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ABSTRACT Objective To assess the effects of coloring beverages on the color stability of two types of hybrid ceramics with different surface treatments. Material and Methods 180 specimens of two hybrid ceramics (Vita Enamic and Mazic Duro) and a feldspathic ceramic (Vita Mark II) were prepared (n=60 in each group). Half of the discs in each group were glazed while the other was polished. The specimens were then divided into three subgroups and immersed in distilled water, carrot juice, and coffee. The overall color difference (∆E) was calculated based on CIE L*a*b* color space. Data were analyzed using three-way and one-way ANOVA; Tukey's honest significant difference was also done for pairwise comparisons (α=0.05). Results Vita Mark II specimens revealed less overall color changes compared to other groups. The ∆E of the glazed Vita Enamic specimens was greater than polished specimens following immersion in distilled water (p=0.03) and coffee (p=0.001), but it was not significant for carrot juice. The same results were obtained for polished Mazic Duro specimens. Relatively similar amounts of ∆E were recorded in polished and glazed subgroups of Vita Mark II. Conclusion The ∆E of hybrid ceramics was higher than Vita Mark II. Polishing could be recommended for surface treatment of hybrid ceramics instead of glazing, saving time and facilitating the process.

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OBJECTIVE: To assess the levels of heavy metals and their antagonists in dairy products available in the markets of São Luís, northeastern Brazil. METHODS: Chemical analysis of the heavy metals copper(Cu), lead(Pb), mercury(Hg), and nickel(Ni) and their antagonists iron(Fe), zinc(Zn), calcium(Ca), selenium(Se), and cobalt(Co) contained in dairy products using inductively coupled plasma optical emission spectrometry (ICP-OES). RESULTS: The main heavy metal observed in dairy products were Hg; Pb; Se and Ni. A significant negative correlation was observed between the concentrations of Cu and Fe (rho = -0.634, p = 0.001), Cu and Zn (rho = -0.794, p = 0.000) in whole milk. A non-significant positive correlation was observed between Pb and Ca (rho = 0.387, p = 0.056), and Hg and Se (rho = 0.055, p = 0.795). CONCLUSIONS: Dairy product brands available in the markets of São Luís could be considered a source of heavy metal contamination (Hg, Pb, Se, Cu, Ni) with weak correlations with their antagonists.

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This study aimed to evaluate the anticholinesterase activities of extracts and fractions of Ocotea daphnifolia in vitro and characterize its constituents. The effects of hexane, ethyl acetate, and ethanolic extracts on acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activity were determined with a spectrophotometry assay. All extracts inhibited cholinesterase activity, and the ethanolic extract (2 mg/mL) exhibited the highest inhibition of both enzymes (99.7% for BuChE and 82.4% for AChE). The ethanolic extract was fractionated by column chromatography resulting in 14 fractions that were also screened for their anticholinesterase effects. Fraction 9 (2 mg/mL) showed the highest activity, inhibiting AChE and BuChE by 71.8% and 90.2%, respectively. This fraction was analyzed by high-performance liquid chromatography high-resolution mass spectrometry which allowed the characterization of seven glycosylated flavonoids (containing kaempferol and quercetin nucleus) and one alkaloid (reticuline). In order to better understand the enzyme-inhibitor interaction of the reticuline toward cholinesterase, molecular modeling studies were performed. Reticuline targeted the catalytic activity site of the enzymes. Ocotea daphnifolia exhibits a dual cholinesterase inhibitory activity and displays the same pattern of intermolecular interactions as described in the literature. The alkaloid reticuline can be considered as an important bioactive constituent of this plant.

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Abstract Six sample preparation procedures were evaluated for selective extraction of Cr(VI) from commercial samples of chromium oxide green (Cr2O3) pigments prior to formation of its diphenylcarbazone complex [CrDPCO]- for determination by visible spectrophotometry: (I) water-soluble chromium; (II) EPA method 3060A without Mg2+; (III) EPA method 3060A with Mg2+; (IV) Na3PO4 based extraction; (V) method IRSA16 based on acidic extraction and; (VI) Na2CO3 based extraction. Evaluation of the influence of concomitant Cr(III) ions, time and stability of the [CrDPCO]- complex was investigated. Recoveries of soluble and insoluble Cr(VI) species were 86% and 80%, respectively, using procedure (VI). Direct calibration against aqueous standards prepared in the extraction medium was successful for Cr(VI) in the concentration range 0.05-1.50 μg L-1. Limits of detection and quantitation were 0.3 µg g-1 and 1.0 µg g-1, respectively, for 250 mg subsamples/25 mL. Procedure (VI) was applied to the analysis of four commercial samples of Cr2O3 pigments, three determined to have Cr(VI) within compliance limits below 1.0 µg g-1, but one at 16.6 ± 0.6 µg g-1, prohibiting use of this pigment in cosmetic formulations. This sample was conveniently employed to evaluate the accuracy of the method. The recommended procedure is simple and accurate and has been adopted by Tecpar's laboratory of Parana Institute of Technology (Curitiba, Brazil).

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ABSTRACT Objective: To analyze the ability of saliva in controlling the growth and the biofilm formation of Streptococcus mutans (S. mutans) as well as the effect of histatin-5 anti-biofilm relate to pH and saliva viscosity. Material and Methods: The S. mutans biofilm assayed by crystal violet 1% and its growth measured by spectrophotometer. The saliva viscosity was analyzed by viscometer, and pH of saliva was measured by pH meter. Results: Based on the optical density values, growth of S. mutans in saliva ranged <300 CFU/mL (0.1 nm) at concentrations of 25%, 12.5% and 6.25% for 24 hours. Whereas at the 48 h and 72 h period of incubation shown an increase in growth of S. mutans ranged 300-600 CFU/mL (0.2-0.36 nm). The inhibitory biofilm formation of S. mutans in saliva was significantly higher at concentrations of 12.5% and 6.25% at 24 h incubation times on a moderate scale, whereas the histatin-5 was effective to inhibit S. mutans biofilm on the 50 and 25 ppm. The saliva possessed a higher inhibitory of biofilm S. mutans than histatin-5 and good level viscosity (0.91-0.92 cP). Conclusion: The saliva was able to control the growth of S. mutans, and histatin-5 can inhibit the biofilm formation S. mutans. Furthermore, the saliva was also able to respond to the pH change with good viscosity of saliva.

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Abstract High sensitivity of qPCR assay can be compromised by the presence of PCR inhibitors in samples analyzed. The aim of this study was to analyze the RT-qPCR assay efficiency considering the RNA quality/quantity and the presence of PCR inhibitors in patients with chemotherapy and/or antibiotic therapy. We analyzed 60 samples using RT-qPCR from individuals suspected of leukemia and 44 samples were quantified by fluorimetry and spectrophotometry. The efficiency of the RT-qPCR assay was evaluated comparing the threshold cycle (Ct) from tested samples and the standard curve. The 260/280 and 260/230 ratios, the presence of PCR inhibitors and the amount of sample (ng) used in the RT-qPCR reaction can be associated with 56.8% (R²=0.56, p<0.05) in the Ct obtained. The decrease of the RT-qPCR efficiency can be explained in 42,8% due to the variation of the 260/280 ratio (R²=0.42,p<0.05). The presence of antibiotics in the blood sample can be associated in 11.3% with the variability of 260/280 ratio (R²=0.11,p<0.05). Presence of chemotherapeutic drugs in the blood sample was not correlated with Ct variation (p=0.17). The spectrophotometer determines a RNA quantification with 2.2 times higher than the fluorimeter (t=2.2, p=0,03) and this difference is correlated with the 260/280 ratio (R²=0.36, p<0.05). Samples with low purity had a reduction in the qPCR efficiency, although we did not observe false results.

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ABSTRACT Purpose: The porcine eye is frequently used as a research model. This paper analyzes the effect of different storage methods on the transparency of pig crystalline lens. Methods: A spectral transmission curve (from 220 to 780 nm) for the crystalline lens was determined experimentally after storage in different conditions: saline solution, formalin, castor oil, and freezing at -80°C. The total transmission in the visible spectrum, which was used as an index of transparency, was calculated from these curves. For comparative purposes, fresh lenses were evaluated and used as controls. Results: Storing the porcine crystalline lens in saline solution or castor oil resulted in a transparency loss of approximately 10% after 24 h and storage in formalin resulted in a loss of nearly 30%. Storage by freezing at -80°C for 4 weeks maintained the transparency of the crystalline lens; the spectral transmission measured immediately after defrosting at room temperature coincided exactly with that of the freshly extracted lens. Conclusions: The transparency of porcine crystalline lens is affected by the storage method. The visible spectrum is the most affected, evidenced by the effect on the transparency and consequently the amount of light transmitted. The results show that freezing at -80°C maintains the transpa rency of the crystalline lens for at least 4 weeks.

RESUMO Objetivos: Olho de porco é frequentemente usa do como modelos de pesquisa. Este estudo analisa o efeito de di ferentes métodos de armazenamento na preservação da transparência do cristalino de porco. Métodos: Uma curva de transmissão espectral (de 220 até 780 nm) para o cristalino foi experimentalmente determinada após armazenamento em diferentes condições: solução salina, formol, óleo de mamona e congelamento a -80°C. Transmissão total do espectro visível, que foi usada como um índice de transparência foi calculada a partir dessas curvas. Para fins comparativos, lentes frescas foram avaliadas e usadas como controles. Resultados: O armazenamento do cristalino suíno em solução salina ou óleo de mamona resultou uma perda de transparência de aproximadamente 10% após 24 h e o armazenamento em formol resultou uma perda de quase 30%. O armazenamento por congelamento a -80°C durante 4 semanas manteve a transparência do cristalino; a transmissão espectral medida imediatamente após o descongelamen to à temperatura ambiente coincidiu exatamente com a da lente extraída recentemente. Conclusão: A transparência do cristalino suíno é afetada pelo método de armazenamento. O espectro visível é o mais afetado, evidenciado pelo efeito sobre a transparência e consequentemente a quantidade de luz transmitida. Os resultados mostram que o congelamento a -80°C mantém a transparência do cristalino suíno por pelo menos 4 semanas.

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PURPOSE: The porcine eye is frequently used as a research model. This paper analyzes the effect of different storage methods on the transparency of pig crystalline lens. METHODS: A spectral transmission curve (from 220 to 780 nm) for the crystalline lens was determined experimentally after storage in different conditions: saline solution, formalin, castor oil, and freezing at -80°C. The total transmission in the visible spectrum, which was used as an index of transparency, was calculated from these curves. For comparative purposes, fresh lenses were evaluated and used as controls. RESULTS: Storing the porcine crystalline lens in saline solution or castor oil resulted in a transparency loss of approximately 10% after 24 h and storage in formalin resulted in a loss of nearly 30%. Storage by freezing at -80°C for 4 weeks maintained the transparency of the crystalline lens; the spectral transmission measured immediately after defrosting at room temperature coincided exactly with that of the freshly extracted lens. CONCLUSIONS: The transparency of porcine crystalline lens is affected by the storage method. The visible spectrum is the most affected, evidenced by the effect on the transparency and consequently the amount of light transmitted. The results show that freezing at -80°C maintains the transpa rency of the crystalline lens for at least 4 weeks.

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A sobrecarga de ferro é uma condição prejudicial para os pacientes, que apresentam uma diminuição significativa na qualidade de vida. Os fármacos quelantes são moléculas que têm capacidade de uso clínico para atuar como atenuadores da sobrecarga de metais. Neste trabalho apresentamos uma análise de sideróforos do tipo hidroxamato e quinona, com o objetivo de ampliar a gama de terapia de sobrecarga de ferro. Para cada composto foi realizado um ensaio competitivo com a sonda calce- ína para verificar a capacidade de ligação do ferro, e um ensaio antioxidante baseado na supressão da oxidação dependente de ferro da dihidrorrodamina (DHR) sob ascorbato. Foi observado que o hidroxamato cíclico piridoxatina apresentou capacidade de sequestrar ferro de substratos de alta afinidade, tanto em meio tamponado quanto em meio intracelular. Em ambas as situações também se mostrou um antioxidante eficiente. Entretanto, parece ser o mais tóxico do grupo dos hidroxamatos (que ainda continha o hidroxamato linear desferricoprogênio e o aromático desferriastercromo). Outros compostos naturais também foram estudados como possíveis candidatos a fármacos para sobrecarga de ferro. Complexos de ferro foram caracterizados por espectrofotometria para avaliar a estequiometria possível, considerando os sítios de ligação para cada composto. Ensaios de fluorescência revelaram que entre os quatro compostos em estudo (ácido clorogênico, lapachol, hemateína e hematoxilina), o complexo entre ferro e hemateína apresenta maior estabilidade relativa do que outros

Iron overload is a harmful condition for patients, who have a significant decrease in life quality. Chelating drugs are molecules that have the capacity for clinical use to act as attenuators of metal overload. In this work we present an analysis of hydroxamate and quinone-type siderophores, intending to broaden the range of iron overload therapy. For each compound it was conducted a competitive assay with the fluorescent probe calcein to verify the iron binding ability, and an antioxidant assay based on suppression of the iron-dependent oxidation of dihydrorhodamine (DHR) under ascorbate. It was observed that cyclic hydroxamate pyridoxatin displayed good ability to scavenge iron from high affinity substrates both in buffer and in intracellular medium. It was also an efficient antioxidant in both setups. However, pyridoxatin seems to be the most toxic from the hydroxamate group (composed also by the linear desferricoprogen and the aromatic desferriasterchrome). Other natural compounds have also been studied as possible candidates for iron-overload drug therapy. Iron complexes were characterized by spectrophotometry to assess the possible stoichiometry considering the binding sites for each compound. Fluorescence assays revealed that among the four compounds in study (chlorogenic acid, lapachol, hematein and hematoxylin), the complex between iron and hematein has higher relative stability than others

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ABSTRACT The non-invasive collection and inexpensive nature of saliva has made it an attractive sample for use for diagnosis and research on several diseases. Storage circumstances may affect salivary component concentrations. The objective was to analyze calcium and phosphate stability in saliva samples stored at different conditions. Saliva of healthy people was stored and analyzed by spectrophotometry under different time and temperature conditions in order to evaluate calcium and phosphate stability. Calcium concentration was measured by Arsenazo III reaction at 600nm and phosphate by an acid-molybdate method at 650nm. Using Lin's concordance correlation coefficient (k), we observed very good agreement (k>0.8) for all samples frozen at -20 oC up to 50 days. Thaw/refreezing cycles can compromise phosphate stability even though there is good agreement (0.61<k<0.8). Because of higher variability for refrigerated samples, they are not the best storage method, although calcium and phosphate levels could be considered stable when the samples were stored at 4 oC for 7 days. Our results revealed that under different conditions, calcium and phosphate levels are stable in saliva samples, and that freezing at -20oC is the storage condition of choice, allowing to accumulate a higher number of samples before analysis, making it suitable for routine and research assays.

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An advanced oxidative process relying on the interaction of peroxymonosulphate and cobalt(II) was implemented for generating the sulphate radicals in flow analysis, in order to accomplish in-line sample preparation thus improving the spectrophotometric determination of phosphate and phosphite in liquid foliar fertilizers. To this end, a flow-batch system with a heated chamber was designed. The sample was handled twice, with and without the step of phosphite oxidation to phosphate, and the formed orthophosphate was quantified after interaction with the vanadate-molybdate reagent. Phosphite was determined as the difference in analytical signals corresponding to sample handling with and without the oxidation step. Influence of Co(II) on the peroxymonosulphate activation, reagent concentrations and added volumes, acidity, temperature and heating time were investigated like aiming at to improve analytical recovery and measurement repeatability, as well as the and system ruggedness. The 6.6-20.0mgL(-1) P2O5 standards were in-line prepared from a single stock solution. Detection limits were estimated as 0.8 and 0.1mgL(-1) for P2O5 and P-PO4. Twenty-four samples are were run per hour, and results are were in agreement with those obtained by the official procedure.

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An economic, simple, quantitative, and non-chromatographic method for the determination of alcohols using microdiffusion principle has been adapted and validated for acetone-butanol-ethanol (ABE) fermentation samples. This method, based on alcohols oxidation using potassium dichromate in acid medium, and detection by spectrophotometry, was evaluated varying, both, temperature (35°C, 45°C, and 55°C) and reaction time (0 to 125min). With a sample analysis time of 90min at 45°C, a limit of detection (LOD), and a limit of quantification (LOQ) of 0.10, and 0.40g/L, respectively. The proposed method has been successfully applied to determine butanol and ethanol concentrations in ABE fermentation samples with the advantage that multiple samples can be analyzed simultaneously. The measurements obtained with the proposed method were in good agreement with those obtained with the Gas Chromatography Method (GCM). This proposed method is useful for routine analysis of alcohols and screening samples in laboratories and industries.

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OBJECTIVE: To assess the color stability of five types of ceramic brackets after immersion in potentially staining solutions. METHODS: Ninety brackets were divided into 5 groups (n = 18) according to brackets commercial brands and the solutions in which they were immersed (coffee, red wine, coke and artificial saliva). The brackets assessed were Transcend (3M/Unitek, Monrovia, CA, USA), Radiance (American Orthodontics, Sheboygan, WI, USA), Mystique (GAC International Inc., Bohemia, NY, USA) and Luxi II (Rocky Mountain Orthodontics, Denver, CO, USA). Chromatic changes were analyzed with the aid of a reflectance spectrophotometer and by visual inspection at five specific time intervals. Assessment periods were as received from the manufacturer (T0), 24 hours (T1), 72 hours (T2), as well as 7 days (T3) and 14 days (T4) of immersion in the aforementioned solutions. Results were submitted to statistical analysis with ANOVA and Bonferroni correction, as well as to a multivariate profile analysis for independent and paired samples with significance level set at 5%. RESULTS: The duration of the immersion period influenced color alteration of all tested brackets, even though these changes could not always be visually observed. Different behaviors were observed for each immersion solution; however, brackets immersed in one solution progressed similarly despite minor variations. CONCLUSIONS: Staining became more intense over time and all brackets underwent color alterations when immersed in the aforementioned solutions.

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OBJECTIVE: To assess the color stability of five types of ceramic brackets after immersion in potentially staining solutions.METHODS: Ninety brackets were divided into 5 groups (n = 18) according to brackets commercial brands and the solutions in which they were immersed (coffee, red wine, coke and artificial saliva). The brackets assessed were Transcend (3M/Unitek, Monrovia, CA, USA), Radiance (American Orthodontics, Sheboygan, WI, USA), Mystique (GAC International Inc., Bohemia, NY, USA) and Luxi II (Rocky Mountain Orthodontics, Denver, CO, USA). Chromatic changes were analyzed with the aid of a reflectance spectrophotometer and by visual inspection at five specific time intervals. Assessment periods were as received from the manufacturer (T0), 24 hours (T1), 72 hours (T2), as well as 7 days (T3) and 14 days (T4) of immersion in the aforementioned solutions. Results were submitted to statistical analysis with ANOVA and Bonferroni correction, as well as to a multivariate profile analysis for independent and paired samples with significance level set at 5%.RESULTS: The duration of the immersion period influenced color alteration of all tested brackets, even though these changes could not always be visually observed. Different behaviors were observed for each immersion solution; however, brackets immersed in one solution progressed similarly despite minor variations.CONCLUSIONS: Staining became more intense over time and all brackets underwent color alterations when immersed in the aforementioned solutions.

OBJETIVO: avaliar a estabilidade da cor de cinco tipos de braquetes cerâmicos após imersão em soluções potencialmente corantes.MÉTODOS: noventa braquetes foram divididos em 5 grupos (n = 18) de acordo com a marca comercial dos braquetes e as soluções em que foram imersos (café, vinho tinto, Coca-Cola e saliva artificial). Os baquetes avaliados foram Transcend (3M / Unitek, Monrovia, CA, EUA), Radiance (American Ortodontia, Sheboygan, WI, EUA), Mystique (GAC International Inc., Bohemia, NY, EUA) e Luxi II (Rocky Mountain Orthodontics, Denver, CO, EUA). Alterações cromáticas foram analisadas com o uso de um espectrofotômetro de reflectância e por inspecção visual, em cinco intervalos de tempo específicos. Os momentos de avaliação foram: 24 horas (T1), 72 horas (T2), 7 dias (T3) e 14 dias (T4) de imersão nas soluções. Os resultados foram submetidos à avaliação estatística com análise de variância e correção de Bonferroni, bem como a uma análise do perfil multivariada para amostras independentes e pareadas, com nível de significância de 5%.RESULTADOS: a duração do período de imersão influenciou na alteração de cor de todos os braquetes testados, mesmo admitindo-se que essas alterações nem sempre puderam ser observadas visualmente. Diferentes comportamentos foram observados em cada solução de imersão; no entanto, braquetes imersos em um mesmo tipo de solução progrediram de forma semelhante, apesar das pequenas variações.CONCLUSÕES: a coloração se tornou mais intensa com o tempo, e todos os braquetes sofreram alteração de cor nas soluções imersas.

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STATEMENT OF PROBLEM: The type of resin-based luting agent might influence the color stability of ceramic veneers. PURPOSE: The purpose of this study was to investigate the effects of resin-based agents and aging on the color stability of ceramic veneers bonded to enamel. MATERIAL AND METHODS: Ceramic disks were cemented to bovine enamel disks with 4 resin-based luting agents (n=10): dual-polymerizing cement (RelyX ARC), light-polymerizing cement (RelyX Veneer), flowable composite resin (Filtek Z350 Flow), or composite resin preheated for 30 minutes at 60°C (Filtek Z350 XT). CIE L*, a*, and b* color coordinates were measured 24 hours after cementation (baseline) with a color spectrophotometer and reevaluated after 10,000 and 20,000 thermal cycles. Color variation was calculated by using CIELab (ΔE*(ab)) and CIEDE2000 (ΔE00) methods. Then 95% confidence intervals were calculated for color variation means between baseline and 10,000 thermal cycles and between 10,000 and 20,000 thermal cycles. The 95% confidence intervals were also calculated for the means of individual color coordinates (L*, a*, and b*). RESULTS: The dual-polymerizing cement had the highest color variation among all luting agents. No significant differences were found in color variation among the light-polymerizing materials. All agents showed ΔE*(ab)>3.46 and ΔE00>2.25 after 20,000 thermal cycles. Variations in L*, a*, and b* coordinates were material dependent. The dual-polymerizing agent was yellowish and reddish after aging. CONCLUSIONS: The dual-polymerizing cement had higher color variation than the light-polymerized materials when used for bonding ceramic veneers to enamel. Flowable and preheated composite resins had similar color stability to that of light-polymerizing resin-based cement.

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The present study concerns the identification of nine thus-far unknown derivatives of carminic acid extracted from pre-Columbian Peruvian textiles dyed with American cochineal-these derivatives are not found in commercially available preparations of the dye. These compounds probably represent a unique fingerprint of dyed textiles from this region, as they have never been reported to occur in other fabrics of historical value. They were separated by reversed-phase high-performance liquid chromatography (phenyl column) and detected using a UV/vis spectrophotometer and two tandem mass spectrometers. Peaks observed in chromatograms registered at 450 and 500 nm were further identified by ESI QqQ MS (mainly in the negative ion mode), supported by high-resolution ESI QIT/ToF MS data. The characteristic fragmentation pathways of isolated carminic acid and its derivatives provided additional information concerning lost neutrals and thus the functional groups and substituents present in the parent molecules. This information mainly related to multiple cleavages of the hexoside moiety (initially cross-ring cleavage), which are characteristic of C-glucosides (loss of 90, 120, and 148 Da). This is accompanied by the elimination of H2O as well as the further loss of 60 Da from the hexoside moiety. Moreover, other losses from the carbonyl groups (44 Da from CO2 loss, 62 Da from ethylene glycol loss, 32 Da from O2 loss, 138 Da from hydroxybenzoic acid, and 120 Da from oxomethylene cyclohexadienone) provided more specific information about structures of the identified derivatives of carminic acid.

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Objetivo Evaluar la capacidad acumuladora de mercurio por parte la planta de ají (Capsicum annuum), en suelos contaminados procedentes del corregimiento Mina Santa Cruz, Sur de Bolívar, Colombia, con el propósito de establecer el riesgo para la salud de la población consumidora. Materiales y Métodos Se tomaron muestras de tejidos (raíces, tallos y hojas) de plantas de C. annuum sembradas en dos suelos contaminados con mercurio y un suelo control, durante sus primeros cinco meses de crecimiento para determinar mercurio total mediante la técnica de espectrofotometría de absorción atómica por vapor frio. Se determinó mercurio total en muestras de frutos de ají consumido en Mina Santa Cruz. Resultados Las concentraciones medias de mercurio total en raíces fueron mayores en comparación con tallos y hojas. Los niveles de mercurio en suelos y el tiempo influyeron en la acumulación en tejidos. Las concentraciones de mercurio en frutos de C. annuum fueron bajas en relación a la ingesta tolerable semanal dispuesta por la OMS. Conclusión Los porcentajes de translocación de mercurio a las partes aéreas de la planta fueron bajos tanto en el suelo control como en los suelos contaminados. A pesar de los bajos niveles de mercurio en este alimento se debe disminuir al máximo el consumo de alimentos contaminados con dicho metal.(AU)

Objective To assess the mercury accumulating capacity in contaminated soils from the community of Mina Santa Cruz, in the south of the department of Bolívar, Colombia, of the pepper plant (Capsicum annuum), in order to establish the risk to the health of the consuming population. Materials and Methods Samples were taken from tissues (roots, stems, and leaves) of pepper plants grown in two soils contaminated with mercury and a control soil during the first five months of growth to determine total mercury through cold vapor atomic absorption spectrometry. Total mercury was determined in the samples of pepper plant fruits consumed in Mina Santa Cruz. Results The mean concentrations of total mercury in the roots were higher than in stems and leaves. Accumulation in tissues was influenced by mercury levels in soil and the growth time of the plants. Mercury concentrations in fruits of pepper plant were lower than tolerable weekly intake provided by WHO. Conclusion Percent of translocation of mercury to aerial parts of the plant were low in both control and contaminated soils. Despite low levels of mercury in this food, it is necessary to minimize the consumption of food contaminated with this metal.(AU)

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A flow injection spectrophotometric procedure employing merging zones is proposed for direct bromopride determination in pharmaceutical formulations and biological fluids. The proposed method is based on the reaction between bromopride and p-dimethylaminocinnamaldehyde (p-DAC) in acid medium, in the presence of sodium dodecyl sulfate (SDS), resulting in formation of a violet product (λmax=565nm). Experimental design methodologies were used to optimize the experimental conditions. The Beer-Lambert law was obeyed in a bromopride concentration range of 3.63×10(-7) to 2.90×10(-5)molL(-1), with a correlation coefficient (r) of 0.9999. The limits of detection and quantification were 1.07×10(-7) and 3.57×10(-7)molL(-1), respectively. The proposed method was successfully applied to the determination of bromopride in pharmaceuticals and human urine, and recoveries of the drug from these media were in the ranges 99.6-101.2% and 98.6-102.1%, respectively. This new flow injection procedure does not require any sample pretreatment steps.

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OBJECTIVE: To evaluate quantitatively the marginal microleakage of restorations carried out with self-etching adhesives with or without prior phosphoric enamel acid etching of silorane or methacrylate resin-based composite restorations subjected to thermal cycling. MATERIALS AND METHODS: Forty cavities were prepared at the proximal surface of bovine incisors and randomly divided according to the etching of the enamel and restorative system used. The groups were restored with methacrylate [Adper SE Plus adhesive (3M ESPE) + Filtek Z250 (3M ESPE)] or silorane [Filtek LS adhesive (3M ESPE) + Filtek LS composite (3M ESPE)] restorative systems, light-cured using a LED unit (Bluephase 16i, Vivadent). After restorative procedure and thermocycling (1000 cycles), the specimens were immersed in methylene blue for 2 h. The specimens were triturated and the powder was used for analysis in an absorbance spectrophotometer. Data were statistically analyzed by 2-way ANOVA (alpha = 0.05). RESULTS: No statistical difference between the restorative materials tested with or without previous acid etching of enamel in Class II marginal microleakage was observed (p > 0.05). CONCLUSIONS: The use of acid etching prior to self-etching adhesives did not interfere on the microleakage of methacrylate- or silorane-based restorations.

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INTRODUCTION: The aim of this study was to evaluate colour alteration of transparent elastic ligatures submitted to exogenous pigmentation. METHODS: Forty test specimens were divided into eight groups corresponding to one commercial brand with five test specimens in each group. The test specimens were immersed into coffee and black tea solutions with the purpose of assessing colour alteration using a portable digital spectrophotometer (Vita Easyshade Compact). The surfaces of the ligatures under scanning electron microscope (SEM) at ×30, ×150 and ×20,000 magnification were evaluated with the purpose of observing the differences in porosity of the ligatures. The Kolmogorov-Smirnov test for normality was applied followed by the one-way analysis of variance (one-way ANOVA) and the level of significance adopted was 95%. RESULTS: All the groups showed modified initial colour that was perceptible to the human eye. The brand that showed greater colour alteration, in comparison with its initial colour, was the American® pearl elastic ligature and the ligatures that presented the smallest colour variation were the Ortho-Organizer®. The surface evaluations of the ligatures showed differences with regard to the topography evidencing more porosity in the ligatures that showed greater staining. CONCLUSION: The group that changed colour significantly was the one that presented the highest porosity, and the brand that was the least altered was the one that showed the lowest porosity.

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