Superior tribology property of zinc phosphate impregnated graphite block at high-temperature oxidative friction

Xu Yuxuan,Tu Chuanjun,Liu Yanli,Liu Ping,Chen Gang,Tan Jiao,Xiong Wei,He Yubo,Liang Shilin,Ma Qingchun 한국탄소학회 2022 Carbon Letters Vol.32 No.5

High-temperature friction performances of graphite blocks (GBs) and zinc phosphate impregnated graphite blocks (IGBs) were evaluated under various friction temperatures. The surface of IGB exhibited extremely lower average friction coefficient values, that was 0.007 at 400 °C and 0.008 at 450 °C, in comparison to that of GB (0.13 at 400 °C and 0.16 at 450 °C, respectively). The worn surface of IGB in the high-temperature friction test was smoother and more complete than that of GB. The wear under high temperature and load caused the transformation of zinc pyrophosphate to zinc metaphosphate and the formation of a continuous large-area boundary lubrication layer combined with graphite and metallic element on the wear surface. The superior tribology property of IGB could be attributed to the digestion of iron oxides by tribo-chemical reactions and passivation of the exposed dangling covalent bonds. Specifically, the layered structure generated on the IGB wear interface effectively decreased the adhesive forces and prevented the surface from serious damage.

Business Environment, Entrepreneurship and Firm Performance in China: From a Configuration Perspective

Xu, XuSonghe,Hu, Yuxuan,Ma, Xingchao 부산대학교 중국연구소 2023 Journal of China Studies Vol.26 No.1

The entrepreneur will behave according to the principle of interest maximization entrepreneurship configuration, first forming the enterprise's internal balance, then, based on the logical order of the priority of system construction in the combination of strategic behavior. Therefore, the dual balance between entrepreneurship allocation and business environment elements is of great significance for enterprises to achieve high performance. Based on the configuration perspective and multiple institutional logic, this paper uses fuzzy-set qualitative comparative analysis (fsQCA) to explore the interaction between business environment elements and entrepreneurship configuration and the combination path to produce high firm performance, with 641 listed equipment manufacturing companies as the sample. The results show the following: ① high firm performance is the result of the interaction between entrepreneurship and the business environment; ② the configuration of entrepreneurship is closely related to the configuration of the business environment, showing differentiation characteristics; and ③ there is heterogeneity in the portfolio path of high performance for firms with different property rights. This paper can help enterprises correctly understand and grasp the balanced relationship between entrepreneurship and business environment elements and allocate entrepreneurship actively according to the changes in the external business environment to reach high enterprise performance. This paper still has some limitations. On the one hand, it is based on 641 listed companies in the equipment manufacturing industry, and the data have certain industry characteristics. In future research, more industries can be included to verify the universal applicability of the conclusions. On the other hand, limited by the length of the research and the number of term conditions by the fsQCA method, the term conditions selected in this paper are environmental variables, while less attention is given to the enterprise's own factors. More comprehensive variables can be included in future research to produce more in-depth and convincing research conclusions.

The role of CTNNB1 and LEF1 in feather follicles development of Anser cygnoides and Anser anser

Yue Sun,Yuxuan Zhou,Petunia Msuthwana,Jing Liu,Chang Liu,Cornelius Tlotliso Sello,Yupu Song,Ziqiang Feng,Shengyi Li,Wei Yang,Yunpeng Xu,Xiaomin Yan,Chuanghang Li,Yujian Sui,Jingtao Hu,Yongfeng Sun 한국유전학회 2020 Genes & Genomics Vol.42 No.7

Background Wingless-types/beta-catenin (Wnt/β-catenin) signaling pathway is one of the most extensively studied transcriptional cascades involved in various types of organogenesis including embryonic and postnatal development. Downy feather quantity is primarily affected by follicular development and gene regulations. Objective This research was aimed to investigate the role of catenin beta-1(CTNNB1) and lymphoid enhancerbinding factor-1 (LEF1) on feather follicles development at different developmental stages. Methods Fluorescence quantitative PCR, Western-blot and immunohistochemical methods were used in Anser cygnoides and Anser anser embryos (E12, E13 E18, and E28) and after birth gosling stages (G18, G48, G88) for gene expression analysis. Results CTNNB1 and LEF1 genes were expressed in Anser cygnoides and Anser anser at different embryonic and after-birth gosling developmental stages and the expression levels were significantly different in different stages (p < 0.05). The mRNA expression of CTNNB1 and LEF1 genes reached the highest level at D88 in Anser cygnoides, while the highest expression levels were at D18 and D88 in Anser anser, and the expression levels of CTNNB1 genes at D88 in all embryonic stages were significantly lower than after-birth stages. CTNNB1 and LEF1 protein expression were the highest at E12 and E28 for Anser cygnoides feather follicles development. While at a similar stage for Anser anser, the expression of CTNNB1 and LEF1 protein was the highest at D48 and D18. Protein expression at embryonic stages was in the epidermis (E) and the hair basal plate (P), the expression site for after-birth stages was in the dermal papilla (DP). Conclusion Our study illustrated that CTNNB1 and LEF1 has an impact on Anser cygnoides and Anser anser feather follicles growth and development.

Engineered exosomes enriched in netrin-1 modRNA promote axonal growth in spinal cord injury by attenuating inflammation and pyroptosis

Lu Xiao,Xu Guangyu,Lin Zhidi,Zou Fei,Liu Siyang,Zhang Yuxuan,Fu Wei,Jiang Jianyuan,Ma Xiaosheng,Song Jian 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Spinal cord injury (SCI) brings a heavy burden to individuals and society, and there is no effective treatment at present. Exosomes (EX) are cell secreted vesicles containing molecules such as nucleic acids and proteins, which hold promise for the treatment of SCI. Netrin-1 is an axon guidance factor that regulates neuronal growth. We investigated the effects of engineered EX enriched in netrin-1 chemically synthetic modified message RNA (modRNA) in treating SCI in an attempt to find a novel therapeutic approach for SCI.Netrin-1 modRNA was transfected into bone marrow mesenchymal stem cells to obtain EX enriched with netrin-1 (EX-netrin1). We built an inflammatory model in vitro with lipopolysaccharide (LPS) in vitro to study the therapeutic effect of EX-netrin1 on SCI. For experiments in vitro, ELISA, CCK-8 assay, immunofluorescence staining, lactate dehydrogenase release experiments test, real-time quantitative polymerase chain reaction, and western blot were conducted. At the same time, we constructed a rat model of SCI. MRI, hematoxylin-eosin and Nissl staining were used to assess the extent of SCI in rats.In vitro experiments showed that EX had no effect on the viability of oligodendrocytes and PC12 cells. EX-netrin1 could attenuate LPS-induced inflammation and pyroptosis and accelerate axonal/dentritic growth in PC12 cells/oligodendrocytes. In addition, netrin-1 could activate the PI3K/AKT/mTOR signalling pathway upon binding to its receptor unc5b. When Unc5b and PI3K were inhibited, the effect of EX-netrin1 was weakened, which could be reversed by PI3K or mTOR activator. Our in vivo experiments indicated that EX-netrin1 could promote recovery in rats with SCI.We found that EX-netrin1 regulated inflammation, pyroptosis and axon growth in SCI via the Unc5b/PI3K/AKT/mTOR pathway, which provides a new strategy for the treatment of SCI.

Water-blocking Asphyxia of N95 Medical Respirator During Hot Environment Work Tasks With Whole-body Enclosed Anti-bioaerosol Suit

Zhu Jintuo,Jiang Qijun,Ye Yuxuan,He Xinjian,Shao Jiang,Li Xinyu,Zhao Xijie,Xu Huan,Hu Qi 한국산업안전보건공단 산업안전보건연구원 2023 Safety and health at work Vol.14 No.4

Background: During hot environment work tasks with whole-body enclosed anti-bioaerosol suit, the combined effect of heavy sweating and exhaled hot humid air may cause the N95 medical respirator to saturate with water/sweat (i.e., water-blocking). Methods: 32 young male subjects with different body mass indexes (BMI) in whole-body protection (N95 medical respirator + one-piece protective suit + head covering + protective face screen + gloves + shoe covers) were asked to simulate waste collecting from each isolated room in a seven-story building at 27-28°C, and the weight, inhalation resistance (Rf), and aerosol penetration of the respirator before worn and after water-blocking were analyzed. Results: All subjects reported water-blocking asphyxia of the N95 respirators within 36-67 min of the task. When water-blocking occurred, the Rf and 10-200 nm total aerosol penetration (Pt) of the respirators reached up to 1270-1810 Pa and 17.3-23.3%, respectively, which were 10 and 8 times of that before wearing. The most penetration particle size of the respirators increased from 49-65 nm before worn to 115-154 nm under water-blocking condition, and the corresponding maximum size-dependent aerosol penetration increased from 2.5-3.5% to 20-27%. With the increase of BMI, the water-blocking occurrence time firstly increased then reduced, while the Rf, Pt, and absorbed water all increased significantly. Conclusions: This study reveals respirator water-blocking and its serious negative impacts on respiratory protection. When performing moderate-to-high-load tasks with whole-body protection in a hot environment, it is recommended that respirator be replaced with a new one at least every hour to avoid water-blocking asphyxia.

Artificial Intelligence in the Prediction of Gastrointestinal Stromal Tumors on Endoscopic Ultrasonography Images: Development, Validation and Comparison with Endosonographers

Lu Yi,Wu Jiachuan,Hu Minhui,Zhong Qinghua,Er Limian,Shi Huihui,Cheng Weihui,Chen Ke,Liu Yuan,Qiu Bingfeng,Xu Qiancheng,Lai Guangshun,Wang Yufeng,Luo Yuxuan,Mu Jinbao,Zhang Wenjie,Zhi Min,Sun Jiachen 거트앤리버 소화기연관학회협의회 2023 Gut and Liver Vol.17 No.6

Background/Aims: The accuracy of endosonographers in diagnosing gastric subepithelial lesions (SELs) using endoscopic ultrasonography (EUS) is influenced by experience and subjectivity. Artificial intelligence (AI) has achieved remarkable development in this field. This study aimed to develop an AI-based EUS diagnostic model for the diagnosis of SELs, and evaluated its efficacy with external validation. Methods: We developed the EUS-AI model with ResNeSt50 using EUS images from two hospitals to predict the histopathology of the gastric SELs originating from muscularis propria. The diagnostic performance of the model was also validated using EUS images obtained from four other hospitals. Results: A total of 2,057 images from 367 patients (375 SELs) were chosen to build the models, and 914 images from 106 patients (108 SELs) were chosen for external validation. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the model for differentiating gastrointestinal stromal tumors (GISTs) and non-GISTs in the external validation sets by images were 82.01%, 68.22%, 86.77%, 59.86%, and 78.12%, respectively. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy in the external validation set by tumors were 83.75%, 71.43%, 89.33%, 60.61%, and 80.56%, respectively. The EUS-AI model showed better performance (especially specificity) than some endosonographers. The model helped improve the sensitivity, specificity, and accuracy of certain endosonographers. Conclusions: We developed an EUS-AI model to classify gastric SELs originating from muscularis propria into GISTs and non-GISTs with good accuracy. The model may help improve the diagnostic performance of endosonographers. Further work is required to develop a multi-modal EUS-AI system.