Surface and subsurface erosion of primary enamel by acid beverages over time

This study evaluated the influence of a cola-type soft drink and a soy-based orange juice on the surface and subsurface erosion of primary enamel, as a function of the exposure time. Seventy-five primary incisors were divided for microhardness test (n=45) or scanning electron microscopy (SEM) analysis (n=30). The specimens were randomly assigned to 3 groups: 1 - artificial saliva (control); 2 - cola-type soft drink; and 3 - soy-based orange juice. Immersion cycles in the beverages were undertaken under agitation for 5 min, 3 times a day, during 60 days. Surface microhardness was measured at 7, 15, 30, 45 and 60 days. After 60 days, specimens were bisected and subsurface microhardness was measured at 30, 60, 90, 120, 150 and 200 µm from the surface exposed. Data were analyzed by ANOVA and Tukey’s test (a=0.05). Groups 2 and 3 presented similar decrease of surface microhardness. Regarding subsurface microhardness, group 2 presented the lowest values. SEM images revealed that after 60 days the surfaces clearly exhibited structural loss, unlike those immersed in artificial saliva. It may be concluded that erosion of the surfaces exposed to the cola-type soft drink was more accentuated and directly proportional to the exposure time.

Viability of using enamel and dentin from bovine origin as a substitute for human counterparts in an intraoral erosion model

This study ascertained whether under dental erosion models that closely mimics the real-life situation enamel and root dentin from bovine origin would be reliable substitutes for human counterparts. Through a 2x2 crossover design, in a first trial, 14 volunteers wore a palatal device containing slabs of bovine and human enamel. Half of the participants ingested (4x daily, for 10 days) orange juice first, crossing over to mineral water, while the remainder received the reverse sequence. In a second trial, volunteers wore devices with slabs of bovine and human root dentin. Except for the duration of each intraoral phase, which lasted 2 rather 10 days, the experiment with root dentin run exactly as for enamel. Dental substrates were analyzed for surface microhardness. Two-way ANOVAs (α=0.05) indicated no difference between the microhardness values recorded for human and bovine enamel (p=0.1350), but bovine root dentin had lower microhardness compared to its human counterpart (p=0.0432). While bovine enamel can reliably substitute its human counterpart in in situ dental erosion models, bovine root dentin does not seem to be a viable alternative to the corresponding human tissue.

Potamotrygon boesemani (Chondrichthyes: Myliobatiformes: Potamotrygonidae), a new species of Neotropical freshwater stingray from Surinam

Potamotrygon boesemani, new species, is described from the Corantijn river drainage in Surinam. The species has a diagnostic dorsal color pattern formed by deep orange to red ocellated spots of irregular form, encircled by relatively broad black rings. Potamotrygon boesemani is distinguished from other ocellated congeners (P. motoro, P. henlei and P. leopoldi) by the more intensely colored ocelli, which are usually yellow in the latter species. From P. motoro it is also distinguished by the darker dorsal background coloration, by the broader black contour of the dorsal ocelli, and by the irregular form of the ocelli as compared to the more rounded shape in the latter species. From P. henlei and P. leopoldi, it is distinguished by the lack of ocelli on tail. From the tentatively identified specimen of P. ocellata, which also has dark orange ocelli, the irregular contour of the ocelli in the new species is also distinctive. The teeth are relatively smaller and in greater number than in P. motoro and P. ocellata, with up to 45 rows in the upper jaw.

Electrochemical degradation of the dye reactive orange 16 using electrochemical flow-cell

Electrochemical removals of color and organic load from solutions containing the dye reactive orange 16 (RO16) were performed in an electrochemical flow-cell, using a platinum working electrode. The influence of the process variables flow-rate, such as NaCl concentration, applied potential and solution pH, were studied. The best color removal achieved was 93% (λ = 493 nm) after 60 min at 2.2 V vs. RHE electrolysis, using 1.00 g L-1 NaCl as supporting electrolyte. The rises in the concentration of NaCl and applied potential increased the color removal rate. The best total organic carbon removal (57%) was obtained at 1.8 V, without the separating membrane, indicating that the ideal conditions for the color removal are not necessarily the same as those to remove the total organic carbon. The degradation efficiency decreased with the solution pH decrease.

Síntese de poli(1,1'-ferrocenilenovinileno) via acoplamento de McMurry

Com base nas grandes modificações das propriedades de materiais poliméricos resultantes da inclusão de unidades organometálicas, descrevem-se neste trabalho a síntese e a caracterização de um polímero organometálico conjugado com estrutura semelhante à de poli(p-fenilenovinileno) (PPV), o qual apresenta grupos 1,1'-ferrocenileno no lugar de 1,4fenileno em sua cadeia principal. Sintetizado por meio de reação de acoplamento de McMurry de 1,1'-ferrocenodialdeído, o poli(1,1'-ferrocenilenovinileno) (PFV) se apresentou na forma de um sólido de cor laranja, amorfo e insolúvel tanto em solventes polares quanto em apolares. Para caracterização do PFV, empregaram-se os métodos de espectroscopia no infravermelho (FTIR), espectroscopia Raman e análise termogravimétrica (TGA).

Stability of fruit bases and chocolate fillings

Syrups with high sugar content and dehydrated fruits in its composition can be added to chocolate fillings to reduce the need of artificial flavor and dyes attributing a natural appeal to the product. Fruit bases were produced with lyophilized strawberry, passion fruit, and sliced orange peel. Rheological dynamic oscillatory tests were applied to determine the products stability and tendency of shelf life. Values of G´< G´´ were observed for strawberry and passion fruit flavor, whereas values of G´ > G´´ were found for orange flavor during the 90 days of storage. It was observed that shear stress values did not vary significantly suggesting product stability during the studied period. For all fillings, it was found a behavior similar to the fruit base indicating that it has great influence on the filling behavior and its stability. The use of a sugar matrix in fillings provided good shelf life for the fruit base, which could be kept under room temperature conditions for a period as long as one year. The good stability and storage conditions allow the use of fruit base for handmade products as well as for industrialized products.

ASSOCIATION BETWEEN SADDLE NOSE DEFORMITY AND RETRO-ORBITAL MASS IN WEGENER`S GRANULOMATOSIS

Objectives: The relationship between saddle nose deformity (SND) in Wegener`s granulomatosis (WG) and other clinical features, including retro-orbital mass formation (ROM), has been poor described. Therefore, this relationship was analyzed retrospectively from 2000 to 2010. Patients and Methods: Eighteen consecutive WG patients with SND diagnosed by computed tomography were matched to 36 WG patients without SND (control group) for gender, age at WG diagnosis and disease duration. Results: No difference was found between the two groups in relation to WG type (limited and systemic forms), ethnicity, laboratory features, constitutional symptoms or clinical manifestations, including upper respiratory tract, and treatment, except for ROM (33.3 vs. 2.8% in SND(+) and SND(-) groups, respectively; p=0.004) and subglottic stenosis (22.2 vs. 2.8%; p=0.038). However, on multivariate analysis, only ROM (OR 17.15; 95% CI 1.11-265.52) was statistically associated to SND. In addition, in more than half of the cases, SND manifested prior to ROM. Conclusions: Results of this prospective analysis showed that SND was strongly associated to ROM in WG. Since early diagnosis and aggressive treatment of orbital involvement could lead to better prognosis, the presence of SND warrants additional vigilance.