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Abstract. This study aimed to set evaluation indicators, i.e., perceptibility and acceptability color difference thresholds, of color stability for acrylic denture base resins for a spectrophotometric assessing method, which offered an alternative to the visual method described in ISO 20795-1:2013. A total of 291 disk specimens 50±1 mm in diameter and 0.5±0.1 mm thick were prepared (ISO 20795-1:2013) and processed through radiation tests in an accelerated aging chamber (ISO 7491:2000) for increasing times of 0 to 42 hours. Color alterations were measured with a spectrophotometer and evaluated using the CIE L*a*b* colorimetric system. Color differences were calculated through the CIEDE2000 color difference formula. Thirty-two dental professionals without color vision deficiencies completed perceptibility and acceptability assessments under controlled conditions in vitro. An S-curve fitting procedure was used to analyze the 50:50% perceptibility and acceptability thresholds. Furthermore, perceptibility and acceptability against the differences of the three color attributes, lightness, chroma, and hue, were also investigated. According to the S-curve fitting procedure, the 50:50% SHUFHSWLELOLW\ WKUHVKROG ZDV ¨(00 (r 2 =0.88) and the 50:50% DFFHSWDELOLW\ WKUHVKROG ZDV ¨(00 (r 2 =0.89). Within the limitations of this study, 1.71/4.00 ¨E00 could be used as perceptibility/acceptability thresholds for acrylic denture base resins.

Magnetically responsive colloidal photonic crystals can change their structural color according to the external magnetic field, which has been widely studied in recent years. However, due to lack of recognition ability towards non-magnetic analytes, these photonic crystals can be applied to constructing a sensor only when an additional stimuli responsive unit is involved. To address this problem, we used a functional protein to modify the magnetically responsive colloidal particles to construct chemically/magnetically dualresponsive nanoparticles. For a proof of concept research in this manuscript, we modified the colloidal particles with streptavidin, and the as obtained nanoparticles were used to detect biotinylated protein via a binding and assembling strategy, which is impossible for conventional photonic crystal sensors. Not only qualitative and quantitative detections were achieved, but also the average diameters of the biotinylated protein were correctly estimated. These results have demonstrated a multipurpose detection feature of our proposed colorimetric sensor.

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Volatile organic compounds (VOCs) are the important factors causing complex air pollution. Strengthening the prevention and control of VOCs pollution is the key work of energy saving and emission reduction in the 13th Five-Year Plan period in China. Automobile industry is a typical VOCs emission industry. A series of VOCs emission standards for automobile manufacturing links have been formulated at home and abroad. However, due to the complex production and emission links of automobile products, the VOCs accounting methods are various. In this paper, the method of VOCs emission accounting based on material balance is introduced in detail. The advantages and disadvantages of this method and its application scope are described. The parameters needed in the method are collected and summarized, which can provide reference for total VOCs control in automobile industry.