The Biocompatibility of Multi-Source Stem Cells and Gelatin-Carboxymethyl Chitosan-Sodium Alginate Hybrid Biomaterials

Wang Xinzhe,Li Siqi,Yu Honglian,Lv Jianzhi,Fan Minglun,Wang Ximing,Wang Xin,Liang Yanting,Mao Lingna,Zhao Zhankui 한국조직공학과 재생의학회 2022 조직공학과 재생의학 Vol.19 No.3

BACKGROUND: Nowadays, biological tissue engineering is a growing field of research. Biocompatibility is a key indicator for measuring tissue engineering biomaterials, which is of great significance for the replacement and repair of damaged tissues. METHODS: In this study, using gelatin, carboxymethyl chitosan, and sodium alginate, a tissue engineering material scaffold that can carry cells was successfully prepared. The material was characterized by Fourier transforms infrared spectroscopy. In addition, the prepared scaffolds have physicochemical properties, such as swelling ratio, biodegradability. we observed the biocompatibility of the hydrogel to different adult stem cells (BMSCs and ADSCs) in vivo and in vitro. Adult stem cells were planted on gelatin-carboxymethyl chitosan-sodium alginate (Gel/SA/CMCS) hydrogels for 7 days in vitro, and the survival of stem cells in vitro was observed by live/died staining. Gel/SA/CMCS hydrogels loaded with stem cells were subcutaneously transplanted into nude mice for 14 days of in vivo culture observation. The survival of adult stem cells was observed by staining for stem cell surface markers (CD29, CD90) and Ki67. RESULTS: The scaffolds had a microporous structure with an appropriate pore size (about 80 lm). Live/died staining showed that adult stem cells could stably survive in Gel/SA/CMCS hydrogels for at least 7 days. After 14 days of culture in nude mice, Ki67 staining showed that the stem cells supported by Gel/SA/CMCS hydrogel still had high proliferation activity. CONCLUSION: Gel/SA/CMCSs hydrogel has a stable interpenetrating porous structure, suitable swelling performance and degradation rate, can promote and support the survival of adult stem cells in vivo and in vitro, and has good biocompatibility. Therefore, Gel/SA/CMCS hydrogel is a strong candidate for biological tissue engineering materials.

A Ferrofluid-based Planar Damper with Magnetic Spring

Siqi Wang,Yongkai Liu,Decai Li 한국자기학회 2018 Journal of Magnetics Vol.23 No.3

The ferrofluid-based damper has been a subject of active research recently in depressing low-frequency vibration of rod due to its relative small viscous damping for the vibration pick-up system. In this work, a novel ferrofluid-based planar damper with magnetic spring is firstly proposed. Compared with the traditional ferrofluid-based damper with the elastic restoring force of ferrofluids, the novel damper is designed with steady magnetic spring to obtain a large relative displacement and dissipate external vibration energy efficiently. Experimental results show that the novel damper has a high damping performance. Under the same initial vibration amplitude of beam, the logarithmic decrement of the system with the novel damper is 31.5 times and 5.5 times larger than those of the system without damper and with the traditional damper, respectively. In addition, compared with the system with the traditional damper, the system with the novel damper can reduce damping time by half.

Design and Analysis of a Plane Vibration-based Electromagnetic Generator Using a Magnetic Spring and Ferrofluid

Siqi Wang,Decai Li 한국물리학회 2015 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.67 No.5

This paper describes the design and characterization of a plane vibration-based electromagnetic generator that is capable of converting low-frequency vibration energy into electrical energy. A magnetic spring is formed by a magnetic attractive force between fixed and movable permanent magnets. The ferrofluid is employed on the bottom of the movable permanent magnet to suspend it and reduce the mechanical damping as a fluid lubricant. When the electromagnetic generator with a ferrofluid of 0.3 g was operated under a resonance condition, the output power reached 0.27 mW, and the power density of the electromagnetic generator was 5.68 μW/cm2. The electromagnetic generator was also used to harvest energy from human motion. The measured average load powers of the electromagnetic generator from human waist motion were 0.835 mW and 1.3 mW during walking and jogging, respectively.

The Sleeping Boy

Wang Siqi 한국콘텐츠학회 2021 ICCC International Digital Design Invitation Exhib Vol.2021 No.8

Failure Envelopes of Bucket Foundations for Offshore Wind Turbinesunder Combined Loading Including Torsion

Siqi Li,Yuan Wang,Qing-wen Li,Jing-qi Huang,Jin-hui Li 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.12

The loading condition of bucket foundations for offshore wind turbines is very complicated and often under combined loading, but the torsion is always ignored. So, it is necessary to investigate the failure envelopes including torsion of bucket foundations. Under the premise of validating the reliability of the numerical model by comparing with other published data, failure envelopes in each loading space are obtained and the applicability of swipe test for the determination of H-T failure envelope and M-T failure envelope of bucket foundations is explored. The impacts of torsion and aspect ratio on the combined bearing capacities are studied. While revealing the law of impacts, equations are proposed to determine the respective failure envelopes and evaluate the combined bearing capacities. The V-H-M-T failure envelope can reveal the torsion effect on envelope under traditional V-H-M loading, the results show that the normalized V-H-M failure envelopes under different torsions almost coincide, torsion effect can be easily considered according to this characteristic.

Esterification of free fatty acids in a rotor-stator spinning disc reactor

Yubin Wang,Xiaoqiu Tao,Jun Li,Siqi Zhang,Yang Jin,Ming Chen 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.8

Fatty acid methyl esters (FAMEs) were produced by the esterification of free fatty acids (FFA) with methanol, and sulfuric acid as the catalyst in a rotor-stator spinning disc reactor (RSSDR). The RSSDR, which shows excellent mixing efficiency and fast phase separation, was used as a novel continuous-flow esterification reactor. The influence of the variables (e.g., rotational speed, volume flow rate, rotor-stator distance, methanol-FFA molar ratio, catalyst dosage, and temperature) on esterification conversion () and productivity of FAMEs (PFAME) were investigated. It was found that the experimental parameters have a great impact on the  and PFAME in the RSSDR system, due to the effect of micromixing intensity and residence time distribution. Furthermore, to compare with other traditional esterification reactors, the values of , PFAME, and PFAME per unit reactor volume (PFAME/VR) in the RSSDR were also employed to assess the performance for the production of FAMEs. It shows that the maximum values of PFAME, and PFAME/VR attained were 0.14mol/min and 3.06×102 mol/(mL min), respectively. Therefore, the RSSDR is proven to be an effective esterification reactor with high esterification conversion in comparison to conventional esterification reactors.

Fourier Mode Decomposition of Unsteady Flows in a Single Injection Port Fluidic Thrust Vectoring Nozzle

Jianming Wang,Siqi Luan,Jianyong Zhu,Xiaodong Mao,Junqiang Wu 한국항공우주학회 2021 International Journal of Aeronautical and Space Sc Vol.22 No.2

The flow field structure of a single injection port fluidic thrust vectoring nozzle was studied by introducing secondary flow injection in the expansion section of the two-dimensional convergent-divergent nozzle. To determine the motion characteristics of unsteady flow in a shock-induced fluidic vectoring nozzle, detached eddy simulation was conducted to simulate the three-dimensional flow field, and the flow mechanism in the nozzle was analyzed. Fourier mode decomposition was used to analyze the pressure coefficient on the symmetrical surface of the nozzle. Results show three natural frequencies in the flow field of the shock-induced fluidic vectoring nozzle. The first-order mode corresponding to frequency f1 = 512.8 Hz mainly illustrates the oscillation of shock waves. The second-order mode corresponding to frequency f2 = 2825 Hz illustrates the shedding of vortices. The third-order mode corresponding to frequency f3 = 4650 Hz is similar to the second-order mode; however, the spatial scales of vortices decrease.

Sealing Behavior Research on the Radial Ferrofluid Seal Structure with Oblique Teeth

Fang Yuan,Siqi Wang,Decai Li,Long Che 한국자기학회 2022 Journal of Magnetics Vol.27 No.1

Considering various unstable factors when the large-diameter spindle operates at a high speed, such as eccentricity, centrifugal force, etc., the ordinary ferrofluid seal structures will show poor sealing performance. This paper proposes an axial-radial bidirectional ferrofluid seal structure with radial oblique teeth to improve the sealing performance. The pressure resistance of the radial ferrofluid seal structure in the magnetic circuit is theoretically analyzed. The magnetic flux distribution characteristic in the gap of the oblique teeth is studied by magnetic field simulation. According to the analysis results of the magnetic induction intensity, to obtain the larger theoretical pressure resistance, the optimal angle of oblique teeth is 77.87°, 64.28° and 62.81° under the radial seal structure with different gaps of 0.1 mm, 0.15 mm and 0.2 mm, respectively. In addition, simulation analysis is carried out to obtain the fluid pressure and velocity distribution of the radial ferrofluid seal structure with different oblique teeth angles. When the oblique teeth angle is small, the pressure drops and gas flow speeds in the ferrofluid area are all lower, and the pressure resistance is higher.

Hepatitis B virus X protein-mediated non-coding RNA aberrations in the development of human hepatocellular carcinoma

Bei Zhang,Siqi Han,Bing Feng,Xiaoyuan Chu,Longbang Chen,Rui Wang 생화학분자생물학회 2017 Experimental and molecular medicine Vol.49 No.-

Hepatitis B virus (HBV) has an important role in the development of human hepatocellular carcinoma (HCC). Accumulated evidence has shown that HBV-encoded X protein (HBx) can induce both genetic alterations in tumor suppressor genes and oncogenes, as well as epigenetic aberrations in HCC pathogens. Non-coding RNAs (ncRNAs) mainly include microRNAs and long non-coding RNAs (lncRNAs). Although ncRNAs cannot code proteins, growing evidence has shown that they have various important biological functions in cell proliferation, cell cycle control, anti-apoptosis, epithelial–mesenchymal transition, tumor invasion and metastasis. This review summarizes the current knowledge regarding the mechanisms and emerging roles of ncRNAs in the pathogenesis of HBV-related HCC. Accumulated data have shown that ncRNAs regulated by HBx have a crucial role in HBV-associated hepatocarcinogenesis. The findings of these studies will contribute to more clinical applications of HBV-related ncRNAs as potential diagnostic markers or as molecular therapeutic targets to prevent and treat HBV-related HCC.

Measurement and Assembly of Microminiature Parts Based on Micro Machine Vision

Xiaojing Yang,Siqi Wang 보안공학연구지원센터 2016 International Journal of Signal Processing, Image Vol.9 No.12

With the development of modern high precision processing technology, precise microminiature electromechanical products have been widely used. Most of the precise microminiature electromechanical products are assembled from microminiature parts.Due to dimensions of the microminiature parts involved are in micro-and nanoscale, which cannot be reached by ordinary cameras, it cannot effectively capture the image of those parts to be assembled, thus affects the assembly. A microscopic vision measurement system of stereo microscope that combined with high resolution CCD camera was developed based on micro machine vision, which uses the MATLAB software to deal with the collected images of microminiature parts such as image smoothing, image sharpening, image segmentation and edge extraction, etc. to study the structures, identification, location and assembly process of microminiature parts. The results show that the visual system we used has accomplished the automatic measurement and precise assembly of miniature parts excellently.