Experimental Investigation of Color Reproduction Quality of Color 3D Printing Based on Colored Layer Features

Color three-dimensional (3D) printing is an advanced 3D printing technique for reproducing colorful 3D objects, but it still has color accuracy issues. Plastic-based color 3D printing is a common color 3D printing process, and most factors affecting its color reproduction quality have been studied from printing materials to parameters in the fixed consecutive layers. In this work, and combined with variable stair thickness, the colored layer sequence in sliced layers of a specific 3D color test chart is deliberately changed to test the effects of colored layer features on its final color reproduction quality. Meanwhile, the colorimetric measurement and image acquisition of printed 3D color test charts are both achieved under standard conditions. Results clearly show that the chromatic aberration values and mean structural similarity (MSSIM) values of color samples have a significant correlation with the colored stair thickness, but both did not display a linear relationship. The correlation trends between colored layer sequence and the above two indexes are more localized to the colored stair thickness. Combined with color structural similarity (SSIM) maps analysis, a comprehensive discussion between colored layer features and color reproduction quality of color 3D printing is presented, providing key insights for developing further accurate numerical models.

Исследование состава пигментов на поверхности женской статуэтки с палеолитической стоянки Костенки 1 методом инфракрасной спектроскопии отражения

The structural and chemical composition of the colored layer located on the surface of a female statuette made of a mammoth tusk from the East Gravettian site of Kostenka 1, layer I, age of 23-21 thousand years, was studied using the IR reflection spectroscopy method. The site is located on the territory of the village of Kostenka in Khokholsky district of Voronezh region of Russia. The statuette was at the bottom of a storage pit with remnants of red paint. The paint layer on the figure consists of alumina and gypsum, the coloring pigments are mainly iron oxides. The obtained data allow to suggest that the technology used by the Paleolithic artist in painting the statuette of the Paleolithic Venus included a stage of preliminary preparation of the surface — priming of the treated surface using gypsum.

Auraptene in the Peels ofCitrus kawachiensis(Kawachi Bankan) Ameliorates Lipopolysaccharide-Induced Inflammation in the Mouse Brain

Examination of the dried peel powder ofCitrus kawachiensis, one of the citrus products of Ehime, Japan, showed that it contained naringin (NGIN; 44.02 ± 0.491 mg/g), narirutin (NRTN; 4.46 ± 0.0563 mg/g), auraptene (AUR; 4.07 ± 0.033 mg/g), and 3,5,6,7,8,3′,4′-heptamethoxyflavone (HMF; 0.27 ± 0.0039 mg/g). When this dried peel powder was orally preadministered at the dose of 1.2 or 2.4 g/kg/day for 7 days into lipopolysaccharide- (LPS-) injected mice, an animal model of systemic inflammation, it suppressed (1) LPS-induced loss of body weight and abnormal behavior in the open field, (2) LPS-induced activation of microglia and astrocytes in the hippocampus, and (3) LPS-induced expression of cyclooxygenase (COX)-2, which were coexpressed in astrocytes of these mice. When NGIN or AUR was preadministered to LPS-injected mice at an amount similar to that in the peel powder, AUR, but not NGIN, had the ability to suppress the LPS-induced inflammation in the brain of these model mice. The dried powder of flavedo tissue (the outer colored layer of the mesocarp of a citrus fruit) and juice, which contained sufficient amounts of AUR, also had anti-inflammatory effect. These results suggest that AUR was the main ingredient responsible for the anti-inflammatory property of the dried peels ofC. kawachiensis.