Dental caries prevalence in children up to 36 months of age attending daycare centers in municipalities with different water fluoride content

This study determined the prevalence of cavitated caries lesions (CCL) and early childhood caries (ECC), and the contribution of some variables in children up to 36 months of age attending daycare centers in municipalities with different fluoride levels in the water supply: AFC (adequate fluoride content) and LFC (low fluoride content). After approval of the Ethics Committee, the parents were interviewed. The children were clinically examined using the same codes and criteria established by the WHO (World Health Organization) and the ADA (American Dental Association). Fisher's exact test (p<0.05) was applied for statistical analysis of data. The dmft indices calculated in the LFC and AFC municipalities were 0.57 and 0.68, respectively. Considering all children examined, 17.6% presented CCL and 33.8% ECC. The economic classification, mother's education level and duration of breastfeeding were considered statistically significant with regards to CCL prevalence. The age group, duration of the habit of drinking milk before bedtime and age at which oral hygiene started were considered statistically significant with regards to ECC prevalence.

Senna occidentalis Link. (Caesalpiniaceae) imbibition curves for NaCl osmotic potential levels up to 0.6 MPa

An investigation is reported on the statistical model of imbibition curves of the seeds of Senna occidentalis Link. (Caesalpiniaceae), up to Phase II (start of root emission) in osmotic potential levels (0; -0.2; -0.4 and -0.6 MPa), induced NaCl or PEG 6000. The statistical model for both solutions was y = a [1 b exp(-cx)] where y is the fresh matter of seed in g, and x the time of evaluation in h. The analysis of variance of the estimated parameters, showed that with the NaCl solution, the -0.4 and -0.6 MPa levels differed significantly from the 0 and -0.2 MPa levels, and that with the PEG solution, the -0.6 MPa differed from the rest. Prolongation of Phase II occurred as the potential decreased, with both solutions. More reduction in water uptake and prolongation of this phase occurred with the PEG treatment.

Vesicle-to-micelle transition in dioctadecyldimethylammonium bromide and dioctadecyldimethylammonium chloride dispersions induced by octaethylene glycol n-dodecyl monoether. An isothermal titration calorimetry study

We have used isothermal titration calorimetry to investigate the vesicle-to-micelle transition in dioctadecyldimethylammonium bromide (DODAB) and chloride (DODAC) vesicle dispersions induced by the nonionic surfactant octaethylene glycol n-dodecyl monoether (C12E8) at room temperature. Small and giant unilamellar vesicles were prepared by sonication and without sonication, respectively, of the pure cationic surfactants at low concentrations in water. The titration of 1.0 mM DODAX (X = Cl- and Br-) by a concentrated micellar solution of C12E8 shows that the enthalpy of interaction (DeltaH(obs)) of C12E8 in micellar form with DODAX is always endothermic. The titration curves are understood on the basis of superposition of the enthalpies of partitioning of C12E8 into the bilayer, of micelle formation and of vesicle-to-micelle transformation. The enthalpy, DeltaH(obs), initially increases owing to the incorporation of C12E8 into the vesicle bilayer until the C12E8/DODAX saturation ratio (R-sat) is reached, then DeltaH(obs) decreases, in different ways for DODAB and DODAC, owing to degradation of vesicles and formation of mixed micelles and intermediary structures up to the C12E8/DODAX solubilization ratio, R-sol. Above R-sol only mixed micelles exist. The surfactant solubilization takes place in three stages. All the critical ratios are lower for DODAB than for DODAC, meaning that C12E8 solubilizes more strongly in DODAB for example, R-sat is 0.8 for DODAB and 1.2 for DODAC. Sonication has no significant effect on the transition.

Superspace approach to the renormalization of the O'Raifeartaigh model up to the second order in the linear delta expansion parameter

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Crystal Structures of Xanthomonas Small Heat Shock Protein Provide a Structural Basis for an Active Molecular Chaperone Oligomer

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

UV-visible absorption characteristics of TEOS-derived and Cr-doped silica sonogels aged in different pH solutions and heat treated up to 600 degrees C

Cr-doped xerogels were obtained by sol-gel process from the acid-catalyzed and ultrasound-stimulated hydrolysis of tetraethoxysilane (TEOS) with addition of CrCl3.6H(2)O in water solution during the liquid step of the process. The gels were aged immersed in different pH solutions for about 30 days, after that they were allowed to dry. The samples were annealed at temperatures ranging from 40 to 600degreesC and analyzed by UV-visible absorption spectroscopy. Cr3+ is the preferable oxidation state of the chromium ion in the gels annealed up to 250-300degreesC, in the case of aging in solutions of pH=5 and 11. A high UV absorption below similar to320 nm, due to the host gel, and different absorption bands, depending on the temperature, due to the chromium ion were observed in the xerogels at temperatures below similar to250degreesC, in the case of aging in solutions of pH=1 and 2. These absorption bands have not been assigned. Above 300degreesC up to 600degreesC, Cr5+, and possibly Cr6+, are the preferable oxidation states of the chromium ion independent of the pH of the aging solution, so the xerogels turn to a yellowish appearance in all cases.

Structural evolution of aerogels prepared from TEOS sono-hydrolysis upon heat treatment up to 1100 degrees C

The structural evolution of aerogels prepared from TEOS sono-hydrolysis was studied as a function of the temperature of heat treatment up to 1100 degreesC by means of small angle X-ray scattering (SAXS) and density measurements. The mass fractal structure of the original wet sonogel (with scattering exponent alpha similar to 2.2) apparently transforms to a surface fractal structure in a length scale lesser than similar to1.5 nm, upon the process resulting in aerogel. Such a structural transformation is interpreted by the formation of new particles with characteristic dimension of similar to1.5 nm, with rough boundaries or electronic density fluctuations (or ultra-micropores) in their interior. The structural arrangement of these particles seem to preserve part of mass fractal characteristics of the original wet sonogel, now in a length scale greater than similar to1.5 nm. The electronic density heterogeneities in the particles start to be eliminated at around 800 degreesC and, at 900 degreesC, the particles become perfectly homogeneous, so the structure can be described as a porous structure with a porosity of similar to68% with similar to9.0 nm mean size pores and similar to4.3 nm mean size solid particles. Above 900 degreesC, a vigorous viscous flux sintering process sets in, eliminating most of the porosity and increasing rapidly the bulk density in an aerogel-glass transformation. (C) 2003 Elsevier B.V. All rights reserved.

A SAXS study of the nanostructural characteristics of TEOS-derived sonogels upon heat treatment up to 1100 degrees C

Xerogels obtained from the acid-catalyzed and ultrasound stimulated hydrolysis of TEOS were submitted to heat treatment at temperatures ranging from 60 to 1100 degreesC and studied by small-angle X-ray scattering (SAXS). The SAXS intensity as a function of the modulus of the scattering vector q was obtained in the range from q(0) = 0.19 to q(m) = 4.4 nm(-1). At 60 degreesC the xerogels exhibit an apparent surface fractal structure with a fractal dimension D-s similar to 2.5 in a length scale ranging from 1/q(1) similar to 1 to 1/q(m) similar to 0.22 nm. This structure becomes extremely rough at 120 degreesC (D-s similar to 3) and at 150 degreesC, it apparently converts to a mass fractal with a fractal dimension D similar to 2.4. This may mean an emptying of the pores with preservation of a share of the original mass fractal structure of the wet aged gel, for it had presented a mass fractal dimension D similar to 2.2. A well characterized porous structure formed by 2.0 nm mean size pores with smooth surface of about 380 m(2)/g is formed at 300 degreesC and remains stable until approximately 800 degreesC. At 900 degreesC the SAXS intensity vanishes indicating the disappearance of the pores in the probed length scale. The elimination of the nanopores occurs by a mechanism in which the number of pores diminishes keeping constant their mean size. The xerogels exhibit a foaming phenomenon above 900 degreesC and scatter following Porod's law as does a surface formed by a coarse structure. (C) 2002 Elsevier B.V. B.V. All rights reserved.

Orbital perturbations using geopotential coefficients up to high degree and order: Highly eccentric orbits

Several methods have been proposed for calculations of the eccentricity function for a high value of the eccentricity, however they cannot be used when the high degree and order coefficients of gravity fields are taken into account. The method proposed by Wnuk(1) is numerically stable in this case, but when is used. a large number of terms occurs in formulas for geopotential perturbations. In this paper we propose an application of expansions of some functions of the eccentric anomaly E as well as Hansen coefficients in power series of (e - e*), where e* is a fixed value of the eccentricity derived by da Silva Fernandes(2,3,4). These series are convergent for all e < 1.

Structural evolution up to 1100 degrees C of xerogels prepared from TEOS sonohydrolysis and liquid phase exchanged by acetone

Silica xerogels were prepared from sonohydrolysis of tetraethoxysilane and exchange of the liquid phase of the wet gel by acetone. Monolithic xerogels were obtained by slow evaporation of acetone. The structural characteristics of the xerogels were studied as a function of temperature up to 1100 degrees C by means of bulk and skeletal density measurements, linear shrinkage measurements and thermal analyses (DTA, TG and DL). The results were correlated with the evolution in the UV-Vis absorption. Particularly, the initial pore structure of the dried acetone-exchanged xerogel was studied by small-angle X-ray scattering and nitrogen adsorption. The acetone-exchanged xerogels exhibit greater porosity in the mesopore region presenting greater mean pore size (similar to 4 nm) when compared to non-exchanged xerogels. The porosity of the xerogels is practically stable in the temperature range between 200 degrees C and 800 degrees C. Evolution in the structure of the solid particles (silica network) is the predominant process upon heating up to about 400 degrees C and pore elimination is the predominant process above 900 degrees C. At 1000 degrees C the xerogels are still monolithic and retain about 5 vol.% pores. The xerogels exhibited foaming phenomenon after hold for 10 h at 1100 degrees C. This temperature is even higher than that found for foaming of non-exchanged xerogels. (c) 2005 Elsevier B.V. All rights reserved.

Energy States of Phosphorous Donor in Silicon in Fields up to 18 T

The evolution of the energy states of the phosphorous donor in silicon with magnetic field has been the subject of previous experimental and theoretical studies to fields of 10 T. We now present experimental optical absorption data to 18 T in combination with theoretical data to the same field. We observe features that are not revealed in the earlier work, including additional interactions and anti-crossings between the different final states. For example, according to the theory, for the "1s -> 2p (+)" transition, there are anti-crossings at about 5, 10, 14, 16, and 18 T. In the experiments, we resolve at least the 5, 10, and 14 T anti-crossings, and our data at 16 and 18 T are consistent with the calculations.

Alkaline ribonuclease activity in maternal serum and in serum of newborns from birth up to thirty days of age. A study made with full-term appropriate-, full-term small- and preterm appropriate-for-gestational-age infants

We have studied the alkaline ribonuclease (RNase) activity in maternal serum and serum of full-term small- (T-SGA), full-term appropriate- (T-AGA) and preterm appropriate-for-gestational age (PT-AGA) newborns. A significantly lower level of RNase was observed in T-AGA and T-SGA newborns on the 30th day of age and in PT-AGA newborns on the 15th and 30th days of age, as compared to other T-AGA, T-SGA and PT-AGA groups of infants at birth. RNase activity was significantly higher in cord blood than in the maternal blood in all categories studied. Moreover, in preterm newborns, RNase activity in cord blood was significantly higher in those presenting a lower gestational age. We did not observe any significant difference in RNase levels in the cord blood of newborns from the 3 categories studied. The same results were observed concerning maternal blood. We, therefore, conclude that RNase activity in cord blood or in maternal blood is not a very statisfactory indicator of fetal malnutrition.

Nuclear photoproduction of pseudoscalar mesons at forward angles up to 6.0 GeV

The nuclear incoherent π 0 photoproduction cross section from 12C is evaluated at forward angles in the 4.0 to 6.0 GeV energy range using the multicollisional intranuclear cascade model MCMC. The model incorporates some improvements in comparison with previous versions associated with the momentum distribution (MD) for light nuclei - extracted from the available (e,e ′p) data - as well as the evaluation of the shadowing effects during the photo-nucleus interaction. The final results of the single and double differential cross sections at forward angles are very sensitive to the MD parameterizations due to the Pauli principle, which largely suppresses the cross sections for low momentum transfer. The attenuation of the nuclear cross section due to pion - nucleus final state interactions is approximately 40% (without nuclear shadowing), which is in nice agreement with the predictions from the Glauber model. The single and double π 0 differential cross sections are presented for possible applications for the interpretation of the inelastic background in the PrimEx experiment at the Jefferson Laboratory. © 2007 American Institute of Physics.

Prevalence of enamel white spots and risk factors in children up to 36 months old

The aim of this study was to determine the prevalence of enamel white spots and the quality of oral hygiene in children up to 36 months old, in municipalities with different fluoride levels in the water supply, analyzing the contribution of several variables. After approval of the Ethics Committee, the parents signed an informed consent form and were interviewed about their educational level, economic classification of the family, nursing habits, use of toothpaste, access to dental service and other information. The children were clinically examined using the same codes and criteria established by the WHO (World Health Organization) and ADA (American Dental Association). The data were processed and analyzed with the Epi-info software program, version 3.2, and Microsoft Excel. Fisher's exact test (p<0.05) was applied to assess the association among the variables. The enamel white spot prevalence was 30.8% and the age group, duration of the bedtime milk feeding habit, age of initial practice of oral hygiene and presence of caries lesions with cavitation were considered statistically significant with regard to enamel white spot prevalence (p < 0.05). No association was found between oral hygiene quality and the study variables. © 2009 Sociedade Brasileira de Pesquisa Odontológica.