Coded Excitation for Ultrasonic Testing: A Review

Originating in the early 20th century, ultrasonic testing has found increasingly extensive applications in medicine, industry, and materials science. Achieving both a high signal-to-noise ratio and high efficiency is crucial in ultrasonic testing. The former means an increase in imaging clarity as well as the detection depth, while the latter facilitates a faster refresh of the image. It is difficult to balance these two indicators with a conventional short pulse to excite the probe, so in general handling methods, these two factors have a trade-off. To solve the above problems, coded excitation (CE) can increase the pulse duration and offers great potential to improve the signal-to-noise ratio with equivalent or even higher efficiency. In this paper, we first review the fundamentals of CE, including signal modulation, signal transmission, signal reception, pulse compression, and optimization methods. Then, we introduce the application of CE in different areas of ultrasonic testing, with a focus on industrial bulk wave single-probe detection, industrial guided wave detection, industrial bulk wave phased array detection, and medical phased array imaging. Finally, we point out the advantages as well as a few future directions of CE

Noninvasive Detection of Salt Stress in Cotton Seedlings by Combining Multicolor Fluorescence–Multispectral Reflectance Imaging with EfficientNet-OB2

Salt stress is considered one of the primary threats to cotton production. Although cotton is found to have reasonable salt tolerance, it is sensitive to salt stress during the seedling stage. This research aimed to propose an effective method for rapidly detecting salt stress of cotton seedlings using multicolor fluorescence–multispectral reflectance imaging coupled with deep learning. A prototyping platform that can obtain multicolor fluorescence and multispectral reflectance images synchronously was developed to get different characteristics of each cotton seedling. The experiments revealed that salt stress harmed cotton seedlings with an increase in malondialdehyde and a decrease in chlorophyll content, superoxide dismutase, and catalase after 17 days of salt stress. The Relief algorithm and principal component analysis were introduced to reduce data dimension with the first 9 principal component images (PC1 to PC9) accounting for 95.2% of the original variations. An optimized EfficientNet-B2 (EfficientNet-OB2), purposely used for a fixed resource budget, was established to detect salt stress by optimizing a proportional number of convolution kernels assigned to the first convolution according to the corresponding contributions of PC1 to PC9 images. EfficientNet-OB2 achieved an accuracy of 84.80%, 91.18%, and 95.10% for 5, 10, and 17 days of salt stress, respectively, which outperformed EfficientNet-B2 and EfficientNet-OB4 with higher training speed and fewer parameters. The results demonstrate the potential of combining multicolor fluorescence–multispectral reflectance imaging with the deep learning model EfficientNet-OB2 for salt stress detection of cotton at the seedling stage, which can be further deployed in mobile platforms for high-throughput screening in the field

Anti-Autophagy Mechanism of Zhi Gan Prescription Based on Network Pharmacology in Nonalcoholic Steatohepatitis Rats

Background and Aims: Zhi Gan prescription (ZGP) has been clinically proven to exert a favorable therapeutic effect on nonalcoholic steatohepatitis (NASH). This study purpose to reveal the underlying molecular mechanisms of ZGP action in NASH.Methods: Systematic network pharmacology was used to identify bioactive components, potential targets, and the underlying mechanism of ZGP action in NASH. High fat (HF)-induced NASH model rats were used to assess the effect of ZGP against NASH, and to verify the possible molecular mechanisms as predicted by network pharmacology.Results: A total of 138 active components and 366 potential targets were acquired in ZGP. In addition, 823 targets of NASH were also screened. In vivo experiments showed that ZGP significantly improved the symptoms in HF-induced NASH rats. qRT-PCR and western blot analyses showed that ZGP could regulate the hub genes, PTEN, IL-6 and TNF in NASH model rats. In addition, ZGP suppressed mitochondrial autophagy through mitochondrial fusion and fission via the PINK/Parkin pathway.Conclusion: ZGP exerts its effects on NASH through mitochondrial autophagy. These findings provide novel insights into the mechanisms of ZGP in NASH.</jats:p

Novel Natural Cellulosic Fiber from Lotus Stem: Structure and Performance Characterization

The systematic exploration of the application prospects of lotus stem fibers (LSFs) in natural composites is significantly important for the development of green, lightweight, functional biomass materials and products. In this study, the physical and chemical properties, micro/nano structures, micromechanical characteristics, cellulose crystallinity, and thermal stability of LSFs were systematically explored. The density, microstructure, and nanoindentation analyses revealed that the LSF is a lightweight natural fiber with a high modulus (11.2–11.7 GPa) and a good hardness (0.41–0.57 GPa). The transmission electron microscopy analysis indicated the existence of four types of sclerenchyma cells in a gradient distribution in the epidermis and exodermis of the LS. The chemical analysis, X-ray diffraction, and Fourier transform infrared spectroscopy indicated that the outer-layer LSFs have a high cellulose content (44.73%), high relative crystallinity index (49.2%) of cellulose, and small cellulose crystallite size (2.2 nm). As a result, these LSFs possess good mechanical properties

Exploring the interconnectivity of biomimetic hierarchical porous Mg scaffolds for bone tissue engineering: Effects of pore size distribution on mechanical properties, degradation behavior and cell migration ability

Interconnectivity is the key characteristic of bone tissue engineering scaffold modulating cell migration, blood vessels invasion and transport of nutrient and waste. However, efforts and understanding of the interconnectivity of porous Mg is limited due to the diverse architectures of pore struts and pore size distribution of Mg scaffold systems. In this work, biomimetic hierarchical porous Mg scaffolds with tailored interconnectivity as well as pore size distribution were prepared by template replication of infiltration casting. Mg scaffold with better interconnectivity showed lower mechanical strength. Enlarging interconnected pores would enhance the interconnectivity of the whole scaffold and reduce the change of ion concentration, pH value and osmolality of the degradation microenvironment due to the lower specific surface area. Nevertheless, the degradation rates of five tested Mg scaffolds were no different because of the same geometry of strut unit. Direct cell culture and evaluation of cell density at both sides of four typical Mg scaffolds indicated that cell migration through hierarchical porous Mg scaffolds could be enhanced by not only bigger interconnected pore size but also larger main pore size. In summary, design of interconnectivity in terms of pore size distribution could regulate mechanical strength, microenvironment in cell culture condition and cell migration potential, and beyond that it shows great potential for personalized therapy which could facilitate the regeneration process

Effects of Dynamic Flow Rates on Degradation Deposition Behavior of Mg Scaffold

Degradability of bone tissue engineering scaffold that matching the regeneration rate could allow a complete replacement of host tissue. However, the porous structure of biodegradable Mg scaffolds certainly generated high specific surface area, and the three-dimensional interconnected pores provided fast pervasive invasion entrance for the corrosive medium, rising concern of the structural integrity during the degradation. To clarify the structural evolution of the three-dimensional (3D) porous structure, semi-static immersion tests were carried out to evaluate the degradation performance in our previous study. Nevertheless, dynamic immersion tests mimicking the in vivo circulatory fluid through the interconnected porous structure have yet been investigated. Moreover, the effects of dynamic flow rates on the degradation deposition behavior of 3D porous Mg scaffolds were rarely reported. In this study, Mg scaffolds degraded at three flow rates exhibited different degradation rates and deposition process. A flow rate of 0.5 mL/min introduced maximum drop of porosity by accumulated deposition products. The deposition products provided limited protection against the degradation process at a flow rate of 1.0 mL/min. The three-dimensional interconnected porous structure of Mg scaffold degraded at 2.0 mL/min well retained after 14 days showing the best interconnectivity resistance to the degradation deposition process. The dynamic immersion tests disclosed the reason for the different degradation rates on account of flow rates, which may bring insight into understanding of varied in vivo degradation rates related to implantation sites. © 202

Rosmarinic Acid Inhibits Mitochondrial Damage by Alleviating Unfolded Protein Response

Mitochondria are essential organelles that perform important roles in cell biologies such as ATP synthesis, metabolic regulation, immunomodulatory, and apoptosis. Parkinson’s disease (PD) is connected with mitochondrial neuronal damage related to mitochondrial unfolded protein response (mtUPR). Rosmarinic acid (RA) is a naturally occurring hydroxylated polyphenolic chemical found in the Boraginaceae and the Labiatae subfamily Nepetoideae. This study looked into RA’s protective effect against mitochondrial loss in the substantia nigra (SN) caused by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), the underlying mechanism associated with the mtUPR. Pretreatment with RA reduced motor impairments and dopaminergic neuronal degeneration in the SN of a mouse model injected with MPTP. Pretreatment of SH-SY5Y cells from cell viability loss, morphological damage, and oxidative stress. Furthermore, RA pre-injection suppressed MPTP-induced mtUPR, lowered the expression of HSPA9, HSPE1, CLPP, LONP1, and SIRT 4, and protected the MPTP-mice and SH-SY5Y cells from mitochondrial failure. These findings imply that RA can prevent Parkinson’s disease by preventing mitochondrial damage in dopaminergic neurons in Parkinson’s disease via alleviating mitochondrial unfolded protein response.</jats:p