Surface roughness of denture base and reline materials after disinfection by immersion in chlorhexidine or microwave irradiation

Background: This study evaluated the effect of disinfection by immersion and microwave irradiation on the roughness of one denture base resin (Lucitone-L) and five relining materials, three hard (Tokuyama Rebase II-TR, New Truliner-NT, Ufigel Hard-UH) and two resilient (Trusoft-T, Sofreliner-S).Methods: Fifty specimens were made and divided into groups: CL2 specimens were brushed with 4% chlorhexidine (1 min), immersed in the same solution (10 min) and immersed in water (3 min); MW2 specimens were immersed in water and microwave irradiated (650W; 6 min); CL2 and MW2 specimens were disinfected twice; CL7 and MW7 specimens were submitted to seven cycles using chlorhexidine or microwave irradiation, respectively; W specimens were not disinfected and remained in water (37 degrees C; 7 days).Results: Results were statistically analysed (p = 0.05) and revealed that, at baseline, the highest mean value was observed for T (p < 0.001). Material NT showed increase in roughness after the first (p = 0.003), second (p = 0.001), seventh (p = 0.000) cycles of microwave disinfection and after 7 days of immersion in water (p = 0.033).Conclusions: Resilient liner S presented significant increase in roughness after the second cycle of disinfection with chlorhexidine (p = 0.003). Material T exhibited significantly decreased roughness in group W (p = 0.010), while microwaving produced severe alterations on its surface.

Pollination Biology of Jacaranda oxyphylla with an Emphasis on Staminode Function

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

PHEROMONES and EXOCRINE GLANDS IN ISOPTERA

Termites are eusocial insects that have a peculiar and intriguing system of communication using pheromones. The termite pheromones are composed of a blend of chemical substances and they coordinate different social interactions or activities, including foraging, building, mating, defense, and nestmate recognition. Some of these sociochemicals are volatile, spreading in the air, and others are contact pheromones, which are transmitted by trophallaxis and grooming. Among the termite semiochemicals, the most known are alarm, trail, sex pheromones, and hydrocarbons responsible for the recognition of nestmates. The sources of the pheromones are exocrine glands located all over the termite body. The principal exocrine structures considered pheromone-producing glands in Isoptera are the frontal, mandibular, salivary or labial, sternal, and tergal glands. The frontal gland is the source of alarm pheromone and defensive chemicals, but the mandibular secretions have been little studied and their function is not well established in Isoptera. The secretion of salivary glands involves numerous chemical compounds, some of them without pheromonal function. The worker saliva contains a phagostimulating pheromone and probably a building pheromone, while the salivary reservoir of some soldiers contains defensive chemicals. The sternal gland is the only source of trail-following pheromone, whereas sex pheromones are secreted by two glandular sources, the sternal and tergal glands. To date, the termite semiochemicals have indicated that few molecules are involved in their chemical communication, that is, the same compound may be secreted by different glands, different castes and species, and for different functions, depending on the concentration. In addition to the pheromonal parsimony, recent studies also indicate the occurrence of a synergic effect among the compounds involved in the chemical communication of Isoptera. (C) 2010 Elsevier B.V.

Cytotoxic effects of permethrin in oocytes of Rhipicephalus sanguineus (Acari: Ixodidae) fully engorged females: I. Direct or indirect action of the acaricide in germ cells?

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

Morphological alterations induced by boric acid and fipronil in the midgut of worker honeybee (Apis mellifera L.) larvae

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Determination of the LC50 of selamectin (active principle of the antiparasitic Revolution (R), Pfizer) applied on engorged female of the tick Rhipicephalus sanguineus (Latreille, 1806) (Acari: Ixodidae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Production of Crude Xylanase from Thermoascus Aurantiacus CBMAI 756 Aiming the Baking Process

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

Neural networks in chemosystematic studies of asteraceae: A classification based on a dichotomic approach

This paper describes the application of artificial neural nets as an alternative and efficient method for the classification of botanical taxa based on chemical data (chemosystematics). A total of 28,000 botanical occurrences of chemical compounds isolated from the Asteraceae family were chosen from the literature, and grouped by chemical class for each species. Four tests were carried out to differentiate and classify different botanical taxa. The qualifying capacity of the artificial neural nets was dichotomically tested at different hierarchical levels of the family, such as subfamilies and groups of Heliantheae subtribes. Furthermore, two specific subtribes of the Heliantheae and two genera of one of these subtribes were also tested. In general, the artificial neural net gave rise to good results, with multiple-correlation values R > 0.90. Hence, it was possible to differentiate the dichotomic character of the botanical taxa studied.

Avaliação comparativa da eficácia de fitoterápicos e produtos químicos carrapaticidas no controle do boophilus microplus (Canestrini, 1887) por meio do biocarrapaticidograma

The aim of this research was to evaluate the efficacy of plant extracts and chemical products for the control of Boophilus microplus. Three commercial products for the control of Boophilus microplus were in vitro evaluated, chemical compounds of cypermethrin + DDVP and organophosphate as recomended by the manufacturer, and also four plant extracts, Azadirachta indica (1%), Cymbopogon densiflorus, Lippia alba and Ipomoea asarifolia at different concentrations. The results showed that the chemical compounds tested had efficacy lower than 95% against the Boophilus microplus samples in the experiment. The extracts of all plants have shown some biological activity in the mortality of ingurgitated females and inhibition of egg crash, however the extract of Azadirachta indica presented efficacy higher than 95% in all tested concentrations, being the best sample tested in this experiment.

Suplementação de acidificantes em rações de leitões desmamados: Desempenho e digestibilidade

In two experimental assays it was evaluated the diet acidifier supplementation effect on performance (assay 1) and on nutrient apparent digestibility coefficients (assay 2). During 42 days in assay 1, 120 piglets weaned at 21-days years old were allotted in8eight experimental block design with3three pigs per experimental unit. The treatments were a control and4four acidified diets. In assay 2,0ten piglets with an average weight of 16,4 kg were allotted in two experimental block design receiving two treatments under five replications (control diet without acidifier or supplied with 1,0% fumaric acid). On performance study the fumaric acid inclusion in the diet permitted a feed intake increase from 0 to 15 days, and weight gain from 0 to 32 days and from 0 to 42 days. In assay 2, the diet 1,0% of fumaric acid inclusion did not modified the apparent digestibility coefficients of dry matter and moreover diet chemical compounds. The similar apparent digestibility coefficient of dietetic nutrients with the acidifier inclusio, probabl, occurred due to the short period of evaluation. The fumaric acid inclusion in weaned piglet diets improved performance of piglets.

Yield and phytochemical characterization of essential oil from Ocimum selloi B. obtained by hydrodistillation and supercritical fluid extraction

The yield and chemical composition of essential oils from leaves of Ocimum selloi B. submitted to organic and mineral fertilization, obtained by hydrodistillation and supercritical fluid extraction (SFE) were compared. Essential oil was extracted in a Clevenger-type apparatus for 2 h 30 min and analyzed by GC-MS (Shimadzu, QP 5050-DB-5 capillary column - 30 m × 0.25 mm × 0.25 μm). Carrier gas was helium (1.7 ml/min); split ratio: 1:30. Temperature program: 50°C, rising to 180°C at 5°C/min, 180°C, rising to 280°C at 10°C/min. Injector temperature: 240°C and detector temperature: 230°C. Identifications of chemical compounds were made by matching their mass spectra and Kovat's indices (IK) values with known compounds reported in the literature. An Applied Separations-apparatus (Speed SFE, model 7071, Allentown, PA, EUA) was used for SFE extractions. They were conducted at pressure 200 bar and temperature 30°C (20 min in static mode and 40 min in dynamic mode). The supercritical CO2 flow rate was (6.8±0.7)×10-5 kg-CO2/s. The essential oil collected was immersed in ethylene glycol bath (5°C). The yield of essential oils obtained by SFE was larger than hydrodistillation in both fertilization treatments (279 and 333% for organic and mineral fertilizations, respectively). There were no differences between the fertilization treatments. The amount of the volatile components showed by GC-MS chromatogram was highest in the essential oil obtained by hydrodistillation than SFE. The main volatile constituents of the essential oils were trans-anethole (Hydrodistillation: organic - 52.4%; mineral - 55.0%/ SFE: Hydrodistillation - 62.8%; mineral - 66.8%) and methyl-chavicol (Hydrodistillation: organic - 37.3%; mineral - 38.3%/ SFE: organic - 8.4%; mineral - 4.3%). A reduction of methyl-chavicol relative proportion of essential oil obtained by SFE was observed. Cys-anethole, α-copaene, trans-cariofilene, germacrene-D, β-selinene, biciclogermacrene and spathulenol were expressed only in hydrodistillation. The extraction of essential oil by SFE presented larger yield of essential oil than hydrodistillation technique, presenting, however, these essential oils, different phytochemical profiles.

Toxicological and histopathological effects of hydramethylnon on Atta sexdens rubropilosa (Hymenoptera: Formicidae) workers

The leaf-cut ants are important agricultural pest, because they can cause intense defoliation in plants and destroy large areas cultivated. Although there are several works for the control of these insects by examining the toxicity of natural chemical compounds on various species of ants, few are focused on analyses of morphological changes caused in the affected organs. The aim of this study was to evaluate the effects of hydramethylnon on Atta sexdens rubropilosa workers through toxicological bioassays and morphological analysis of the post-pharyngeal glands, midgut, and Malpighian tubules of these ants. Hydramethylnon dissolved either in acetone (HA) or in a mixture of acetone and soy oil (HAO) was added to the artificial diet at a concentration of 200 μg/mL. The workers fed daily with the diet containing hydramethylnon showed higher mortality than the controls, especially when HAO was used. Moreover, light and electron microscopy revealed morphological alterations in the midgut and Malpighian tubules of workers treated with HA, whereas alterations of the post-pharyngeal glands were observed in the HAO-treated group. These results indicated that the presence of soy oil provided an alternate route for the ingestion of the formicide's active ingredient and corroborated previous studies that suggested a role for the post-pharyngeal glands in lipid metabolism. Our findings suggest that the oil may carry hydramethylnon to the gland lumen, resulting in lower quantity of the active ingredient in the intestinal lumen and Malpighian tubules that explains the lower degree of morphological alterations in these structures in the workers treated with HAO. These results may provide insight into the toxicological effects of hydramethylnon on leaf-cutting ants and the use of vegetable oil as an adjuvant in baits to control ants. © 2012 Elsevier Ltd.

Cellular responses in the Malpighian tubules of Scaptotrigona postica (Latreille, 1807) exposed to low doses of fipronil and boric acid

Studies of sub-lethal effects of pesticide residues on stingless bees are scarce and morphological analysis of organs would add information to toxicological analysis in order to clarify the continuous exposure of Scaptotrigona postica to insecticides. The aim of this study was to evaluate the morphology and histochemistry of the Malpighian tubules (excretory organ) of S. postica exposed to fipronil or boric acid to detect cellular responses that indicate toxicity or adaptative mechanisms to stress induced by exposure of worker bees to low doses of these chemical compounds. Newly emerged bees were submitted to toxicological bioassays and morphological analyses by optical microscopy and Transmission Electron Microscopy, as well as histochemical methods, were performed to detect proteins and glycoconjugates. Additionally, immunohistochemical detection of DNA fragmentation and HSP70 (70-kDa Heat shock protein) were performed to detect cell death and stress response, respectively. Statistical analysis, for the bioassays conducted with ingestion of contaminated diet with boric acid at 0.75% (w/w) or with fipronil at 0.1μg/kg of food, showed that the survival of bees that ingested the contaminated diets were significantly different to the survival rate presented by the control group (P<0.0001). Although some characteristics indicative of initiation of cell death were observed, the cells remained metabolically active in the processes of excretion and inactivation of chemical compounds. The data from this study reinforce the importance of research on sublethal effects of low doses of pesticides on bees in an attempt to assess a possible realistic dose and evaluate the risk assessment of stingless bee S. postica foraging in the vicinity of cultivated fields and/or in green urban areas. © 2013 Elsevier Ltd.

Determination of 2-methylimidazole and 4-methylimidazole in caramel colors by capillary electrophoresis

The use of chemical preservative compounds is common in the food products industry. Caramel color is the most usual additive used in beverages, desserts, and breads worldwide. During its fabrication process, 2- and 4-methylimidazole (MeI), highly carcinogenic compounds, are generated. In these cases, the development of reliable analytical methods for the monitoring of undesirable compounds is necessary. The primary procedure for the analysis of 2- and 4-MeI is using LC- or GC-MS techniques. These procedures are time-consuming and require large amounts of organic solvents and several pretreatment steps. This prevents the routine use of this procedure. This paper describes a rapid, efficient, and simple method using capillary electrophoresis (CE) for the separation and determination of 2- and 4-MeI in caramel colors. The analyses were performed using a 75 μm i.d. uncoated fused-silica capillary with an effective length of 40 cm and a running electrolyte consisting of 160 mmol L-1 phosphate plus 30% acetonitrile. The pH was adjusted to 2.5 with triethylamine. The analytes were separated within 6 min at a voltage of 20 kV. Method validation revealed good repeatability of both migration time (<0.8% RSD) and peak area (<2% RSD). Analytical curves for 2- and 4-MeI were linear in the 0.4-40 mg L-1 concentration interval. Detection limits were 0.16 mg L-1 for 4-MeI and 0.22 mg L-1 for 2-MeI. The extraction recoveries were satisfactory. The developed method showed many advantages when compared to the previously used method. © 2013 American Chemical Society.

Hydrogen production by biogas steam reforming: A technical, economic and ecological analysis

Fuel cells are electrochemical energy conversion devices that convert fuel and oxidant electrochemically into electrical energy, water and heat. Compared to traditional electricity generation technologies that use combustion processes to convert fuel into heat, and then into mechanical energy, fuel cells convert the hydrogen and oxygen chemical energy into electrical energy, without intermediate conversion processes, and with higher efficiency. In order to make the fuel cells an achievable and useful technology, it is firstly necessary to develop an economic and efficient way for hydrogen production. Molecular hydrogen is always found combined with other chemical compounds in nature, so it must be isolated. In this paper, the technical, economical and ecological aspects of hydrogen production by biogas steam reforming are presented. The economic feasibility calculation was performed to evaluate how interesting the process is by analyzing the investment, operation and maintenance costs of the biogas steam reformer and the hydrogen production cost achieved the value of 0.27 US$/kWh with a payback period of 8 years. An ecological efficiency of 94.95%, which is a good ecological value, was obtained. The results obtained by these analyses showed that this type of hydrogen production is an environmentally attractive route. © 2013 Elsevier Ltd.