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81.
Color stability of denture shade tabs is affected by exposure to daylight and decontamination protocols
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Eduardo José Soares Rafaella Tonani Marta Maria Martins Giamatei Contente Carolina Noronha Ferraz Arruda Fernanda de Carvalho Panzeri Pires‐de‐Souza 《Color research and application》2018,43(5):779-784
The purpose of this study was to investigate the effect of light exposure and decontamination protocols on the color stability of denture shade guide tabs. Fifty tabs for shades 62, 66, and 69 (Biotone IPN, Dentsply Sirona) were submitted to baseline L*a*b* measurements (EasyShade, Vita), separated into 5 experimental groups (n = 10), and subjected to one of the following conditions: G1–distilled water (DW‐H2O)–control; G2 ?70% alcohol; G3–sodium hypochlorite 1% (NaClO); G4–no light exposure; G5–natural light exposure for 6 months. The experimental conditions were designed to simulate 6 months of clinical use. After the test period, final color measurements were recorded. The mean tristimulus coordinate difference (ΔL*,Δa*,Δb*) and total color difference values () were analyzed using 2‐way ANOVA and the Tukey test, α = .05. G2 (alcohol) produced less (P < .05) color change in shade 69 than G3 (NaClO). G5 (light exposure) affected the color stability for all shades, producing a statistical difference (P < .05) from G4 (no light exposure). It was concluded that natural light changes the color stability of the shade guides and that decontamination with 70% alcohol had the least impact on the color stability of the shade guide tabs. 相似文献
82.
This study aimed to evaluate the effect of feed pH (2.2 - original effluent pH – up to 6.0) and temperature (20 up to 40°C) on the performance of integrated ultrafiltration (UF) and nanofiltration (NF) applied to gold mining effluent. pH increase led to a significant decrease in UF permeate flux. NF showed high retention efficiencies of ions when temperature was below 30°C. Retention of high-valence counter-ions to balance the charge of retained co-ions seemed to be the strongest NF mechanisms. Process performance at feed pH of 5.0 was superior in terms of fouling, retention efficiency, and investment cost. 相似文献
83.
The effect of macadamia oil intake on muscular inflammation and oxidative profile kinetics after exhaustive exercise
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84.
Pires RA Fernandez C Nunes TG 《Journal of materials science. Materials in medicine》2007,18(5):787-796
A commercial photopolymerizable resin-modified glass-ionomer (Fuji II LC) was studied using a variety of nuclear magnetic
resonance (NMR) techniques. 1H and 19F stray-field imaging (STRAFI) enabled to follow the acid–base reaction kinetics in self-cured (SC) samples. Gelation and
maturation processes with 25 min and 40 h average time constants, respectively, were distinguished. In self- & photo-cured
(SPC) samples, two processes were also observed, which occurred with 2 s and 47 s average time constants. 1H, 27Al and 29Si magic angle spinning (MAS) NMR, 13C cross-polarization (CP)/MAS NMR and 27Al multiple quanta (MQ)MAS NMR spectroscopy were used to obtain structural information on the glass and cements that were
either SC or SPC. The presence of methacrylate groups was identified in the solid component. Unreacted hydroxyl ethylmethacrylate
(HEMA) was detected in self-cured cement. 27Al data showed that approximately 28% and 20% of Al is leached out from glass particles in SC and SPC samples, respectively.
The upfield shift detected in 29Si MAS NMR spectra of the cements is consistent with a decrease in the number of Al species in the second coordination sphere
of the silicon structures. Scanning electron microscopy (SEM) showed existence of 3D shrinkage of the cement matrix in photo-cured
cements. 相似文献
85.
86.
The physical properties found during the swelling process of poly(2‐hydroxyethyl methacrylate) (PHEMA) and of copolymers of HEMA with mono‐n‐methyl itaconate, synthesized by solution and bulk polymerization, are reported. The swelling kinetics were followed at four different temperatures (295, 300, 305 and 310 K). Experimental data follow second‐order swelling kinetics, from where the kinetic rate constant k∞ and the swelling capacity at equilibrium W∞ were calculated as a function of temperature. The kinetic rate constant obeys Arrhenius behaviour. The following network parameters were determined for the hydrogels: Young's moduli E, effective crosslinking density ve, molar mass per crosslink MC, volume fraction ϕ2 and polymer‐liquid interaction parameter χ. © 2000 Society of Chemical Industry 相似文献
87.
Jos R. S. Rodrigues Akira Kaito Valdir Soldi Alfredo T. N. Pires 《Polymer International》1998,46(2):138-142
The microscopic behaviour of blends of poly(ethylene oxide) with two different low molecular weight liquid crystals (LC) was studied in order to evaluate miscibility. One of the liquid crystal components had a phase transition temperature lower than the melting temperature of poly(ethylene oxide) (PEO), and the other a higher value. The low molecular weight liquid crystal components were 4-cyano-4′-n-heptylbiphenyl (7CB) and p-cyanophenyl p-pentyloxybenzoate (pCP). Thermal analysis and polarized optical and scanning electron microscopy were employed. The melting temperature (Tm) depression of PEO increased with LC content in the blend, suggesting that the PEO was miscible with both liquid crystals in the isotropic phase. The spherulitic structural morphology of the semicrystalline components is affected by the presence of liquid crystals. © 1998 SCI. 相似文献
88.
89.
De Castro WV Pires MA Oliveira MA Vianna-Soares CD Nunan EA Pianetti GA Moreira-Campos LM De Castro WV Mertens-Talcott SU Derendorf H 《Drug development and industrial pharmacy》2006,32(9):1103-1109
In attempts to design delayed-release tablets of diclofenac sodium, seven experimental batches were produced. The influence of super-disintegrant croscarmellose sodium (CCS), the granulation process, and the thickness of Eudragit® L 100 coating film were evaluated. The values of dissolution efficiency and the similarity factor were used to compare the dissolution profiles of each experimental batch and the reference Voltaren®. Both methods appear to be applicable and useful in comparing dissolution profiles. Based on such values four batches were considered similar when contrasted with the reference. The results suggest an optimal relationship between the amount of CCS and the thickness of the coating film, which provides appropriate dissolution rate of diclofenac sodium from the dosage forms. 相似文献
90.
Ian Nascimento Vieira Beatriz Souza Leite Pires de Lima Breno Pinheiro Jacob 《International journal for numerical methods in engineering》2012,91(10):1023-1044
This work describes the development, implementation, and assessment of enhanced variants of three different groups of bio‐inspired methodologies: genetic algorithms, particle swarm optimization, and artificial immune system. The algorithms are implemented on a computational tool for the synthesis and optimization of offshore oil production risers that connect a floating platform at the sea surface to the wellheads at the sea bottom. Optimization procedures using bio‐inspired algorithms for such real‐world engineering problems require the calculation of the objective function through a large number of time‐consuming finite element nonlinear dynamic analyses, for the evaluation of the structural behavior of each candidate configuration. Therefore, the performance of the algorithms may be measured by the smaller number of objective function evaluations associated to a given target fitness value. The results indicate that the artificial immune system approach, incorporating some enhancements presented in this work, is more effective than the genetic algorithms and particle swarm optimization methods, requiring a smaller number of evaluations to obtain better solutions. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献