417 results on '"Yaowen Liu"'
Search Results
2. Electrochemical C−H deuteration of pyridine derivatives with D2O
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Zhiwei Zhao, Ranran Zhang, Yaowen Liu, Zile Zhu, Qiuyan Wang, and Youai Qiu
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Science - Abstract
Abstract Herein, we develop a straightforward, metal-free, and acid-/base-free electrochemical C4-selective C − H deuteration of pyridine derivatives with economic and convenient D2O at room temperature. This strategy features an efficient and environmentally friendly approach with high chemo- and regioselectivity, affording a wide range of D-compounds, such as pyridines, quinolones, N-ligands and biorelevant compounds. Notably, the mechanistic experiments and cyclic voltammetry (CV) studies demonstrate that N-butyl-2-phenylpyridinium iodide is a crucial intermediate during the electrochemical transformation, which provides a general and efficient way for deuteration of pyridine derivatives.
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- 2024
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3. Strain-modulated magnetic droplet precession in spin-torque nano-oscillators
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Sai Zhou, Cuixiu Zheng, Haoxiang Xu, and Yaowen Liu
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Physics ,QC1-999 - Abstract
In this paper, we present a promising method for modulating the frequency of magnetic droplets using strain induced by an adjacent piezoelectric layer. This strain results in significant changes in droplet frequency (∼6 GHz) and variations in diameter or mode, while maintaining a fixed current density of 1.4×10^{12}A/m^{2} under both high and low fields. By applying strain pulses, we successfully modulate the magnetic droplet frequency, paving the way for potential implementation of digital binary frequency shift-keying modulation technique with magnetic droplets. Moreover, the effects of Oersted field and the Zhang-Li torque induced by lateral current have also been discussed, showing a minimal impact on the oscillation frequencies, especially at high fields.
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- 2024
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4. Aging related obesity and type 2 diabetes mellitus suppress neuromuscular communication and aggravate skeletal muscle dysfunction in rhesus monkeys
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Shaoxia Pu, Yaowen Liu, Wenjun Wu, Fei Sun, Hongsheng Lu, Xiaocui Xu, Yanhua Su, Wenming Cheng, and Haizhen Wang
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Rhesus monkeys ,Obesity ,Type 2 diabetes ,Aging ,Muscle proteome ,Science (General) ,Q1-390 ,Social sciences (General) ,H1-99 - Abstract
Age-related functional deterioration in skeletal muscle raises the risk for falls, disability, and mortality in the elderly, particularly in obese people or those with type 2 diabetes mellitus (T2D). However, the response of the skeletal muscle to transitioning from obesity to diabetes remains poorly defined, despite that obesity is classified as a stage of pre-diabetes. We screened and selected spontaneously obese and diabetic rhesus monkeys and examined altered protein expression in skeletal muscle of healthy aging (CON), obesity aging (OB), and type 2 diabetes mellitus aging (T2D) rhesus monkeys using Tandem Mass Tags (TMT)-based quantitative proteomic analysis. In total, we identified 142 differentially expressed proteins. Muscle-nerve communication proteins were firstly suppressed at obese-stage. With the disintegration of skeletal muscle, mitochondrial complex I and other energy homeostasis relate proteins were significantly disordered at T2D stage. Indicating that aging related obesity suppressed muscle-nerve communication and contribute to T2D related functional deterioration of skeletal muscles in elderly rhesus monkeys. Some alterations of muscular functional regulator are detected in both obesity and T2D samples, suggesting some T2D related skeletal muscular hypofunctions are occurring at obesity or pre-obesity stage. Muscle-nerve communication proteins and muscular function related proteins could be potential therapy target or early diagnose marker of for skeletal muscular hypofunctions in aging obesity populations.
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- 2024
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5. Complete mitochondrial genome of Mastigias papua (Scyphozoa: Rhizostomeae: Mastigiidae) based on next-generation sequencing and phylogenetic analysis
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Wangxiao Xia, Hui Jiang, Wenbo Fan, Xiaomin Li, Yaowen Liu, Lixian Xu, and Xingchun Gou
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Mastigias papua ,mitochondrial genome ,next-generation sequencing ,phylogenetic analysis ,Genetics ,QH426-470 - Abstract
AbstractWe assembled the complete mitochondrial genome (mitogenome) of Mastigias papua (Scyphozoa: Rhizostomeae: Mastigiidae) by the data generated from the next-generation sequencing platform. The complete mitogenome of M. papua was 16,560 bp in length, containing 14 protein-coding genes, two transfer RNA genes, and two ribosomal RNA genes. The base compositions were A 30.65%, C 15.16%, G 16.34%, and T 37.86%, with a gene arrangement similar to the mitogenomes derived from other representatives of Scyphozoa. Based on the 13 common protein-coding genes of 16 species within Scyphozoa, we constructed the phylogenetic tree and found that M. papua has a close relationship with Cassiopea andromeda and Cassiopea xamachana. All these species belong to an order of jellyfish Rhizostomeae, which have similar morphological characteristics. This is agreement with the conclusion we got by the phylogenetic relationship analysis using molecular data. This research has practical implications for advancing understanding of the phylogenetic relationships, taxonomic classifications, and phylogeography within Scyphozoa.
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- 2023
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6. Pineapple Detection with YOLOv7-Tiny Network Model Improved via Pruning and a Lightweight Backbone Sub-Network
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Jiehao Li, Yaowen Liu, Chenglin Li, Qunfei Luo, and Jiahuan Lu
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object detection ,neural network ,YOLOv7-tiny ,lightweight ,model pruning ,pineapple detection ,Science - Abstract
High-complexity network models are challenging to execute on agricultural robots with limited computing capabilities in a large-scale pineapple planting environment in real time. Traditional module replacement often struggles to reduce model complexity while maintaining stable network accuracy effectively. This paper investigates a pineapple detection framework with a YOLOv7-tiny model improved via pruning and a lightweight backbone sub-network (the RGDP-YOLOv7-tiny model). The ReXNet network is designed to significantly reduce the number of parameters in the YOLOv7-tiny backbone network layer during the group-level pruning process. Meanwhile, to enhance the efficacy of the lightweight network, a GSConv network has been developed and integrated into the neck network, to further diminish the number of parameters. In addition, the detection network incorporates a decoupled head network aimed at separating the tasks of classification and localization, which can enhance the model’s convergence speed. The experimental results indicate that the network before pruning optimization achieved an improvement of 3.0% and 2.2%, in terms of mean average precision and F1 score, respectively. After pruning optimization, the RGDP-YOLOv7-tiny network was compressed to just 2.27 M in parameter count, 4.5 × 109 in computational complexity, and 5.0MB in model size, which were 37.8%, 34.1%, and 40.7% of the original YOLOv7-tiny network, respectively. Concurrently, the mean average precision and F1 score reached 87.9% and 87.4%, respectively, with increases of 0.8% and 1.3%. Ultimately, the model’s generalization performance was validated through heatmap visualization experiments. Overall, the proposed pineapple object detection framework can effectively enhance detection accuracy. In a large-scale fruit cultivation environment, especially under the constraints of hardware limitations and limited computational power in the real-time detection processes of agricultural robots, it facilitates the practical application of artificial intelligence algorithms in agricultural engineering.
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- 2024
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7. Magnon Excitation Modes in Ferromagnetic and Antiferromagnetic Systems
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Xing Chen, Cuixiu Zheng, and Yaowen Liu
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magnon spintronics ,antiferromagnets ,magnetization dynamics ,ferromagnetic resonance ,magnon-magnon coupling ,Chemistry ,QD1-999 - Abstract
Magnons, recognized as the quanta of spin waves, offer a pathway for transmitting information without the need for electron motion, thus emerging as a leading candidate for the next generation of low-power electronics. Firstly, this study gives an overview by examining magnon modes possessing infinite wavelengths or zero wave numbers (known as ferromagnetic resonance) in classical ferromagnetic, antiferromagnetic, and synthetic antiferromagnetic systems. It delves into the dynamics of magnetization, particularly focusing on magnetic moments precession and the corresponding dispersion relationships under two distinct acoustic and optic eigenmodes. Furthermore, it elaborates on a novel hybrid quantum system termed magnon-magnon coupling. The study elucidates the mechanism behind the robust coupling between acoustic and optic magnon modes. Finally, we briefly discuss the current challenges and future research directions in this field.
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- 2024
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8. Sub-terahertz excitations in a synthetic antiferromagnet with perpendicular anisotropy
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Cuixiu Zheng, Chao Chen, Shanshan Hu, Sai Zhou, Hao-Hsuan Chen, and Yaowen Liu
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Biotechnology ,TP248.13-248.65 ,Physics ,QC1-999 - Abstract
In this paper, micromagnetic simulations are employed to investigate terahertz (THz) magnetic excitations in a spin torque nano-oscillator (STNO) with a perpendicularly magnetized synthetic antiferromagnetic (SAF) free layer. The magnetization precession of the free layer can be finely tuned into the sub-THz range without the necessity of external magnetic fields. The excited frequency exhibits two distinctive regions, namely region-I and region-II, depending on the applied current strength. In region-I, characterized by relatively small currents, the two ferromagnetic layers are stabilized at two separate precession orbits. The frequency in this region decreases with current strength, exhibiting similar features as the Néel vector change observed in antiferromagnets. In contrast, region-II is defined by currents where the two ferromagnetic layers synchronize into the same precession orbit. The frequency increases with current, correlating with the variation in the net magnetization of the SAF layer. An analytical model is developed through the canonical transformation of Lagrange’s equation, which can describe the frequency dependence on both the applied current and the antiferromagnetic interlayer coupling strengths. The simulations and the analytical model show good agreement, offering a more profound understanding of the magnetic excitation properties in STNOs with ultrathin SAF free layers. These insights are crucial for the design of advanced terahertz spintronic devices.
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- 2024
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9. Impact of exercise training on gut microbiome imbalance in obese individuals: a study based on Mendelian randomization analysis
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Haonan Qian, Yuxin Zuo, Shixiong Wen, Xilong Wang, Yaowen Liu, and Tianwei Li
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gut microbiome ,exercise ,microbial community ,causality ,Mendelian randomization ,Physiology ,QP1-981 - Abstract
Objective: The aim of this study was to investigate the relationship between exercise and gut Microbiome and to assess its possible causality.Methods: Using Mendelian randomization (MR) research methods, we collected genetic data from different populations, including genetic variants associated with relative abundance or presence of microbial taxa as instrumental variables. At the same time, we extracted results related to obesity and gut Microbiome from existing relevant studies and used inverse variance weighting (IVW), weighted median, and MR-Egger regression to assess the causal relationship between obesity and gut Microbiome. We plotted forest plots and scatter plots of the association between obesity and gut Microbiome.Results: Gut Microbiome was positively associated with obesity, and four bacterial genera (Akkermansia, RuminococcaceaeUCG011, Holdemania, and Intestinimonas) were associated with obesity according to inverse variance-weighted estimation in at least one MR method. Inverse variance weighted estimation showed that obesity was associated with obesity in Akkermansia (OR = 0.810, 95% CI 0.608–1.079, p = 0.04), RuminococcaceaeUCG011 (OR = 1.238, 95% CI 0. 511–2.999, p = 0.04), Holdemania Intestinimonas (OR = 1.214, 95% CI 1.002–1.470, p = 0.03), and Intestinimonas (OR = 0.747, 95% CI 0.514–1.086, p = 0.01) had a relevant effect. Obesity decreased the abundance of Akkermansia, Intestinimonas microbiome and increased the abundance of RuminococcaceaeUCG011, Holdemania microbiome.Conclusion: The results of this study, conducted using a two-sample Mendelian randomization method, suggest a causal relationship between obesity and intestinal microbiome. Obesity decreased the abundance of Akkermansia, Intestinimonas microbiome and increased the abundance of RuminococcaceaeUCG011, Holdemania microbiome. More randomized controlled trials are necessary to elucidate the protective effects of exercise on gut Microbiome and its unique protective mechanisms.
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- 2024
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10. Impact of supplement of Qingke flours on physiochemical properties, sensory and in vitro starch digestibility of wheat bread and its enhancement by bread quality improvers
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Shang Lin, Bingyu Huang, Shuxiang Liu, Yaowen Liu, Qing Zhang, and Wen Qin
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Qingke ,Hydroxypropyl methylcellulose ,Sodium stearoyl lactylate ,Transglutaminase ,Starch digestibility ,Nutrition. Foods and food supply ,TX341-641 ,Food processing and manufacture ,TP368-456 - Abstract
The aim is to upgrade the formulation to produce wheat bread with lower starch digestibility by supplemented with Qingke flour. Physiochemical properties of multi-scale Qingke flours were examined to select the most satisfied Qingke flour for breadmaking. Data showed multi-scale Qingke samples differed in total starch content, water/oil binding capacity, freeze–thaw stability, but had similar swelling capacity and thermodynamic properties. Addition of Qingke flours significantly reduced the total in vitro starch digestion of bread from 80% to 41% and decreased the rapidly digested starch content from 53% to 27%. However, Qingke flours caused a worse bread quality, texture and sensory e.g. lower bread specific volume (4.26–3.3 mL/g), larger hardness (398–1170 g) and chewiness (296–707 mJ). Meanwhile, hydroxypropyl methylcellulose, sodium stearoyl lactylate and transglutaminase could improve the bread quality and sensory. Lastly, results revealed Qingke-supplemented bread could generate new volatile compounds, hence having a different aroma compared to original wheat bread.
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- 2023
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11. A Local-Global Feature Fusing Method for Point Clouds Semantic Segmentation
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Yuanwei Bi, Lujian Zhang, Yaowen Liu, Yansen Huang, and Hao Liu
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Feature cross enhancement ,global feature extraction ,point clouds ,semantic segmentation ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
In recent years, the abundance of information in 3D data has made the semantic segmentation of 3D point clouds a topic of great interest. However, current methods often rely solely on the original three-dimensional coordinates of the point cloud as input geometric features, leading to poor generalization performance. Additionally, occlusion of the point cloud data can negatively impact segmentation accuracy when only local information is considered. To address these issues, this paper proposes a network named LGFF-Net. To fully utilize the original information of point clouds, we designed a Local Feature Aggregation (LFA) module that treats geometric and semantic information equally and preserves the original properties while cross-augmenting them. On the other hand, we proposed a simple and effective Global Feature Extraction (GFE) module to extract global features. Finally, we hierarchically fuse local and global features using a U-shaped segmentation structure. Compared to state-of-the-art networks, our method achieves competitive results on several benchmark datasets, including Semantic Topographic Point Labeling-Synthetic 3D, Toronto_3D, Stanford Large 3-D Indoor Space, and ScanNet. We also conduct multiple ablation experiments to validate the efficacy of LGFF-Net.
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- 2023
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12. Macroscopic Electromagnetic Cooperative Network-Enhanced MXene/Ni Chains Aerogel-Based Microwave Absorber with Ultra-Low Matching Thickness
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Fei Pan, Yanping Rao, Dan Batalu, Lei Cai, Yanyan Dong, Xiaojie Zhu, Yuyang Shi, Zhong Shi, Yaowen Liu, and Wei Lu
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Electromagnetic wave absorption ,Ti3CNTx MXene ,Highly oriented Ni chains ,Electromagnetic cooperation ,Magnetic coupling ,Technology - Abstract
Abstract Electromagnetic cooperative strategy has been presented as a mainstream approach that can effectively optimize the matching thickness of dielectric loss dominant system. However, it is still challenging for dielectric–magnetic loss coexisting-type absorber to develop electromagnetic wave (EMW) performance with ultra-low matching thickness (≤ 1 mm). Breaking the limitation of traditional electromagnetic response at microscopic/mesoscopic scale, a ficus microcarpa-like magnetic aerogel with macroscopical electromagnetic cooperative effect was fabricated through highly oriented self-assembly engineering. The highly oriented Ni chains with unique macroscopic morphology (~ 1 cm in length) were achieved via a special magnetic field-induced growth. Strong magnetic coupling was observed in the Ni chains confirmed by the micromagnetic simulation. The deductive calculation validates that maintaining high value of electromagnetic parameters at high frequencies is the prerequisites of ultrathin absorber. The electromagnetic cooperative networks with uninterrupted and dual pathways spread through the entire aerogel skeleton, resulting in the impressive permittivity even at high frequencies. Consequently, the aerogel exhibits a remarkable EMW performance at an ultrathin thickness of 1 mm. Thus, based on the modulation of electromagnetic parameters, this work proposed a macroscopic ordered structure with the electromagnetic cooperative effect useful to develop a suitable strategy for achieving ultrathin EMW absorbers.
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- 2022
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13. Effects of different levels of nano-selenium on growth performance, antioxidant capacity, biochemical parameters, and selenium content in Landes geese
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Yaowen Liu, Xu Liu, Xinghua Xiang, Xiangyong Qu, and Songchang Guo
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antioxidant status ,average daily gain ,diets ,serum biochemical parameters ,supplementation ,Animal culture ,SF1-1100 - Abstract
ABSTRACT The objective of this study was to evaluate the effects of dietary supplementation with different levels of nano-selenium (NS) on growth performance, antioxidant activity, biochemical parameters, and selenium content in Landes geese. A total of 120 80-week-old healthy Landes geese (4.44±0.03 kg) were randomly assigned to three groups, each with four replicates of 10 birds. The control birds were fed a basal diet without further dietary supplementation (0.0 mg/kg of NS) and the two experimental groups were fed the basal diet supplemented with dietary NS at 0.2 or 0.4 mg/kg of feed. The results demonstrated that NS dietary supplementation had no significant effect on growth performance. Increased total superoxide dismutase activity in serum, breast muscle and liver, glutathione peroxidase level in serum and liver, and catalase in breast muscle and liver were observed for both NS supplemented groups. Additionally, reduced malondialdehyde in serum, breast muscle, and liver was detected in both NS-supplemented groups. Compared with the control, the birds fed diets supplemented with NS had lower concentrations of alanine aminotransferase, triglyceride, aspartate aminotransferase, and low-density lipoprotein cholesterol in serum, while high-density lipoprotein cholesterol was increased. Furthermore, increased selenium, especially in the liver, was found in groups with dietary supplementation of NS. These findings suggest the supplementation of NS in diets can improve antioxidant status, biochemical parameters, and tissue selenium content, although it has no significant effect on growth performance of Landes geese.
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- 2023
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14. Effect of water-in-oil-in-water (W/O/W) double emulsions to encapsulate nisin on the quality and storage stability of fresh noodles
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Songming Luo, Jundong Chen, Yuanbo Zeng, Jianwu Dai, Suqing Li, Jing Yan, and Yaowen Liu
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Rock bean protein ,Microcapsules ,Noodles ,Nutrition. Foods and food supply ,TX341-641 ,Food processing and manufacture ,TP368-456 - Abstract
Rock-bean protein (RP) was extracted from wild rock beans by ultrasonic treatment and microwave extraction. The RP has a high content of 7S and 11S globulin components and good heat stability. Subsequently, water-oil-water double emulsions were prepared using a water core containing nisin, momordica charantia extract (MCE), and Lactobacillus plantarum as functional additives, corn oil as the intermediate wall, and RP/gum arabic (GA) as the outer wall material. For a ratio of corn oil to water of 5:1, the maximum encapsulation efficiency was 28.22%, and RP/GA had good dispersion characteristics, where the smallest average particle size was achieved for a 1:1 ratio. Finally, the microcapsules were used to study the effect of its addition to noodles. The addition of 2 wt% of the microcapsules to low-gluten flour resulted in a dough with suitable rheology, and can extend the shelf life of the fresh noodles prepared using this dough.
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- 2022
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15. Effect of initial water content and dry density on the self-healing of desiccation cracks in compacted hipparion red clay
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Yanbo Zhu, Huitao Zheng, Hengxing Lan, Yaowen Liu, Langping Li, Boyu Fu, and Changcheng Du
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Hipparion red clay ,desiccation crack ,crack self-healing ,critical water content ,self-healing amount ,Science - Abstract
The self-healing of desiccation cracks in compacted clayey soils is important for mechanism revelation of cracking behavior in compacted soils. Although the crack self-healing behavior has been found, the influence of soil physical indices on it is still unclear, especially initial water content and dry density of specimen. This study aims to identify and evaluate the effect of initial water content and dry density on self-healing of desiccation cracks. Firstly, a series of desiccation tests were conducted on compacted Hipparion red clay specimens under different initial conditions. Secondly, the two-dimensional morphology of desiccation cracks and strain field changes on specimen surface were examined using the pore and crack analysis system and digital image correlation techniques. The result shows that the desiccation cracks on specimen surface exhibits self-healing behavior during drying. Based on the observed crack self-healing behavior, the desiccation cracking of compacted Hipparion red clay undergoes four stages including initiation, development, self-healing, and stabilization. During the self-healing stage, the critical water content for occurrence of crack self-healing and the crack self-healing amount referring to the crack ratio reduction from peak value to the stable value, are dry density dependent and water content dependent variables. In particular, the higher the initial water content and the lower the dry density of compacted specimen are, the larger the crack self-healing amount is. This crack self-healing difference in specimen with different initial conditions is caused by the vertical anisotropic shrinkage of substrate soil below non-propagating cracks due to its pore structure difference. This study provides a new perspective on the mechanism of desiccation crack in clayey soils affected by initial conditions.
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- 2022
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16. Combination of calcium lactate impregnation with UV-C irradiation maintains quality and improves antioxidant capacity of fresh-cut kiwifruit slices
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Xiaomin Hu, Yi Chen, Xinye Wu, Wenxin Liu, Xianyu Jing, Yaowen Liu, Jing Yan, Shuxiang Liu, and Wen Qin
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Fresh-cut fruits and vegetables ,Antioxidant defense capacity ,Antioxidant enzymes ,Phenolic ,Correlation analysis ,Nutrition. Foods and food supply ,TX341-641 ,Food processing and manufacture ,TP368-456 - Abstract
This study investigated the combined effects of calcium lactate (CA-L, 3 g L−1) and shortwave ultraviolet (UV-C, 4.0 kJ m−2) irradiation on quality attributes and antioxidant defense capacity of fresh-cut kiwifruits at refrigerated storage for 7 d. The results indicated that CA-L and UV-C joint treatment, compared to either treatment alone, alleviated microbial load, showed higher quality on ascorbic acid (AsA), green color, total chlorophyll, flesh hardness, total sugar, total acid and malonaldehyde (MDA) content. Besides, it inhibited O2·- and ·OH generation, induced H2O2 production, improved the activity of antioxidant enzymes (SOD, CAT and APX), activated critical enzymes (PAL, C4H and 4CL) in phenylpropanoid metabolism pathway and further enhanced total phenolic and proanthocyanidin content. Above results demonstrated that UV-C together with CA-L treatment could synergistically maintain overall quality and improve antioxidant capacity of kiwifruit slices. Therefore, the combination of CA-L and UV-C treatment showed a potential practical application in fresh-cut kiwifruits.
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- 2022
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17. Comparison of performance, fatty acid composition, enzymes and gene expression between overfed Xupu geese with large and small liver
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Xu Liu, Yaowen Liu, Hao Cheng, Yuying Deng, Xiaowei Xiong, and Xiangyong Qu
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xupu geese ,liver ,serum parameters ,fatty acid composition ,genes expression ,Animal culture ,SF1-1100 - Abstract
The aim of our study was to compare overfeeding performance, fatty acid composition, enzymes activity and gene expression between overfed Xupu geese with large and small liver. A total of sixty 80 d male Xupu geese were overfed by the same feed intake under the same conditions. The liver weight exhibited normal distribution. Based on the weight of liver, samples were divided into large liver (LL) and small liver (SL) Xupu geese. After overfeeding for 28 d: compared with the SL-Xupu geese, liver weight and liver-to-body weight ratio increased (p
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- 2021
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18. Efficacy and Mechanism of Thymol/KGM/LG Edible Coating Solution on Inhibition of Mucor circinelloides Isolated From Okra
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Qinqiu Zhang, Wen Qin, Xinjie Hu, Jing Yan, Yaowen Liu, Zhuwei Wang, Lang Liu, Jie Ding, Peng Huang, and Jiya Wu
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okra ,Mucor circinelloides ,pathogens ,Thymol/KGM/LG edible coating solution ,antifungal mechanism ,Microbiology ,QR1-502 - Abstract
With the increasing demand and quality requirement for the natural nutritious food in modern society, okra has attracted much attention because of its high nutritional value and remarkable functionality. However, the occurrence of postharvest diseases of fresh okra severely limited the application and the value of okra. Therefore, in this study, the dominant pathogens causing postharvest diseases such as soft rot were isolated from naturally decaying okra. It was identified as Mucor circinelloides by its morphological characteristics and standard internal transcribed spacer ribosomal DNA sequence. Furthermore, the biological characteristics of M. circinelloides were studied, and the inhibitory effect of thymol/KGM/LG (TKL) edible coating solution on M. circinelloides and its possible mechanism was discussed. In addition, TKL edible coating solution had a dose-dependent inhibitory effect on M. circinelloides, with a 50% inhibitory concentration (EC50) of 113.55 mg/L. The TKL edible coating solution at 960 mg/L of thymol completely inhibited mycelial growth and spore germination of M. circinelloides. The results showed that the best carbon source of M. circinelloides was maltose, the best nitrogen source was beef extract and potassium nitrate, the best pH was 6, the best temperature was 28°C, the best NaCl concentration was 0.5%, and the light was conducive to the growth of M. circinelloides. It was also observed by scanning electron microscope (SEM) that TKL was more likely to destroy the cell wall integrity of M. circinelloides, inhibit spore morphology and change mycelium structure. Meanwhile, the activity of chitinase (CHI), an enzyme related to cell wall synthesis of M. circinelloides, was significantly decreased after being treated by TKL with thymol at 100 mg/L (TKL100). The content of Malondialdehyde (MDA) in M. circinelloides decreased significantly from 12 h to 48 h, which may cause oxidative damage to the cell membrane. The activity polygalacturonase (PG), pectin methylgalacturonase (PMG), and cellulase (Cx) of M. circinelloides decreased significantly. Therefore, the results showed that TKL had a good bacteriostatic effect on okra soft rot pathogen, and the main bacteriostatic mechanism might be the damage of cell membrane, degradation of the cell wall, inhibition of metabolic activities, and reduction of metabolites, which is helpful to further understand the inhibitory effect of TKL on okra soft rot pathogen and its mechanism.
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- 2022
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19. Electromagnetic activity: a possible player in epilepsy
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Yi Guo, Yaowen Liu, and Xuefeng Wang
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Electromagnetic activity ,Epilepsy ,Electroencephalogram ,Magnetoencephalography ,Repetitive transcranial magnetic stimulation ,Neurology. Diseases of the nervous system ,RC346-429 - Abstract
Abstract Epilepsy is a common disease with frequent occurrences. Many precipitating factors contribute to epileptic seizures, such as hyperventilation and alcohol consumption. An increasing number of studies have also found that electromagnetic activity in the environment can also affect epileptic seizures. However, many neuromodulatory devices that produce electromagnetic fields have been applied in the diagnosis and treatment of epilepsy. In this paper, we performed literature search in the PubMed, Medline and EMBASE databases and reviewed retrospective, prospective, or cross-sectional studies and case reports on the effects of electromagnetic activity on epilepsy. The application of electromagnetic activity in the diagnosis and treatment of epilepsy is also reviewed.
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- 2020
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20. Spin-Torque Oscillator Based on Magnetic Domain and Meron
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Gang Lv, Hong Zhang, Xuecheng Cao, Feng Gao, Guihua Li, Fengwei Sun, Zhiwei Hou, and Yaowen Liu
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spin-torque oscillator ,micromagnetic simulation ,domain structure ,dzyaloshinskii-moriya interaction ,spin orbit coupling ,Physics ,QC1-999 - Abstract
In this work, micromagnetic simulations demonstrate that a steady oscillation mode accompanied by magnetic domain splitting and the creation and annihilation of meron can be excited by spin-polarized currents. It is found that the in-plane magnetic anisotropy and Dzyaloshinskii-Moriya interaction (DMI) have a greater influence on the oscillation frequency. The oscillation frequency can vary from 3 GHz to 31 GHz by controlling anisotropy strength under a fixed current density. By changing DMI strength, the oscillation frequency varies from 9 to 13.6 GHz and from 29.7 to 37 GHz. Compared with ferromagnetic skyrmion-based spin-torque oscillators (STOs), the STOs based on this magnetic domain and meron further increase the oscillation frequency. Our results may provide theoretical support for the research and development of future high-frequency STOs.
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- 2022
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21. Use of Heat-Shock and Edible Coating to Improve the Postharvest Preservation of Blueberries
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Chunyan Liu, Jie Ding, Peng Huang, Hongying Li, Yan Liu, Yuwei Zhang, Xinjie Hu, Shanggui Deng, Yaowen Liu, and Wen Qin
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blueberry ,heat-shock treatment ,edible coating ,postharvest quality ,Chemical technology ,TP1-1185 - Abstract
The quality of blueberry fruit is easily altered after harvest. We investigated the regulatory mechanism of heat-shock (postharvest treatment) and edible coating (preharvest treatment) on the post-harvest physiological quality of blueberry from the perspective of physiological, biochemical and organoleptic characteristics. In our research, the optimal TKL concentration and the appropriate range of heat-shock temperatures were first screened based on actual application results, and then a combination of heat-shock temperature and TKL coating with significant differences in preservation effects was selected to investigate the effects of different heat-shock temperatures and TKL60 composite coating on post-harvest quality and volatile compound concentration of blueberries under refrigerated conditions. Our results showed that TKL with 60 mg/L thymol can retard the development of the degree of membrane lipid peroxidation and effectively reduce the incidence of fruit decay and the severity of blueberries infected with major pathogens at 25 °C. Meanwhile, heat-shock treatments were effective in maintaining the quality of blueberries, with a certain advantage from 45 °C to 65 °C after 8 d of storage at ambient temperature, but these treated groups were slightly inferior to TKL60 groups for fresh-keeping effect. Remarkably, the combination of heat-shock treatment and edible coating application could extend the shelf life of blueberries by 7–14 d compared to the results obtained with coating alone under low temperature storage. Specifically, heat treatment at 45 °C for 60 min after TKL60 coating (HT2) retarded the decrease in the levels of ascorbic acid, total anthocyanin, total acid and soluble solids. Gas chromatography–mass spectrometry hierarchical clustering analysis showed that this treatment also improved the aroma of the fruit, which maintained a certain similarity with that of fresh blueberries after 14 d. Principal component analysis (PCA) of the results of the evaluations carried out using an electronic nose (E-nose) and electronic tongue (E-tongue) showed that blueberries of the HT2 treated group did not show a large placement change of the PC1 distribution area from that of the fresh and blank control group. Accordingly, the combination of coating with heat-shock treatment can effectively improve the post-harvest quality and aroma compound concentration of blueberries, showing good application potential in storage and preservation of fresh fruits such as blueberries.
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- 2023
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22. Electrospun antibacterial and antiviral poly(ε-caprolactone)/zein/Ag bead-on-string membranes and its application in air filtration
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Yaowen Liu, Siying Li, Wenting Lan, Md Alomgir Hossen, Wen Qin, and Kangju Lee
- Subjects
Electrospinning ,Ultrasonic-assisted ,Air filtration ,Antibacterial ,Materials of engineering and construction. Mechanics of materials ,TA401-492 - Abstract
In this study, poly (ε-caprolactone) (PCL)/zein/Ag nanoparticle (AgNP) fibrous membranes were prepared by ultrasonication-assisted electrospinning. The effects of the AgNP content and ultrasonication time on the membrane morphology, chemical structure, biodegradability, mechanical properties, antibacterial/antiviral activity, and air filtration performance were studied. The best-performing membrane (AgNP content = 1% (w/v), sonication time = 30 min) exhibited a bead-on-string morphology, an air permeability of 93.6 ± 1.5 mm s−1, and the Escherichia coli and Staphylococcus aureus removal efficiencies of 98.1 ± 1.2% and 97.4 ± 2.5%, respectively. In an experiment with E. coli phage, the above-mentioned membrane exhibited a 97.1 ± 2.1% virus removal efficiency after 60 min. The high performance of this bead-on-string membrane for air filtration was ascribed to the low packing density due to the presence of open interconnected beaded airflow channels and small beads.
- Published
- 2021
- Full Text
- View/download PDF
23. Synthesis and properties of core-shell thymol-loaded zein/shellac nanoparticles by coaxial electrospray as edible coatings
- Author
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Yaowen Liu, Siying Li, Hui Li, Md Alomgir Hossen, Dur E. Sameen, Jianwu Dai, Wen Qin, and KangJu Lee
- Subjects
Thymol ,Zein ,Shellac ,Coaxial electrospray ,Nanoparticles ,Fresh-cut cantaloupe ,Materials of engineering and construction. Mechanics of materials ,TA401-492 - Abstract
In this study, a coaxial electrospray process was used to produce nanoparticles, in which thymol was encapsulated in a core–shell of zein and shellac. We then investigated fluid velocity and solution concentrations on the electrospray. Scanning electron microscopy revealed that the thymol/zein/shellac particles prepared at a flow rate ratio of 0.6:0.3 mL/h were rounder with smaller diameters. The highest encapsulation efficiency of thymol was 81.34%, the average particle size was 606.53 nm, and the retention rate of thymol was 68.74% after 30 days. Moreover, we investigated the thermal stability, antimicrobial activity, and simulated gastrointestinal release curves of the nanoparticles. Finally, the nanoparticles were used as a coating for fresh-cut cantaloupe. Compared with the blank nanoparticle control group, the coating significantly extended the shelf life of cantaloupe to 16 days. Our results indicate that these nanoparticles have great potential for application in food preservation.
- Published
- 2021
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- View/download PDF
24. Characterization and preliminary safety evaluation of nano-SiO2 isolated from instant coffee
- Author
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Yaowen Liu, Ying Huang, Zhen Mou, Rui Li, Md Alomgir Hossen, Jianwu Dai, Wen Qin, and KangJu Lee
- Subjects
Nano-SiO2 ,Risk assessment ,Instant coffee ,Zebra fish ,Environmental pollution ,TD172-193.5 ,Environmental sciences ,GE1-350 - Abstract
The physiological and toxicological evaluation of nano-silicon dioxide (nano-SiO2) particles in food is important for ensuring food safety. In this study, nano-SiO2 particles isolated from five brands of instant coffee, were structurally characterized using transmission electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, dynamic light scattering, and zeta potential analyses. Their toxicity was assessed by measuring cell viability, membrane integrity, and reactive oxygen species (ROS) levels in model gastrointestinal cells (GES-1 and Caco-2). Additionally, mortality, deformity rate, heart rate and death of whole zebra fish embryos were measured. The five types of nano-SiO2 samples comprised amorphous particles with a purity of approximately 99%, which met the food additive standard. Considering that the original particle size ranged from 10 to 50 nm, the samples were classified as nano-SiO2 food additives. Nano-SiO2 did not significantly impact the activity of GES-1 or Caco-2 cells, and no significant cell membrane damage was observed (Caco-2 cells exhibited mild micro damage); however, a slight increase in intracellular RPS levels was detected. Moreover, nano-SiO2 was found to cause head deformity, pericardial edema, yolk sac edema and tail bending. Collectively, the results show that nano-SiO2 time- and dose-dependently affects GES-1 and Caco-2 cell viability, as well as the mortality, heart rate, and abnormality rate of zebra fish embryos. Specifically, a high concentration (≥ 200 μg/mL) and long exposure time (≥ 48 h) of food additive nano-SiO2 affected GES-1, Caco-2 cells, and the gastrointestinal tract in zebra fish embryos.
- Published
- 2021
- Full Text
- View/download PDF
25. Tuning antibacterial properties of poly(vinyl alcohol)/TiO2 composite films by chemically grafting with 3,3′,4,4′-biphenyltetracarboxylic acid
- Author
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Yaowen Liu, Siying Li, Junlan Xie, Md Alomgir Hossen, Jianwu Dai, and KangJu Lee
- Subjects
3,3′,4,4′-biphenyltetracarboxylic acid ,Polyvinyl alcohol ,Reactive oxygen species ,Polymers and polymer manufacture ,TP1080-1185 - Abstract
Polyvinyl alcohol (PVA)/titanium dioxide nanoparticles (TiO2 NPs)/3,3′,4,4′-Benzophenone tetracarboxylic acid (BPTA) antibacterial films were prepared by solvent casting and chemical grafting using PVA as the base material and TiO2 NPs and BPTA as antibacterial materials. Scanning electron microscopy results showed that the distribution of TiO2 NPs inside the polymer matrix was substantially uniform. X-ray diffraction (XRD) and FTIR-ATR spectroscopy were used to demonstrate the successful embedding of NPs and the formation of ester bonds in the grafting process, respectively. In the antibacterial experiment, the PVA/1%TiO2 NPs/BPTA film exhibited higher antibacterial activity than other films. Compared with the control group, the surviving population of S. aureus and E. coli decreased by 99.62 ± 0.38% and 98.27 ± 1.47%, respectively. The mechanism of reactive oxygen species (ROS) production was discussed, and the amount of ROS produced by the composite films under light and dark conditions was quantitatively measured. A cycling experiment after quenching ROS showed that the PVA/1%TiO2 NPs/BPTA composite film retained 81.01% and 66.12% of the original charging capacity of the OH• radical and H2O2 after seven cycles. In terms of biodegradability, the degradation performance of the PVA/TiO2 NPs/BPTA composite film was stronger than that of the pure PVA film. Thus, the PVA/TiO2 NPs/BPTA film is considered a promising antibacterial material with superior characteristics of structural stability, reusability, and functionality under both light and dark conditions.
- Published
- 2021
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- View/download PDF
26. Effects of ultrasonic treatment and homogenization on physicochemical properties of okara dietary fibers for 3D printing cookies
- Author
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Yaowen Liu, Shengkui Yi, Tingting Ye, Ying Leng, Md Alomgir Hossen, Dur E. Sameen, Jianwu Dai, Suqing Li, and Wen Qin
- Subjects
Okara ,Modified ,Dietary fiber ,3D printing ,Cookie ,Chemistry ,QD1-999 ,Acoustics. Sound ,QC221-246 - Abstract
This paper presents a means to modify the attributes of okara fiber using ultrasonic and high-speed shearing treatment. The results of scanning electron microscopy and differential scanning calorimetry reveal that the modified okara fiber demonstrates small particle size and high thermal stability. When the 500 W–15,000 rpm combination is used for okara-fiber treatment, the latter exhibits excellent swelling (SC) as well as water- and oil-holding capacities. When 6% of modified okara fiber is added to the dough, the resulting cookies demonstrate the best printing performance. Subsequently, the printing parameters can be optimized to obtain the best filling rate of 30%. The corresponding nozzle diameter and printing speed equal 0.8 mm and 50 mm/s, respectively. Finally, the 3D-printed cookies containing okara fiber are compared against those commonly available in the market via sensory evaluation. As observed, the 3D-printed cookies were more acceptable to people. Therefore, the addition of the okara dietary fiber to the cookie dough not only improves the okara utilization rate but also increases the dietary-fiber content in the cookie, thereby alleviating the occurrence of obesity in modern society.
- Published
- 2021
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- View/download PDF
27. Modelling of Magnetic Stray Fields in Multilayer Magnetic Films with In-Plane or Perpendicular Anisotropy
- Author
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Sai Zhou, Yiyue Wang, and Yaowen Liu
- Subjects
magnetic films ,magnetic stray field ,demagnetizing field ,Maxwell’s magnetostatics ,Chemistry ,QD1-999 - Abstract
The magnetic stray field is an unavoidable consequence of magnetic multilayers, which may have a significant influence on the performance of spintronic devices. Based on Maxwell’s magnetostatics theory, here we numerically calculated the distributions of magnetic stray fields and self-demagnetizing fields in a series of patterned multilayer thin-film structures with either an in-plane or a perpendicularly magnetized ferromagnetic layer. The stray field above the ferromagnetic layer is inhomogeneous, showing the dramatic changes near the sample edge, but the uniformity in the center region could be improved with the increasing sample size. The stray field strength tends to zero for large samples, increases with the increase in the hard-layer thickness, and decreases with the increase in the distance D away from the ferromagnetic layer. In the multilayer samples, the separately simulated stray field and self-demagnetizing field within the soft layer agree well with the classic magnetostatic relationship of B=μ0(Hd+M). For the in-plane magnetized trilayer sample, the magnetic-flux density within the soft ferromagnetic layer slightly decreases in the antiparallel magnetization alignment and increases in the parallel alignment state with the increase in the intermediate non-magnetic-layer thickness. In contrast, for the sample with the perpendicular magnetization, the magnetic-flux density decreases as the non-magnetic layer is thickened for both the antiparallel and parallel state. This study may provide a theoretical basis for the design of thin-film spintronic devices.
- Published
- 2022
- Full Text
- View/download PDF
28. Authentication of Shenqi Fuzheng Injection via UPLC-Coupled Ion Mobility—Mass Spectrometry and Chemometrics with Kendrick Mass Defect Filter Data Mining
- Author
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Xingdong Wu, Yaowen Liu, Zijia Zhang, Zhihuang Ou, Guoxiang Wang, Tengqian Zhang, Huali Long, Min Lei, Liangfeng Liu, Wenhua Huang, Jinjun Hou, Wanying Wu, and De-an Guo
- Subjects
chromatographic fingerprint ,high performance liquid chromatography-tandem mass spectrometry ,Radix codonopsis ,Radix astragali ,Shenqi Fuzheng injection ,Organic chemistry ,QD241-441 - Abstract
Nearly 5% of the Shenqi Fuzheng Injection’s dry weight comes from the secondary metabolites of Radix codonopsis and Radix astragali. However, the chemical composition of these metabolites is still vague, which hinders the authentication of Shenqi Fuzheng Injection (SFI). Ultra-high performance liquid chromatography with a charged aerosol detector was used to achieve the profiling of these secondary metabolites in SFI in a single chromatogram. The chemical information in the chromatographic profile was characterized by ion mobility and high-resolution mass spectrometry. Polygonal mass defect filtering (PMDF) combined with Kendrick mass defect filtering (KMDF) was performed to screen potential secondary metabolites. A total of 223 secondary metabolites were characterized from the SFI fingerprints, including 58 flavonoids, 71 saponins, 50 alkaloids, 30 polyene and polycynes, and 14 other compounds. Among them, 106 components, mainly flavonoids and saponins, are contributed by Radix astragali, while 54 components, mainly alkaloids and polyene and polycynes, are contributed by Radix codonopsis, with 33 components coming from both herbs. There were 64 components characterized using the KMDF method, which increased the number of characterized components in SFI by 28.70%. This study provides a solid foundation for the authentification of SFIs and the analysis of its chemical composition.
- Published
- 2022
- Full Text
- View/download PDF
29. Enhanced photocatalytic degradation of organic dyes by ultrasonic-assisted electrospray TiO2/graphene oxide on polyacrylonitrile/β-cyclodextrin nanofibrous membranes
- Author
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Rong Zhang, Yanlan Ma, Wenting Lan, Dur E Sameen, Saeed Ahmed, Jianwu Dai, Wen Qin, Suqing Li, and Yaowen Liu
- Subjects
Polyacrylonitrile ,TiO2 ,Graphene oxide ,Ultrasonic ,Dye degradation ,Chemistry ,QD1-999 ,Acoustics. Sound ,QC221-246 - Abstract
Polyacrylonitrile (PAN)/β-cyclodextrin (β-CD) composite nanofibrous membranes immobilized with nano-titanium dioxide (TiO2) and graphene oxide (GO) were prepared by electrospinning and ultrasonic-assisted electrospinning. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), and X-ray diffraction (XRD) confirmed that TiO2 and GO were more evenly dispersed on the surface and inside of the nanofibers after 45 min of ultrasonic treatment. Adding TiO2 and GO reduced the fiber diameter; the minimum fiber diameter was 84.66 ± 40.58 nm when the mass ratio of TiO2-to-GO was 8:2 (PAN/β-CD nanofibrous membranes was 191.10 ± 45.66 nm). Using the anionic dye methyl orange (MO) and the cationic dye methylene blue (MB) as pollutant models, the photocatalytic activity of the nanofibrous membrane under natural sunlight was evaluated. It was found that PAN/β-CD/TiO2/GO composite nanofibrous membrane with an 8:2 mass ratio of TiO2-to-GO exhibited the best degradation efficiency for the dyes. The degradation efficiency for MB and MO were 93.52 ± 1.83% and 90.92 ± 1.52%, respectively. Meanwhile, the PAN/β-CD/TiO2/GO composite nanofibrous membrane also displayed good antibacterial properties and the degradation efficiency for MB and MO remained above 80% after 3 cycles. In general, the PAN/β-CD/TiO2/GO nanofibrous membrane is eco-friendly, reusable, and has great potential for the removal of dyes from industrial wastewaters.
- Published
- 2021
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- View/download PDF
30. High-Quality Genome Assembly of Chrysaora quinquecirrha Provides Insights Into the Adaptive Evolution of Jellyfish
- Author
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Wangxiao Xia, Haorong Li, Wenmin Cheng, Honghui Li, Yajing Mi, Xingchun Gou, and Yaowen Liu
- Subjects
jellyfish ,genome ,evolution ,assembly ,adaptation ,Genetics ,QH426-470 - Abstract
Jellyfish, such as Chrysaora quinquecirrha, hold an important evolutionary position and have great ecological value. However, limited genomic resources are currently available for studying their basic genetic and development processes. Here, we de novo assembled the first high-quality reference genome of C. quinquecirrha, and successfully annotated 21,606 protein-coding genes. Codon usage analysis identified the frequent use of low-GC-content codons during protein-coding gene translation. Analysis of the relative evolution rate indicated that jellyfish had a faster evolution rate than sea anemones but slower rate than the species in Hydra. Phylogenetic analysis with two other species of jellyfish indicated that Aurelia aurita and Nemopilema nomurai have a closer relationship with each other than with C. quinquecirrha, with divergence from their common ancestor occurring ≈475.7 million years ago. Our study not only showed the genomic characteristics and molecular adaptive evolution of C. quinquecirrha, but also provides valuable genomic resources for further study on complex developmental processes and environmental adaptations.
- Published
- 2020
- Full Text
- View/download PDF
31. Physicochemical properties of gelatin films containing tea polyphenol-loaded chitosan nanoparticles generated by electrospray
- Author
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Yihao Wang, Rong Zhang, Wen Qin, Jianwu Dai, Qing Zhang, KangJu Lee, and Yaowen Liu
- Subjects
Materials of engineering and construction. Mechanics of materials ,TA401-492 - Abstract
In this study, gelatin (GEL) extracted from grass carp and tea polyphenols (TP) were encapsulated in chitosan (CS) nanoparticles using an innovative electrospray based ionic gelation method. CS-TP nanoparticles were fully optimized in terms of encapsulation efficiency and polydispersity. The average diameter of the optimal CS-TP nanoparticles was 205 ± 14 nm, and encapsulation efficiency of 66.7% ± 9.9% was achieved. The effects of CS-TP nanoparticles on the physicochemical properties of the GEL/CS-TP composite films were studied. Our results showed that the combination of CS-TP and grass carp gelatin (GEL) can not only weaken the strong interaction between GEL and TP, but also improved the swelling and mechanical properties of GEL. Furthermore, GEL/CS-TP30% composite film showed strong barrier and good mechanical properties, low UV transmission, exhibited high free radical-scavenging ability and prolonged the stability of an easily oxidizable oil for over 14 days, making it a suitable film for use as an edible packaging material. Keywords: Gelatin, Chitosan, Tea polyphenols, Composite films
- Published
- 2020
- Full Text
- View/download PDF
32. Manipulation of Time- and Frequency-Domain Dynamics by Magnon-Magnon Coupling in Synthetic Antiferromagnets
- Author
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Xing Chen, Cuixiu Zheng, Sai Zhou, Yaowen Liu, and Zongzhi Zhang
- Subjects
magnons ,synthetic antiferromagnets ,antiferromagnetic resonance ,micromagnetics ,Chemistry ,QD1-999 - Abstract
Magnons (the quanta of spin waves) could be used to encode information in beyond Moore computing applications. In this study, the magnon coupling between acoustic mode and optic mode in synthetic antiferromagnets (SAFs) is investigated by micromagnetic simulations. For a symmetrical SAF system, the time-evolution magnetizations of the two ferromagnetic layers oscillate in-phase at the acoustic mode and out-of-phase at the optic mode, showing an obvious crossing point in their antiferromagnetic resonance spectra. However, the symmetry breaking in an asymmetrical SAF system by the thickness difference, can induce an anti-crossing gap between the two frequency branches of resonance modes and thereby a strong magnon-magnon coupling appears between the resonance modes. The magnon coupling induced a hybridized resonance mode and its phase difference varies with the coupling strength. The maximum coupling occurs at the bias magnetic field at which the two ferromagnetic layers oscillate with a 90° phase difference. Besides, we show how the resonance modes in SAFs change from the in-phase state to the out-of-phase state by slightly tuning the magnon-magnon coupling strength. Our work provides a clear physical picture for the understanding of magnon-magnon coupling in a SAF system and may provide an opportunity to handle the magnon interaction in synthetic antiferromagnetic spintronics.
- Published
- 2021
- Full Text
- View/download PDF
33. Application of surface–downhole combined microseismic monitoring technology in the Fuling shale gas field and its enlightenment
- Author
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Yaowen Liu, Rugang Liao, Yuan Zhang, Dongwei Gao, Huaili Zhang, Ting Li, and Chi Zhang
- Subjects
Sichuan Basin ,Fuling shale gas field ,Well factory ,Fracturing (rock) ,Surface microseismic ,Downhole microseismic ,SRV prediction ,Artificial fracture ,Gas industry ,TP751-762 - Abstract
The Fuling shale gas field in the Sichuan Basin, as a national shale gas demonstration area, is the largest commercially developed shale gas field in the world except those in North America. The fracturing technology in the mode of “well factory” has been applied widely in the gas field, but it is necessary to perform further investigation on the way to evaluate effectively the fracturing effect of multi-well platform “well factory” and the distribution laws of its induced fracture networks. In this paper, the fractures induced by the “well factory” at the JY 48 platform were real-time monitored by a surface–downhole combined microseismic monitoring technology. The geometric size and extension direction of artificial fractures induced in the model of “well factory” fracturing in the Jiaoshiba block of Fuling Shale Gas Field were preliminarily understood. Moreover, the fracturing parameters under the mode of “well factory” were recognized by using the comprehensive interpretation results of surface–downhole combined microseismic monitoring technology, together with the SRV fracturing prediction chart. Eventually, the distribution laws of artificial fractures during the “well-factory-zipper” fracturing in the Fuling Shale Gas Field were clarified definitely. This paper provides guidance for the optimization of fracturing parameters at the later stage.
- Published
- 2017
- Full Text
- View/download PDF
34. Identification and manipulation of spin wave polarizations in perpendicularly magnetized synthetic antiferromagnets
- Author
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Xing Chen, Cuixiu Zheng, Yu Zhang, Sai Zhou, Yaowen Liu, and Zongzhi Zhang
- Subjects
synthetic antiferromagnets ,interlayer exchange coupling ,spin wave ,perpendicular magnetic anisotropy ,micromagnetics ,Science ,Physics ,QC1-999 - Abstract
Interlayer exchange-coupled synthetic antiferromagnets (SAFs) have the combined advantages of both high frequency of antiferromagnets and easy detection of ferromagnets. Here, magnetic excitations are investigated by theoretical analysis and micromagnetic simulations in SAFs that consist of two identical ferromagnetic layers with perpendicular magnetic anisotropy. Different from the common in-phase acoustic mode and out-of-phase optic mode, linearly or circularly polarized spin wave modes can be excited at zero bias field by using different types of microwave magnetic fields. Once a bias magnetic field is applied along the easy-axis, left-handed (LH) and right-handed (RH) polarization modes are observed, and the resonance frequency of RH (LH) mode of the SAFs increases (decreases) linearly with the increase of bias magnetic fields until a critical spin-flop field is reached, which is in accordance with collinear antiferromagnets with easy-axis anisotropy. These simulation results agree with the theoretical derivation and provide fundamental insight into the nature of dynamic properties of the perpendicularly magnetized SAFs, which may provide new prospects for spintronic applications.
- Published
- 2021
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- View/download PDF
35. Long-Term Antibacterial Effect of Electrospun Polyvinyl Alcohol/Polyacrylate Sodium Nanofiber Containing Nisin-Loaded Nanoparticles
- Author
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Yue Jiang, Donghui Ma, Tengteng Ji, Dur E Sameen, Saeed Ahmed, Suqing Li, and Yaowen Liu
- Subjects
nisin ,encapsulation ,ultrasonic ,polyvinyl alcohol ,polyacrylate sodium ,nanofibers ,Chemistry ,QD1-999 - Abstract
Response Surface Methodology (RSM) was used to assess the optimal conditions for a Water/Oil/Water (W/O/W) emulsion for encapsulated nisin (EN). Nano-encapsulated nisin had high encapsulation efficiencies (EE) (86.66 ± 1.59%), small particle size (320 ± 20 nm), and low polydispersity index (0.27). Biodegradable polyvinyl alcohol (PVA) and polyacrylate sodium (PAAS) were blended with EN and prepared by electrospinning. Scanning electron microscopy (SEM) revealed PVA/PAAS/EN nanofibers with good morphology, and that their EN activity and mechanical properties were enhanced. When the ultrasonication time was 15 min and 15% EN was added, the nanofibers had optimal mechanical, light transmittance, and barrier properties. Besides, the release behavior of nisin from the nanofibers fit the Korsemeyer–Peppas (KP) model, a maximum nisin release rate of 85.28 ± 2.38% was achieved over 16 days. At 4 °C, the growth of Escherichia coli and Staphylococcus aureus was inhibited for 16 days in nanofibers under different ultrasonic times. The application of the fiber in food packaging can effectively inhibit the activity of food microorganisms and prolong the shelf life of strawberries, displaying a great potential application for food preservation.
- Published
- 2020
- Full Text
- View/download PDF
36. Effects of Ultrasonication Time on the Properties of Polyvinyl Alcohol/Sodium Carboxymethyl Cellulose/Nano-ZnO/Multilayer Graphene Nanoplatelet Composite Films
- Author
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Tengteng Ji, Rong Zhang, Xiaorong Dong, Dur E Sameen, Saeed Ahmed, Suqing Li, and Yaowen Liu
- Subjects
carboxymethyl cellulose ,zinc oxide ,multilayer graphene nanoplatelets ,Chemistry ,QD1-999 - Abstract
Ultrasonication-assisted solution casting was used to prepare polyvinyl alcohol (PVA)/sodium carboxymethyl cellulose (CMC)/nano-ZnO/multilayer graphene nanoplatelet (xGnP) composite films; the performances (mechanical properties, water vapor permeability (WVP), biodegradability and antibacterial activity) of these films were investigated as a function of the ZnO NPs:xGnP mass ratio and ultrasonication time. Intermolecular interactions among ZnO NPs, xGnP and the PVA/CMC matrix were shown to improve WVP, while X-ray diffraction and scanning electron microscopy analyses revealed that the internal reticular structure of ultrasound-treated PVA/CMC/ZnO NPs/xGnP composite films was in a fluffier state than that of the untreated composite films and the PVA/CMC film. The incorporation of ZnO NPs and xGnP into the composite film reduced its tensile strength and elongation at break, and increased antibacterial activity and biodegradability. In addition, we carried out the experiment of strawberry preservation and measured weight loss ratio, firmness, content of total soluble solids and titration acid. Finally, the composite film of 7:3 had the best preservation effect on strawberries. Thus, the obtained results paved the way to develop novel biodegradable composite films with antimicrobial activity for a wide range of applications.
- Published
- 2020
- Full Text
- View/download PDF
37. Mapping Water Quality Parameters in Urban Rivers from Hyperspectral Images Using a New Self-Adapting Selection of Multiple Artificial Neural Networks
- Author
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Yishan Zhang, Lun Wu, Huazhong Ren, Yu Liu, Yongqian Zheng, Yaowen Liu, and Jiaji Dong
- Subjects
self-adapting ,deep learning ,multiple neural network ,hyperspectral image ,water quality monitoring ,Science - Abstract
Protection of water environments is an important part of overall environmental protection; hence, many people devote their efforts to monitoring and improving water quality. In this study, a self-adapting selection method of multiple artificial neural networks (ANNs) using hyperspectral remote sensing and ground-measured water quality data is proposed to quantitatively predict water quality parameters, including phosphorus, nitrogen, biochemical oxygen demand (BOD), chemical oxygen demand (COD), and chlorophyll a. Seventy-nine ground measured data samples are used as training data in the establishment of the proposed model, and 30 samples are used as testing data. The proposed method based on traditional ANNs of numerical prediction involves feature selection of bands, self-adapting selection based on multiple selection criteria, stepwise backtracking, and combined weighted correlation. Water quality parameters are estimated with coefficient of determination R 2 ranging from 0.93 (phosphorus) to 0.98 (nitrogen), which is higher than the value (0.7 to 0.8) obtained by traditional ANNs. MPAE (mean percent of absolute error) values ranging from 5% to 11% are used rather than root mean square error to evaluate the predicting precision of the proposed model because the magnitude of each water quality parameter considerably differs, thereby providing reasonable and interpretable results. Compared with other ANNs with backpropagation, this study proposes an auto-adapting method assisted by the above-mentioned methods to select the best model with all settings, such as the number of hidden layers, number of neurons in each hidden layer, choice of optimizer, and activation function. Different settings for ANNS with backpropagation are important to improve precision and compatibility for different data. Furthermore, the proposed method is applied to hyperspectral remote sensing images collected using an unmanned aerial vehicle for monitoring the water quality in the Shiqi River, Zhongshan City, Guangdong Province, China. Obtained results indicate the locations of pollution sources.
- Published
- 2020
- Full Text
- View/download PDF
38. Merging magnetic droplets by a magnetic field pulse
- Author
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Chengjie Wang, Dun Xiao, and Yaowen Liu
- Subjects
Physics ,QC1-999 - Abstract
Reliable manipulation of magnetic droplets is of immense importance for their applications in spin torque oscillators. Using micromagnetic simulations, we find that the antiphase precession state, which originates in the dynamic dipolar interaction effect, is a favorable stable state for two magnetic droplets nucleated at two identical nano-contacts. A magnetic field pulse can be used to destroy their stability and merge them into a big droplet. The merging process strongly depends on the pulse width as well as the pulse strength.
- Published
- 2018
- Full Text
- View/download PDF
39. Phase-locking of multiple magnetic droplets by a microwave magnetic field
- Author
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Chengjie Wang, Dun Xiao, Yan Zhou, J. Åkerman, and Yaowen Liu
- Subjects
Physics ,QC1-999 - Abstract
Manipulating dissipative magnetic droplet is of great interest for both the fundamental and technological reasons due to its potential applications in the high frequency spin-torque nano-oscillators. In this paper, a magnetic droplet pair localized in two identical or non-identical nano-contacts in a magnetic thin film with perpendicular anisotropy can phase-lock into a single resonance state by using an oscillating microwave magnetic field. This resonance state is a little away from the intrinsic precession frequency of the magnetic droplets. We found that the phase-locking frequency range increases with the increase of the microwave field strength. Furthermore, multiple droplets with a random initial phase can also be synchronized by a microwave field.
- Published
- 2017
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- View/download PDF
40. Extraction and Characterization of Self-Assembled Collagen Isolated from Grass Carp and Crucian Carp
- Author
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Li He, Wenting Lan, Yue Wang, Saeed Ahmed, and Yaowen Liu
- Subjects
collagen ,self-assembly ,grass carp ,crucian carp ,Chemical technology ,TP1-1185 - Abstract
Collagens were extracted from grass carp skin (GCC), grass carp scales (GSC), and crucian carp skin (CCC) using an acid-enzyme combination method, and their characteristics and self-assembly properties were analyzed. Electrophoretic patterns characterized all three as type I collagens. An ultraviolet analysis identified the optimal wavelengths for collagen detection, while a Fourier transform infrared spectroscopy analysis confirmed the triple-helical structure of the collagens. The GCC, GSC, and CCC had denaturation temperatures of 39.75, 34.49, and 39.05 °C, respectively. All three were shown to self-assemble into fibrils at 30 °C in the presence of NaCl, but the fibril formation rate of CCC (40%) was slightly higher than those of GCC (28%) and GSC (27%). The GSC were shown to form a more strongly intertwined fibril network with a characteristic D-periodicity. The fish collagens extracted in this study have potential applications in the development of functionalized materials.
- Published
- 2019
- Full Text
- View/download PDF
41. Preparation and Characterization of Corn Starch Bio-Active Edible Packaging Films Based on Zein Incorporated with Orange-Peel Oil
- Author
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Yue Wang, Rong Zhang, Saeed Ahmed, Wen Qin, and Yaowen Liu
- Subjects
corn starch ,orange-peel oil ,zein ,Therapeutics. Pharmacology ,RM1-950 - Abstract
Zein, corn starch (CS), and orange-peel oil (OPO) extracted from orange peels were used to prepare novel corn starch/orange-peel oil/zein nanocapsules (OZN) bio-active food packaging materials. The results showed that the OZN were round, smooth and in compact morphology with an average diameter of 102.7 ± 10.5 nm from OPO and zein (3:10, w/w). By testing the turbidity and atomic force microscopy (AFM) of OZN and the mechanical properties and water vapor permeability of the composite films, the comprehensive properties of composite films with different mass ratios were analyzed. It showed that the addition of OZN improved the mechanical and moisture barrier properties and extended the release time of OPO. When the ratio of OZN and CS is 5:5, the highest elongation at break and tensile strengths is achieved, at values of 30.91% ± 2.52% and 12.19 ± 1.97 MPa respectively. The relative release concentration of OPO was highest at a ratio of 5/5, and over time it would last longer to maintain a higher release concentration. Besides, the oxidation resistance of the composite film was good, especially when the ration of starch CS to OZN was 5/5, it had the highest DPPH radical scavenging activity (30.16% ± 1.69%). Thus, it can be used as a bio-active edible food packaging film to ensure the safety of food products and reduce environmental pressure to some extent.
- Published
- 2019
- Full Text
- View/download PDF
42. Effect of PLA/PBAT Antibacterial Film on Storage Quality of Passion Fruit during the Shelf-Life
- Author
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Rong Zhang, Wenting Lan, Jie Ding, Saeed Ahmed, Wen Qin, Li He, and Yaowen Liu
- Subjects
passion fruit ,PLA/PBAT antibacterial films ,storage quality ,Organic chemistry ,QD241-441 - Abstract
In this experiment, we studied the effect of poly(lactic acid)/poly(butylene adipate-co-terephthalate) (PLA/PBAT) blend films on the efficiency of passion fruit preservation at 20 °C. The weight loss, shrinkage index, firmness, and total sugar of passion fruit packaged with PLA/PBAT films had no significant differences compared with PE films during 21 days (p > 0.05). PLA/PBAT films can more effectively reduce the rising of ethanol content and delay the total acid, ascorbic acid, and sensory evaluation. Compared with unpackaged (CK) and polyethylene (PE) films, PLA/PBAT films are more conducive to preserve the overall flavor of passion fruit during storage time, in agreement with sensory evaluation, tested by E-nose, E-tongue, and GC-MS, which also proved that it can effectively maintain the edible quality of passion fruit during storage time. We believe that our study makes a significant contribution to literature because it paves the way to the generalization and application of packaging films based on composite antibacterial polymers and facilitates the commercialization of fresh passion fruit as an important health food.
- Published
- 2019
- Full Text
- View/download PDF
43. Preparation of Chitosan/Corn Starch/Cinnamaldehyde Films for Strawberry Preservation
- Author
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Yue Wang, Rui Li, Rui Lu, Jie Xu, Ke Hu, and Yaowen Liu
- Subjects
chitosan ,corn starch ,cinnamaldehyde ,Chemical technology ,TP1-1185 - Abstract
In this study, the casting method was used to make chitosan (CS)/corn starch/cinnamaldehyde film, and the preservation performance of the film was examined. The results showed that the tensile strength of the film can reach to 31.24 ± 0.22 MPa when the mass ratios of CS, corn starch, and glycerin were 2.5%, 7%, and 0.5% respectively. The addition of cinnamaldehyde made the films have great inhibitory effect on Botrytis cinerea, Rhizopus, and Escherichia coli. In particular, the film had a significant fresh-keeping effect on strawberries, which reduced the loss of nutritional value, when aiming at soluble solids, titratable acid value, weight loss rate, and other indexes of strawberries. Thus, the films can slow down the physiological changes of strawberries and extend their shelf life to 11 days. Therefore, this work demonstrates the noteworthy potential of these novel films, incorporating natural antimicrobial compounds as innovative solutions to be used in active food packaging to extend the shelf-life of food products.
- Published
- 2019
- Full Text
- View/download PDF
44. Effect of Potassium Sorbate and Ultrasonic Treatment on the Properties of Fish Scale Collagen/Polyvinyl Alcohol Composite Film
- Author
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Xue Liang, Shiyi Feng, Saeed Ahmed, Wen Qin, and Yaowen Liu
- Subjects
potassium sorbate ,fish scale collagen ,polyvinyl alcohol ,ultrasonic treatment ,composite films ,antibacterial activity ,Organic chemistry ,QD241-441 - Abstract
Composite films containing different amounts of potassium sorbate (KS) were prepared by using fish scale collagen (Col) and polyvinyl alcohol (PVA). Fourier transform infrared spectroscopy (FTIR), light transmittance, mechanical, water vapor transmission rate (WVTR), and the antibacterial properties of the composite films were analyzed. The results showed that the addition of Col significantly reduced the light transmittance of the composite film, but KS had no significant effect on the light transmission. The tensile strength decreased first and then increased with the addition of KS, while the WVTR increased first and then decreased. The composite film exhibited a certain degree of antibacterial properties against E. coli and S. aureus. In addition, we found that ultrasonic treatment reduced the WVTR, and also improved tensile strength and elongation at break of the composite films, but had no significant effect on other properties. The KS/Col/PVA films have the potential to be used as antimicrobial food packaging.
- Published
- 2019
- Full Text
- View/download PDF
45. Effect of Sonication Duration in the Performance of Polyvinyl Alcohol/Chitosan Bilayer Films and Their Effect on Strawberry Preservation
- Author
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Jie Ding, Rong Zhang, Saeed Ahmed, Yaowen Liu, and Wen Qin
- Subjects
polyvinyl alcohol ,chitosan ,bilayer films ,strawberry preservation ,Organic chemistry ,QD241-441 - Abstract
In this study, we fabricated polyvinyl alcohol (PVA)/chitosan (CS) bilayer films by casting and investigated the effects of preparation conditions and CS content (2, 2.5, or 3 wt.%) on the ability of these films to preserve packaged strawberries. The best performance was achieved at a CS loading of 2.5 wt.% (ultrasound time, 25 min); the strain and stress values were 143.15 ± 6.43% and 70.67 ± 0.85 MPa, respectively, oxygen permeability was 0.16 ± 0.08 cm2·m2·day−1·MPa−1, water vapor permeability was 14.93 ± 4.09 g·cm−1·s−1·Pa−1, and the shelf life of fresh strawberries packaged in the PVA/CS 2.5 wt.% bilayer film was determined to be 21 days at 5 ± 2 °C and a relative humidity of 60 ± 5%. Treatment with PVA/CS bilayer films prevented the decrease in the firmness of strawberries during storage (21 days). The evaluated physicochemical parameters (weight loss, decay, firmness, titratable acidity, soluble solid content, ascorbic acid content, and color) indicated that treatment with PVA/CS bilayer films led to better maintenance of the fruit quality. We believe that our study makes a significant contribution to literature because it paves the way to the fabrication of smart packaging materials and facilitates the commercialization of fresh strawberries as an important health food.
- Published
- 2019
- Full Text
- View/download PDF
46. Electrospun Polyvinyl Alcohol/d-Limonene Fibers Prepared by Ultrasonic Processing for Antibacterial Active Packaging Material
- Author
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Weijie Lan, Xue Liang, Wenting Lan, Saeed Ahmed, Yaowen Liu, and Wen Qin
- Subjects
polyvinyl alcohol ,d-limonene ,antibacterial active packaging ,Organic chemistry ,QD241-441 - Abstract
Novel fibers containing different ratios of PVA and d-limonene were fabricated using electrospinning for antibacterial active packaging applications. The PVA/d-limonene fibers were thoroughly characterized using a scanning electron microscope, fourier-transform infrared spectrometry, thermal gravimetry, differential scanning calorimetry, tensile tests, and oxygen permeability tests. The results of these analyses showed that the highest tensile strength and elongation at break values of 3.87 ± 0.25 MPa and 55.62 ± 2.93%, respectively, were achieved for a PVA/d-limonene ratio of 7:3 (v/v) and an ultrasonication time of 15 min during processing. This material also showed the lowest oxygen permeation and the best degradability and bacteriostatic properties of all samples.
- Published
- 2019
- Full Text
- View/download PDF
47. Research on the Application of MWCNTs/PLA Composite Material in the Manufacturing of Conductive Composite Products in 3D Printing
- Author
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Jinjie Luo, Haibao Wang, Duquan Zuo, Anping Ji, and Yaowen Liu
- Subjects
PLA ,MWCNTs ,3D printer ,Mechanical engineering and machinery ,TJ1-1570 - Abstract
As an advanced manufacturing technology that has been developed in recent years, three-dimensional (3D) printing of macromolecular materials can create complex-shaped components that cannot be realized by traditional processing. However, only a few types of macromolecular materials are suitable for 3D printing: the structure must have a single function, and manufacturing macromolecular functional devices is difficult. In this study, using poly lactic acid (PLA) as a matrix, conductive composites were prepared by adding various contents of multi-walled carbon nanotubes (MWCNTs). The printability and properties of MWCNT/PLA composites with different MWCNT proportions were studied by using the fused deposition modeling (FDM) processing technology of 3D printing. The experimental results showed that high conductivity can be realized in 3D-printed products with a composite material containing 5% MWCNTs; its conductivity was 0.4 ± 0.2 S/cm, its tensile strength was 78.4 ± 12.4 MPa, and its elongation at break was 94.4% ± 14.3%. It had a good melt flow rate and thermal properties, and it enabled smooth printing, thus meeting all the requirements for the 3D printing of consumables.
- Published
- 2018
- Full Text
- View/download PDF
48. Physical and Antibacterial Properties of Sodium Alginate—Sodium Carboxymethylcellulose Films Containing Lactococcus lactis
- Author
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Jingsong Ye, Donghui Ma, Wen Qin, and Yaowen Liu
- Subjects
edible films ,Lactococcus lactis ,sodium alginate ,sodium carboxymethylcellulose ,Organic chemistry ,QD241-441 - Abstract
Edible films have gradually become a research focus for food packaging materials due to a variety of benefits, including environmental friendliness, good barrier properties, and good carrying capacity. In this experimental study, we used sodium alginate as a film-forming substrate, sodium carboxymethylcellulose as a modifier, and glycerol as a plasticizer, then Lactococcus lactis was added to film solutions to form bacteriostatic films via the tape casting method. With the addition of Lactococcus lactis, the films did not significantly change thickness, while the transparency decreased and a significant increase in red and yellow hues was observed. Meanwhile, the dispersion of bacterial cells in film solutions destroyed intermolecular interactions in the solutions during film formation and increased the volume of voids in the Lactococcus lactis-containing films, thereby slightly decreasing the tensile strength of the films, but significantly increasing water vapor permeability. Moreover, the films with added Lactococcus lactis showed significant bacteriostatic activity against Staphylococcus aureus at 4 °C. In a seven-day bacteriostatic test, the films with Lactococcus lactis added at a level of 1.5 g/100 g resulted in a decrease in the viable cell count of Staphylococcus aureus by at least four logarithmic units. This study of Lactococcus lactis-containing films has provided a new method and strategy for antibacterial preservation of foods.
- Published
- 2018
- Full Text
- View/download PDF
49. Modeling of magnetization precession in spin-torque nano-oscillators with a tilted polarizer
- Author
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Gang Lv, Hong Zhang, Xuecheng Cao, Yaowen Liu, Zhiwei Hou, Yufeng Qin, Guihua Li, and Linhui Wang
- Subjects
Physics ,QC1-999 - Abstract
The spin-torque induced magnetization precession dynamics are studied in a spin-valve with a tilted spin polarizer. Macrospin simulations demonstrate that the frequency of precession state depends both on the external DC current and the intrinsic parameters of devices such as the tilted angle of spin polarizer, the damping factor and saturation magnetization of the free layer. The dependence role of those parameters is characterized by phase diagrams. An analytical model is presented, which can successfully interpret the features of precession frequency.
- Published
- 2015
- Full Text
- View/download PDF
50. Development of Poly(lactic acid)/Chitosan Fibers Loaded with Essential Oil for Antimicrobial Applications
- Author
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Yaowen Liu, Shuyao Wang, Rong Zhang, Wenting Lan, and Wen Qin
- Subjects
cinnamon essential oil ,chitosan ,poly(lactic acid) ,antibacterial fibers ,Chemistry ,QD1-999 - Abstract
Cinnamon essential oil (CEO) was successfully encapsulated into chitosan (CS) nanoparticles at different loading amounts (1%, 1.5%, 2%, and 2.5% v/v) using oil-in-water (o/w) emulsion and ionic-gelation methods. In order to form active packaging, poly(lactic acid) (PLA) was used to fabricate PLA/CS-CEO composite fibers using a simple electrospinning method. The shape, size, zeta potential, and encapsulation efficacy of the CS-CEO nanoparticles were investigated. The composition, morphology, and release behavior of the composite fibers were investigated. PLA/CS-CEO-1.5 showed good stability and favorable sustained release of CEO, resulting in improved antimicrobial activity compared to the other blends. The PLA/CS-CEO fibers showed high long-term inactivation rates against Escherichia coli and Staphylococcus aureus due to the sustained release of CEO, indicating that the developed PLA/CS-CEO fibers have great potential for active food packaging applications.
- Published
- 2017
- Full Text
- View/download PDF
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