Antioxidant enzyme activity and hydrogen peroxide content during the drying of Arabica coffee beans

The development of the germination process and drought stress during the drying of coffee can generate reactive oxygen species, which can be neutralized by way of antioxidant mechanisms. No studies related to antioxidant enzymes during the drying of coffee were found in the literature, and considering their importance, the enzymatic activities of superoxide dismutase (SOD), guaiacol peroxidase (GPOX) and glutathione reductase (GR), and also the hydrogen peroxide content were evaluated during the drying of two types of coffee bean, one processed as natural coffee and the other as pulped natural coffee. The results showed a reduction in the SOD, GPOX and GR enzymatic activities of the natural coffee as compared to the pulped natural coffee during the drying period. Moreover, the hydrogen peroxide content of the natural coffee was greater than that of the pulped natural coffee. These results suggest the development of oxidative stress during the coffee drying process, controlled more efficiently in pulped natural coffee by the early action of GPOX during the drying process. Nevertheless, differential responses by SOD isoenzymes and possibly the role of other peroxidases also appear to be involved in the responses observed. © 2013 Springer-Verlag Berlin Heidelberg.

Toward pH-controllable bioelectrocatalysis for hydrogen peroxide based on polymer brushes

In the present work, a biosensor was built with smart material based on polymer brushes. The biosensor demonstrated a pH-sensitive on-off property, and it was further used to control or modulate the electrochemical responses of the biosensor. This property could be used to realize pH-controlled electrochemical reaction of hydrogen peroxide and HRP immobilized on polymer brushes. The composite film also showed excellent amperometric i-t response toward hydrogen peroxide in the concentration range of 0-13 μM. In future, this platform might be used for self-regulating targeted diagnostic, drug delivery and biofuel cell based on controllable bioelectrocatalysis. © 2013 Elsevier B.V.

Influence of plaster drying on the amount of residual monomer in heat-cured acrylic resins

Aim: To evaluate the influence of plaster condition, dry or not, on the amount of residual monomer in heat-cured acrylic resin. Methods: Thirty acrylic resin specimens (65×10×3 mm) were fabricated and randomly assigned to 5 groups (n=6). The evaluated resins were heat-cured acrylic resins by conventional or microwave polymerization techniques and the plaster was previously dried in microwave oven in two groups. Each specimen was individually immersed in a test tube containing methanol (7 days) for surface analysis. In the groups for which internal monomer was evaluated, the specimens were fragmented and the small fragments were weighed prior to immersion in methanol. The analysis was made by high performance liquid chromatography (HPLC). Data were analyzed by ANOVA and Tukey test (p<5%) Results: showed statistical differences among the groups. Conclusions: The previous plaster drying influenced the residual monomer amount showing a decrease of these levels.

Photoelastic analysis of the influence of residual ridge inclination in conjugated class i mandibular prostheses with different attachment systems

Objectives: The aim of this study was to evaluate the stress distribution in mandibular free-end removable partial dentures (RPD) associated with FPD in the abutment teeth considering different inclinations of the residual ridge: (1) horizontal and (2) distal descending ridges and two designs of free-end RPD with different attachment systems were tested: (1) clasp and (2) system ERA. Methods. Axial loads (100 N) were applied on the teeth of the RPD. The images were recorded and the stress distribution was evaluated through photoelastic fringes. Results. In general, the distal descending ridge presented more photoelastic fringes in the region of the roots of the abutment teeth while the horizontal ridge exhibited higher compression in the base of the prosthesis. In the horizontal ridge, the denture with clasp presented more favourable stress distribution than the denture with the system ERA. In the distal descending ridge, the denture with the system ERA relieved the region of the abutment teeth and overloaded the residual ridge. Conclusion: The horizontal ridge presented more favourable performance; the dentures with clasp exhibited better performance for both ridges evaluated; the denture with the system ERA presented better results in the distal descending ridge. © 2013 Informa Healthcare.

Cloreto de potássio revestido em efeito residual no feijoeiro de inverno irrigado na região de cerrado

In order to maintain the nutrients available to plants have been studied controlled release fertilizers. In this context, the objective was to evaluate the residual effect of doses of potassium chloride, coated or not, applied in the corn crop, regarding the crop components and grains yield of irrigated winter common bean, cultivated in followed, in Cerrado region. The experiment was conducted in Selvíria - MS, Brazil, 51°22- west longitude and 20°22- south latitude, in a clayey Oxisol, in 2009 and 2010. A randomized block design with four repetitions was used, disposed in a factorial scheme 4 x 2, being: four K2O doses (0, 40, 80 and 120 kg ha-1) and two potassium sources (potassium chloride and coated potassium chloride by polymers) applied at sowing in the corn crop. The coated potassium chloride by polymers have the same residual effect as conventional KCl, because it provides results similar for the K and chlorophyll leaf contents, crop components and grains yield of winter common bean irrigated. The increment of potassium doses in the previous crop (corn) have residual effect, because it influenced positively the number of grains per plant in 2009 and increased linearly the chlorophyll leaf content and the grains yield of winter common bean irrigated in 2010, regardless of the source used for K.

Efeito residual de fontes de fósforo nos atributos químicos do solo, nutrição e produtividade de biomassa da cana-de-açúcar

In tropical regions, the residual effect of phosphate fertilizer source is of crucial importance. This study aimed to evaluate the effects of application of P sources in chemical properties of soil, nutrition and productivity of sugarcane plant and during the first and second ratoon. The sources of P applied in furrows at planting were, triple superphosphate, Arad phosphate, bone meal (100 kg ha-1 P2O5 total) and a control without P, the varieties of sugarcane studied were IAC86-2480 and SP79-1011. A randomized block design in a 4 × 2 factorial was used, with four replications. The study was conducted in the municipality of Alta Floresta-MT, Brazil, in Typic Hapludox. After each cutting, in soil P content, pH and Ca were evaluated. In the plant, the production of green and dry matter of shoots, the concentration of P in the biomass harvested, the export of P and agronomic efficiency of the sources of P were determined. The bone meal had a higher agronomic efficiency resulted in greater accumulation and export of P by crop, higher content of available Ca and P and increase soil pH. The Arad reactive phosphate increased its agronomic efficiency between crop cycles.

Effect of carbamide peroxide bleaching gel on composite resin flexural strength and microhardness

This study investigated the effect of 16% carbamide peroxide (Whiteness Perfect/FGM) on the Vickers microhardness and flexural strength of the restorative composites Filtek Z100 (hybrid), Filtek Z350 (nanofill), Brilliant (micro-hybrid) and Opallis (micro-hybrid). Discshaped (4×2 mm; n=5) and bar-shaped (12×2×1 mm; n=10) specimens of each restorative material were randomly divided into 2 groups: (G1) 16 weeks stored in distilled water; (G2) 16 weeks stored in distilled water, with 16% carbamide peroxide application during 6 h per day for the last 4 weeks. The mechanical properties were evaluated using a Vickers microhardness tester and a mechanical testing machine. Data were analyzed by twoway ANOVA and Tukey's (HSD) post-hoc test (α=0.05). Filtek Z100 presented the highest microhardness value, followed by Filtek Z350 and finally by Brilliant and Opallis (p=0.00). Filtek Z100 and Brilliant exhibited the highest flexural strength value, followed by Filtek Z350 and Opallis (p=0.00). Bleaching treatment decreased significantly microhardness of Brilliant and Opallis (p=0.00). The flexural strength of all studied materials was not affected by the home bleaching (p=0.28).

Toxic effects of daily applications of 10% carbamide peroxide on odontoblast-like MDPC-23 cells

Background. Tooth bleaching has been widely studied, mainly due to the possible undesirable effects that can be caused by this esthetic procedure. The cytotoxicity of the bleaching agents and its components to pulp cells has been demonstrated in several researches. The aim of this study was to evaluate the toxic effects of successive applications of 10% carbamide peroxide (CP) gel on odontoblast-like cells. Materials and methods. Enamel-dentin discs obtained from bovine incisors were adapted to artificial pulp chambers (APCs). The groups were formed as follows: G1: Without treatment (control group); G2: 10% carbamide peroxide, CP (five applications/one per day); G3: 10% CP (one unique application); and G4: 35% hydrogen peroxide, HP (three applications of 15 min each). After treatment, cell metabolism (MTT), alkaline phosphatase (ALP) activity and plasma membrane damage (flow cytometry) were analyzed. Results. Reductions in cell metabolism and alkaline phosphatase activity along with severe damage of the cytoplasmic membrane were noted in G2. In G3, no damage was observed, compared to the control group. Intermediary values of toxicity were obtained after 35% HP application. Conclusion. It can be concluded that one application of 10% CP did not cause toxic effects in odontoblast-like cells, but the successive application of this product promoted severe cytotoxic effects. The daily application of the bleaching agents, such as used in the at-home bleaching technique, can increase the damages caused by this treatment to the dental pulp cells. © 2013 Informa Healthcare.

Sistemas de manejo e efeito residual do potássio na produtividade e nutrição do feijão-caupi

Cowpea [Vigna unguiculata (L) Walp] have great social and economic importance for the Para State. It grows well in areas with low precipitation and two crop cycles can be obtained annually. This study aimed to assess the effect of the residual fertilization from a previous culture (Sorghum bicolor L. Moench) and crop systems on cowpea yield and macronutrient concentration on leaves of three cowpea cultivars (BRSMilênio, BRS-Urubuquara e BRS-Guariba). The study was conducted at the UFRA. The treatments were two crop systems (minimum tillage and conventional), four levels of potassium (50, 100, 200 e 300 kg de KCl ha-1 applied to a previous sorghum culture) and the three cowpea cultivars. Treatments were organized as a three (4 x 2 x 3) factor experiment on a randomized complete block design. The soil was a yellow latosol. In each experiment plot five plants were selected to determine shoot dry matter and foliar nutrient concentration. Grain yield was determined after harvesting all plants on the experiment plot. The residual KCl fertilization affected foliar nutrient content, but did not affect shoot dry mass or yield of grain. Yield was higher in the minimum tillage system. Highest yield (1590 kg ha-1) was recorded int the cv. 'Guariba' when 100 kg of KCl ha-1 had been used in the previous crop. The highest content of leaf N and K was found in cowpea under minimum tillage system. The amount of P and Mg were higher in the conventional system whereas the amount of Ca did not change.

Efeito residual da aplicação superficial de calcário e gesso nas culturas de soja, aveia-preta e sorgo granífero

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

Efeito residual do calcário no solo, no estado nutricional e na produtividade da mangueira cv. Palmer

Pós-graduação em Agronomia (Ciência do Solo) - FCAV

Efeito residual do calcário e da escória de siderurgia na primeira soqueira da cultura da cana-de-açúcar

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Produção de biodiesel a partir de óleo residual reciclado e realização de testes comparativos com outros tipos de biodiesel e proporções de mistura em um moto-gerador

Pós-graduação em Engenharia Mecânica - FEIS

Propagação da atitude de satélites artificiais estabilizados por rotação: torque residual médio com o modelo de quadripolo para o campo geomagnético

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

Cogeração a partir da biomassa residual de cana-de-açúcar: estudo de caso

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)