ABSTRACT
ABSTRACT The accelerated aging process is incorporated into the design and development of intravascular catheters to assess their reliability assuring that this medical device is safe and effective for the intended use during their shelf life. The accelerated aging process is based on a common approach that assumes that the rate of aging increases by a factor of 2^(∆T/10), where ∆T is the temperature increment. However, with the life data obtained from this empirical method is difficult to do inferences about reliability. This paper presents an accelerated destructive degradation test using thermal stress to obtain degradation data directly relates reliability to critical performance characteristic, which is the tensile strength in the intravascular catheter tip considered as a critical concern in patients' safety. The degradation data model is given by a stochastic Wiener process with the drift parameter being represented as Arrhenius function. The parameters of the Wiener process and Arrhenius function are estimated using maximum likelihood; these parameters are used to estimate the first-passage time (time to failure) distribution when the intravascular catheters degradation path reaches a tensile strength critical value in each thermal stress level. Based on this, a complete product reliability assessment is performed and presented.
RESUMEN El proceso de envejecimiento acelerado es incorporado en el diseño y desarrollo de catéteres intravasculares para evaluar su confiabilidad y asegurar que el dispositivo medico es seguro y efectivo para su uso durante su vida de estante. Este proceso está basado en un enfoque que asume que la tasa de envejecimiento se incrementa por un factor de 2^(∆T/10), en donde ∆T es el incremento de temperatura. Sin embargo, con los datos de vida obtenidos de este método empírico resulta complicado realizar inferencias sobre la confiabilidad del dispositivo. Este articulo presenta una prueba de degradación acelerada destructiva que considera un estrés termal para obtener datos de degradación que se relaciona directamente la confiabilidad con la resistencia tensil de la punta de un catéter intravascular y que es considerada como una característica critica para la seguridad de los pacientes. El modelo de degradación esta dado por un proceso estocástico Wiener, con el parámetro de deriva representado la relación de Arrhenius. Los parámetros del proceso Wiener y la relación de Arrhenius son estimados mediante máxima verosimilitud; estos parámetros son usados para estimar la distribución de primer paso, la cual se caracteriza cuando la resistencia de un catéter alcanza el nivel crítico de resistencia en cada nivel de estrés. Considerando esto, se lleva a cabo y se presenta una evaluación de confiabilidad completa del producto.
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Objective: The objective of the present in-vitro study was to verify the efficacy of two spectrophotometer-based shade matching systems for color matching of ceramics after artificial accelerated aging (AAA). Material and Methods: The ceramics used were porcelain laminated veneers. Seventy standard-shaped discs (thickness x diameter: 0.5 mm x 10 mm) of B1 shades were used. Based upon the type of resin cement used, the specimens were divided into seven groups (10/group). The following light-cured cements were used: RelyX-Veneer (L-RV), Variolink-Veneer (L-VV), and Variolink-Esthetic (L-VE). The dual-cured cements were: RelyX Ultimate (D-RU), RelyX-Unicem (D-RC), and Variolink-Esthetics DC (D-VE). The control group consisted of ceramic only. All specimens were thermocycled in water for 3,500 cycles between 5 oC -55 oC, with dwell times of 30 s in each bath and a transfer time of 10 s between baths. All specimens were thermocycled in water for 3,500 cycles between 5 oC and 55 oC, and color measurement was done using the VITA Easyshade and ColorEye spectrophotometers. Baseline color reading was performed 24-hours after cementation. Differences in color (DE) of EasyShade and ColorEye before and after AAA were determined and compared statistically. Group comparisons were done using the paired t-tests. Level of significance was set at P< 0.05. Results: The mean differences in color (ΔE) values obtained from EasyShade spectrophotometer for light- and dual-cured cements, were 0.843±0.89 (L-RV ), 4.11±0.69 (L-VV) and 0.833±0.47 (L-VE); and 2.22±0.64 (D-RU), 3.37±0.83 (D-RC) and 0.38±0.92 (D-VE), respectively. The mean differences in color (ΔE) values obtained from ColorEye spectrophotometer for light- and dual-cured cements, were 0.68±0.86 (L-RV ), 4.55±0.83 (L-VV) and 2.68±0.26 (L-VE); and 2.06±0.84 (D-RU), 1.8±1.08 (D-RC) and 0.96±0.71 (D-VE), respectively. There was no significant difference in the mean DE values among the groups. Conclusion: The VITA Easyshade and ColorEye shade matching systems are comparable in terms of their efficacy for color matching of cerammics after AAA.(AU)
Objetivos: O objetivo do presente estudo in vitro foi verificar a eficácia de dois espectrofotômetros baseados em escalas de cor para avaliação de cor de cerâmicas após envelhecimento artificial acelerado (EAA). Material e Métodos: As cerâmicas utilizadas foram laminados cerâmicos. Foram usados setenta discos de formato padrão (0,5mm de espessura x 10 mm de diâmetro) de tonalidades B1. Com base no tipo de cimento resinoso utilizado, os corpos-de-prova foram divididos em sete grupos (10 / grupo). Foram utilizados os seguintes cimentos fotopolimerizáveis: RelyX-Veneer (L-RV), Variolink-Veneer (L-VV) e Variolink-Esthetic (L-VE). Os cimentos de cura dual foram: RelyX Ultimate (D-RU), RelyX-Unicem (D-RC) e Variolink-Esthetics DC (D-VE). O grupo controle consistia apenas de cerâmica. Todos os corpos-de-prova foram termociclados em água por 3.500 ciclos entre 5oC-55oC, com tempos de permanência de 30s em cada banho e um tempo de transferência de 10s entre os banhos. A medição da cor foi feita usando os espectrofotômetros VITA Easyshade e ColorEye. A leitura da cor inicial foi realizada 24 horas após a cimentação. As diferenças na cor (ΔE) do EasyShade e ColorEye antes e depois do EAA foram determinadas e comparadas estatisticamente. As comparações dos grupos foram feitas usando o teste t pareados. O nível de significância foi estabelecido em p <0,05. Resultados: os valores médios de diferenças na cor (ΔE) obtidos no espectrofotômetro EasyShade para cimentos fotopolimerizáveis e duais foram de 0,843 ± 0,89 (L-RV), 4,11 ± 0,69 (L-VV) e 0,833 ± 0,47 (L-VE ); e 2,22 ± 0,64 (D-RU), 3,37 ± 0,83 (D-RC) e 0,38 ± 0,92 (D-VE), respectivamente. os valores médios de diferenças na cor (ΔE) obtidos no espectrofotômetro ColorEye para cimentos fotopolimerizáveis e duais foram de 0,68 ± 0,86 (L-RV), 4,55 ± 0,83 (L-VV) e 2,68 ± 0,26 (L-VE); e 2,06 ± 0,84 (D-RU), 1,8 ± 1,08 (D-RC) e 0,96 ± 0,71 (D-VE), respectivamente. Não houve diferença significativa nos valores médios de ΔE entre os grupos. Conclusão: Os sistemas de combinação de cores VITA Easyshade e ColorEye são comparáveis em termos de eficácia para avaliação de cores de cerâmicas após EAA. (AU)
Subject(s)
In Vitro Techniques , Spectrophotometers , Dental Materials , Dental VeneersABSTRACT
The objective of this work is to evaluate the influence of accelerated aging test at 41ºC on the germination and seed vigor of Piptadenia moniliformisBenth. Two experiments were conducted. Experiment 1: seeds were submitted to dormancy overcoming treatments. They were immersed into sulfuric acid for 0 (intact seeds), 5, 10, 15, 20 and 25 minutes. Experiment 2: two methods were evaluated for the accelerated aging test at 41ºC, that is, the traditional method and the saturated NaCl solution method with exposure periods of 0, 24, 48, 72 and 96 hours. After each treatment, the seeds were subjected to electrical conductivity and germination tests. Seeds overcame their dormancy when immersed into concentrated sulfuric acid for 5, 10, 15, 20 or 25 minutes, but thegermination was faster when immersed for 20 minutes. The different methods for the accelerated aging test, decreased the germination potential and seed vigor of P. moniliformisafter 24 hours of exposure. Regarding the method used, the saturated solution provided, in general, the best results since the seed water content was lower, thus reducing the proliferation of fungi. The electrical conductivity test showed that, by increasing the aging period regardless of the method, there is an increase in seed deterioration, corroborating with germination results, which showed that the correlation was moderate and negative and indicated that the higher the conductivity, the lower the percentage and the germination speed index. The immersion of seeds of P. moniliformisinto concentrated sulfuric acid for 20 minutes provides a fast and increased germination. The methods for accelerated agingat 41ºC, traditional and saturated solution, can be used as vigor tests to evaluate the physiological quality of seeds.
Subject(s)
Aging , Fabaceae/anatomy & histology , Fabaceae/physiology , Fabaceae/chemistry , Heat-Shock ResponseABSTRACT
Full arch models play an important role in clear aligner orthodontic therapy and the preparation of prosthodontic appliances. Three dimensional (3D) printed full arches are very popular with the benefit of easy production and good mechanical properties for fabricating clear aligner. However, the accuracy of 3D printed full arches after long storage have not been proved yet. The objective of this study was to estimate the long-term accuracy of 3D full arches produced by the four types of 3D printers (stereo-lithography apparatus (SLA), digital light projector (DLP), Polyjet™ (POL), and fused deposition modeling (FDM)) following an accelerated aging treatment. The highest accuracy was produced by POL (before treatment) and SLA (after treatment) group, respectively. Comparisons between absolute mean trueness for the 3D printed full arches before and after treatment indicated that the deviation of the trueness values of FDM group were significantly higher than those of other experimental groups (p<0.05). In addition, all trueness relative errors for FDM group were greater than 0.04 after treatment, which was high compared to those of other experimental groups. Therefore, the long-term storage of full arches fabricated by FDM type 3D printer is not recommended and the 3D printed full arches should be used immediately whenever possible.
Subject(s)
Aging , Printing, Three-DimensionalABSTRACT
Objective Few studies are reported on the aging of veneering ceramics. This study was to investigate the effects of aging on surface roughness, composition and hardness of veneering ceramics for zirconia frameworks.Methods Twenty specimens were fabricated with each of the five types of veneering ceramics for zirconia frameworks － Vintage ZR (ZR), Cerabien ZR (CZR), VitaVM9 (VM9), Cercon ceram KISS (KISS) and IPS e.max ceram (e.max). The specimens were randomly divided into an aging and a control group of equal number, the former subjected to accelerated aging at 200 ℃ and 2 atm for 5 hours while the latter left untreated. The surface roughness and Vickers hardness of the specimens were measured using laser profilometry and Vicker's indentation test machine and their surface topography and chemical composition examined by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS).Results Compared with the control group, the aged specimens fabricated with ZR showed significantly increased surface roughness parameters Ra (\[0.157±0.009\] vs \[0.197±0.008\] μm, P=0.000), Rp (\[0.356±0.031\] vs \[0.446±0.036\] μm, P=0.000) and Rv (\[0.411±0.034\] vs \[0.498±0.036\] μm, P=0.000), and so did those fabricated with CZR, VM9 and KISS (P=0.000). The Ra, Rp and Rv parameter values of the aged specimens with CZR were remarkably higher than those with VM9, KISS and e.max (P < 0.001), but those of the aged specimens with e.max markedly lower than those with ZR, CZR, VM9 and KISS (P<0.01). The RSm value was significantly higher in all the aged specimens than in the control (P<0.001), and so was the oxygen content (P<0.05), but the levels of sodium and potassium were lower in the former than in the latter group (P<0.05). Compared with the control group, the silicon content was significantly decreased in the aged specimens with ZR, KISS and e.max (P<0.01), and so was that of calcium in those with ZR and VM9 (P<0.05). The Vickers hardness of the aged specimens with ZR was remarkably lower than that of the control (\[5.01±0.28\] vs \[6.91±0.51\] GPa, P=0.000), and so was that of the other aged specemens (P=0.000).Conclusion Accelerated aging can significantly alter the surface properties, enhance the stability and prolong the working life of veneering ceramics for zirconia frameworks.
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Maxillofacial prostheses need frequent refabrication due to degradation of color and deterioration of physical properties of the elastomer. Aims: This study attempted to evaluate the change in color stability, Shore A hardness, and surface roughness of two maxillofacial silicones, A-2186 and Cosmesil M511, when submitted to chemical disinfection and accelerated aging. Settings and Design: This was a comparative in vitro study. Subjects and Methods: The materials included two silicone elastomers – A-2186 and Cosmesil M511 (Factor II Incorporated) – functional intrinsic red pigment and three disinfectants – Fittydent tablet, chlorhexidine gluconate 4%, and neutral soap. The specimens in each group of elastomer were evaluated initially for color, hardness, and surface roughness, which were further divided into subgroups and subjected to disinfection and accelerated aging. The evaluation of color was performed with the help of an ultraviolet reflectance spectrophotometer. Shore A hardness was evaluated using a durometer and surface roughness, with a digital roughness tester followed by scanning electron microscopy analysis. Statistical Analysis Used: Analysis of variance and Tukey's multiple comparison test were used for statistical analysis. Results: Accelerated aging caused a significant decrease in color, increase in Shore A hardness, and variation in surface roughness in both silicone elastomer groups. Chemical disinfection presented significant changes in color and surface roughness whereas no significant effect on Shore hardness, irrespective of the disinfectant used. Conclusions: The maxillofacial silicone elastomers presented deterioration in color, hardening, and significant variations in surface roughness when subjected to chemical disinfection and accelerated aging, which provides a valid baseline for future research.
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Objetivou-se com este trabalho avaliar o desempenho de sementes de oito genótipos de Carica papaya L. antes e após o envelhecimento acelerado. Foram avaliadas as características físicas: umidade, comprimento, diâmetro e peso de mil sementes. Sementes não envelhecidas (controle) e sementes submetidas ao envelhecimento acelerado (43 ºC por 72 h) foram semeadas em rolo de papel germitest e mantidas em BOD a 20-30 ºC. Foram avaliadas: porcentagem e frequência de germinação, índice de velocidade de germinação, tempo médio de germinação e porcentagem de plantas normais. Após 30 dias da semeadura foram avaliados comprimentos da parte aérea e da raiz, massas fresca e seca das plântulas. Em sementes não envelhecidas, o genótipo Caliman 01 apresentou maiores porcentagem, velocidade e homogeneidade de germinação, e maior porcentagem de plântulas normais. As sementes do Híbrido JS12 x Waimanalo apresentaram maior vigor após o envelhecimento (84% de germinação e 93% de plântulas normais). A análise de diversidade identificou como dissimilares os genótipos Caliman 01 em sementes não envelhecidas e o Híbrido JS12 x Waimanalo em sementes após o envelhecimento. Estes genótipos apresentam maior desempenho com base nas características físicas e fisiológicas das sementes e na análise de diversidade nas respectivas condições. O tempo médio de germinação é a característica que mais contribui para a separação dos genótipos em sementes não envelhecidas enquanto, em sementes envelhecidas, é o comprimento de raiz.
The objective of this study was to evaluate the seeds performance in eight Carica papaya genotypes, before and after accelerated aging test. We evaluated the seeds physical characteristics: humidity, length, diameter and weight of thousand seeds. Not aging seeds (control) and seeds subjected to accelerated aging test (43 º C for 72 h) were germinates in paper roll germitest and maintained in BOD at 20-30 º C. From the daily count, was evaluated the germination percentage and frequency, the speed of germination index, germination time, and the normal plants percentage. After 30 days of culture were evaluated lengths of shoot and root, fresh and dry weight of seedlings. In control seeds, the Caliman 01 genotype had higher percentage, speed and uniformity of germination, and higher normal seedlings percentage. Seeds of the Hybrid JS12 x Waimanalo genotype showed higher vigor after aging (84% of germination and 93% of normal seedlings). The diversity analysis identified as dissimilar the Caliman 01 genotype in control seeds and the Hybrid JS12 x Waimanalo genotype in after aging seeds. This genotypes have higher performance based on assessments of physical and physiological quality of seeds and diversity analysis in this conditions. The germination time was the feature that most contributes to the separation of genotypes in control seeds, and the root length in after aging seeds.
Subject(s)
Seeds , Multivariate Analysis , Germination , CaricaABSTRACT
Objective:To observe the effects of aging performance on the property of dental zirconia sintered by microwave furnace and conventional furnace.Methods:48 zirconia wafer specimens were fabricated and randomly divided equally into 2 groups.The samples were sintered in a microwave furnace(Mgroup)and a conventional furnace(C group)respectively.The samples from the 2 groups were divided into 2 sub-groups and treated by room temperature and dry condition(A group)and 1 34 ℃ with 0.2 MPa pres-sure(B group,accelerated aging)respectively.The m phase fraction of the samples was determined by X-ray diffraction analysis.The biaxial flexural strength was examined by universal testing machine.The fracture cross section was observed by SEM.Results:CB and MB groups showed higher m phase fraction than CA and MA groups(P 0.05).Conclusion:The aging perform-ance of zircinia sintered by microwave method were similar to that sintered by conventional method.
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Este estudo avaliou a alteração de cor do silicone Ortho Pauher, tendo como padrão ouro o silicone MDX 4 - 4210, frente ao envelhecimento e à pigmentação. Foram obtidos sessenta espécimes para cada material, os quais receberam pigmentação intrínseca ou pigmentação intrínseca e extrínseca. Como pigmento, foi utilizado pó de maquiagem. Os espécimes foram distribuídos aleatoriamente em três grupos e submetidos ao envelhecimento ou por termociclagem, luz ultravioleta ou para compor o grupo controle. Como controle, espécimes foram mantidos em um recipiente hermeticamente fechado na ausência de luz. O envelhecimento simulou um período de uso de 12 meses. Os testes ANOVA e Tukey (p < 0,05) indicaram diferença significante entre o grupo controle e osgrupos envelhecidos por termociclagem e luz ultravioleta, sendo que estes se mostraram iguais. Em relação aos materiais, não houve diferença entre eles. Houve diferença entre as pigmentações. Na interação, o Ortho Pauher sofreu maior variação de cor causada pela luz ultravioleta, enquanto o MDX, pela termociclagem. Comparando-seos materiais com pigmentação intrínseca, nos três grupos de envelhecimento houve diferença entre o controle e a luz ultravioleta, sendo que a maior alteração foi encontrada para o Ortho Pauher. Para os materiais com pigmentação intrínseca e extrínseca, houve diferença nos três grupos de envelhecimento, com maior variação para o MDX.Notam-se comportamentos distintos dos materiais em função da pigmentação e do envelhecimento, devendo-se considerar a associação entre material, tipo de pigmento e tipo de exposição para que se faça a indicação clínica corretamente, podendo-se considerar o Ortho Pauher na confecção de próteses maxilofaciais.
This study evaluated the color change of the silicone Ortho Pauher, with the standard gold silicone MDX 4 - 4210, facing the aging and pigmentation. Sixty specimens were obtained for each material, which received intrinsic or intrinsic and extrinsic pigmentation. Powder makeup was used as pigment. The specimens were randomly dividedinto three groups and subjected to aging or thermal cycling, ultraviolet light or to compose the control group. As control, specimens were kept in an airtight container in the absence of light. Aging simulated a period of 12 months. ANOVA and Tukey tests (p < 0.05) indicated a significant difference between control group and the groups aging by thermal cycling and ultraviolet light, which were equal. In relation to materials, there was no difference between them. There was a difference between pigmentation. In the interaction, Ortho Pauher suffered major color changescaused by ultraviolet light, while the MDX, by thermocycling. Comparing the materials with intrinsic pigmentation, the aging in the three groups was difference between control and ultraviolet light, and the greatest change was found for the Ortho Pauher. For materials with intrinsic pigmentation and extrinsic, there were differences between the three groups of the aging, with greater variation for the MDX. Note the different behavior of materials as a function of pigmentation and aging, one should considered the relationship between material, pigment type and type ofexposure in order to do properly the clinical indication, and may be considered silicone Ortho Pauher in making of the maxillofacial prosthesis.
Subject(s)
Silicones , Ultraviolet Rays , Aging , Pigmentation , Analysis of Variance , Color , Maxillofacial ProsthesisABSTRACT
Este trabalho foi desenvolvido com o objetivo de ajustar um modelo de regressão não-linear para estimar o desempenho germinativo de sementes de três lotes comerciais de milho híbrido OC 705, submetidas ao teste de envelhecimento acelerado, à temperatura de 43ºC. Utilizou-se o modelo logístico y(t)=C/(1+exp(B(t-M))) para ajustar os dados. As medidas de viés de Box e de curvaturas paramétrica e intrínseca foram usadas para o diagnóstico do modelo. O modelo proposto ajusta-se adequadamente aos dados de percentuais germinativos de sementes de milho híbrido OC 705, para todos os lotes. Com base nas estimativas dos parâmetros e qualidade de ajuste, o lote três foi identificado como sendo o melhor para comercialização, por apresentar menor redução no poder germinativo ao longo do tempo.
This research was developed with the goal to adjust a nonlinear regression model to estimate seed germination performance of three commercial seed lots of hybrid maize OC 705, subjected to accelerated aging test at a temperature of 43oC. The logistic model y(t)=C/(1+exp (B (t-M))) was used to fit the data. Measures of bias Box and parametric intrinsic bends were used for the diagnosis of the model. The proposed model fits properly to seed germination percentage data of hybrid corn seeds for OC 705, for all seed lots. Based on estimates of the parameters and fit quality, the seed lot three was identified as being the best for marketing, by presenting less reduction in seed germination power over time.
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Dentro de um programa de controle de qualidade, a avaliação do vigor de sementes é fundamental e necessária para o sucesso da produção. Este trabalho teve como objetivo avaliar a eficiência de diferentes testes de vigor na avaliação da qualidade fisiológica de sementes de triticale (X. triticosecale Wittmack), buscando a diferenciação de lotes. Cinco lotes da cultivar 'IPR 111' foram submetidos ao teste de germinação, primeira contagem, teste de frio, condutividade elétrica (50 sementes 50mL-1 de água; 25°C 24h-1), lixiviação de potássio (50 sementes 75mL-1 de água; 25°C 3h-1), envelhecimento acelerado (43°C 48h-1) e teor de água. O teste de condutividade elétrica e lixiviação de potássio são eficientes na diferenciação do vigor de lotes de sementes de triticale.
In a program of seed quality assurance, the evaluation of seed vigor is fundamental and necessary to the global production process outcome. The objective of this experiment was to verify the efficiency of different vigor tests for evaluation of triticale seeds (X. triticosecale Wittmack) seeking the lots differentiation. Five lots of triticale seeds (cv. IPR 111) were submitted to the following evaluations: germination, first counting of germination test, cold test, electrical conductivity test (50 seeds into 50ml of water, at 25°C for 24 hours), accelerated aging test (43°C 48h-1) in distilled water (100 percent RH), and also seed water content. The test of electrical conductivity and potassium leaching was efficient to distinguish vigor of triticale.
ABSTRACT
A qualidade das sementes esta relacionada de forma direta ao seu potencial fisiológico, representado pela germinação e/ou vigor, expressando sua capacidade de originar plântulas normais. O objetivo do estudo foi a análise dos efeitos da temperatura e do tempo de exposição ao teste de envelhecimento acelerado sobre os parâmetros: germinação, germinação na primeira contagem, emergência, Índice de velocidade de emergência, comprimento de parte aérea e massa seca. O ensaio foi conduzido no delineamento inteiramente casualizado, com quatro repetições. As sementes foram submetidas à dois métodos de envelhecimento acelerado: o tradicional com água destilada e outro com solução saturada de 40 g NaCl 100 mL-1 de água, em duas temperaturas (38 ºC e 41 ºC) e em três períodos de exposição (48, 72 e 96 horas). Melhor se pode verificar o potencial fisiológico das sementes de coentro, quando submetido às condições estressantes: na temperatura de 41 °C com o período de exposição de 96 h (Teste envelhecimento acelerado tradicional) e na temperatura de 41 ºC com período de exposição de 48 h (com solução saturada). Os testes de germinação e primeira contagem evidenciaram diferenças na qualidade fisiológica inicial das sementes em função dos tratamentos aplicados.
The quality quality of the seeds this related of direct form to it physiologic potential, acted by the germination and/or energy, expressing it capacity to originate normal plantules. The objective of the study was the analysis of the effects of the temperature and of the time of exhibition to the test of accelerated aging on the parameters: germination, germination in the first counting, emergency, Index of emergency speed, length of aerial part and mass dries. The rehearsal was driven in the delineamento entirely casualizado, with four repetitions. The seeds were submitted to two methods of accelerated aging: the traditional with distilled water and other with saturated solution of 40 g NaCl 100 mL-1 of water, in two temperatures (38 ºC and 41 ºC) and in three exhibition periods (48, 72 and 96 hours). Better the physiologic potential of the cilantro seeds can be verified, when submitted to the stressful conditions: in the temperature of 41 °C with the period of exhibition of 96 h (it Tests traditional aging) and in the temperature of 41 °C with period of exhibition of 48 h (with saturated solution). The germination tests and first counting evidenced differences in the quality physiologic initial of the seeds in function of the applied treatments.
Subject(s)
Seeds/metabolism , Coriandrum/classification , Seeds/growth & development , GerminationABSTRACT
Este trabalho teve por objetivo avaliar o crescimento inicial de plântulas de sorgo, provenientes de sementes submetidas e não ao envelhecimento e ao osmocondicionamento, sob condições de estresse salino. O delineamento experimental foi o inteiramente casualizado com quatro repetições, no esquema fatorial 2x2x3, constando de 12 tratamentos: dois lotes de sementes (envelhecidas e não); dois tipos de sementes (osmocondicionadas e não) e três níveis de salinidade (0, 100 e 200mM de NaCl). O osmocondicionamento com polietilenoglicol 6000 ou priming de sementes não envelhecidas promoveu um aumento de 25 por cento na sobrevivência das plântulas sob condições de alta salinidade (200mM de NaCl), mas, quando essa técnica foi aplicada em sementes envelhecidas, ocorreram incrementos de 31,3 e 50 por cento na taxa de mortalidade de plântulas cultivadas na presença de NaCl a 100 e 200mM. Quanto à manutenção do crescimento das plântulas, o osmocondicionamento proporcionou atenuação dos efeitos negativos da salinidade (NaCl a 100mM) naquelas oriundas de sementes envelhecidas, sendo tal fato confirmado por meio da manutenção da produção de biomassa vegetal.
The aim of this research was the evaluate seedlings growth from primed and aged seeds of sorghum under ideal conditions and salt stress. The experiment was a completely randomized design with four replications, following a factorial arrangement of 2x2x3, with eight treatments: two groups of seeds (aged or not), two types of seeds (primed or not) and three growth conditions (0, 100 e 200mM of NaCl). The osmoconditioning of no aged seeds promoted an increase of 25 percent in the seedling survival under conditions of high salinity (NaCl at 200mM), but when this technique was applied in aged seeds caused 18.8 percent and 31.3 percent of increase in the mortality of the seedlings grown in the presence of NaCl at 100 and 200mM, respectively. Regarding to the maintenance of seedling growth, the osmoconditioning provided mitigating the negative effects of salinity (NaCl at 100mM) for seedlings from aged seeds, and this fact is confirmed by the maintenance of plant biomass yield.
ABSTRACT
O objetivo do trabalho foi verificar a qualidade fisiológica de sementes da camomila submetidas a diferentes tempos de envelhecimento acelerado e ao estresse salino. Os experimentos foram realizados no Laboratório de Técnica de Sementes na PUCPR em São José dos Pinhais, Paraná. Os tempos de envelhecimento acelerado foram de 0, 24, 48, 72 e 96 h e o estresse salino foi induzido por soluções de cloreto de sódio com potenciais osmóticos de 0; -0,2; -0,4; -0,6; -0,8; -1,0 MPa, ambos com quatro repetições. Foram avaliados a germinação, o índice de velocidade de germinação (IVG), o tempo médio de germinação (TMG), a velocidade media de germinação (VMG) e a entropia. O delineamento experimental adotado foi o de blocos casualizados . Concluiu-se que as sementes de camomila tiveram sua qualidade fisiológica afetada após 24h de envelhecimento acelerado e sob estresse salino causado por solução de potencial osmótico de -0,6 MPa.
The aim of this study was to verify the physiological quality of chamomile seeds subjected to different accelerated aging periods and salt stress. The experiments were carried out in the Laboratory of Seed Technique, PUCPR, São José dos Pinhais, Paraná State, Brazil. The accelerated aging periods were 0, 24, 48, 72 and 96 h and the salt stress was induced by sodium chloride solutions with osmotic potentials of 0, -0.2, -0.4, -0.6, -0.8, -1.0 MPa, both with four replicates. The analyzed variables were: germination, germination velocity index (GVI), average germination time (AGT), average germination velocity (AGV) and entropy. Experimental design was in randomized blocks. Chamomile seeds had their physiological quality affected after 24 h of accelerated aging and under salt stress caused by the solution with osmotic potential of -0.6 MPa.
Subject(s)
Chamomile , Physiological Phenomena/physiology , Salinity , Seeds/physiology , Time Factors , Osmotic Fragility/physiology , Germination/physiology , Quality ControlABSTRACT
A qualidade de sementes de mamona tem sido avaliada rotineiramente pelo teste de germinação, cujos resultados, muitas vezes, não são confirmados em campo. Nesse contexto, os testes de vigor são essenciais, pois retratam o comportamento das sementes sob maior amplitude de ambiente. Neste trabalho, objetivou-se avaliar a eficiência de métodos para determinar o potencial fisiológico de sementes de mamona. Para tanto, foram utilizados sete lotes de sementes de mamona, cultivar AL-Guarany, apresentando teor de água de aproximadamente 7 por cento , que foram submetidos aos seguintes testes: germinação, primeira contagem de germinação, frio (a 10ºC/7 dias e a 25ºC/5 dias), porcentagem e velocidade de emergência de plântulas, envelhecimento acelerado a 41ºC e 45ºC e 100 por cento UR, por 48, 72 e 96 horas e condutividade elétrica (25 sementes embebidas em 75 e 100mL de água destilada, a 25ºC, por 2, 4, 6, 8, 24, 48 e 72 horas). Os testes de frio e de envelhecimento acelerado (41ºC/72 horas e 100 por cento UR) foram eficientes para avaliação do potencial fisiológico de sementes de mamona, permitindo classificação de lotes quanto ao vigor semelhante à emergência de plântulas em solo. O teste de condutividade elétrica não se mostrou adequado para avaliação do potencial fisiológico das sementes de mamona.
This work had the objective to determine the efficiency of different tests for the evaluation of physiological potential of castor bean seeds. Seven seed lots of AL-Guarany cultivar were submitted to the following tests: seed moisture content, standard germination, first count, cold test (10ºC/7 days followed by germination at 25ºC/5 days), seedling emergence, speed emergence index, accelerated aging (at 41ºC and 45ºC and 100 percent RH, for 48, 72, and 96h) and electrical conductivity (25 seeds soaked into 75 and 100mL of distilled water, at 25ºC, for 2, 4, 6, 8, 24, 48, and 72 h). The trial was conducted in randomized completely design, with four replications. The means of treatments were compared by Tukey test at 5 percent probability. Results showed that cold test and accelerated aging (41ºC/72 hours) were efficient to evaluate the physiological potential of castor bean seeds, allowing the classification of lots regarding vigor to be similar to the seedling emergence test. Electrical conductivity test was not adequate for the evaluation of physiological potential of these seeds.
ABSTRACT
Dentro de um programa de controle de qualidade, a avaliação do vigor de sementes é fundamental e necessária para o sucesso da produção. Com o objetivo de avaliar a eficiência de diferentes testes de vigor na avaliação da qualidade fisiológica de sementes de milho-doce na tentativa de diferenciação de lotes quanto ao nível de vigor e previsão de emergência de plântulas em campo e ao potencial de armazenamento, 10 lotes do híbrido DO-04 shrunken-2 (sh-2) foram submetidos a teste de germinação, primeira contagem, precocidade de emissão de raiz primária (32, 48, 56 e 72h), teste de frio, condutividade elétrica (50 sementes 75mL-1 de água; 25°C/4, 6, 8 e 24h), envelhecimento acelerado (42°C) em água destilada (100 por centoUR), solução saturada de cloreto de potássio (87 por centoUR) e solução saturada de cloreto de sódio (76 por cento UR), avaliando-se quatro períodos de exposição (24, 48, 72 e 96h), teor de água, emergência de plântulas em campo e germinação após armazenamento das sementes (10°C e 40 por centoUR), avaliada quadrimestralmente por 16 meses. A condutividade elétrica (por 6, 8 e 24h) foi o único teste eficiente na diferenciação do vigor de lotes de sementes de milho-doce (sh2); no entanto, não apresentou correlação com a emergência de plântulas em campo ou armazenamento.
In a program of seed quality assurance, the evaluation of seed vigor is fundamental and necessary to the global production process outcome. The objective of this experiment was to verify the efficiency of different vigor tests for evaluation of sweet corn seeds quality towards lots differentiation and prevision of seedling emergence and storage capacity of those. Ten lots of DO-04 shrunken-2 (sh2) hybrid sweet corn seeds were submitted to the following evaluations: germination, first counting of germination test, earliness of primary root emission (32, 48, 56 and 72 hours), cold test, electrical conductivity test (50 seeds into 75ml of water, at 25°C for 4, 6, 8 and 24 hours), accelerated aging test (42°C) in distilled water (100 percent RH), potassium chloride saturated solution (87 percent RH) and sodium chloride saturated solution (76 percent RH). Four exposition periods (24, 48, 72 and 96 hours) were evaluated and also seed water content, field seedlings emergence and germination after seeds storage (10°C and 40 percentRH) during sixteen months. The electrical conductivity test (for 6, 8 and 24 hours) was the unique test efficient to distinguish vigor of sweet corn (sh2) seeds lots, but it did not present correlation with field seedlings emergence or storage capacity.
ABSTRACT
Este estudio tuvo como objetivo analizar el efecto del envejecimiento artificial acelerado (EAA) sobre la resistencia a compresión de las resinas compuestas Filtek Z-250 (F), Charisma (C), Durafil VS (D), Supreme para cuerpo (SNc) e Supreme translúcido (SNt). Fueron confeccionados 16 especímenes con cada resina compuesta con dimensiones de 4x8mm. Las resinas fueron inseridas en tres incrementos y sobre el último incremento fue colocada una matriz de poliéster y una lamina de vidrio con la finalidad obtener una superficie regular. Cada incremento fue polimerizado con una intensidad de luz entre 580 y 600 mW/cm², la cual era monitoreada con un radiómetro (Gnatus) durante todo el tiempo de utilización. Veinticuatro horas después de la obtención de las muestras, 8 muestras de cada material fueron sometidas a los ensayos de compresión (grupo control) los cuales fueron realizados en una maquina EMIC DL 2000, con una célula de carga de 2000Kgf y velocidad de 0,5mm/min. Las otras 8 muestras de cada material fueron colocados en la máquina de EAA, las cuales permanecieron durante 196 horas, las mismas que equivalen a 5 años de envejecimiento y enseguida sometidos a los ensayos de compresión. Los resultados, fueron sometidos al ANOVA y test de Tukey (p<0,05) los cuales mostraron que las resinas SNt y D, no tuvieron diferencias estadísticas cuando fueron comparadas después de 24h y del EAA; las demás resinas mostraron resultados EAA>24h. Se pudo concluir que el envejecimiento artificial acelerado aumento la resistencia a compresión de las resinas F, C e SNc.
The aim of this study was to analyze the effect of artificially accelerated aging (AAA) on the resistance to compression of resin composites Filtek Z-250 (F), Charisma (C), Durafill VS (D), Supreme for body (SNC) and Supreme Translucent (SNt). Sixteen test specimens measuring 4 x 8 mm were made of each resin composite. The resins were inserted in three increments, and on the last of them, a polyester strip and glass slide were placed for the purpose of obtaining a regular surface. Each increment was polymerized by light intensity of 580 to 600 mw/cm², which was monitored with a radiometer (Gnatus) throughout the time of use. Twenty-four hours after the samples were obtained, 8 specimens of each material were submitted to the compression test (Control Group) performed with an EMIC DL 2000, machine, with a 2000 Kgf load cell at a speed of 0.5 mm/min. The other 8 samples of each material were placed in an AAA machine, and remained there for 196 hours, equivalent to 5 years of aging. Next they were submitted to the compression test. The values were submitted to ANOVA and the Tukey test (p<0.05). The results showed that for resins SNt and D there were no statistically significant differences when compared at 24h and after AAA; the other resins showed results of AAA>24h. It was concluded that artificially accelerated aging increased the resistance to compression of the resin composites F, C and SNc.
ABSTRACT
STATEMENT OF PROBLEM: The discoloration of anterior teeth restoration is one of the material problems demanding retreatment. OBJECTIVES: To evaluate the color stability and affecting factors on esthetic restorative materials when subjected to accelerated aging. MATERIAL AND METHODS: This study was conducted using porcelain disks (IPS Empress 2-glazed, IPS Empress 2-polished), direct restorative resin disks (SYNERGY Duo) and indirect restorative resin disks (Sinfony, TESCERA ATL). Accelerated aging was done by precipitating the specimens in 38 degrees C distilled water and irradiating with xenon light, and the total irradiation was 397.98 KJ/mm. Color and microhardness change of the specimens were measured before accelerated aging and after 100 hours, 200 hours and 300 hours of accelerated aging, and Surface of the specimens were examined with SEM before and after 300 hours of accelerated aging. RESULTS: 1. After 300 hours' accelerated aging, a delta E value was 3.3 or lower in IPS Empress 2-glazed, IPS Empress 2-polished and Sinfony. 2. After 300 hours' accelerated aging, gloss was lost and surface changes including microcracks were observed in TESCERA ATL and SYNERGY Duo, and color changes of them ranged between 3.58 and 6.40 delta E units. 3. During 300 hours' accelerated aging, the microhardness of surface was increased by 3.21 - 19.64 percent in all kinds of composites resin. CONCLUSION: After 300 hours' accelerated aging, SEM images IPS Empress 2-glazed, IPS Empress 2-polished and Sinfony showed little morphological change and their color changes were considered to be clinically acceptable. And there was significant correlation between microhardness changes and color changes of composites (P < .05).
Subject(s)
Aging , Composite Resins , Dental Porcelain , Light , Retreatment , Tooth , Water , XenonABSTRACT
STATEMENT OF PROBLEM: Direct denture reline resins tend to discolor during service in the oral environment by intrinsic and extrinsic factor. PURPOSE: This study was designed to evaluate the color stability of direct denture reline resins. MATERIAL AND METHODS: Mild Rebaron(GC Corp., Japan), Meta Base M(Sun medical Co., Japan), Mild Rebaron LC(GC Corp., Japan) and as a control group, Vertex SC(Dentimex Zeist, Holland) were chosen for this study. Ten specimens of each direct denture reline resins were fabricated. Treatment methods designed for this study were the coffee staining test(7days) and the accelerated aging test(100hours). The color changes before and after treatment were measured by Tristimulous colorimeter(Yasuda seiki seisakusho, Ltd. Japan) and analyzed. RESULTS: All the direct denture reline resins subjected to the coffee staining test and the accelerated aging test showed noticible difference in color change. After coffee staining test, Meta Base M showed the highest color change followed by Vertex SC, Mild Rebaron LC and Mild Rebaron. There were no statistical differences between Meta Base M and Vertex SC and between Mild Rebaron LC and Mild Rebaron(p>0.05). After accelerated aging test, Mild Rebaron LC showed the highest color change followed by Vertex SC, Meta Base M and Mild Rebaron. There were no statistical differences only between Mild Rebaron and Mata Base M(p>0.05) but among the others, there were statistical differences(p<0.05). CONCLUSION: Within the limitation of this study, all the direct denture reline resins subjected to the extrinsic and intrinsic factors showed noticible difference in color change, and there were differences among manufacturers.
Subject(s)
Aging , Coffee , Dentures , Intrinsic FactorABSTRACT
The color stability of current prosthetic composites is unknown, even though the quality of com-posite materials has been improving. This study examined the intrinsic color stability of various current prosthetic resins (ceramic-polymers) after an accelerated aging process and the extrinsic color stability after immersion in a coffee solution. By comparing the amount of dis-coloration after aging with that without aging, the effect of the accelerated aging process on external discoloration could be evaluated. Three current prosthetic composites (Artglass, Targis, Sculpture), one light polymerized direct composite (Z100) and one dental porcelain control (Ceramco) were assessed. The col-or changes (delta E) of all the specimens were determined using the CIE L*a*b* color order system with a reflected spectrophotometer. The results were as follows: 1. The prosthetic composite materials subjected to the accelerated aging test showed no sig-nificant difference in color changes (p> .05). 2. In the coffee solution immersion test after the aging process, the color changes of the Targis and Artglass groups were not different from that of the Z100 group, which showed the highest color change. 3. In the immersion only test, a significantly high color change was observed in the sculpture glazing group. 4. The aging process influenced on the color changes more in the Targis, Artglass and Z100 groups than in the Sculpture and Ceramco groups.