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SUMMARY As a potential beverage, coffee leaf tea may possess both qualities of brewed coffee and regular tea. Thus, making it an attractive beverage in years to come. One of the main qualities is the leaf's phenolic content, which is chiefly attributed with health benefits. However, the leaf's total phenolic content may be adversely affected by heat during the drying process. Coffee leaves were dried using a combined drying process, high-temperature short-time (HTST) and convective drying, to assess the optimal drying parameters for both total phenolic content preservation and drying time reduction. To reach conclusions, a central composite rotational design (CCRD) was employed. With both temperature and thickness as independent variables, a response surface using time as dependent variable was generated. The temperature ranged from 80°C to 110°C and the thickness from 1cm to 3cm. Results indicate that the HTST pretreatment significantly reduced the drying time without affecting the total phenolic content; that is, the CCRD analysis on the effect of the HTST pretreatment on the total phenolic content did not yield statistically significant results.
RESUMEN Como bebida potencial, el té de hojas de café posee cualidades, tanto de café preparado como de té regular, por lo tanto, será una bebida interesante en los próximos años. Una de las principales cualidades es el contenido fenólico de las hojas, a lo cual, se atribuyen beneficios sobre la salud; sin embargo, el contenido fenólico total (TPC), se puede ver afectado negativamente por el calor, durante el proceso de secado. Hojas de café fueron secadas usando un proceso de secado combinado, tiempo corto y alta temperatura (HTST) y secado convectivo, para establecer los parámetros óptimos de secado, tanto para la preservación del TPC como para la reducción del tiempo de secado. Para obtener conclusiones, un diseño de experimentos rotacional central compuesto (CCRD) fue aplicado. Usando como variables independientes la temperatura y el espesor, se generó una superficie de respuesta, empleando el tiempo, como variable dependiente. El rango de temperatura usado fue entre 80 y 110 y de espesor, entre 1 y 3cm. Los resultados indican que el pretratamiento de HTST redujo significativamente el tiempo de secado, sin afectar el TPC, es decir, el análisis del CCRD sobre el efecto del pretratamiento del HTST en el TPC no obtuvo resultados estadísticamente significativos.
ABSTRACT
The aim of this work was describe the germination and evaluate the desiccation and reduction in desiccation sensitivity of Hancornia speciosa Gomes seeds. Initially, we evaluated the germination characteristics and morphophysiological aspects of seedlings. The seeds in the first experiment were subjected to fast desiccation (activated silica gel) and slow desiccation (laboratory conditions) until the water content reached 40%, 30%, 20%, and 15% ± 2%. To reduce the desiccation sensitivity, in the second experiment, the seeds were soaked in polyethylene glycol (PEG) at potentials of -0.1 and - 0.3 MPa for 120 h, with or without abscisic acid (ABA) (10-4µM), and subsequently subjected to fast desiccation until a water content of 15% was reached, based on the results from the first experiment. The seed vigor in both experiments was evaluated by the primary root protrusion tests, percentage of normal seedlings, germination speed index, length and mass (shoot, underground, and total). Seedlings of H. speciosa feature a stem-like xylopodium structure. The seeds were tolerant to water reduction up to 15% by fast desiccation and 30% by slow desiccation. Moreover, priming was not efficient in reducing the desiccation sensitivity of H. speciosa seeds.
Objetivou-se neste trabalho descrever a germinação e avaliar a secagem e a redução da sensibilidade à dessecação em sementes de Hancornia speciosa Gomes. Inicialmente, foi realizada a descrição das características de germinação e aspectos morfofisiológicos das plântulas. Para primeiro experimento, as sementes foram submetidas à secagem rápida (sílica gel ativada) e à secagem lenta (condições de ambiente de laboratório) até atingirem os teores de água de 40, 30, 20 e 15 ± 2%. Na tentativa da redução da sensibilidade à dessecação em um segundo experimento, as sementes foram embebidas em polietileno glicol (PEG) nos potenciais de -0,1 e -0,3 MPa por 120 horas associados ou não ao ácido abscísico (ABA) (10-4M) e posteriormente submetidas a secagem rápida no teor de água de 15%, de acordo com os resultados do primeiro experimento. O potencial fisiológico das sementes, em ambos os experimentos, foi avaliado por meio dos testes de protrusão da raiz primária, porcentagem de plântulas normais, índice de velocidade de germinação, comprimento e massa seca de plântulas (parte aérea, sistema subterrâneo e total). As plântulas de H. speciosa apresentam xilopódio de estrutura caulinar. As sementes toleram a redução do teor de água até 15% na secagem rápida e de 30% para secagem lenta. O condicionamento osmótico não foi eficiente para reduzir a sensibilidade à dessecação de sementes de H. speciosa.
Subject(s)
Polyethylene Glycols , Seeds , Abscisic Acid , Germination , Apocynaceae , DesiccationABSTRACT
Objetivo: Este estudo se propôs avaliar o efeito de diferentes tempos de secagem de dois adesivos tipo total-etch & rinse e ciclagem térmica na resistência adesiva entre cerâmica feldspatica e cimento resinoso. Material e Métodos: Trinta e dois blocos (12×10×4 mm) de cerâmica feldspática e respectivos blocos (32) de resina composta foram obtidos. A superfície de cimentação de cada bloco cerâmico foicondicionada por ácido fluorídrico (HF), silanizada (S), e recebeu a aplicação de um dos dois sistemas adesivos testados (SB - Single Bond 2, 3M-ESPE; ou PB Prime & Bond NT, Dentsply). Então a superfície com o adesivo foi seca em diferentes tempos (5, 10 e 15s) antes da cimentação. Após, um cimento resinoso foi aplicado sobre a superfície de cimentação e o bloco correspondente de resina foi cimentado. Os palitos para microtração foram obtidos, sendo que metade deles foram imediatamente testados, enquanto os demais foram submetidos à ciclagem térmica e armazenagem (150 dias). Para os grupos sem envelhecimento, o tempo de secagem mais longo (15s) aumentou a resistência para o adesivo SB, enquanto que reduziu a resistência para o adesivoPB. Resultados: Para os grupos envelhecidos, as resistências adesivas dos diferentes tempos de secagem não foram diferentes estatisticamente, independente do adesivo. A falha predominante foi coesiva do cimento resinoso, seguido pela falha na interface cerâmica cimento. Conclusão: Conclui se que tempos mais longos de secagem podem melhorar a resistência adesiva à cerâmica testada, usando o adesivo SB. Por outro lado, tempos mais curtos podem otimizar a adesão para o adesivo PB. O envelhecimento afetou a adesão somente nos grupos do adesivo SB
Objective: This study evaluated the effect of drying times of two total-etch & rinse adhesives on the resin bond strength to a feldsphatic ceramic, before and after aging. Material and Methods:Feldsphatic-ceramic CAD-CAM bars were cut into blocks (12×10×4 mm) with a cutting machine (N = 32). Impressions were made of each ceramic block with silicone putty material and the negativespace was filled with a composite resin. The bonding ceramic surface was etched with hydrofluoric acid, silanized, and the adhesive system (SB- Single Bond 2, 3M-ESPE; or PB- Prime & Bond NT, Dentsply) was applied. The samples were dried at different times (5, 10 and 15 s) before the cementation. The resin and ceramic blocks were cemented bya dual cure resin cement. All samples were stored in distilled water at 37 °C for 24 h. For the μ-TBS test, the samples were sliced into microbars. Half of the bars of each block was tested after 24 h and, the other bars were submitted to thermocycling (12,000×) and water storage (150 d). For the 24 h groups, the longer drying time increased (p < 0.05) the bond strength of SB (water/alcohol adhesive), while reduced (p < 0.05) for the PB group (acetone based adhesive). Results: For the aged groups, the bond strength for the different drying times had no significant difference, for the both adhesives. Conclusion: Longer drying times increased the bond strength values of SB. Smaller drying times increased the bond strength values of PB. The aging protocol influenced the bond strength of SB groups.
Subject(s)
Dental Materials , Resin CementsABSTRACT
Aims: To evaluate the effect of air-drying time of adhesives on shear bond strength of different adhesive systems. Methodology: The occlusal surfaces of 175 mandibular third molars were ground to obtain flat dentin surfaces and then divided into three groups according to three adhesive systems used: (1) Conventional three-step adhesive (Scotchbond Multi-purpose Plus); 2) Self-etch adhesive (Adper Easy Bond) and 3) Single bottle self-etch adhesive (Scotchbond Universal adhesive). Regarding the application of adhesives before resin composite application, it was gently air-dried for 3 s in Groups 1, whereas, the adhesive was left wet in Group 2. The group 3, that was air-dried until the liquid did not move (5 s), was served as control. Following bonding of resin cement (Filtek Supreme) to dentin, the specimens were light cured for 20s with a LED. After storage in water at 37ºC for one week, the strength measurements were accomplished with universal testing machine (Lloyd LRX) until the failure occurs. Failure modes were examined using a stereomicroscope and scanning electron microscope. The data were analyzed with two-way analysis of variance Original Research Article British Journal of Medicine & Medical Research, 4(27): 4523-4532, 2014 4524 (ANOVA) and TukeyHSD tests (α=0.05). Results: The two-way ANOVA revealed that adhesive systems had a significant effect on shear bond strength values (p<0.001). However, air-drying time did not influence shear bond strength (p=0.442). Additionally, there was no interaction effect between adhesive systems and air-drying time (p=0.835). Conclusion: The data suggests that increased air-drying time of adhesives does not significantly affect bond strength.
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Objective: To explore the effects of different drying methods on the transformation of bioactive constituents, such as stilbene glycosides and anthraquinones, in Polygoni Multiflori Radix (PMR), and to provide a scientific evidence for the suitable drying method for PMR. Methods: Using crude PMR as materials, six drying methods including shade-drying, sun-drying, oven-drying, freeze-drying, microwave-drying, and far-infrared-drying were used to process the samples of PMR. HPLC was used to simultaneously determine the contents of stilbene glycosides, free and conjugated anthraquinones with different drying methods and drying time. Results: The contents of stilbene glycosides in the samples processed with the above methods were as follows in descending order: sun-drying > far-infrared-drying > freeze-drying > shade-drying > oven-drying > microwave-drying; The shade-drying and sun-drying methods were more suitable for the conjugated anthraquinones transforming into the free ones and the contents of conjugated anthraquinones in the sample processed with far-infrared-drying method were the highest. The comprehensive evaluation index obtained with principal component analysis showed that the far-infrared-drying method is significantly higher than those with other drying methods for PMR. Conclusion: Far-infrared-drying method is the suitable approach for the primary drying processing of PMR.
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Objective: To explore the suitable drying methods for Rhei Radix et Rhizoma (RRR) with color, drying time, drying rate, and content of active ingredients as indexes. Methods: Rheum palmatum was used in the test and the color of RRR was studied according to Chinese Pharmacopeia 2010. The extract was obtained by hot-dip method. The contents of anthraquinone, gallic acid, and catechin were determined using HPLC. Results: RRR treated with oven-drying, shade-drying, sun-drying, and fumigated with sulfur-drying below 65 °C showed good color and the cross-section was claybank. The cross-section of RRR treated with oven-drying over 65 °C showed dark brown. The highest contents of extract and anthraquinone in RRR treated by sun-drying were 34.32% and 1.90% and followed by those treated by oven-drying at 45 °C with 33.53% and 1.68%, respectively. High temperature caused the decrease of anthraquinone in RRR. The contents of gallic acid and catechin reduced with the increase of temperature under the constant temperature oven-drying process. Conclusion: The suitable drying method for RRR is oven-drying at constant 45 °C or sun-drying.
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OBJECTIVES: To investigate the effect of dentin moisture degree and air-drying time on dentin-bond strength of two different one-step self-etching adhesive systems. MATERIALS AND METHODS: Twenty-four human third molars were used for microtensile bond strength testing of G-Bond and Clearfil S3 Bond. The dentin surface was either blot-dried or air-dried before applying these adhesive agents. After application of the adhesive agent, three different air drying times were evaluated: 1, 5, and 10 sec. Composite resin was build up to 4 mm thickness and light cured for 40 sec with 2 separate layers. Then the tooth was sectioned and trimmed to measure the microtensile bond strength using a universal testing machine. The measured bond strengths were analyzed with three-way ANOVA and regression analysis was done (p = 0.05). RESULTS: All three factors, materials, dentin wetness and air drying time, showed significant effect on the microtensile bond strength. Clearfil S3 Bond, dry dentin surface and 10 sec air drying time showed higher bond strength. CONCLUSIONS: Within the limitation of this experiment, air drying time after the application of the one-step self-etching adhesive agent was the most significant factor affecting the bond strength, followed by the material difference and dentin moisture before applying the adhesive agent.
Subject(s)
Humans , Adhesives , Collodion , Dentin , Dentin-Bonding Agents , Light , Methacrylates , Molar, Third , Resin Cements , ToothABSTRACT
STATEMENT OF PROBLEM: Use of custom tray and tray adhesive is clinically recommended for elastomeric impression material. However there is not clear mention of drying time of tray adhesive in achieving appropriate bonding strength of tray material and impression material. PURPOSE: This study is to investigate an appropriate drying time of tray adhesives by evaluating tensile bonding strength between two types of polyvinylsiloxane impression materials and resin tray, according to various drying time intervals of tray adhesives, and with different manufacturing company combination of impression material and tray adhesive. MATERIAL AND METHODS: Adhesives used in this study were Silfix (Dentsply Caulk, Milford, Del, USA) and VPS Tray Adhesive (3M ESPE, Seefeld, Germany) and impression materials were Aquasil Ultra (monophase regular set, Dentsply Caulk, Milford, Del, USA) and Imprint II Garant (regular body, 3M ESPE, Seefeld, Germany). They were used combinations from the same manufacture and exchanged combinations of the two. The drying time was designed to air dry, 5 minutes, 10 minutes, 15 minutes, 20 minutes, and 25 minutes. Total 240 of test specimens were prepared by auto-polymerizing tray material (Instant Tray Mix, Lang, Wheeling, Il, USA) with 10 specimens in each group. The specimens were placed in the Universal Testing machine (Instron, model 3366, Instron Corp, University avenue, Nowood, MA, USA) to perform the tensile test (cross head speed 5 mm/min). The statistically efficient drying time was evaluated through ANOVA and Scheffe test. All the tests were performed at 95% confidence level. RESULTS: The results revealed that at least 10 minutes is needed for Silfix-Aquasil, and 15 minutes for VPS Tray Adhesive-Imprint II, to attain an appropriate tensile bonding strength. VPS Tray Adhesive-Imprint II had a superior tensile bonding strength when compared to Silfix-Aquasil over 15 minutes. Silfix-Aquasil had a superior bonding strength to VPS Tray Adhesive-Aquasil, and VPS Tray Adhesive-Imprint II had a superior tensile bonding strength to Silfix-Imprint II at all drying periods. CONCLUSION: Significant increase in tensile bonding strength with Silfix-Aquasil and VPS Tray adhesive-Imprint II combination until 10 and 15 minutes respectively. Tray adhesive-impression material combination from the same company presented higher tensile bonding strength at all drying time intervals than when using tray adhesive-impression material of different manufactures.
Subject(s)
Adhesives , Collodion , Dental Impression Materials , Elastomers , Head , Polymers , Polymethyl Methacrylate , Polyvinyls , SiloxanesABSTRACT
0.05),but drying time was significantly various(P