Numerically Study of the Flow Field and Spatter Particles in Laser-based Powder Bed Fusion Manufacturing

Jiayue Wang,Yuwen Zhu,Hui Li,Sheng Liu,Shengnan Shen,Lei Wang,Shifeng Wen 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.9 No.4

Laser-based powder bed fusion (L-PBF) is an additive manufacturing (AM) technology that uses a high-energy–density laser to scan through a powder bed and completely melts the metal powder. The environment inside the printer chamber, including the flow field of the shielding gas and the spatter particles induced by laser–powder interactions, is essential for product quality. For the first time, this work built a full-size model of printer chamber, and numerically investigated the interaction between the shielding argon flow and the laser induced spatter particles with considering laser temperature. A full-size geometric model of a commercial L-PBF printer with a Gaussian heat source was constructed, as well as a movable particle-release source model for particle injection. The distribution of the argon flow field, the temperature field, and the trajectory and deposition of spatter particles, particularly above the workbench during the L-PBF process were quantitatively analyzed. The results show that the gas flow within 30 mm above the workbench is uniform, and in the upper region of the printer chamber, the flow field is disorderly. The laser can only induce high temperature and upward gas flow in a small region close to the workbench (the height less than 1.6 mm), and the laser induced velocity disturbance in rest regions of the L-PBF printer is negligible. Particles injected towards the outlet (ID4) are mostly blown into the outlet, and in the other four injection directions, more than 90% of spatter particles are deposited inside the printer chamber, especially more than 50% deposited on the workbench. Increasing the laser power (from 100 to 200 W) has little effect on particle deposition on the workbench. Results will be helpful for improving the L-PBF product quality.

Effect of Leukocyte-Platelet Rich Fibrin (L-PRF) on Tissue Regeneration and Proliferation of Human Gingival Fibroblast Cells Cultured Using a Modified Method

Mudalal Mahmoud,Wang Zhanqi,Mustafa Shockry,Liu Yiping,Wang Yao,Yu Jize,Wang Shengnan,Sun Xiaolin,Zhou Yanmin 한국조직공학과 재생의학회 2021 조직공학과 재생의학 Vol.18 No.5

Background: An in vitro study on rapid culturing method of human gingival fibroblast cells (HGFCs) was established to investigate the potential use of the leukocyte-platelet rich fibrin (L-PRF) in tissue engineering technology, different medical fields, including periodontology and implantology. Methods: Eight biopsies were obtained from eight different donors and a modified culturing technique was developed to obtain HGFCs. The modified 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide MTT assay was used to compare the cell viability when the modified culturing method was used in comparison to the standard method. Blood samples were collected from the same patients and L-PRF was isolated using a standard protocol. The releases of platelet-derived growth factor-AA and transforming growth factor-beta1 at various time intervals were observed using enzyme-linked immunosorbent assay (ELISA) kit. The proliferative effect of L-PRF on HGFCs was assessed by the cell counting kit—8 assay. Results: A simple and rapid modified method for in vitro HGFC culture yielded a cellular monolayer within three to nine days after cell culture. L-PRF with three-dimensional polymer fibers released growth factors that peaked during the first three hours and continued to produce up to 10 days. The L-PRF presented a dose-dependent effect on HGFCs proliferation where HGFCs proliferation increased with an increase in L-PRF concentration. Conclusion: The modified technique for the culture of HGFCs might be useful for the development of future experimental and clinical studies, besides L-PRF has great therapeutic potential in oral surgery fields. Background: An in vitro study on rapid culturing method of human gingival fibroblast cells (HGFCs) was established to investigate the potential use of the leukocyte-platelet rich fibrin (L-PRF) in tissue engineering technology, different medical fields, including periodontology and implantology. Methods: Eight biopsies were obtained from eight different donors and a modified culturing technique was developed to obtain HGFCs. The modified 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide MTT assay was used to compare the cell viability when the modified culturing method was used in comparison to the standard method. Blood samples were collected from the same patients and L-PRF was isolated using a standard protocol. The releases of platelet-derived growth factor-AA and transforming growth factor-beta1 at various time intervals were observed using enzyme-linked immunosorbent assay (ELISA) kit. The proliferative effect of L-PRF on HGFCs was assessed by the cell counting kit—8 assay. Results: A simple and rapid modified method for in vitro HGFC culture yielded a cellular monolayer within three to nine days after cell culture. L-PRF with three-dimensional polymer fibers released growth factors that peaked during the first three hours and continued to produce up to 10 days. The L-PRF presented a dose-dependent effect on HGFCs proliferation where HGFCs proliferation increased with an increase in L-PRF concentration. Conclusion: The modified technique for the culture of HGFCs might be useful for the development of future experimental and clinical studies, besides L-PRF has great therapeutic potential in oral surgery fields.

Overexpressing microRNA-203 alleviates myocardial infarction via interacting with long non-coding RNA MIAT and mitochondrial coupling factor 6

Fan Wang,Renliang Yu,Shengnan Wen,Jie Yin,Yugen Shi,Hesheng Hu,Suhua Yan 대한약학회 2021 Archives of Pharmacal Research Vol.44 No.5

Myocardial infarction (MI) is one of the leadingcauses of high mortality worldwide. Long non-codingRNA myocardial infarction associated transcript (MIAT)and mitochondrial coupling factor 6 (CF6) aggravate MI. This study aimed to elucidate whether miR-203 interactedwith MIAT and CF6 in MI. Results revealed that MIAT andCF6 expressions were upregulated and that miR-203 wasdownregulated in mouse myocardial tissues after MI, as wellas in hypoxic mouse cardiomyocytes. The overexpressionof MIAT in mouse cardiomyocytes raised CF6 expression,whereas the knockdown of MIAT had the opposite eff ect. Mechanistically, the luciferase reporter and RNA pull-downassays corroborated the binding between miR-203 and CF63′UTR and between miR-203 and MIAT. The simultaneousoverexpression of miR-203 and MIAT restored the reductionof CF6 caused by miR-203 overexpression alone, andthe overexpression of miR-203 diminished the percentage ofinfarct area and the apoptosis of cardiomyocytes in vivo. Our fi ndings corroborate that overexpressing miR-203 alleviatesMI via interacting with MIAT and CF6.

A combined application of molecular docking technology and indirect ELISA for the serodiagnosis of bovine tuberculosis

Song, Shengnan,Zhang, Qian,Yang, Hang,Guo, Jia,Xu, Mingguo,Yang, Ningning,Yi, Jihai,Wang, Zhen,Chen, Chuangfu The Korean Society of Veterinary Science 2022 Journal of Veterinary Science Vol.23 No.3

Background: There is an urgent need to find reliable and rapid bovine tuberculosis (bTB) diagnostics in response to the rising prevalence of bTB worldwide. Toll-like receptor 2 (TLR2) recognizes components of bTB and initiates antigen-presenting cells to mediate humoral immunity. Evaluating the affinity of antigens with TLR2 can form the basis of a new method for the diagnosis of bTB based on humoral immunity. Objectives: To develop a reliable and rapid strategy to improve diagnostic tools for bTB. Methods: In this study, we expressed and purified the sixteen bTB-specific recombinant proteins in Escherichia coli. The two antigenic proteins, MPT70 and MPT83, which were most valuable for serological diagnosis of bTB were screened. Molecular docking technology was used to analyze the affinity of MPT70, MPT83, dominant epitope peptide of MPT70 (M1), and dominant epitope peptide MPT83 (M2) with TLR2, combined with the detection results of enzyme-linked immunosorbent assay to evaluate the molecular docking effect. Results: The results showed that interaction surface Cα-atom root mean square deviation of proteins (M1, M2, MPT70, MPT83)-TLR2 protein are less than 2.5 A, showing a high affinity. It is verified by clinical serum samples that MPT70, MPT83, MPT70-MPT83 showed good diagnostic potential for the detection of anti-bTB IgG and M1, M2 can replace the whole protein as the detection antigen. Conclusions: Molecular docking to evaluate the affinity of bTB protein and TLR2 combined with ELISA provides new insights for the diagnosis of bTB.

A combined application of molecular docking technology and indirect ELISA for the serodiagnosis of bovine tuberculosis

Song, Shengnan,Zhang, Qian,Yang, Hang,Guo, Jia,Xu, Mingguo,Yang, Ningning,Yi, Jihai,Wang, Zhen,Chen, Chuangfu The Korean Society of Veterinary Science 2022 Journal of Veterinary Science Vol. No.

Background: There is an urgent need to find reliable and rapid bovine tuberculosis (bTB) diagnostics in response to the rising prevalence of bTB worldwide. Toll-like receptor 2 (TLR2) recognizes components of bTB and initiates antigen-presenting cells to mediate humoral immunity. Evaluating the affinity of antigens with TLR2 can form the basis of a new method for the diagnosis of bTB based on humoral immunity. Objectives: To develop a reliable and rapid strategy to improve diagnostic tools for bTB. Methods: In this study, we expressed and purified the sixteen bTB-specific recombinant proteins in Escherichia coli. The two antigenic proteins, MPT70 and MPT83, which were most valuable for serological diagnosis of bTB were screened. Molecular docking technology was used to analyze the affinity of MPT70, MPT83, dominant epitope peptide of MPT70 (M1), and dominant epitope peptide MPT83 (M2) with TLR2, combined with the detection results of enzyme-linked immunosorbent assay to evaluate the molecular docking effect. Results: The results showed that interaction surface Cα-atom root mean square deviation of proteins (M1, M2, MPT70, MPT83)-TLR2 protein are less than 2.5 A, showing a high affinity. It is verified by clinical serum samples that MPT70, MPT83, MPT70-MPT83 showed good diagnostic potential for the detection of anti-bTB IgG and M1, M2 can replace the whole protein as the detection antigen. Conclusions: Molecular docking to evaluate the affinity of bTB protein and TLR2 combined with ELISA provides new insights for the diagnosis of bTB.

Sox12 Is a Cancer Stem-Like Cell Marker in Hepatocellular Carcinoma

Zou, Song,Wang, Chen,Liu, Jiansheng,Wang, Qun,Zhang, Dongdong,Zhu, Shengnan,Xu, Shengyuan,Kang, Mafei,He, Shaozhong Korean Society for Molecular and Cellular Biology 2017 Molecules and cells Vol.40 No.11

Recent studies on molecular carcinogenesis suggest that the chemo-resistance of some cancers is largely due to presence of cancer stem cells (CSCs), which affect the chemotherapy outcome for hepatocellular carcinoma (HCC). However, currently no consensus on a CSC phenotype in HCC has been obtained. Here, we examined Sox12 as a novel CSC marker in HCC. Sox12+ versus Sox12- cells were purified from HCC cell lines. The Sox12+ cells were compared with Sox12- HCC cells for tumor sphere formation, chemo-resistance, tumor formation after serial adoptive transplantations in nude mice, and the frequency of developing distal metastasis. We found that compared to Sox12- HCC cells, Sox12+ HCC cells generated significantly more tumor spheres in culture, were more chemo-resistant to cisplatin, were detected in circulation more frequently, and formed distal tumor more frequently. Moreover, Sox12 appeared to functionally contribute to the stemness of HCC cells. Thus, we conclude that Sox12 may be a novel marker for enriching CSCs in HCC.

Preparations, application of polysaccharide–protein nanoparticles and their assembly at the oil–water interface

Hui Yang,Shengnan Wang,Lina Yang,He Liu 한국식품과학회 2024 Food Science and Biotechnology Vol.33 No.1

With the development of nanotechnology, nanoparticles have played an important role in pharmaceuticals, foods and materials, in particular, protein/polysaccharide based composite nanoparticles have received attention from researchers for safety and green production. This paper summarized in detail the preparation methods, applications of protein/polysaccharide nanoparticles (PPNPs) in recent years, especially the mechanism of stabilizing the oil–water interface. Currently, the polysaccharides applied are more traditional, such as chitosan, pectin and carboxymethyl cellulose, so there is still a lot of room for the development of raw materials that can be used to prepare PPNPs. Based on this, we also proposed three promising polysaccharides: seaweed polysaccharide, lycium barbarum polysaccharide and lactobacillus exopolysaccharides, describing their characteristics as well as their application prospects, this article can serve as a reference for interested researchers.

The bearing capacity of monolithic composite beams with laminated slab throughout fire process

Junli Lyu,Shengnan Zhou,Qichao Chen,Yong Wang 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.38 No.1

To investigate the failure form, bending stiffness, and residual bearing capacity of monolithic composite beams with laminated slab throughout the fire process, fire tests of four monolithic composite beams with laminated slab were performed under constant load and temperature increase. Different factors such as post-pouring layer thickness, lap length of the prefabricated bottom slab, and stud spacing were considered in the fire test. The test results demonstrate that, under the same fire time and external load, the post-pouring layer thickness and stud spacing are important parameters that affect the fire resistance of monolithic composite beams with laminated slab. Similarly, the post-pouring layer thickness and stud spacing are the predominant factors affecting the bending stiffness of monolithic composite beams with laminated slab after fire exposure. The failure forms of monolithic composite beams with laminated slab after the fire are approximately the same as those at room temperature. In both cases, the beams underwent bending failure. However, after exposure to the high-temperature fire, cracks appeared earlier in the monolithic composite beams with laminated slab, and both the residual bearing capacity and bending stiffness were reduced by varying degrees. In this test, the bending bearing capacity and ductility of monolithic composite beams with laminated slab after fire exposure were reduced by 23.3% and 55.4%, respectively, compared with those tested at room temperature. Calculation methods for the residual bearing capacity and bending stiffness of monolithic composite beams with laminated slab in and after the fire are proposed, which demonstrated good accuracy.

A Fuzzy Cerebellar Model Articulation Controller Based Visual Servo System for Robot

Wei Sun,Cong Wang,Shengnan Liu,Baoqiang Wu,Minghua Ouyang 제어·로봇·시스템학회 2012 International Journal of Control, Automation, and Vol.10 No.2

This paper presents a novel online learning visual servo controller integrating the FCMAC with proportion controller for the control of position of manipulator end-effector. Since the FCMAC has good learning capability and fast learning speed, and can save much computer memory space by fuzzy processing of input space division and memory unit activation, it is used to develop an adaptive control law by learning the relationship between the image feature errors and manipulator input, and the aim of online learning of the FCMAC is to minimize the output of proportion controller. Further-more, the FCMAC has no need for models of robot manipulator and image feature extraction, so that the capability of proposed controller for tasks under uncertain environment can be improved. Finally, the proposed controller is proved to be effective by the experiment, and compared with BP neural net-work.

Sox12 Is a Cancer Stem-Like Cell Marker in Hepatocellular Carcinoma

Song Zou,Chen Wang,Jiansheng Liu,Qun Wang,Dongdong Zhang,Shengnan Zhu,Shengyuan Xu,Mafei Kang,Shaozhong He 한국분자세포생물학회 2017 Molecules and cells Vol.40 No.11

Recent studies on molecular carcinogenesis suggest that the chemo-resistance of some cancers is largely due to presence of cancer stem cells (CSCs), which affect the chemotherapy outcome for hepatocellular carcinoma (HCC). However, currently no consensus on a CSC phenotype in HCC has been obtained. Here, we examined Sox12 as a novel CSC marker in HCC. Sox12+ versus Sox12- cells were purified from HCC cell lines. The Sox12+ cells were compared with Sox12- HCC cells for tumor sphere formation, chemo-resistance, tumor formation after serial adoptive transplantations in nude mice, and the frequency of developing distal metastasis. We found that compared to Sox12- HCC cells, Sox12+ HCC cells generated significantly more tumor spheres in culture, were more chemo-resistant to cisplatin, were detected in circulation more frequently, and formed distal tumor more frequently. Moreover, Sox12 ap-peared to functionally contribute to the stemness of HCC cells. Thus, we conclude that Sox12 may be a novel marker for enriching CSCs in HCC.