines have not been produced and animal models for chronic Chagas have not been developed. Vector control has been successful and Chagas incidence has come to a halt. We do not have a population candidate to vaccination now in Brazil. And if we had, we would not know how to evaluate the success of vaccination in a short time period. A vaccine may not seem important at the moment. However, scientific reasons and incertitudes about the future recommend that a search for a vaccine be continued.

Experimental infections with Paracoccidioides brasiliensis obtained from armadillos: comparison to clinical isolates

Paracoccidioides brasiliensis causes paracoccidioidomycosis (PCM) that is one of the most prevalent systemic human mycoses in Latin America. Armadillos show a high incidence of PCM infection and could, therefore, be a natural reservoir for this fungus. In this study were compared the virulence profiles of isolates obtained from nine-banded armadillos (Dasypus novemcinctus) (PbT1 and PbT4) and isolates from PCM patients (Pb265 and Bt83). Pathogenicity was evaluated by fungal load and analysis of colony morphology. Immunity against the fungus was tested by delayed type hypersensitivity test (DTH) and antibody quantification by ELISA. The higher virulence of PbT1 and PbT4 was suggested by higher fungal load in spleen and lungs. Armadillo isolates and Bt83 presented a cotton-like surface contrasting with the cerebriform appearance of Pb265. All isolates induced cellular and humoral immune responses in infected BALB/c mice. DTH reactions were similarly induced by the four isolates, however, a great variability was observed in specific antibody levels, being the highest ones induced by Bt83 and PbT4. The present work confirms that armadillos harbor P. brasiliensis, whose multiplication and induced immunity in experimentally infected mice are heterogeneous, resembling the behavior of isolates from human PCM. This study reinforces the possibility that armadillos play an important role in the biological cycle of this pathogen.

Descriptor-and fragment-based QSAR models for a series of Schistosoma mansoni purine nucleoside inhibitors

The enzyme purine nucleoside phosphorylase from Schistosoma mansoni (SmPNP) is an attractive molecular target for the treatment of major parasitic infectious diseases, with special emphasis on its role in the discovery of new drugs against schistosomiasis, a tropical disease that affects millions of people worldwide. In the present work, we have determined the inhibitory potency and developed descriptor- and fragment-based quantitative structure-activity relationships (QSAR) for a series of 9-deazaguanine analogs as inhibitors of SmPNP. Significant statistical parameters (descriptor-based model: r² = 0.79, q² = 0.62, r²pred = 0.52; and fragment-based model: r² = 0.95, q² = 0.81, r²pred = 0.80) were obtained, indicating the potential of the models for untested compounds. The fragment-based model was then used to predict the inhibitory potency of a test set of compounds, and the predicted values are in good agreement with the experimental results

Neural networks and statistical analysis for classification of corneal videokeratography maps based on Zernike coefficients: a quantitative comparison

PURPOSE: The main goal of this study was to develop and compare two different techniques for classification of specific types of corneal shapes when Zernike coefficients are used as inputs. A feed-forward artificial Neural Network (NN) and discriminant analysis (DA) techniques were used. METHODS: The inputs both for the NN and DA were the first 15 standard Zernike coefficients for 80 previously classified corneal elevation data files from an Eyesys System 2000 Videokeratograph (VK), installed at the Departamento de Oftalmologia of the Escola Paulista de Medicina, São Paulo. The NN had 5 output neurons which were associated with 5 typical corneal shapes: keratoconus, with-the-rule astigmatism, against-the-rule astigmatism, "regular" or "normal" shape and post-PRK. RESULTS: The NN and DA responses were statistically analyzed in terms of precision ([true positive+true negative]/total number of cases). Mean overall results for all cases for the NN and DA techniques were, respectively, 94% and 84.8%. CONCLUSION: Although we used a relatively small database, results obtained in the present study indicate that Zernike polynomials as descriptors of corneal shape may be a reliable parameter as input data for diagnostic automation of VK maps, using either NN or DA.