Effects of supplementation with different zinc-based products on the growth and health of Nile tilapia.

Zinc is one of the essential microelements for the metabolism of animals. Zinc nanoparticles may have higher bioavailability due to their low specific surface area, facilitating absorption by fish. The present study aimed to evaluate the effects of supplementation with different zinc-based products on the growth and health of Nile tilapia Oreochromis niloticus. Zinc, in different sizes (nanoparticles or bulk) and forms (inorganic or organic), were used as a supplement in the tilapia diet at a dose of 15 mg kg feed-1 for 60 days. At the end of the feeding trial, production performance, hemato-immunological parameters, activity of antioxidant system enzymes, exposure to Streptococcus agalactiae and zinc concentration in the muscle were examined. After the bacterial challenge, the mean corpuscular hemoglobin concentration (MCHC) significantly increased in the fish treated with organic zinc, inorganic nano zinc, and organic nano zinc, while in the control group (inorganic zinc), MCHC remained unchanged. Regarding defense cells, dietary inorganic nano zinc increased the number of basophils (1.50 ± 1.10) compared to organic zinc (0.80 ± 0.90). Lymphocyte count increased after the challenge only in the organic zinc treatments (bulk and nanoparticles). Neutrophils decreased in the control (inorganic zinc) (2.20 ± 1.70) and inorganic nano zinc (2.60 ± 2.70) treatments after the challenge. When compared before and after the bacterial challenge, the plasma antimicrobial titer significantly increased after the bacterial challenge in all treatments. No significant differences were observed for total proteins, enzymes (SOD and CAT), cumulative survival and zinc deposition on fillet. In conclusion, organic zinc in nanoparticles or bulk size increased Nile tilapia innate defense during bacterial infection. However, the other parameters evaluated were not affected by zinc particle size or form (organic or inorganic), indicating that further evaluations should be conducted with organic zinc in nanoparticles or bulk size in the tilapia diet.

The effect of repeated firings on the color of feldspathic ceramics.

The aim of this study was to determine the extent to which repeated firings would change the color of feldspathic ceramics. Specimens were fabricated from five commercially available feldspathic ceramics using a circular stainless steel matrix 11 mm in diameter and 1.0 mm thick (n = 10, shade = A3). Repeated firings were performed and color analysis was completed with a colorimeter using the CIELA B color coordinates. Two-way ANOVA was used to analyze the data, followed by Tukey's post-hoc test (a = 0.05). Three factors were used as determinants: a, a measure of the chroma along the red-green axis; b, a measure of the chroma along the yellow-blue axis; and L, a measure of the lightness-darkness of the specimen on a scale from 0 (black) to 100 (white). The results indicated that a and b values increased and L values decreased after repeated firings, resulting in reddish, yellowish, and darker specimens, respectively (P = 0.001). As the number of firings increased, significant color alterations occurred in the color parameters of the specimens. These alterations resulted in color changes (delta E) that could be considered unacceptable in clinical practice.

Color stability of a nanofill composite: effect of different immersion media.

OBJECTIVE: The aim of this in vitro study was to evaluate the color stability of a nanofill composite resin (Filtek Z350) in different immersion media. MATERIALS AND METHODS: Twelve resin-based composite specimens were prepared using a silicon cylindrical mold measuring congruent with 1mm of thickness and congruent with 10mm of diameter. Specimens were light-cured for 40 s from both sides using a LED Radii at 1400 mW/cm(2) and were randomized into 4 groups (n= 3) according to immersion media: coffee, yerba mate, grape juice or water (control solution). A digital spectrophotometer was used to evaluate the color changes at baseline and at 1-week after immersion in each solution. Specimens were stored in the different staining media for 4 h/day during 1 week. The color differences (DE) were analyzed by paired t-test and one-way ANOVA with complementary Tukey test (p<0.05). RESULTS: After 1-week of immersion, a perceptive color change for the group stored in the grape juice compared to baseline (p=0.008) was observed. Coffee and yerba mate did not show any color changes visible for the human eyes or significantly different from the control group (p>0.05) CONCLUSIONS: The findings of the present study suggest that the tested nanofill resin-based composite was susceptible to staining by substances present in the grape juice.

Color stability of a nanofill composite: effect of different immersion media

OBJECTIVE: The aim of this in vitro study was to evaluate the color stability of a nanofill composite resin (Filtek Z350) in different immersion media. MATERIALS AND METHODS: Twelve resin-based composite specimens were prepared using a silicon cylindrical mold measuring ≅1mm of thickness and ≅ 10mm of diameter. Specimens were light-cured for 40 s from both sides using a LED Radii at 1400 mW/cm² and were randomized into 4 groups (n= 3) according to immersion media: coffee, yerba mate, grape juice or water (control solution). A digital spectrophotometer was used to evaluate the color changes at baseline and at 1-week after immersion in each solution. Specimens were stored in the different staining media for 4 h/day during 1 week. The color differences (DE) were analyzed by paired t-test and one-way ANOVA with complementary Tukey test (p<0.05). RESULTS: After 1-week of immersion, a perceptive color change for the group stored in the grape juice compared to baseline (p=0.008) was observed. Coffee and yerba mate did not show any color changes visible for the human eyes or significantly different from the control group (p>0.05) CONCLUSIONS: The findings of the present study suggest that the tested nanofill resin-based composite was susceptible to staining by substances present in the grape juice.