On the width of the last scattering surface

We discuss the physical effects of some accelerated world models on the width of the last scattering surface (LSS) of the cosmic microwave background radiation (CMBR). The models considered in our analysis are X-matter (XCDM) and a Chaplygin type gas. The redshift of the LSS does not depend on the kind of dark energy (if XCDM of Chaplygin). Further, for a Chaplygin gas, the width of the LSS is also only weakly dependent on the kind of scenario (if we have dark energy plus cold dark matter or the unified picture).Comment: 10 pages, 1 figure, 2 tables, accepted to IJMP

Effect of iron content on the catalytic properties of activated carbon-supported magnetite derived from biomass

In recent times, the intense human activity has led to an increase of the agriculture wastes in the environment. "In order to find new applications for these materials, the effect of iron content (2.5, 5, 10 and 15%) on the catalytic properties of activated carbon-supported iron oxide, prepared from coconut shells, was studied. The iron amount affected the textural and reducing properties of the solids and particle sizes. Hematite was found for the most iron-poor sample, while particles of magnetite with a core of hematite were found for the others. These catalysts were effective in the methylene blue removal from aqueous solutions by adsorption and Fenton reaction. The solid with 15% of iron was the most active one probably due to the highest iron amount on the surface. These catalysts are environmentally friendly, contributing to the decrease of the solid wastes in the environment as well as to purify textile effluents, preserving water resources.Nos últimos tempos, a intensa atividade humana levou a um aumento de resíduos agrícolas no meio ambiente. Visando a encontrar novas aplicações para estes materiais estudou-se, neste trabalho, o efeito do teor de ferro (2.5, 5, 10 e 15%) sobre as propriedades catalíticas de óxido de ferro suportado em carvão ativado, preparado a partir de cascas de coco. O teor de ferro afetou as propriedades texturais e redutoras dos sólidos. Detectou-se hematita na amostra mais pobre em ferro e magnetita com um núcleo de hematita nas demais. Estes catalisadores foram eficazes na remoção do azul de metileno em soluções aquosas por adsorção e pela reação de Fenton. O sólido com 15% de ferro foi o mais ativo, provavelmente devido à maior quantidade de sítios ativos na superfície. Estes catalisadores são ambientalmente amigáveis, contribuindo para a redução de resíduos sólidos no meio ambiente e purificação de efluentes têxteis, preservando os recursos hídricos.Facultad de Ciencias ExactasCentro de Investigación y Desarrollo en Ciencias Aplicada

Células C em bócio colóide

PURPOSE: The aim of this investigation was to quantitatively evaluate C-cells in colloid goiters, analyzing 36 thyroids that were obtained through thyroidectomy from 24 patients with goiter and 12 normal glands from adult patients without thyroid disease, which were used as the control group. MATERIAL AND METHODS: On average, 6 different thyroid areas were sampled and labeled by immunohistochemistry with a monoclonal anticalcitonin antibody, utilizing the avidin-biotin-peroxidase complex. C-cells were counted in fields measuring 1 square centimeter, and the mean number of cells per field was then calculated. Data were statistically analyzed using the Mann-Whitney test. RESULTS: In the colloid goiter group, the number of C-cells ranged from 0 to 23 per field, while in normal controls they ranged from 20 to 148 per field. CONCLUSIONS: These results demonstrate a significant decrease of C-cell number in the colloid goiter group compared with control group, indicating that the hyperplastic process is restricted to follicular cells, to the detriment of C-cells, which probably cease to receive trophic stimuli.OBJETIVO: Pesquisar, quantitativamente, as células C em bócio colóide com o propósito de investigar a relação destas células na patogênese do bócio. MÉTODO: Foram analisadas 35 tiróides obtidas de tiroidectomia, sendo 24 de pacientes com bócio colóide e 11 tiróides normais de adulto usadas como controle. Seis diferentes áreas foram amostradas em média e coradas com o anticorpo monoclonal anticalcitonina. As células C foram contadas em campos de 1 cm² e o número médio de células/campo foi calculado. Os dados foram estudados estatisticamente pelo teste de Kruskal-Wallis. RESULTADOS: O número de células C variou de 0 a 23/cm² em bócio colóide e em tiróides normais de 20 a 148/cm². CONCLUSÕES: Os resultados demonstraram redução significativa no número de células C em bócio colóide comparando com tiróides normais, indicando que o processo hiperplásico é restrito às células foliculares em detrimento das células C, as quais, provavelmente, deixam de receber estímulos tróficos e se degeneram

Effectiveness Of Dental Bleaching In Depth After Using Different Bleaching Agents.

This study evaluated the effectiveness of low- and high-concentration bleaching agents on enamel and deep dentin. Stained bovine incisors fragments were randomized placed into 10 groups (n=5), according to the sample thicknesses (2.0 mm or 3.5 mm) and bleaching agent: 10% carbamide peroxide (CP) (4 h a day/21 days); 6% hydrogen peroxide (HP) with calcium (1:30 h a day/21 days); HP 20% with calcium (50 min a day/3 sessions with a 7-day interval); HP 35% (3 x 15 min a day/3 sessions with a 7-day interval); HP 35% with calcium (40 min a day/3 sessions with a 7-day interval). The samples were stored in artificial saliva during the experiment. The color change was evaluated using a spectrophotometer at the initial analysis, after artificially staining with black tea and after each of the bleaching weeks, and data was expressed in CIE Lab System values. The L* coordinate data was submitted to analysis of variance and Tukey-Kramer test and the ?E values data was submitted for analysis of variance in a split-plot ANOVA and Tukey's test (?=0.05). None of the bleaching agents tested differed from the reflectance values on the enamel surface. For deep dentin HP 20% and HP 35%, both with calcium, showed the lowest reflectance values, which differed from CP 10%. It is concluded that high concentration hydrogen peroxide with calcium was less effective in deep dentin than 10% carbamide peroxide. Key words:Dental bleaching; hydrogen peroxide; carbamide peroxide; dental staining.5e100-

Multicommuted flow system for the determination of glucose in animal blood serum exploiting enzymatic reaction and chemiluminescence detection

An automatic flow procedure based on multicommutation dedicated for the determination of glucose in animal blood serum using glucose oxidase with chemiluminescence detection is described. The flow manifold consisted of a set of three-way solenoid valves assembled to implement multicommutation. A microcomputer furnished with an electronic interface and software written in Quick BASIC 4.5 controlled the manifold and performed data acquisition. Glucose oxidase was immobilized on porous silica beads (glass aminopropyl) and packed in a minicolumn (15 × 5 mm). The procedure was based on the enzymatic degradation of glucose, producing hydrogen peroxide, which oxidized luminol in the presence of hexacyanoferrate(III), causing the chemiluminescence. The system was tested by analysing a set of serum animal samples without previous treatment. Results were in agreement with those obtained with the conventional method (LABTEST Kit) at the 95% confidence level. The detection limit and variation coefficient were estimated as 12.0 mg l(−1) (99.7% confidence level) and 3.5% (n = 20), respectively. The sampling rate was about 60 determinations h(−1) with sample concentrations ranging from 50 to 600 mg l(−1) glucose. The consumptions of serum sample, hexacyanoferrate(III) and luminol were 46 μl, 10.0 mg and 0.2 mg/determination, respectively

Effect of iron content on the catalytic properties of activated carbon-supported magnetite derived from biomass

In recent times, the intense human activity has led to an increase of the agriculture wastes in the environment. "In order to find new applications for these materials, the effect of iron content (2.5, 5, 10 and 15%) on the catalytic properties of activated carbon-supported iron oxide, prepared from coconut shells, was studied. The iron amount affected the textural and reducing properties of the solids and particle sizes. Hematite was found for the most iron-poor sample, while particles of magnetite with a core of hematite were found for the others. These catalysts were effective in the methylene blue removal from aqueous solutions by adsorption and Fenton reaction. The solid with 15% of iron was the most active one probably due to the highest iron amount on the surface. These catalysts are environmentally friendly, contributing to the decrease of the solid wastes in the environment as well as to purify textile effluents, preserving water resources.Nos últimos tempos, a intensa atividade humana levou a um aumento de resíduos agrícolas no meio ambiente. Visando a encontrar novas aplicações para estes materiais estudou-se, neste trabalho, o efeito do teor de ferro (2.5, 5, 10 e 15%) sobre as propriedades catalíticas de óxido de ferro suportado em carvão ativado, preparado a partir de cascas de coco. O teor de ferro afetou as propriedades texturais e redutoras dos sólidos. Detectou-se hematita na amostra mais pobre em ferro e magnetita com um núcleo de hematita nas demais. Estes catalisadores foram eficazes na remoção do azul de metileno em soluções aquosas por adsorção e pela reação de Fenton. O sólido com 15% de ferro foi o mais ativo, provavelmente devido à maior quantidade de sítios ativos na superfície. Estes catalisadores são ambientalmente amigáveis, contribuindo para a redução de resíduos sólidos no meio ambiente e purificação de efluentes têxteis, preservando os recursos hídricos.Facultad de Ciencias ExactasCentro de Investigación y Desarrollo en Ciencias Aplicada

Bioinsecticide-Predator interactions: Azadirachtin behavioral and reproductive impairment of the coconut mite predator Neoseiulus baraki

Synthetic pesticide use has been the dominant form of pest control since the 1940s. However, biopesticides are emerging as sustainable pest control alternatives, with prevailing use in organic agricultural production systems. Foremost among botanical biopesticides is the limonoid azadirachtin, whose perceived environmental safety has come under debate and scrutiny in recent years. Coconut production, particularly organic coconut production, is one of the agricultural systems in which azadirachtin is used as a primary method of pest control for the management of the invasive coconut mite, Aceria guerreronis Keifer (Acari: Eriophyidae). The management of this mite species also greatly benefits from predation by Neoseiulus baraki (Athias-Henriot) (Acari: Phytoseiidae). Here, we assessed the potential behavioral impacts of azadirachtin on the coconut mite predator, N. baraki. We explored the effects of this biopesticide on overall predator activity, female searching time, and mating behavior and fecundity. Azadirachtin impairs the overall activity of the predator, reducing it to nearly half; however, female searching was not affected. In contrast, mating behavior was compromised by azadirachtin exposure particularly when male predators were exposed to the biopesticide. Consequently, predator fecundity was also compromised by azadirachtin, furthering doubts about its environmental safety and selectivity towards biological control agents