A study on the wake structure of the double vortex tubes in a ventilated supercavity

Wei Wang,Cong Wang,Yingjie Wei,Wuchao Song 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.4

To study the wake structure of the double vortex tubes in a ventilated supercavity, the computational fluid dynamics (CFD) method based on the finite volume method and the volume of fluids (VOF) multiphase flow model were used to solve the Reynolds-averaged Navier-Stokes (RANS) equations for performing numerical simulation analysis on the wake structure of a supercavitating vehicle. By analyzing the reasons for the upward drift in the tail section of the supercavity and the formation of the double vortex tubes, the effects of gravity and the attack angle of the vehicle on the formation of gas leakage in the double vortex tubes of the supercavity were explained. The pressure and vorticity inside the vortex tubes were thereby analyzed as well. The results showed that, in addition to the gravitational condition, the wetted area of the vehicle with an attack angle also caused the supercavitating tail to form gas leakage in the form of double vortex tubes. Moreover, the wetted area played a dominant role compared to the role of gravity. The supercavity closure to the inside tail section was a high-pressure area, and this area separated downstream into two parts, resulting in the generation of the double vortex tubes. The vorticity and pressure in the vicinity of the vortex tubes attenuated downstream in the direction of the vortex tubes. When the tail section of the cavity leaked gas via three vortex tubes, the values of the vorticity inside the upper part of the vortex tubes became very small, and the air flow inside the upper part of the vortex tubes increased with the attack angle of the vehicle.

Micro-Expression Recognition Base on Optical Flow Features and Improved MobileNetV2

( Wei Xu ),( Hao Zheng ),( Zhongxue Yang ),( Yingjie Yang ) 한국인터넷정보학회 2021 KSII Transactions on Internet and Information Syst Vol.15 No.6

When a person tries to conceal emotions, real emotions will manifest themselves in the form of micro-expressions. Research on facial micro-expression recognition is still extremely challenging in the field of pattern recognition. This is because it is difficult to implement the best feature extraction method to cope with micro-expressions with small changes and short duration. Most methods are based on hand-crafted features to extract subtle facial movements. In this study, we introduce a method that incorporates optical flow and deep learning. First, we take out the onset frame and the apex frame from each video sequence. Then, the motion features between these two frames are extracted using the optical flow method. Finally, the features are inputted into an improved MobileNetV2 model, where SVM is applied to classify expressions. In order to evaluate the effectiveness of the method, we conduct experiments on the public spontaneous micro-expression database CASME II. Under the condition of applying the leave-one-subject-out cross-validation method, the recognition accuracy rate reaches 53.01%, and the F-score reaches 0.5231. The results show that the proposed method can significantly improve the micro-expression recognition performance.

Simulation of the Field Emission from a Hemisphere-on-Post Nanowire: Revision of the Fowler–Nordheim Formula in Terms of Nonuniformity and Resistance

Jindi Wei,Gengmin Zhang,Yingjie Xing,Jin Yang,Wensheng Zhou 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.8

The electric field on a hemisphere-on-post nanowire is numerically calculated using the finite element method (FEM). The FEM calculation results show that the field is sufficiently strong for extracting a significant field emission current only in a small area at the top of the hemisphere, while the contribution to the field emission from the other part of the hemisphere and the flank side of the cylinder is negligible owing to the rapid drop of the electric field. Both the local current density at the top of the hemisphere (Jc) and the average current density across the nanowire cross-section (Ja) are calculated and the Ja-to-Jc ratio (α) is introduced to reflect the non-uniformity of the field emission. An empirical formula with proper parameters that can best fit the simulation results is derived for describing the dependence of α on the macroscopic electric field (Fm). As a result, the Ja–Fm relationship is attained and the revision to the traditional Fowler–Nordheim (FN) formula caused by the nonuniformity of field distribution is found in both the pre-exponent part and the exponent part, so that the deviation of the FN plots from linearity often observed in experiments is partly accounted for. Moreover, the resistance at the emitter-substrate interface is shown to cause saturation in the field emission current and a downward bending of the FN plot in the high-field region.

Ginsenoside Rg3 nanoparticles with permeation enhancing based chitosan derivatives were encapsulated with doxorubicin by thermosensitive hydrogel and anti-cancer evaluation of peritumoral hydrogel injection combined with PD-L1 antibody

Wu Hao,Wei Guoli,Luo Lixia,Li Lingchang,Gao Yibo,Tan Xiaobin,Wang Sen,Chang Haoxiao,Liu Yuxi,Wei Yingjie,Song Jie,Zhang Zhenhai,Huo Jiege 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Combination of chemotherapy and immune checkpoint inhibitor therapy has greatly improved the anticancer effect on multiple malignancies. However, the efficiency on triple-negative breast cancer (TNBC) is limited, since most patients bear “cold” tumors with low tumor immunogenicity. Doxorubicin (DOX), one of the most effective chemotherapy agents, can induce immunogenic cell death (ICD) and thus initiating immune response.In this study, to maximize the ICD effect induced by DOX, chitosan and cell-penetrating peptide (R6F3)-modified nanoparticles (PNPs) loaded with ginsenoside Rg3 (Rg3) were fabricated using the self-assembly technique, followed by co-encapsulation with DOX based on thermo-sensitive hydrogel. Orthotopic tumor model and contralateral tumor model were established to observe the antitumor efficacy of the thermo-sensitive hydrogel combined with anti-PD-L1 immunotherapy, besides, the biocompatibility was also evaluated by histopathological.Rg3-PNPs strengthened the immunogenic cell death (ICD) effect induced by DOX. Moreover, the hydrogel co-loading Rg3-PNPs and DOX provoked stronger immune response in originally nonimmunogenic 4T1 tumors than DOX monotherapy. Following combination with PD-L1 blocking, substantial antitumor effect was achieved due to the recruitment of memory T cells and the decline of adaptive PD-L1 enrichment.The hydrogel encapsulating DOX and highly permeable Rg3-PNPs provided an efficient strategy for remodeling immunosuppressive tumor microenvironment and converting immune “cold” 4T1 into “hot” tumors.

Metabolism of ginsenosides Rk3 and Rh4 from steamed notoginseng in zebrafish by ultraperformance liquid chromatography/quadrupole-time-of-flight mass spectrometry

Bin Chen,Yingjie Wei,Dandan Wang,Xiaobin Jia 대한약학회 2015 Archives of Pharmacal Research Vol.38 No.8

In this work, the metabolite profiles of ginsenosides Rk3 and Rh4 from steamed notoginseng in zebrafish were qualitatively investigated, and their possible metabolic pathways were subsequently proposed. Metabolites of ginsenosides Rk3 and Rh4 after exposing to zebrafish for 24 h were identified by Ultraperformance Liquid Chromatography/Quadrupole -Time-of-Flight Mass Spectrometry (UPLC-TOF/MS). The separation was performed with a UPLC BEH C18 column using a binary gradient elution of 0.1 % formic acetonitrile -0.1 % formic acid water. The quasi-molecular ions of compounds were detected in negative mode. According to the quasi-molecular ions and MS2 spectra, after comparison with reference standards, molecular mass information and the potential structures about metabolites of ginsenosides Rk3 and Rh4 were obtained. In all, 5 and 6 metabolites of ginsenoside Rk3 and Rh4 including M1(M6), M2(M7), M3–M5 and N1, N2(N7), N3–N6 were identified in zebrafish respectively, which were to our knowledge reported for the first time. The results indicated that ginsenosides Rk3 and Rh4 were metabolized via desugarization, glucuronidation, sulfation, dehydroxylation, and loss of C-17 and C-23 residue pathways in zebrafish. Loss of glucose at position C-6 and glucuronidation at position C-3 or C-6 in zebrafish were considered as the main physiologic processes of ginsenosides Rk3 and Rh4.

Mechanical Stimulation and Diameter of Fiber Scaffolds Affect the Differentiation of Rabbit Annulus Fibrous Stem Cells

Zhou Pinghui,Wei Bangguo,Guan Jingjing,Chen Yu,Zhu Yansong,Ye Yuchen,Meng Yue,Guan Jianzhong,Mao Yingji 한국조직공학과 재생의학회 2021 조직공학과 재생의학 Vol.18 No.1

BACKGROUND: Degeneration of the annulus fibrosus (AF), an important structure of the intervertebral disc, is one of the main causes of degenerative disc disease. Fabrication of scaffolds replicating the stratified microstructure of the AF is critical for the successful regeneration of AF. METHODS: In this study, we cultured rabbit AF-derived stem cells (AFSCs) using fabricated electrospun fibrous poly-L-lactic acid scaffolds with different diameters. We applied cyclic tensile strain (CTS) on the scaffolds to regulate the differentiation of AFSCs into specific cell types that resided at the inner, middle, and outer zones of the AF. RESULTS: We found that the morphologies of AFSCs on the smaller-fiber-diameter scaffolds were nearly round, whereas spindle-like cells morphologies were observed on large-diameter scaffolds. CTS enhanced these phenomena and made the cells slender. The expression levels of collagen-I in cells increased as a function of the fiber diameter, whereas collagen-II and aggrecan exhibited opposite trends. Moreover, the application of CTS upregulated the gene expressions of collagen-I, collagen-II, and aggrecan. CONCLUSION: Overlaying the scaffolds with different CTS-stimulated cells could eventually lead to engineered AF tissues with hierarchical structures that approximated the native AF tissue. Thus, the proposed methodologies could be potentially applied for AF regeneration. BACKGROUND: Degeneration of the annulus fibrosus (AF), an important structure of the intervertebral disc, is one of the main causes of degenerative disc disease. Fabrication of scaffolds replicating the stratified microstructure of the AF is critical for the successful regeneration of AF. METHODS: In this study, we cultured rabbit AF-derived stem cells (AFSCs) using fabricated electrospun fibrous poly-L-lactic acid scaffolds with different diameters. We applied cyclic tensile strain (CTS) on the scaffolds to regulate the differentiation of AFSCs into specific cell types that resided at the inner, middle, and outer zones of the AF. RESULTS: We found that the morphologies of AFSCs on the smaller-fiber-diameter scaffolds were nearly round, whereas spindle-like cells morphologies were observed on large-diameter scaffolds. CTS enhanced these phenomena and made the cells slender. The expression levels of collagen-I in cells increased as a function of the fiber diameter, whereas collagen-II and aggrecan exhibited opposite trends. Moreover, the application of CTS upregulated the gene expressions of collagen-I, collagen-II, and aggrecan. CONCLUSION: Overlaying the scaffolds with different CTS-stimulated cells could eventually lead to engineered AF tissues with hierarchical structures that approximated the native AF tissue. Thus, the proposed methodologies could be potentially applied for AF regeneration.

Evaluating and Mitigating Malicious Data Aggregates in Named Data Networking

( Kai Wang ),( Wei Bao ),( Yingjie Wang ),( Xiangrong Tong ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.9

Named Data Networking (NDN) has emerged and become one of the most promising architectures for future Internet. However, like traditional IP-based networking paradigm, NDN may not evade some typical network threats such as malicious data aggregates (MDA), which may lead to bandwidth exhaustion, traffic congestion and router overload. This paper firstly analyzes the damage effect of MDA using realistic simulations in large-scale network topology, showing that it is not just theoretical, and then designs a fine-grained MDA mitigation mechanism (MDAM) based on the cooperation between routers via alert messages. Simulations results show that MDAM can significantly reduce the Pending Interest Table overload in involved routers, and bring in normal data-returning rate and data-retrieval delay.

Metabolite profiles of ginsenosides Rk1 and Rg5 in zebrafish using ultraperformance liquid chromatography/quadrupole-time-of-flight MS

Shen, Wenwen,Wei, Yingjie,Tang, Daoquan,Jia, Xiaobin,Chen, Bin The Korean Society of Ginseng 2017 Journal of Ginseng Research Vol.41 No.1

Background: In the present study, metabolite profiles of ginsenosides Rk1 and Rg5 from red ginseng or red notoginseng in zebrafish were qualitatively analyzed with ultraperformance liquid chromatography/quadrupole-time-of-flight MS, and the possible metabolic were pathways proposed. Methods: After exposing to zebrafish for 24 h, we determined the metabolites of ginsenosides Rk1 and Rg5. The chromatography was accomplished on UPLC BEH C18 column using a binary gradient elution of 0.1% formic acetonitrile-0.1% formic acid water. The quasimolecular ions of compounds were analyzed in the negative mode. With reference to quasimolecular ions and MS2 spectra, by comparing with reference standards and matching the empirical molecular formula with that of known published compounds, and then the potential structures of metabolites of ginsenosides Rk1 and Rg5 were acquired. Results: Four and seven metabolites of ginsenoside Rk1 and ginsenoside Rg5, respectively, were identified in zebrafish. The mechanisms involved were further deduced to be desugarization, glucuronidation, sulfation, and dehydroxymethylation pathways. Dehydroxylation and loss of C-17 residue were also metabolic pathways of ginsenoside Rg5 in zebrafish. Conclusion: Loss of glucose at position C-3 and glucuronidation at position C-12 in zebrafish were regarded as the primary physiological processes of ginsenosides Rk1 and Rg5.

Long-circulating siRNA nanoparticles for validating Prohibitin1-targeted non-small cell lung cancer treatment

Zhu, Xi,Xu, Yingjie,Solis, Luisa M.,Tao, Wei,Wang, Liangzhe,Behrens, Carmen,Xu, Xiaoyang,Zhao, Lili,Liu, Danny,Wu, Jun,Zhang, Ning,Wistuba, Ignacio I.,Farokhzad, Omid C.,Zetter, Bruce R.,Shi, Jinjun National Academy of Sciences 2015 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.112 No.25

<P><B>Significance</B></P><P>This study developed a new generation lipid–polymer hybrid nanoparticle platform for effective systemic delivery of small interfering RNA (siRNA) to tumors, which represents a challenging hurdle for the widespread application of RNA interference (RNAi) in cancer research and therapy. With promising in vivo features such as long blood circulation, high tumor accumulation, and effective gene silencing, the hybrid siRNA nanoparticles were successfully used to reveal and validate a putative therapeutic target, Prohibitin1 (PHB1), in non-small cell lung cancer treatment. In vivo antitumor efficacy results and human tissue microarray analysis further suggested the feasibility of utilizing PHB1 siRNA nanoparticles as a novel therapeutic agent. This hybrid RNAi nanoparticle platform may serve as a valuable tool for validating potential cancer targets and developing new cancer therapies.</P><P>RNA interference (RNAi) represents a promising strategy for identification and validation of putative therapeutic targets and for treatment of a myriad of important human diseases including cancer. However, the effective systemic in vivo delivery of small interfering RNA (siRNA) to tumors remains a formidable challenge. Using a robust self-assembly strategy, we develop a unique nanoparticle (NP) platform composed of a solid polymer/cationic lipid hybrid core and a lipid-poly(ethylene glycol) (lipid-PEG) shell for systemic siRNA delivery. The new generation lipid–polymer hybrid NPs are small and uniform, and can efficiently encapsulate siRNA and control its sustained release. They exhibit long blood circulation (<I>t</I><SUB>1/2</SUB> ∼8 h), high tumor accumulation, effective gene silencing, and negligible in vivo side effects. With this RNAi NP, we delineate and validate the therapeutic role of Prohibitin1 (PHB1), a target protein that has not been systemically evaluated in vivo due to the lack of specific and effective inhibitors, in treating non-small cell lung cancer (NSCLC) as evidenced by the drastic inhibition of tumor growth upon PHB1 silencing. Human tissue microarray analysis also reveals that high PHB1 tumor expression is associated with poorer overall survival in patients with NSCLC, further suggesting PHB1 as a therapeutic target. We expect this long-circulating RNAi NP platform to be of high interest for validating potential cancer targets in vivo and for the development of new cancer therapies.</P>

Measurement of Intra-Fraction Displacement of the Mediastinal Metastatic Lymph Nodes Using Four-Dimensional CT in Non-Small Cell Lung Cancer

Suzhen Wang,Jianbin Li,Yingjie Zhang,Wei Wang,Fengxiang Li,Tingyong Fan,Min Xu,Qian Shao 대한영상의학회 2012 Korean Journal of Radiology Vol.13 No.4

Objective: To measure the intra-fraction displacements of the mediastinal metastatic lymph nodes by using four-dimensional CT (4D-CT) in non-small cell lung cancer (NSCLC). Materials and Methods: Twenty-four patients with NSCLC, who were to be treated by using three dimensional conformal radiation therapy (3D-CRT), underwent a 4D-CT simulation during free breathing. The mediastinal metastatic lymph nodes were delineated on the CT images of 10 phases of the breath cycle. The lymph nodes were grouped as the upper, middle and lower mediastinal groups depending on the mediastinal regions. The displacements of the center of the lymph node in the left-right (LR), anterior-posterior (AP), and superior-inferior (SI) directions were measured. Results: The mean displacements of the center of the mediastinal lymph node in the LR, AP, and SI directions were 2.24 mm, 1.87 mm, and 3.28 mm, respectively. There were statistically significant differences between the displacements in the SI and LR, and the SI and AP directions (p < 0.05). For the middle and lower mediastinal lymph nodes, the displacement difference between the AP and SI was statistically significant (p = 0.005; p = 0.015), while there was no significant difference between the LR and AP directions (p < 0.05). Conclusion: The metastatic mediastinal lymph node movements are different in the LR, AP, and SI directions in patients with NSCLC, particularly for the middle and lower mediastinal lymph nodes. The spatial non-uniform margins should be considered for the metastatic mediastinal lymph nodes in involved-field radiotherapy. Objective: To measure the intra-fraction displacements of the mediastinal metastatic lymph nodes by using four-dimensional CT (4D-CT) in non-small cell lung cancer (NSCLC). Materials and Methods: Twenty-four patients with NSCLC, who were to be treated by using three dimensional conformal radiation therapy (3D-CRT), underwent a 4D-CT simulation during free breathing. The mediastinal metastatic lymph nodes were delineated on the CT images of 10 phases of the breath cycle. The lymph nodes were grouped as the upper, middle and lower mediastinal groups depending on the mediastinal regions. The displacements of the center of the lymph node in the left-right (LR), anterior-posterior (AP), and superior-inferior (SI) directions were measured. Results: The mean displacements of the center of the mediastinal lymph node in the LR, AP, and SI directions were 2.24 mm, 1.87 mm, and 3.28 mm, respectively. There were statistically significant differences between the displacements in the SI and LR, and the SI and AP directions (p < 0.05). For the middle and lower mediastinal lymph nodes, the displacement difference between the AP and SI was statistically significant (p = 0.005; p = 0.015), while there was no significant difference between the LR and AP directions (p < 0.05). Conclusion: The metastatic mediastinal lymph node movements are different in the LR, AP, and SI directions in patients with NSCLC, particularly for the middle and lower mediastinal lymph nodes. The spatial non-uniform margins should be considered for the metastatic mediastinal lymph nodes in involved-field radiotherapy.