The pharmacology and toxicology of a broad variety of therapies and chemicals have significantly improved with the aid of the increasing in vitro models of complex human tissues. Offering versatile and precise control over the cell population, extracellular matrix (ECM) deposition, dynamic microenvironment, and sophisticated microarchitecture, which is desired for the in vitro modeling of complex tissues, 3D bio-printing is a rapidly growing technology to be employed in the field. In this review, we will discuss the recent advancement of printing techniques and bio-ink sources, which have been spurred on by the increasing demand for modeling tactics and have facilitated the development of the refined tissue models as well as the modeling strategies, followed by a state-of-the-art update on the specialized work on cancer, heart, muscle and liver. In the end, the toxicological modeling strategies, substantial challenges, and future perspectives for 3D printed tissue models were explored.

Recent studies have shown cultural differences in color preference. However, the color preference of people in China, which was found to have its own pattern, was yet to be studied in depth. The current study investigated color preference and the associated age and gender differences in an adult national sample (N = 1290) to provide a culture‐specific characteristic of color perception. Participants rated how much they liked each of 31 colors (four chroma‐lightness levels of red, orange, yellow, green, cyan, blue, and purple, plus three achromatic colors). We found a unique saturated color preference pattern characterized by red, cyan, and blue being preferred the most and orange as the least preferred chromatic color. The “red preference” phenomenon was observed in Chinese adults. Light colors were preferred the most in terms of chroma‐lightness level, followed by saturated, muted, and dark colors. The results of a principal component analysis of the 28 chromatic colors showed that blue‐green‐like colors (cool colors) constituted the largest proportion of color preference. The preference for orange and several dark colors increased with age, while that for bluish colors, purple, yellow, white, black, and light colors decreased. In terms of gender, women liked cyan, white, pink, and light colors and disliked red, orange, and dark colors more than men did. Our findings provide new empirical evidence about the color preference of Chinese and may offer some insight into the study of color preference and lay the foundations for future theoretical and practical research.

Three-dimensional (3D) bioprinting techniques have emerged as the most popular methods to fabricate 3D-engineered tissues; however, there are challenges in simultaneously satisfying the requirements of high cell density (HCD), high cell viability, and fine fabrication resolution. In particular, bioprinting resolution of digital light processing–based 3D bioprinting suffers with increasing bioink cell density due to light scattering. We developed a novel approach to mitigate this scattering-induced deterioration of bioprinting resolution. The inclusion of iodixanol in the bioink enables a 10-fold reduction in light scattering and a substantial improvement in fabrication resolution for bioinks with an HCD. Fifty-micrometer fabrication resolution was achieved for a bioink with 0.1 billion per milliliter cell density. To showcase the potential application in tissue/organ 3D bioprinting, HCD thick tissues with fine vascular networks were fabricated. The tissues were viable in a perfusion culture system, with endothelialization and angiogenesis observed after 14 days of culture.

The long baseline simultaneous multiband (BVRI) observations of blazar 3C 273 are presented. We have made 758 optical multiband observations with the Yunnan Astronomical Observatory (YAO) 103 cm and Shanghai Astronomical Observatory (SHAO) 156 cm from 2003 January to 2005 April. In our observational campaign, the average colour indices are B−V= 0.21, V−R= 0.26 and R−I= 0.31. The mean magnitudes in B, V, R and I are 12.895, 12.698, 12.441 and 12.139, respectively. The source is in a steady state over observational campaign. The correlations between colour index and brightness are discussed. We find that the correlations of B−V versus B, V−R versus V and R−I versus R have significant negative correlation, while B−V versus V, V−R versus R and R−I versus I have positive correlation. These strong correlations imply that the spectrum becomes bluer (flatter) when the source becomes brighter, and redden (softer) when the source fades both in intraday and long‐term variability. The spectral evolution trends of 3C 273 are consistent with those of BL Lac objects.

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