Dileta Cecchetti

Flexural and diametral tensile strength of composite resins

This study evaluated the flexural strength (sf) and the diametral tensile strength (st) of light-cured composite resins, testing the hypothesis that there is a positive relation between these properties. Twenty specimens were fabricated for each material (Filtek Z250- 3M-Espe; AM- Amelogen, Ultradent; VE- Vit-l-escence, Ultradent; EX- Esthet-X, Dentsply/Caulk), following ISO 4049 and ANSI/ADA 27 specifications and the manufacturers instructions. For the st test, cylindrical shaped (4 mm x 6 mm) specimens (n = 10) were placed with their long axes perpendicular to the applied compressive load at a crosshead speed of 1.0 mm/min. The sf was measured using the 3-point bending test, in which bar shaped specimens (n = 10) were tested at a crosshead speed of 0.5 mm/min. Both tests were performed in a universal testing machine (EMIC 2000) recording the fracture load (N). Strength values (MPa) were calculated and statistically analyzed by ANOVA and Tukey (a = 0.05). The mean and standard deviation values (MPa) were Z250-45.06 +/- 5.7; AM-35.61 +/- 5.4; VE-34.45 +/- 7.8; and EX-42.87 +/- 6.6 for st; and Z250-126.52 +/- 3.3; AM-87.75 +/- 3.8; VE-104.66 +/- 4.4; and EX-119.48 +/- 2.1 for sf. EX and Z250 showed higher st and sf values than the other materials evaluated (p < 0.05), which followed a decreasing trend of mean values. The results confirmed the study hypothesis, showing a positive relation between the material properties examined.

Produção de cultivares de morangueiro polinizadas pela abelha jataí em ambiente protegido

A cultura do morangueiro, tradicionalmente produzida a campo, teve seu sistema de cultivo modificado, sendo hoje produzido tambem em ambientes protegidos. Essa tecnologia pode, porem, ocasionar a producao de frutos deformados, devido a polinizacao entomofila insuficiente. O objetivo deste trabalho foi avaliar a produtividade dos frutos de morangueiro em ambiente protegido, utilizando a abelha jatai como agente polinizador. Foram avaliadas quatro cultivares de morangueiro (Oso Grande, Tudla, Chandler e Dover), na ausencia e presenca de duas e quatro colmeias da Tetragonisca angustula (abelha sem ferrao Jatai). Os tratamentos constituiram um fatorial 4 x 3, dispostos em um delineamento completamente casualizado, com sete repeticoes e 6 plantas uteis por parcela. Os rendimentos obtidos nas cvs. Oso Grande, Tudla e Chandler demonstram que a presenca da abelha jatai na polinizacao em ambiente protegido contribui para o aumento da produtividade. A cv. Dover e a que se mostrou menos dependente de agentes polinizadores. A presenca de abelhas eleva a porcentagem de frutos comerciaveis. A recomendacao e da utilizacao de quatro colmeias de Tetragonisca angustula para cada 170 m2 de area protegida.

Influence of shade and irradiation time on the hardness of composite resins

This study tested the following hypotheses: 1. increasing light irradiation time (IT) produces greater values of superficial hardness on different depths (0 and 3 mm); and 2. a dark shade composite (A3) needs longer IT than a light shade composite (A1) to produce similar hardness. Disk-shaped specimens (n=24 per shade) were fabricated using a 3-mm-thick increment of composite resin (Z100). Specimens were randomly assigned to 3 groups (n=8) according to the IT (400 mW/cm2) at the upper (U) surface: A1-10 and A3-10: 10 s; A1-20 and A3-20: 20 s; A1-40 and A3-40: 40 s. Specimens were stored in black lightproof containers at 37 masculineC for 24 h before indentation in a hardness tester. Three Vickers indentations were performed on the U and lower (L) surfaces of each specimen. The indent diagonals were measured and the hardness value calculated. The results were analyzed statistically by ANOVA and Tukeys test (alpha=0.05). Statistically significant differences were found between U and L surfaces of each composite shade-IT combination (p=0.0001) and among the ITs of same shade-surface combination (p=0.0001), except between groups A1-20U and A1-40U, confirming the study hypothesis 1 and partially rejecting the hypothesis 2.

Fluoride Release from Restorative Materials

The aim of this study was to evaluate in vitro fluoride (F) release from 4 restorative materials (3M ESPE): Ketak Molar Easymix [KME - conventional glass ionomer cement (GIC)]; Rely-X luting 2 [RL2 - resin-modified GIC (RMGIC)]; Vitremer (VIT- RMGIC); and Filtek Z250 [Z250 - negative control]. Disc-shaped specimens were fabricated according to the manufacturers instructions and placed into 10 mL of reverse osmosis water at 37°C until the analyses were done using a liquid membrane for selective F ion electrode (Orion 710). F release was evaluated every 6 h in the first day and thereafter daily during 28 days (d). The results were analyzed statistically by two-way ANOVA and Tukeys test (α=0.05). Mean F release and standard deviation values (in ppm) were: KME: 6 h- 0.34 ± 0.04; 24 h- 1.22 ± 0.30; 7 d- 0.29 ± 0.09; 14 d- 0.20 ± 0.04; 28 d- 0.16 ± 0.01; RL2: 6 h- 2.46 ± 0.48; 24 h-12.33 ± 2.93; 7 d- 1.37 ± 0.38; 14 d- 0.80 ± 0.13; 28 d- 0.80 ± 0.21; VIT: 6 h- 0.98 ± 0.35; 24 h- 4.35 ± 1.22; 7 d- 0.66 ± 0.23; 14 d- 0.40 ± 0.07; 28 d- 0.39 ± 0.08; Z250: 6 h- 0.029 ± 0.001; 24 h- 0.024 ± 0.009; 7 d- 0.023 ± 0.004; 14 d- 0.025 ± 0.001; 28 d- 0.028 ± 0.001. RL2 RMGIC released more F than the other materials in all periods. The greatest release of F occurred in the first 24 h.

Desempenho de leguminosas nativas (Adesmia) e exóticas (Lotus, Trifolium), em função do estádio fenológico no primeiro corte

This work had the objective to evaluate phenological and productive aspects of native (Adesmia latifolia, A. tristis) and exotics legumes (Lotus corniculatus, L. uliginosus, Trifolium repens) as for the phenological stage on first-cutting: vegetative (CEV) and flowering (CEF). The plants were established as monoculture in the field and evaluated between May/2000 and September/2001, in Passo Fundo, Rio Grande do Sul. After the first cutting the plants were defoliated in 45 days intervals. There were nine cuttings in CEV-management and seven in the CEF-management. The phenological stage on first-cutting modified significantly (P<0,05) the dry matter (DM) production of T. repens (CEV = 9.000 kg/ha of DM, CEF = 7.000 kg/ha of DM) and A. tristis (CEV = 4.000 kg/ha of DM, CEF = 8.000 kg/ha of DM). L. corniculatus produced about 15.000 kg/ha of DM and A. latifolia, 2.000 to 3.000 kg/ha of DM, regardless the management. L. uliginosus did not flowered, producing 7.000 kg/ha of DM in the CEV-management. The native legumes showed poor persistence with death of the plants (A. tristis) and stolons (A. latifolia) at the end of the growing season. The highest production of the T. repens was in the spring and for the Lotus species, in the summer.

Comportamento de leguminosas (Adesmia, Lotus, Trifolium) em mistura com festuca

Overseeding temperate legumes is one of the most practices to increase the quantity, quality and sustainability of perennial pastures in Southern Brazil. During the years of 2000 and 2001 the response of six temperate legumes (Adesmia latifolia (wild), Lotus corniculatus, L. subbiflorus, L. uliginosus and Trifolium repens cv. Yi and cv. Regal) was evaluated in mixture with tall fescue (Festuca arundinacea). There was a period of 475 days between sowing date and the last cut and six cuts were made; on the autumn-winter/2000 only one cut was made, on the spring-summer, three cuts and on the autumn-winter/2001, two cuts. The intervals between cuts ranged between 43 and 91 days, being reduced in the warm season. During the total assay period, the average of the mixtures yielded 15038 kg/ha of DM; in the warm season 54% of this total was produced, with an average growth rate of 46 kg/ha/day of DM. In the cold season of 2000 and 2001 this rate was of 22 and 24 kg/ha/day of DM. The birdsfoot trefoil and white clover cv. Yi were the most productive legumes; the former was the best in the warm season (3500 kg/ha of DM) and the last participated with 86,3% in the mixture in the autumn-winter/2001, with 2300 kg/ha/day of DM. The mixtures containing these legumes presented the smallest quantity of weeds and produced 13663 and 11,184 kg/ha of DM respectively, being 82% and 71% of these totals composed of legumes, fescue and ryegrass. A. latifolia did not have a good establishment and its contribution was only 0,84% in the first cut. The L. subbiflorus had a good establishment on the first year, but it disappeared from the mixture in the second year. L. uliginosus had a good establishment and persistence producing up to 1400 kg/ha of DM in the autumn/2001.

Perfil socioeconômico dos feirantes e consumidores da Feira do Produtor de Passo Fundo, RS

Though the Passo Fundo farmers market has been in existed for over 22 years, the social and economic status of farmers and consumers attended has not been documented yet. Consequently, this study sought to provide the first detailed socioeconomic profile of farmers and consumers that participate in the market. Questionnaires were administered to 58 farmers that hold permanent stalls at the market and another to 471 consumers. The questionnaires had queries regarding the socioeconomic aspects of farmers and consumers, and products offered/purchased at the market, such as, vegetables, fruits, grains, products of animal origin, and handicrafts. While most consumers ranged from 35 to 65 years of age, farmers tended to be between 40 and 55 years old. One-third of farmers had a familiar nucleus composed of up to three people and most had completed elementary school. Nearly 80% of farmers reported a monthly income of under 1,000 Brazilian Reais (R

Porosidade e retenção de água em um argissolo sob manejos convencional e direto submetido a compressões unidimensionais

), or roughly

Efeito do Soil-borne wheat mosaic virus sobre o metabolismo de cinco genótipos de trigo com diferentes níveis de resistência à doença

620 US. Typical consumers of the Passo Fundo Farmers market are of the middle to lower (B2, C and D) social classes. Roughly 60% of them declared monthly incomes between 500 and 2000 R

Triângulo de Bonwill e sua relação com o gênero e o tipo de oclusão dos pacientes

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