Effect of finishing technique on the occurrence and length of microcracks in resin-based materials

Purpose: To evaluate the presence and length of microcracks in resin-based materials finished with different techniques, using optical coherence tomography (OCT). Methods: Standardized Class V preparations (3×2×2mm) were made in the facial and lingual surfaces of 20 recently-extracted human third molars. 20 preparations were restored with a resin-based composite material (RBC; Filtek Supreme Ultra) and the other 20 with a resin modified glass-ionomer material (RMGI; Ketac Nano). After final polymerization, specimens were further stratified by finishing system: aluminum oxide discs (Sof-Lex) or spiral fluted carbide bur series (H48L). By random allocation, each extracted tooth therefore received one RBC and one RMGI restoration, and equal numbers of restorations from each material were finished using each finishing system (n= 10). After 24 hours of storage in 100% humidity at room temperature, the specimens were evaluated at ×20 to ×600 under environmental SEM. Cross-sectional occlusal-cervical B-mode images were obtained in increments of 25 mm from the mesial margin to the distal margin of the restoration using a spectral-domain (SD) OCT system and analyzed using Image J software to identify and measure microcrack penetration into each restoration. The total length (mm) at the point of the deepest microcrack penetration in each specimen was recorded. Data were statistically analyzed using a t-test. Results: No microcracks were observed in the RBC samples. However, microcrack presence was identified in all of the RMGI specimens. The t-test showed a statistically significant difference (P< 0.05) in mean microcrack length values based on the finishing technique used for the RMGI samples. [SofLex: 0.67 (Plusmn; 0.28) mm; carbide: 1.26 (Plusmn; 0.30)] mm. Two-way ANOVA showed significant differences in the factors "finishing technique" and "restorative material" (P< 0.001). The interaction of these two factors was also statistically significant (P< 0.001). For the tested RMGI, Tukey post-hoc test revealed that the finishing with aluminum oxide groups resulted in statistically significant lower mean microcrack length when compared to spiral fluted carbide burs (P< 0.001)

Crescimento e produção de taro 'Chinês' influenciados por tipos de mudas e camadas de bagaço de cana-de-açúcar Plant growth and yield of 'Chinês' corms taro influenced by propagation methods and sugar-cane mulch

Foram conduzidos dois experimentos consecutivos, numa mesma área, em Viçosa (MG), de 19/11/1997 a 08/08/1998 (experimento I) e de 01/09/1998 a 06/06/1999 (experimento II), com o taro 'Chinês' (BGH 5928). Utilizou-se o delineamento experimental de blocos ao acaso, em esquema fatorial 4 x 7 (tipos de mudas x camadas de bagaço de cana-de-açúcar), com três repetições. No experimento I avaliaram-se os efeitos de quatro tipos de mudas (rizoma-mãe e rizomas filhos grande, médio e pequeno, com 80; 55; 35 e 20 g de massa fresca média, respectivamente) e sete espessuras de camadas de bagaço em cobertura (0; 4; 8; 12; 16; 20 e 24 cm). No experimento II avaliou-se o efeito residual das camadas de bagaço utilizadas no experimento I, mantendo-se os mesmos tipos de mudas, com massas semelhantes. Avaliaram-se o estande e altura de plantas, índice de área foliar (IAF) e produção final de classes de rizomas. Menores estandes foram obtidos no experimento I e para o tipo de muda filho pequeno, principalmente na ausência de bagaço. Mudas com maior massa e camadas intermediárias de bagaço proporcionaram plantas mais vigorosas e com maiores valores de IAF. Não houve interação entre camadas de bagaço e tipos de mudas, para produção de rizomas, em ambos experimentos. No experimento I verificou-se efeito significativo para ambos os fatores, isoladamente, com maiores produções de rizomas totais e comerciáveis obtidas para o tipo de muda rizomas-mãe, seguido de filho grande, e camada de bagaço entre 16,4 a 17,4 cm de espessura. No experimento II houve efeito apenas de tipos de mudas com maiores produções de rizomas totais e comerciáveis para as mudas tipos rizoma-mãe e filho grande.<br>Two consecutive experiments were carried out, in the same area, from 11/19/1997 to 08/08/1998 (experiment I) and from 09/01/1998 to 06/06/1999 (experiment II), with taro 'Chinês' (BGH 5928). The experiments consisted of 28 treatments, in a randomized complete block design, arranged in a factorial 4 x 7 (types of seedlings x layers of sugar-cane mulch), with three repetitions. In experiment I the effect of four types of seedlings were evaluated (corm and comels large, medium and small, with 80; 55; 35 and 20 g of medium fresh mass, respectively) and seven thickness of mulch layers on covering (0; 4; 8; 12; 16; 20 and 24 cm). In experiment II the residual effect of the mulch layers used in experiment I was evaluated, the same types of seedlings staying with similar masses. The stand and height of plants, leaf area index (LAI) and final corm yield and classes of cormels were evaluated. Smaller stands were obtained in experiment I and for the type of seedling graded as small cormel, mainly in the absence of mulch. Seedlings with larger masses and intermediate layers of mulch provided more vigorous plants and with higher values of LAI. There was no interaction between mulch layers x types of seedlings, for yield of corm and cormels, in both experiments. In experiment I significant effect was verified for both factors, separately, with larger yield of total and commercial cormels obtained for the type seedling corm (head), followed by large cormel, and mulch layer from 16.4 to 17.4 cm of thickness. In experiment II, an evident effect of types of seedlings with larger yield of total and commercial cormels for the seedlings types corm and large cormel was observed

Restructured fish product from white croacker (Micropogonias furnieri) mince using microbial transglutaminas

This study aimed at determining the influence of three concentrations of commercial transglutaminase enzyme in restructured fillet of minced fish from white croacker (Micropogonias furnieri), one of the four marine species with notability in Brazil. The restructured fillet developed had advantages when compared to traditional fillet, such as absence of spine and less flavour intensity (washes cycles). Washing process for white croacker mince was compared with five clarification agents: water (control), phosphoric acid (H3PO4), sodium chloride (NaCl), calcium carbonate (CaCO3) and sodium bicarbonate (NaHCO3). The higher quality product (whiteness) was obtained with calcium carbonate washes. Three concentrations (1.5, 1.0 and 0.5%) of microbial transglutaminase MGTase (Active TG-B %v/v and Active TG-BP %w/w) were compared, in order to produce fish restructured product (boneless fillet). The concentration of 1.5% (both enzymes), produced better results. The restructured products were compared by sensory analysis and showed better sensory parameters (appearance, odour, flavour and texture) samples treated with Active TG-B (solution form).<br>Este estudo teve como objetivo determinar a influência de três concentrações de enzima transglutaminase comercial em filés reestruturado a partir de polpa de corvina (Micropogonias furnieri), uma das quatro espécies marinhas notáveis no Brasil. O filé reestruturado desenvolvido tem vantagens quando comparado aos filés tradicionais, tais como, a ausência da espinhas e sabor menos intenso (ciclos de lavagens). O processo de lavagem da polpa de corvina foi comparado com cinco agentes clarificantes: água (controle), ácido fosfórico (H3PO4), cloreto de sódio (NaCl), carbonato de cálcio (CaCO3) e bicarbonato de sódio (NaHCO3). O produto de qualidade superior (mais branco) foi obtido com a lavagem com carbonato de cálcio. Três concentrações (1,5%, 1,0% e 0,5%) de transglutaminase microbiana (Activa TG-B % v/v e Activa TG-BP % p/p) foram comparadas a fim de produzir o produto reestruturado (filé sem espinha). A concentração de 1,5% (ambas as enzimas) produziu melhores resultados. Os produtos reestruturados foram comparados através de análise sensorial, e apresentaram melhores parâmetros sensoriais (aparência, odor, sabor e textura), as amostras tratadas com Activa TG-B (forma de solução)

Produção de laranja 'Pêra' em sistemas de preparo de solo e manejo nas entrelinhas Fruit yields of 'Pêra' orange under different soil tillage and interrow management systems

O preparo convencional do solo utilizado na implantação de pomares cítricos com base na remoção da cobertura vegetal e no revolvimento do solo em área total, assim como o manejo de pomares com eliminação da cobertura vegetal das entrelinhas, têm causado erosão e redução da fertilidade dos solos, com reflexos negativos sobre as plantas cítricas e o ambiente. O objetivo deste estudo foi avaliar sistemas de manejo que contribuam para controle da erosão e melhoria da fertilidade de Argissolos originados do arenito Caiuá, cultivados com citros no noroeste do Paraná. Foram avaliados dois sistemas de preparo do solo: convencional (PC), em área total, e preparo em faixas (PF), de 2 m de largura, com diferentes formas de manejo nas entrelinhas. O estudo foi realizado em um pomar de laranja 'Pêra' (Citrus sinensis) enxertada em limoeiro 'Cravo' (Citrus limonia), em um Argissolo Vermelho distrófico latossólico. O experimento foi implantado em área ocupada por pastagem (Brachiaria humidicola), em agosto de 1993, no espaçamento de 7 x 4 m, em delineamento de blocos ao acaso, com três repetições e seis tratamentos, sendo: (1) PC e cultivo intercalar com abacaxi, sucedido por controle da vegetação espontânea com herbicida pós-emergente; (2) PC e cobertura vegetal com a leguminosa Calopogonium mucronoides; (3) PC e cobertura vegetal com a leguminosa perene amendoim forrageiro Arachis pintoi; (4) PC e cobertura vegetal com gramínea mato-grosso ou batatais Paspalum notatum; (5) PC e cobertura com vegetação espontânea da gramínea Brachiaria humidicola; e (6) PF e manutenção da gramínea (pastagem) remanescente (Brachiaria humidicola). De 1996 a 2005, foram avaliadas a composição química do solo e das folhas e a produção de frutos. No solo, foram observados incrementos significativos no teor de C orgânico (CO) nos tratamentos 4 e 6, em relação aos tratamentos 1 e 3. Não houve diferenças significativas entre os tratamentos para produção acumulada de frutos nas safras de 1996 a 2005. O preparo de solo em faixas, com manutenção de gramínea remanescente nas entrelinhas, mostrou-se apropriado para implantação dos pomares. As plantas de cobertura permanente utilizadas nas entrelinhas do pomar não comprometeram a produção de laranja, sendo importantes para melhoria da fertilidade do solo. As gramíneas foram mais indicadas que as leguminosas como cobertura vegetal nas entrelinhas do pomar.<br>The conventional soil tillage used in the implantation of citrus orchards is based on the removal of the plant residues and soil tilling in the entire area, and the management of orchards on the elimination of any plant residues from the interrows. This has led to erosion and reduced soil fertility, with negative effects on the trees and the environment. The objective of this study was to evaluate soil management systems that decrease soil erosion and improve the fertility status of a Typic Paleudults originated from Caiuá sandstone, cultivated with citrus in the northwestern state of Paraná, Brazil. Two soil tillage systems were evaluated: conventional tillage (CT) in the entire area, and strip-tillage (ST) with 2 m width, with different interrow management systems. The citrus cultivar was Pêra orange (Citrus sinensis) grafted onto 'Rangpur' lime (Citrus limonia) rootstock. The citrus orchard was established in August 1993, and the tree rows were spaced 7 m apart with 4 m between trees. The experiment was set up in a randomized block design with three replications and six treatments: (1) CT and pineapple intercropping in the first year followed by weed control with post emergence herbicide; (2) CT and annual cover crop with the leguminous crop Calopogonium mucronoides; (3) CT and perennial cover crop with the leguminous peanut Arachis pintoi; (4) CT and evergreen cover crop with Bahiagrass Paspalum notatum; (5) CT and cover crop with spontaneous Brachiaria humidicola grass vegetation and (6) ST and maintenance of the remaining grass (pasture) of Brachiaria humidicola. From 1993 to 2005, the soil and leaf chemical composition and fruit yields were evaluated. Soil analyses showed a significant increment in organic carbon content in the treatments 4 and 6 compared to the treatments 1 and 3. There were no significant differences among the treatments for the accumulated fruit yields from 1996 to 2005. The soil tillage in strips with grass remaining in the interrows was considered appropriate for the citrus orchard establishment. The grass species were more suitable than the leguminous plants for the improvement of soil fertility