The Mechanism of Bitterness Suppression in Huanglian Jiedu Decoction

Background Bitterness is one of the main reasons that affect the clinical efficacy of traditional Chinese medicine (TCM). Preliminary research shows γ-cyclodextrin (γ-CD) and neotame can significantly improve the taste of TCM, while its mechanism still remains unknown. Huanglian jiedu decoction (HLJDD), as a typical representative of the bitter prescription of TCM, will be a breakthrough point to study the taste correcting strategy of TCM in this study. Methods Firstly, UPLC-MS/MS was used to identify the ingredients of HLJDT. Secondly, pharmacophore model of bitter taste receptors (BTR) Tas2r10, Tas2r14 and Tas2r46 was built by Discovery Studio 4.0 software. Thirdly, bitter taste compounds in HLJDD were identified by pharmacophore model. Finally, molecular modeling was used to explore how γ-CD and neotame make effect. Results We found γ-CD masked bitterness by preventing bitter components from contacting its receptor, or reducing the affinity between them. While components are extremely rigid such as coptisine, cannot complete self-assemble with γ-CD. Hence, inclusion (γ-CD) is difficult to achieve good effects for drugs containing those compounds such as Coptidis Rhizoma and Phellodendri Chinrnsis Cortex. However, neotame can strongly bind with those extremely bitter compounds such as coptisine and epiberberine in Coptidis Rhizoma and Phellodendri Chinrnsis Cortex, and thus can mask taste of them significantly. Conclusions The strategy achieves a significant bitter block effect from blocking the formation of the bitter signal to hindering its transmission after the formation of the signal, achieving a multilevel and significant taste effect. This article provides references for the research and development of flavoring companions for TCM, which will help improving the clinical efficacy of TCM.

High Performance Metasurface Antennas

Recently, metasurfaces (MSs) have received tremendous attention because their electromagnetic properties can be controlled at will. Generally, metasurface with hyperbolic phase distributions, namely, focusing metasurface, can be used to design high-gain antennas. Besides, metasurface has the ability of controlling the polarization state of electromagnetic wave. In this chapter, we first propose a new ultrathin broadband reflected MS and take it into application for high-gain planar antenna. Then, we propose multilayer multifunctional transmitted MSs to simultaneously enhance the gain and transform the linear polarization to circular polarization of the patch antenna. This kind of high-gain antenna eliminates the feed-block effect of the reflected ones.

EVALUATION OF DEBLOCKING METHODS FOR CHANG’E-4 DESCENT IMAGES

Chang’e-4 lunar probe has successfully landed on the far side of the moon in Von Kármán crater inside the South Pole-Aitken (SPA) basin at 10:26 am on January 3, 2019. Due to the reduction of the coding rate, obvious block effects appear at the boundaries of descent images. Unblock, adaptive fast bilateral filtering, structure-texture enhancement and high-order Markov random field methods, are applied to remove the block effect of the descent images. Based on analysing the quality of descent images, quantitative comparison of four methods is performed using simulated compressed 1:64 descent images and real images. Comprehensive analysis was performed using typical measures such as PSNR, SSIM and NIQE. Experimental results show that adaptive fast bilateral filtering is better than other methods. The deblocked 1:64 image sequences have been used to assist localizing the landing point quickly during the mission.

A Study on the Modified Arrhenius Equation Using the Oxygen Permeation Block Model of Crosslink Structure

Polymers are widely used in various industries because of their characteristics such as elasticity, abrasion resistance, fatigue resistance and low temperature. In particular, the tensile characteristic of rubber composites is important for the stability of industrial equipment because it determines the energy absorption rates and vibration damping. However, when a product is used for a long period of time, polymers become hardened owing to the changes in characteristics because of aging, thereby reducing the performance and increasing the possibility of accidents. Therefore, accurately predicting the mechanical properties of polymers is important for preventing industrial accidents while operating a machine. In general reactions, the linear Arrhenius equation is used to predict the aging characteristics; however, for rubber composites, it is more accurate to predict the aging characteristics using nonlinear equations rather than linear equations. However, the reason that the characteristic equation of the polymer appears nonlinear is not well known, and studies on the change in the characteristics of the natural and butadiene rubber owing to degradation are still lacking. In this study, a tensile test is performed with different aging temperatures and aging time to evaluate the aging characteristics of rubber composites using strain energy density. We propose a block effect of crosslink structure to express the nonlinear aging characteristics, assuming that a limited reaction can occur owing to the blocking of reactants in the rubber composites. Consequently, we found that a relationship exists between the crosslink structure and aging characteristics when the reduction in crosslink space owing to aging is represented stochastically. In addition, a modified Arrhenius equation, which is expressed as a function of time, is proposed to predict the degradation rate for all aging temperatures and aging times, and the formula is validated by comparing the degradation rate obtained experimentally with the degradation rate predicted by the modified Arrhenius equation.