Phase retrieval for dual-projection pattern based on orthogonal frequency encoding to suppress superposing effects.

When grating patterns are simultaneously projected by a dual-projection structured-light system, interference-like blur and brightness overexposure in the superposed area often cause miscalculation of the phase of the grating pattern. In this study, we proposed a novel method, to the best of our knowledge, that utilizes orthogonal grating encoding to retrieve the phases of superposed grating patterns. Specifically, we determined the frequency of the dual-projection pattern based on the condition that enabled the separation of superposed orthogonal signals in wireless communication. Additionally, the maximum intensity of the projected pattern was determined using the intensity-saturation relationship. By performing a discrete Fourier transform on a series of superposed grating patterns, we obtained the wrapped phase of the corresponding projected grating patterns in the space-time dimension. Finally, we reconstructed the measured object by fusing the point clouds obtained from the dual-projection structured-light system. The experimental results demonstrated that the encoded orthogonal grating patterns could eliminate interference-like blurring and brightness overexposure during superposition and obtain high-precision phase maps and 3D reconstruction results, which provides the possibility for the simultaneous reconstruction of multiprojection structured light.

Crack mechanism and experimental verification on straightening of AZ31B magnesium alloy plate.

When plates with edge cracks in the rolling process is straightened by cyclic tensile and compressive stress, the tip of edge crack always accompanied by stress concentration, which leads to crack propagation. In this paper, damage parameters are imported into the plate straightening model based on determining the GTN damage parameters of magnesium alloy materials by inverse finite element calibration method, the influence of different straightening process schemes and prefabricated V-shaped crack geometry on crack growth is analyzed through the way of the combination of simulation and straightening experiment. The results show that the peak values of equivalent stress and equivalent strain under each straightening roll appear at the crack tip. The value of longitudinal stress and equivalent stain decrease with the distance to crack tip becomes larger. The peak value of longitudinal stress appears when the crack circumferential angle is about 100°, and the crack tip is easy to form crack propagation; when the plate passes roll 2 and roll 4, the equivalent stress and strain concentration at the crack tip are most obvious; when the reduction reaches a certain degree, the void volume fraction (VVF) reaches the VVF of the material breaking; with the increase of the entrance reduction, the number of VVF at the crack tip which reaches the material fracture increases, and the length of crack propagation increases; the stress concentration at the tip of V-shaped crack with large length-width ratio is obvious, and the VVF is more likely to reach the VVF at the time of material fracture, crack initiates and propagates easily.

Numerical study of granular flow in a slit funnel with a novel structure to avoid particle clogging.

To solve the problem of particle clogging in slit funnels and to obtain a stable discharge flow rate, we proposed a new funnel structure, namely the slit baffle funnel. We conducted a systematic investigation using the discrete element method (DEM) to study the effects of funnel half-angle θ, outlet width W, and baffle height H on flow rate and flow pattern. We found that the proposed structure could effectively avoid particle clogging and guarantee a continuous and stable flow rate with small outlet width. Under the condition of H >3 d, a bigger flow rate was obtained at a smaller funnel half-angle. This new funnel structure could be applied to solve clogging problems associated with granular matter in the slit geometry in mining, agriculture, food, and pharmaceuticals.

Adaptive Bidirectional Gray-Scale Center of Gravity Extraction Algorithm of Laser Stripes.

Aiming at the realization of fast and high-precision detection of the workpiece, an adaptive bidirectional gray-scale center of gravity extraction algorithm for laser stripes is proposed in this paper. The algorithm is processed in the following steps. Firstly, the initial image processing area is set according to the floating field of the camera's light stripe, followed by setting the adaptive image processing area according to the actual position of the light stripe. Secondly, the center of light stripe is obtained by using the method of combining the upper contour with the barycenter of the bidirectional gray-scale. The obtained center of the light stripe is optimized by reducing the deviation from adjacent center points. Finally, the slope and intercept are used to complete the breakpoint. The experimental results show that the algorithm has the advantages of high speed and precision and has specific adaptability to the laser stripes of the complex environment. Compared with other conventional algorithms, it greatly improves and can be used in industrial detection.

Design and fabrication of an integrated 3D dynamic multicellular liver-on-a-chip and its application in hepatotoxicity screening.

Nowadays, major methods of in vitro hepatotoxicity research are still based on traditional static two- or three-dimensional cell culture, although these means could investigate some toxic chemicals induced hepatotoxicity, but most of these toxicities failed to reappear in human, at least not in similar or calculable dose level. These failures may cause by the monoculture of only hepatocytes, ignored the signal communication to other non-parenchymal cells in liver tissue, also other complex microenvironment such as endothelial barrier, shear stress and other factors which were really existed in vivo but absent here, final leading to a low reliability of experimental results. In this study, a three-dimensional dynamic multi-cellular liver-on-a-chip device (3D-DMLoC) was developed to reproduce the microenvironment of in vivo liver tissue, including the simulation of hepatic sinusoid, perisinusoidal space and continuous liquid perfusion, hepatocytes could gather to some 3D cell spheroids in this chip. The perfusion could bring a real-time exchange of chemicals, nutrients, metabolites, supply suitable oxygen and a weak shear stress. The pressure and oxygen distribution inner the chip were simulated and evaluated by COMSOL Multiphysics software. HepaRG were co-cultured with HUVEC for 7 days in this chip, expression of hepatic polarization protein ZO-1 and MRP2, liver function factors ALB, UREA and CYP450s were almost all higher than in traditional static culture. Several drugs and heavy metal ions induced hepatotoxicity were then investigated, LDH released from hepatocyte spheroids in mostly 3D-DMLoC groups were higher than same-dosed 2D group, indicated the spheroids were more sensibility to the toxins. The hepatoxicity might be induced by acute hepatocytes injury according to the ratios of secreted AST/ALT contents. In conclusion, a liver-on-a-chip device was successfully developed and verified for better reproducing the in vivo physiological microenvironment of liver. It could be applied for easily, efficiently, and accurately screening the potential hepatotoxic chemicals in future.

Integrated Proteomics, Biological Functional Assessments, and Metabolomics Reveal Toosendanin-Induced Hepatic Energy Metabolic Disorders.

Toosendanin (TSN), a compound from Melia toosendan, exhibits severe hepatotoxicity, which restricts its clinical application. However, the mechanism is not clear. Our previous research found that covalent modification of TSN for proteins might be a possible reason using human liver microsomes, and the glycolytic enzymes, triosephosphate isomerase 1 (TPIS) and α-enolase (ENOA), were responsible for the hepatotoxicity. In this study, we tried to prove these findings in cell and animal models by integration of proteomics, metabolomics, and biological methods. Proteomics analysis in rats showed that TPIS and ENOA were covalently modified by TSN reactive metabolites. The biological functional assessments revealed that the modifications inhibited the activity of TPIS and induced the activity of ENOA, in vitro and in vivo, followed by an increase in the level of cellular methylglyoxal, advanced glycation end products, and reactive oxygen species/superoxide, and the induction of mitochondrial dysfunction, which further inhibited oxidative phosphorylation and stimulated glycolysis. Furthermore, metabolomics demonstrated the decrease in the level of metabolites in the tricarboxylic acid cycle, fatty acid ß-oxidation, and amino acid metabolism; i.e., TSN induced hepatocyte energy metabolism disorder. In conclusion, these data suggest novel mechanistic insights into TSN-induced liver injury on the upstream level and provide valuable proteins and energy metabolic targets for diagnosis and therapy in the clinic.

Design and fabrication of a liver-on-a-chip platform for convenient, highly efficient, and safe in situ perfusion culture of 3D hepatic spheroids.

Spheroid-based three-dimensional (3D) liver culture models, offering a desirable biomimetic microenvironment, are useful for recapitulating liver functions in vitro. However, a user-friendly, robust and specially optimized method has not been well developed for a convenient, highly efficient, and safe in situ perfusion culture of spheroid-based 3D liver models. Here, we have developed a biomimetic and reversibly assembled liver-on-a-chip (3D-LOC) platform and presented a proof of concept for long-term perfusion culture of 3D human HepG2/C3A spheroids for building a 3D liver spheroid model. On the basis of a fast and reversible seal of concave microwell-based PDMS-membrane-PDMS sandwich multilayer chips, it enables a high-throughput and parallel perfusion culture of 1080 cell spheroids in a high mass transfer and low fluid shear stress biomimetic microenvironment as well as allowing the convenient collection and analysis of the cell spheroids. In terms of reducing spheroid loss and maintaining cell morphology and viability in long-term perfusion culture, the cell spheroids in the 3D-LOC were more safe and efficient. Notably, the polarisation, liver-specific functions, and metabolic activity of the cell spheroids in 3D-LOC were also remarkably improved and exhibited better long-term maintenance over conventional perfusion methods. Additionally, a robust micromilling method that incorporates secondary PDMS coating techniques (SPCs) for fabricating V-shaped concave microwells was also developed. The V-shaped concave microwell arrays exhibited a higher distribution density and aperture ratio, making it easy to form large-scale and uniform-sized cell spheroids with minimum cell loss. In summary, the proposed 3D-LOC could provide a convenient and robust solution for the long-term safe perfusion culture of hepatic spheroids and be beneficial for a variety of potential applications including development of bio-artificial livers, disease modeling, and drug toxicity screening.

Temperature and energy effects on secondary electron emission from SiC ceramics induced by Xe17+ ions.

Secondary electron emission yield from the surface of SiC ceramics induced by Xe17+ ions has been measured as a function of target temperature and incident energy. In the temperature range of 463-659 K, the total yield gradually decreases with increasing target temperature. The decrease is about 57% for 3.2 MeV Xe17+ impact, and about 62% for 4.0 MeV Xe17+ impact, which is much larger than the decrease observed previously for ion impact at low charged states. The yield dependence on the temperature is discussed in terms of work function, because both kinetic electron emission and potential electron emission are influenced by work function. In addition, our experimental data show that the total electron yield gradually increases with the kinetic energy of projectile, when the target is at a constant temperature higher than room temperature. This result can be explained by electronic stopping power which plays an important role in kinetic electron emission.