Simultaneous determination of As, Cu, Mn, Sb, and Se in drinking water by GFAAS with transversely heated graphite atomizer and longitudinal zeeman-effect background correction

A method has been developed for the direct and simultaneous determination of As, Cu, Mn, Sb, and Se in drinking water by electrothermal atomic absorption spectrometry (ETAAS) using a transversely heated graphite tube atomizer (THGA) with longitudinal Zeeman-effect background correction. The thermal behavior of analytes during the pyrolysis and atomization stages was investigated in 0.028 mol L-1 HNO3, 0.14 mol L-1 HNO3 and 1 + 1 (v/v) diluted water using mixtures of Pd(NO3)2 + Mg(NO3)2 as the chemical modifier. With 5 μg Pd + 3 μg Mg as the modifier, the pyrolysis and atomization temperatures of the heating program of the atomizer were fixed at 1400°C and 2100°C, respectively, and 20 μL of the water sample (sample + 0.28 mol L-1 HNO3, 1 + 1, v/v), dispensed into the graphite tube, analytical curves were established ranging from 5.00 -50.0 μg L-1 for As, Sb, Se; 10.0 - 100 μg L-1 for Cu; and 20.0 - 200 μg L-1 for Mn. The characteristic masses were around 39 pg As, 17 pg Cu, 60 pg Mn, 43 pg Sb, and 45 pg Se, and the lifetime of the tube was around 500 firings. The limits of detection (LOD) based on integrated absorbance (0.7 μg L-1 As, 0.2 μg L-1 Cu, 0.6 μg L-1 Mn, 0.3 μg L-1 Sb, 0.9 μg L-1 Se) exceeded the requirements of the Brazilian Food Regulations (decree # 310-ANVS from the Health Department), which established the maximum permissible level for As, Cu, Mn, Sb, and Se at 50 μg L-1, 1000 μg L-1, 2000 μg L-1, 5 μg L-1, and 50 μg L-1, respectively. The relative standard deviations (n = 12) were typically < 5.3% for As, < 0.5% for Cu, < 2.1% for Mn, < 11.7% for Sb, and < 9.2% for Se. The recoveries of As, Cu, Mn, Sb, and Se added to the mineral water samples varied from 102-111%, 91-107%, 92-109%, 89-97%, and 101-109%, respectively. Accuracy for the determination of As, Cu, Mn, Sb, and Se was checked using standard reference materials NIST SRM 1640 - Trace Elements in Natural Water, NIST SRM 1643d - Trace Elements in Water, and 10 mineral water samples. A paired t-test showed that the results were in agreement with the certified values of the standard reference materials at the 95% confidence level.

Resistivity (DC) method applied to aouifer protection studies

Resistivity (DC) method using vertical electrical soundings (Schlumberger array) are conducted In the vicinity of Canoas/RS, applied to environmental studies with the objective of Investigating groundwater conditions, The present paper shows a geoelectrlcal Identification of the lithology and an estimate of the relationship between the resistivity and Dar Zarrouk parameters (transverse unit resistance and longitudinal unit conductance) with the properties such as aquifer transmlssivlty and protection of ground water resources, In the saturated sediments, resistivity values defined the following sequence: clay layers (resistivity < 40 ohm-m) and sand layers (resistivity > 40 ohm-m), Two sand layers were identified; one corresponding to the unconfined aquifer and another to the confined aquifer between two clay layers, In the map of the transverse unit resistance of the unconfined aquifer, the tendencies of high values can be associated with the zones of high transmissivity; hence, these zones are suggested for the installation of monitoring wells, The map of longitudinal conductance Illustrates the Impermeability of the confining clay layer, Values of S > 1.0 siemens would indicate zones in which the confined aquifer would be protected; In comparison, values of S < 1.0 siemens would indicate zones of probable risks of contamination. © 2006 Sociedade Brasileira de Geofísica.

Magnetoelectric coefficient in strontium ruthenate buffered lanthanum modified bismuth ferrite thin films grown by chemical method

This paper focuses on the magnetoelectric coupling (ME) at room temperature in lanthanum modified bismuth ferrite thin film (BLFO) deposited on SrRuO 3-buffered Pt/TiO 2/SiO 2/Si(100) substrates by the soft chemical method. BLFO film was coherently grown at a temperature of 500 °C. The magnetoelectric coefficient measurement was performed to evidence magnetoelectric coupling behavior. Room temperature magnetic coercive field indicates that the film is magnetically soft. The maximum magnetoelectric coefficient in the longitudinal direction was close to 12 V/cmOe. Dielectric permittivity and dielectric loss demonstrated only slight dispersion with frequency due the less two-dimensional stress in the plane of the film. Polarization reversal was investigated by applying dc voltage through a conductive tip during the area scanning. We observed that various types of domain behavior such as 71 ° and 180° domain switching, and pinned domain formation occurred. Copyright © 2009 American Scientific Publishers All rights reserved.

Piezoresponse force microscopy characterization of rare-earth doped BiFeO3 thin films grown by the soft chemical method

The multiferroic behavior with ion modification using rare-earth cations on crystal structures, along with the insulating properties of BiFeO3 (BFO) thin films was investigated using piezoresponse force microscopy. Rare-earth-substituted BFO films with chemical compositions of (Bi 1.00-xRExFe1.00O3 (x=0; 0.15), RE=La and Nd were fabricated on Pt (111)/Ti/SiO2/Si substrates using a chemical solution deposition technique. A crystalline phase of tetragonal BFO was obtained by heat treatment in ambient atmosphere at 500 °C for 2 h. Ion modification using La3+ and Nd3+ cations lowered the leakage current density of the BFO films at room temperature from approximately 10-6 down to 10-8 A/cm2. The observed improved magnetism of the Nd3+ substituted BFO thin films can be related to the plate-like morphology in a nanometer scale. We observed that various types of domain behavior such as 71° and 180° domain switching, and pinned domain formation occurred. The maximum magnetoelectric coefficient in the longitudinal direction was close to 12 V/cm Oe. © 2012 Elsevier Ltd and Techna Group S.r.l.

Hipomineralização molar-inciso: avaliação longitudinal em crianças de 6 a 9 anos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeito de dentifrícios com concentração reduzida de fluoreto suplementados com polifosfatos na incidência de lesões de cárie dentária e na ingestão de fluoreto: estudo clínico longitudinal em crianças

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

Avaliação longitudinal do crescimento craniofacial de indivíduos classe II tratados e não tratados

Pós-graduação em Ciências Odontológicas - FOAR

Longitudinal evaluation of fluoride levels in nails of 18-30-month-old children that were using toothpastes with 500 and 1100 mu g F/g

ObjectivesThis study aimed to evaluate the fluoride concentration in the fingernails and toenails of children aged 18-30months during use of fluoride-containing toothpastes supplemented with calcium glycerophosphate (CaGP) or sodium trimetaphosphate (TMP).MethodsAccording to the toothpaste used, children (n=56) were randomly assigned into three groups: 500gF/g with 1% TMP, 500gF/g with 0.25% CaGP, and 1100gF/g. Fingernails and toenails were collected monthly over a period of 330days, from the beginning of toothpaste use. Fluoride concentration in the water consumed by the volunteers and fluoride intake from diet and toothpaste were also determined. Fluoride analyses were performed with the electrode after hexamethyldisiloxane-facilitated diffusion or by the direct method, according to the samples. Data passed normality and homoscedasticity tests and were analyzed by 2-way analysis of variance (anova) and 1-way anova followed by Student-Newman-Keuls test (P<0.05).ResultsFluoride levels in the fingernails and toenails as well as fluoride intake from toothpaste were similar for the groups treated with 500gF/g with 1% TMP and 500gF/g with 0.25% CaGP toothpastes, but significantly lower than the 1100 gF/g group (P<0.05). No significant differences were noted among the groups regarding fluoride intake from diet and that by water consumed by the volunteers (P>0.05).ConclusionThe results of the longitudinal study suggest that the level of fluoride present in nails was lower with the use of toothpastes with a low fluoride concentration.

Comportamento locomotor, quadro clínico, incidência de quedas e nível de atividade física em pacientes com doença de Parkinson: um estudo longitudinal de dois anos

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

Associação da catastrofização da dor com a incidência e a intensidade da dor perineal aguda e persistente após parto normal: estudo longitudinal tipo coorte

BACKGROUND AND OBJECTIVES: Vaginal birth delivery may result in acute and persistent perineal pain postpartum. This study evaluated the association between catastrophizing, a phenomenon of poor psychological adjustment to pain leading the individual to magnify the painful experience making it more intense, and the incidence and severity of perineal pain and its relationship to perineal trauma. METHOD: Cohort study conducted with pregnant women in labor. We used the pain catastrophizing scale during hospitalization and assessed the degree of perineal lesion and pain severity in the first 24 hours and after 8 weeks of delivery using a numerical pain scale. RESULTS: We evaluated 55 women, with acute pain reported by 69.1%, moderate/severe pain by 36.3%, and persistent pain by 14.5%. Catastrophizing mean score was 2.15 ± 1.24. Catastrophizing patients showed a 2.90 relative risk (RR) for perineal pain (95% CI: 1.08-7.75) and RR: 1.31 for developing persistent perineal pain (95% CI: 1.05-1.64). They also showed a RR: 2.2 for developing acute and severe perineal pain (95% CI: 1.11-4.33). CONCLUSIONS: The incidence of acute and persistent perineal pain after vaginal delivery is high. Catastrophizing pregnant women are at increased risk for developing acute and persistent perineal pain, as well as severe pain. Perineal trauma increased the risk of persistent perineal pain.

Longitudinal evaluation of the structural integrity of teeth affected by molar incisor hypomineralisation

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

Estudo longitudinal sobre a prática de aleitamento materno e fatores associados ao desmame precoce

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

High-throughput non-destructive nuclear magnetic resonance method to measure intramuscular fat content in beef

High intake of saturated fat from meats has been associated with cardiovascular disease, cancer, diabetes, and others diseases. In this paper, we are introducing a simple, high-throughput, and non-destructive low-resolution nuclear magnetic resonance method that has the potential to analyze the intramuscular fat content (IMF) in more than 1,000 beef portions per hour. The results can be used in nutritional fact labels, replacing the currently used average value. The method is based on longitudinal (T(1)) and transverse (T(2)) relaxation time information obtained by a continuous wave-free precession (CWFP) sequence. CWFP yields a higher correlation coefficient (r=0.9) than the conventional Carr-Purcell-Meiboom- Gill (CPMG) method (r=-0.25) for IMF in beef and is just as fast and a simpler pulse sequence than CPMG. The method can also be applied to other meat products.

Longitudinal reference ranges for fetal ultrasound biometry in twin pregnancies

OBJECTIVE: The purpose of this study was to establish longitudinal reference ranges for fetal ultrasound biometry measurements and growth parameters in twin pregnancies. METHOD: A total of 200 uncomplicated twin pregnancies before 21 weeks of gestation were recruited for this prospective, longitudinal study. Women who abandoned follow-up, pregnancies with unknown outcomes or pregnancies with complications were excluded. Ultrasound scans were performed every three weeks, and biparietal and occipitofrontal diameters, head and abdominal circumferences, and femur diaphysis length measurements were obtained for each fetus at each visit. Estimated fetal weight, biparietal/occipitofrontal diameter, head circumference/abdominal circumference, and femur diaphysis length/abdominal circumference ratios were also calculated. Multilevel regression analysis was performed on normalized data. RESULTS: A total of 807 ultrasound examinations were performed in 125 twin pregnancies between 14 and 38 weeks of gestation (6.5 +/- 1.4 scans/pregnancy). Regression analysis demonstrated significant correlations for all variables with gestational age, namely log of the biparietal diameter (r = 0.98), log of the occipitofrontal diameter (r = 0.98), log of the head circumference (r = 0.99), log of the abdominal circumference (r = 0.98), square root of the femur length (r = 0.99), log of the estimated fetal weight (r = 0.99), biparietal/occipitofrontal ratio (r = -0.11), head/abdomen circumference ratio (r = -0.56), and log of the femur length/abdominal circumference ratio (r = 0.61). Values corresponding to the 10th, 50th, and 90th percentiles for estimated fetal weight at 28, 32, and 36 weeks, respectively, were as follows: 937, 1,096, 1,284 g; 1,462, 1,720, 2,025 g; and 2,020, 2,399, 2,849 g. CONCLUSION: In twin pregnancies, fetal ultrasound biometry measurements and growth parameters show a significant correlation with gestational age.

ANALYSIS OF THE NATURAL VIBRATION FREQUENCY TEST METHOD TO OBTAIN THE MODULUS OF ELASTICITY OF WOOD STRUCTURAL COMPONENTS

There are several techniques to characterize the elastic modulus of wood and those currently using the natural frequencies of vibration stand out as they are non-destructive techniques, producing results that can be repeated and compared over time. This study reports on the effectiveness of the testing methods based on the natural frequencies of vibration versus static bending to obtain the elastic properties of reforested structural wood components usually employed in civil construction. The following components were evaluated: 24 beams of Eucalyptus sp. with nominal dimensions (40 x 60 x 2.000 mm) and 14 beams of Pinus oocarpa with nominal dimensions (45 x 90 x 2.300 mm) both without treatment; 30 boards with nominal dimensions (40 x 240 x 2.010 mm) and 30 boards with nominal dimensions (40 x 240 x 3.050 mm), both of Pinus oocarpa and with chromate copper arsenate (CCA) preservative treatment. The results obtained in thiswork show good correlation when compared to the results obtained by the static bending mechanical method, especially when applying the natural frequency of longitudinal vibration. The use of longitudinal frequency was reliable and practical, therefore recommended for determining the modulus of elasticity of wood structural elements. It was also found that no specific support is needed for the specimens using the longitudinal frequency, as well as no previous calibrations, reducing the execution time and enabling to test many samples.