Lazer: significados e ressonâncias da educação não-formal do idoso

Pós-graduação em Ciências da Motricidade - IBRC

Ploidy, sex and crossing over in an evolutionary aging model

Nowadays, many forms of reproduction coexist in nature: Asexual, Sexual, apomictic and meiotic parthenogenesis, hermaphroditism and parasex. The mechanisms of their evolution and what made them successful reproductive alternatives are very challenging and debated questions. Here, using a simple evolutionary aging model, we give I possible scenario. By studying the performance of Populations where individuals may have diverse characteristics-different ploidies, sex with or without crossing over, as well as the absence of sex-we find all evolution sequence that may explain why there are actually two major or leading groups: Sexual and asexual. We also investigate the dependence of these characteristics on different conditions of fertility and deleterious mutations. Finally, if the primeval organisms oil Earth were, in fact, asexual individuals we conjecture that the sexual form of reproduction could have more easily been set and found its niche during a period of low-intensity mutations. (c) 2005 Elsevier B.V. All rights reserved.

Electrical conductivity as an indicator of pea seed aging of stored at different temperatures

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

Accelerated aging and seedling field emergence in soybean

Informações sobre a relação entre resultados de testes de vigor conduzidos em laboratório e da emergência de plântulas em campo são fundamentais para a tomada de decisões pelos produtores de sementes. O presente trabalho teve por objetivo verificar a associação entre os resultados do teste de envelhecimento acelerado e a emergência de plântulas de soja [Glycine max (L.) Merrill] em campo, em diferentes safras agrícolas e épocas de semeadura. Assim, foram efetuadas as seguintes avaliações: determinação do grau de umidade das sementes; testes de germinação, de envelhecimento acelerado e de condutividade elétrica, bem como emergência de plântulas em campo. A estimativa mais precisa do desempenho das plântulas em campo foi verificada numa faixa de valores de envelhecimento acelerado > 90%, estimando emergência em campo superior a 80% (r² = 0,90). O teste de envelhecimento acelerado permitiu avaliar a emergência de plântulas de soja em campo. No entanto, à medida que as condições ambientais do local de semeadura foram desviando-se das mais adequadas, a eficiência decresceu.

Bark and ambrosia beetle (Coleoptera : Scolytidae) responses to volatiles from aging loblolly pine billets

Many species of bark and ambrosia beetles use host volatiles as cues for breeding site location. In a study where the objectives were to identify the different volatiles released by Pinus taeda L. billets as they age, to determine the arrival sequence of scolytids (Colcoptera: Scolytidae), and to correlate volatile emission by the billets with beetle catches, 25 species of scolytids were trapped. Bark beetles were more attracted to the billets in the beginning of the period. whereas ambrosia beetles arrived later. Among the bark beetles, Dendroctonus terebrans (Olivier) was significantly more attracted during the Ist 3 wk after tree felling, Hylastes tenuis Eichhoff in the Ist 2 wk. Pityophtorus pulicarius (Zimmermann) in weeks 2 and 3, and Ips grandicollis (Eichhoff) was more attracted on weeks 3 and 4. Among the ambrosia beetles, Xyleborinus saxeseni (Ratzeburg) was more attracted to billets during weeks 4-6, whereas Xyleborus pubescens Zimmermann and Xyleborus californicus Wood were more attracted during week 6. The billets showed marked decline in attractiveness to all scolytids after 8 wk. Volatiles collected during the beetle trapping periods included 15 hydrocarbon monoterpenes, 18 oxygenated monoterpenes, 4-allylanisole, and ethanol. The hydrocarbon monoterpenes and 4-allylanisole decreased sharply over time, but oxygenated monoterpenes and ethanol increased up to weeks 4-6, after which they also decreased. Good correlations between certain billet volatiles and catches for some beetle species were obtained, but their biological significance could not be determined.

Temporal relationship between successful pancreas transplantation and control of ocular complications in alloxan-induced diabetic rats

Purpose. The impact of pancreas transplantation (PT) on the progression of eye disease is still controversial. This study evaluated the course of retinopathy in transplanted rats in two different diabetic stages.Methods. Sixty inbred male Lewis rats were assigned to four experimental groups: NC-15 nondiabetic control rats; DC-15 untreated diabetic control rats; PT1-15 diabetic rats that received syngeneic pancreas transplants 2 weeks after alloxan diabetes induction; PT2-15 diabetic rats that received pancreas transplants 12 weeks after diabetes onset. Clinical and laboratory parameters and tens opacity were examined in all rats prior to treatment and at 1-, 6-, and 12-months follow-up. Nucleated eyes from five rats in each group processed for ultrastructural study of the retinal at 6 and 12 months after PT or at follow-up.Results. Cataracts were observed in 20%, 60%, and 100% of DC rats at 1-, 6-, and 12-months follow-up, respectively. Early PT (2 weeks) significantly reduced the prevalence of this complication but not late (12 weeks) PT. PT1 rats also showed improved ultrastructure of the superficial and deep capillary plexuses of the retina, and of Muller cells, compared with DC and PT2. In the last group, retinopathy continued to evolve despite successful PT.Conclusion. Our results suggested that prevention of diabetic ocular lesions by PT was closely dependent on earlier performance of the procedure.

COLOR STABILITY of SEALED COMPOSITE RESIN RESTORATIVE MATERIALS AFTER ULTRAVIOLET ARTIFICIAL AGING and IMMERSION IN STAINING SOLUTIONS

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

Effect of Artificial Aging on the Roughness and Microhardness of Sealed Composites

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

Effect of Chemical Disinfection and Accelerated Aging on Color Stability of Maxillofacial Silicone with Opacifiers

Purpose: The purpose of this study was to evaluate the color stability of MDX4-4210 maxillofacial elastomer with opacifier addition submitted to chemical disinfection and accelerated aging.Materials and Methods: Ninety specimens were obtained from Silastic MDX4-4210 silicone. The specimens were divided into three groups (n = 30): Group I: colorless, Group II: barium sulfate opacifier, Group III: titanium dioxide opacifier. Specimens of each group (n = 10) were disinfected with effervescent tablets, neutral soap, or 4% chlorhexidine gluconate. Disinfection was conducted three times a week for 2 months. Afterward, the specimens were submitted to different periods of accelerated aging. Color evaluation was carried out after 60 days (disinfection period) and after 252, 504, and 1008 hours of accelerated aging, using a reflection spectrophotometer. Color alterations were calculated by the CIE L*a*b* system. Data were analyzed by three-way ANOVA and Tukey test (alpha = 0.05).Results: Group II exhibited the lowest color change, whereas Group III the highest (p < 0.05), regardless of the chemical disinfection and accelerated aging periods.Conclusion: Opacifier addition, chemical disinfection, and accelerated aging procedures affected the color stability of the maxillofacial silicone.

Effect of polymerization and accelerated aging on iris color stability of ocular prosthesis

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

Effects of pigment, disinfection, and accelerated aging on the hardness and deterioration of a facial silicone elastomer

The failure of facial prostheses is caused by limitations in their flexibility and durability. Therefore, we evaluated the effects of disinfection and aging on Shore A hardness and deterioration of a facial silicone with different pigmentations. Twenty samples with addition of each pigment (ceramic (C), make-up (M)) and without pigment (L) were made. For each pigment type and no pigment, 10 samples were subjected to two types of disinfectant solution (soap (S) and Efferdent (E)), totaling sixty samples. The specimens were disinfected three times per week for 60 days, and subjected to accelerated aging for 1008 h. The hardness of the facial silicone was measured with a durometer, and its deterioration was evaluated by obtaining the weight difference over time. Both the hardness and weight of the samples were measured at baseline, after chemical disinfection, and periodically during accelerated aging (252, 504, and 1008 h). Deterioration was calculated during the periods between baseline and chemical disinfection, and between baseline and each aging period. The results were analyzed using three-way repeated measures ANOVA and the Tukey's HSD Post-hoc test (alpha = 0.05). Specifically, samples containing pigment exhibited significantly higher hardness and deterioration values than those lacking pigment (P < 0.05). In addition, period of time (disinfection and accelerated aging) statistically increased the hardness and deterioration values of the silicone (P < 0.05). It can be concluded that both pigment and time statistically affected the hardness and deterioration of the silicone elastomer. (c) 2012 Elsevier Ltd. All rights reserved.

Effect of Disinfection and Accelerated Aging on Color Stability of Colorless and Pigmented Facial Silicone

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Chromatic stability of acrylic resins of artificial eyes submitted to accelerated aging and polishing

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Alteration of blue pigment in artificial iris in ocular prosthesis: Effect of paint, drying method and artificial aging

The artificial iris is the structure responsible for the dissimulation and aesthetics of ocular prosthesis. The objective of the present study was to evaluate the color stability of artificial iris of microwaveable polymerized ocular prosthesis, as a function of paint type, drying method and accelerated aging. A total of 40 discs of microwaveable polymerized acrylic resin were fabricated, and divided according to the blue paint type ( n = 5): hydrosoluble acrylic, nitrocellulose automotive, hydrosoluble gouache and oil paints. Paints where dried either at natural or at infrared light bulb method. Each specimen was constituted of one disc in colorless acrylic resin and another colored with a basic sclera pigment. Painting was performed in one surface of one of the discs. The specimens were submitted to an artificial aging chamber under ultraviolet light, during 1008 h. A reflective spectrophotometer was used to evaluate color changes. Data were evaluated by 3-way repeated-measures ANOVA and the Tukey HSD test (alpha = 0.05). All paints suffered color alteration. The oil paint presented the highest color resistance to artificial aging regardless of drying method. (C) 2010 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

Color stability of maxillofacial silicone with nanoparticle pigment and opacifier submitted to disinfection and artificial aging

The purpose of this study was to evaluate the color stability of a maxillofacial elastomer with the addition of a nanoparticle pigment and/or an opacifier submitted to chemical disinfection and artificial aging. Specimens were divided into four groups (n = 30): group I: silicone without pigment or opacifier, group II: ceramic powder pigment, group III: Barium sulfate (BaSO(4)) opacifier, and group IV: ceramic powder and BaSO(4) opacifier. Specimens of each group (n = 10) were disinfected with effervescent tablets, neutral soap, or 4% chlorhexidine gluconate. Disinfection was done three times a week during two months. Afterward, specimens were submitted to different periods of artificial aging. Color evaluation was initially done, after 60 days (disinfection period) and after 252, 504, and 1008 h of artificial aging with aid of a reflection spectrophotometer. Data were analyzed by three-way ANOVA and Tukey test (alpha = 0.05). The isolated factor disinfection did not statistically influence the values of color stability among groups. The association between pigment and BaSO(4) opacifier (GIV) was more stable in relationship to color change (Delta E). All values of Delta E obtained, independent of the disinfectant and the period of artificial aging, were considered acceptable in agreement with the norms presented in literature. (C) 2011 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.3625401]