High-Performance Stretchable Conductive Composite Fibers from Surface-Modified Silver Nanowires and Thermoplastic Polyurethane by Wet Spinning

Lu, Ying,Jiang, Jianwei,Yoon, Sungho,Kim, Kyung-Shik,Kim, Jae-Hyun,Park, Sanghyuk,Kim, Sang-Ho,Piao, Longhai American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.2

<P>Highly stretchable and conductive fibers have attracted great interest as a fundamental building block for the next generation of textile-based electronics. Because of its high conductivity and high aspect ratio, the Ag nanowire (AgNW) has been considered one of the most promising conducting materials for the percolation network-based conductive films and composites. However, the poor dispersibility of AgNWs in hydrophobic polymers has hindered their application to stretchable conductive composite fibers. In this paper, we present a highly stretchable and conductive composite fiber from the co-spinning of surface-modified AgNWs and thermoplastic polyurethane (PU). The surface modification of AgNWs with a polyethylene glycol derivative improved the compatibility of PU and AgNWs, which allowed the NWs to disperse homogeneously in the elastomeric matrix, forming effective percolation networks and causing the composite fiber to show enhanced electrical and mechanical performance. The maximum AgNW mass fraction in the composite fiber was 75.9 wt %, and its initial electrical conductivity was as high as 14 205 S/cm. The composite fibers also exhibited superior stretchability: the maximum rupture strain of the composite fiber with 14.6 wt % AgNW was 786%, and the composite fiber was also conductive even when it was stretched up to 200%. In addition, 2-dimensional (2-D) Ag nanoplates were added to the AgNW/PU composite fibers to increase the stability of the conductive network under repeated stretching and releasing. The Ag nanoplates acted as a bridge to effectively prevent the AgNWs from slippage and greatly improved the stability of the conductive network.</P>

Next Location Prediction with a Graph Convolutional Network Based on a Seq2seq Framework

( Jianwei Chen ),( Jianbo Li ),( Manzoor Ahmed ),( Junjie Pang ),( Minchao Lu ),( Xiufang Sun ) 한국인터넷정보학회 2020 KSII Transactions on Internet and Information Syst Vol.14 No.5

Predicting human mobility has always been an important task in Location-based Social Network. Previous efforts fail to capture spatial dependence effectively, mainly reflected in weakening the location topology information. In this paper, we propose a neural network-based method which can capture spatial-temporal dependence to predict the next location of a person. Specifically, we involve a graph convolutional network (GCN) based on a seq2seq framework to capture the location topology information and temporal dependence, respectively. The encoder of the seq2seq framework first generates the hidden state and cell state of the historical trajectories. The GCN is then used to generate graph embeddings of the location topology graph. Finally, we predict future trajectories by aggregated temporal dependence and graph embeddings in the decoder. For evaluation, we leverage two real-world datasets, Foursquare and Gowalla. The experimental results demonstrate that our model has a better performance than the compared models.

Extended Equal Service and Differentiated Service Models for Peer-to-Peer File Sharing

Jianwei Zhang,Yongchao Wang,Wei Xing,Dongming Lu 한국통신학회 2013 Journal of communications and networks Vol.15 No.2

Peer-to-peer (P2P) systems have proved the most effective and popular file sharing applications in recent years. Previous studies mainly focused on equal service and differentiated service strategies when peers have no initial data before their downloads. For an upload-constrained P2P file sharing system, wemodel both the equal service process and the differentiated service process when the initial data distribution of peers satisfies some special conditions. Moreover, we show how to minimize the time required to distribute the file to any number of peers. The proposed fluid-based models can reveal the intrinsic relations among the initial data amount, the peer set size, and the minimum last finish time. The closed-form expressions derived from the extended models can closely approximate chunk-based models and systems, especially for relatively large files. As an application of the extended models, we show how to provide differentiated service efficiently to multiple peer sets. Since no limits are imposed on the upload bandwidth of peers or the size of each peer set, we believe that our analytic process and the results achieved can provide not only fundamental insights into bandwidth allocation and data scheduling but also a helpful reference for both improving systemperformance and building an effective incentive mechanism for P2P file sharing systems.

Extended Equal Service and Differentiated Service Models for Peer-to-Peer File Sharing

Zhang, Jianwei,Wang, Yongchao,Xing, Wei,Lu, Dongming The Korea Institute of Information and Commucation 2013 Journal of communications and networks Vol.15 No.2

Peer-to-peer (P2P) systems have proved the most effective and popular file sharing applications in recent years. Previous studies mainly focused on equal service and differentiated service strategies when peers have no initial data before their downloads. For an upload-constrained P2P file sharing system, we model both the equal service process and the differentiated service process when the initial data distribution of peers satisfies some special conditions. Moreover, we show how to minimize the time required to distribute the file to any number of peers. The proposed fluid-based models can reveal the intrinsic relations among the initial data amount, the peer set size, and the minimum last finish time. The closed-form expressions derived from the extended models can closely approximate chunk-based models and systems, especially for relatively large files. As an application of the extended models, we show how to provide differentiated service efficiently to multiple peer sets. Since no limits are imposed on the upload bandwidth of peers or the size of each peer set, we believe that our analytic process and the results achieved can provide not only fundamental insights into bandwidth allocation and data scheduling but also a helpful reference for both improving system performance and building an effective incentive mechanism for P2P file sharing systems.

Wet-Spinning Fabrication of Flexible Conductive Composite Fibers from Silver Nanowires and Fibroin

Ying Lu,Jianwei Jiang,Sanghyuk Park,Dong Wang,Longhai Piao,Jinkwon Kim 대한화학회 2020 Bulletin of the Korean Chemical Society Vol.41 No.2

Biocompatible flexible conductive composite fibers have attracted great research interest because of multitude of their potential applications, such as wearable devices, biomedical sensors, and actuators. Herein, highly conductive and flexible silver nanowire (AgNW)/fibroin composite fibers were fabricated by using a wet-spinning technique. The composite fiber conductivity was as high as 5670?S/cm at an AgNW concentration of 29.1?wt%. The composite fibers also exhibited high flexibilities and could be folded without losing their conductivities. Furthermore, the composite fiber fabricated with a 3? draw ratio exhibited a breaking strain of 27.3% and breaking stress of 118.1 cN/dtex. Our attempt to produce such biocompatible flexible conductive composite fibers by using sustainable regenerated silk fibroins and compatible AgNWs via wet spinning may provide a practical way for fabricating functional biocompatible fiber materials.

Erythropoietin-Modified Mesenchymal Stem Cells Enhance Anti-fibrosis Efficacy in Mouse Liver Fibrosis Model

Wang Xianyao,Wang Huizhen,Lu Junhou,Feng Zhanhui,Liu Zhongshan,Song Hailiang,Wang Heng,Zhou Yanhua,Xu Jianwei 한국조직공학과 재생의학회 2020 조직공학과 재생의학 Vol.17 No.5

BACKGROUND: Mesenchymal stem cell (MSC)-based cell transplantation is an effective means of treating chronic liver injury, fibrosis and end-stage liver disease. However, extensive studies have found that only a small number of transplanted cells migrate to the site of injury or lesion, and repair efficacy is very limited. METHODS: Bone marrow-derived MSCs (BM-MSCs) were generated that overexpressed the erythropoietin (EPO) gene using a lentivirus. Cell Counting Kit-8 was used to detect the viability of BM-MSCs after overexpressing EPO. Cell migration and apoptosis were verified using Boyden chamber and flow cytometry, respectively. Finally, the anti-fibrosis efficacy of EPO-MSCs was evaluated in vivo using immunohistochemical analysis. RESULTS: EPO overexpression promoted cell viability and migration of BM-MSCs without inducing apoptosis, and EPO-MSC treatment significantly alleviated liver fibrosis in a carbon tetrachloride (CCl4) induced mouse liver fibrosis model. CONCLUSION: EPO-MSCs enhance anti-fibrotic efficacy, with higher cell viability and stronger migration ability compared with treatment with BM-MSCs only. These findings support improving the efficiency of MSCs transplantation as a potential therapeutic strategy for liver fibrosis.

Experimental study on characteristic of sloshing impact load in elastic tank with low and partial filling under rolling coupled pitching

Wu, Wenfeng,Zhen, Changwen,Lu, Jinshu,Tu, Jiaoyang,Zhang, Jianwei,Yang, Yubin,Zhu, Kebi,Duan, Junxian The Society of Naval Architects of Korea 2020 International Journal of Naval Architecture and Oc Vol.12 No.1

A series of experiments covering lowest three natural frequencies of rolling coupled pitching were conducted to investigate liquid sloshing with low liquid depth. The test results show that the most violent liquid sloshing in rolling and pitching is located in the vicinity of the first order natural frequency (f1). When the excitation frequency of rolling and pitching is located between 0.98f1 and 1.113f1, roof-bursting phenomenon of liquid appeared, and the maximum impact pressure is at 1.09f1. When the external excitation frequency is at 1.113f1, the number of sloshing shocks decreases sharply. Furthermore, the space distribution of the impact pressure on the left bulkhead and the top bulkhead was analyzed. It is concluded that with low liquid filling, the impact load is greater near the free surface and the top of tank, and the impact position of the side bulkhead increases with the increasing of the frequency near the resonant frequency.

Nomogram for Predicting Central Lymph Node Metastasis in Papillary Thyroid Cancer: A Retrospective Cohort Study of Two Clinical Centers

Zheyu Yang,Yu Heng,Jianwei Lin,Chenghao Lu,Dingye Yu,Lei Tao,Wei Cai 대한암학회 2020 Cancer Research and Treatment Vol.52 No.4

Purpose Central lymph node metastasis (CNM) are highly prevalent but hard to detect preoperatively in papillary thyroid carcinoma (PTC) patients, while the significance of prophylactic compartment central lymph node dissection (CLND) remains controversial as a treatment option. We aim to establish a nomogram assessing risks of CNM in PTC patients, and explore whether prophylactic CLND should be recommended. Materials and Methods One thousand four hundred thirty-eight patients from two clinical centers that underwent thyroidectomy with CLND for PTC within the period 2016-2019 were retrospectively analyzed. Univariate and multivariate analysis were performed to examine risk factors associated with CNM. A nomogram for predicting CNM was established, thereafter internally and externally validated. Results Seven variables were found to be significantly associated with CNM and were used to construct the model. These were as follows: thyroid capsular invasion, multifocality, creatinine > 70 μmol/L, age < 40, tumor size > 1 cm, body mass index < 22, and carcinoembryonic antigen > 1 ng/mL. The nomogram had good discrimination with a concordance index of 0.854 (95% confidence interval [CI], 0.843 to 0.867), supported by an external validation point estimate of 0.825 (95% CI, 0.793 to 0.857). A decision curve analysis was made to evaluate nomogram and ultrasonography for predicting CNM. Conclusion A validated nomogram utilizing readily available preoperative variables was developed to predict the probability of central lymph node metastases in patients presenting with PTC. This nomogram may help surgeons make appropriate surgical decisions in the management of PTC, especially in terms of whether prophylactic CLND is warranted.

Autophagy of bovine mammary epithelial cell induced by intracellular Staphylococcus aureus

Na Geng,Kangping Liu,Jianwei Lu,Yuliang Xu,Xiaozhou Wang,Run Wang,Jianzhu Liu,Yongxia Liu,Bo Han 한국미생물학회 2020 The journal of microbiology Vol.58 No.4

Bovine mastitis is a common disease in the dairy industry that causes great economic losses. As the primary pathogen of contagious mastitis, Staphylococcus aureus (S. aureus) can invade bovine mammary epithelial cells, thus evading immune defenses and resulting in persistent infection. Recently, autophagy has been considered an important mechanism for host cells to clear intracellular pathogens. In the current study, autophagy caused by S. aureus was detected, and the correlation between autophagy and intracellular S. aureus survival was assessed. First, a model of intracellular S. aureus infection was established. Then, the autophagy of MAC-T cells was evaluated by confocal microscopy and western blot. Moreover, the activation of the PI3K-Akt-mTOR and ERK1/2 signaling pathways was determined by western blot. Finally, the relationship between intracellular bacteria and autophagy was analyzed by using autophagy regulators (3-methyladenine [3-MA], rapamycin [Rapa] and chloroquine [CQ]). The results showed that S. aureus caused obvious induction of autophagosome formation, transformation of LC3I/II, and degradation of p62/SQSTM1 in MAC-T cells; furthermore, the PI3K-Akt-mTOR and ERK1/2 signaling pathways were activated. The number of intracellular S. aureus increased significantly with autophagy activation by rapamycin, whereas the number decreased when the autophagy flux was inhibited by chloroquine. Therefore, this study indicated that intracellular S. aureus can induce autophagy and utilize it to survive in bovine mammary epithelial cells.

Incorporating Bidirectional Heuristic Search and Improved ACO in Route Planning

Guangming Xiong,Xiaoyun Li,Shuai Zhou,Hao Lu,Yan Jiang,Jianwei Gong 보안공학연구지원센터 2015 International Journal of Hybrid Information Techno Vol.8 No.7

A multi-objective multi-node dynamic route planning system for a vehicle is presented in this paper. In this system, a bidirectional heuristic search algorithm is designed to perform path planning between two nodes in a topological map created by OpenStreetMap for urban scenarios. And then an improved multi-objective Ant Colony Optimization (ACO) algorithm considering the timeliness of goal nodes is proposed to generate the node sequence. Experimental results validated the proposed approach.