Continuous Isolation of Stem-Cell-Derived Extracellular Vesicles (SC-EVs) by Recycled Magnetic Beads in Microfluidic Channels

유하은,Kim Jaejeung,YUJIANNING,Hyun Kyung-A,Lim Jae-Yol,Yoon Yeo-Jun,Park Sunyoung,Jung Hyo-Il 한국바이오칩학회 2023 BioChip Journal Vol.17 No.4

Stem cells produce nanosized particles known as extracellular vesicles (SC-EVs), which therapeutically aff ect stem cells. EVs are more abundantly produced, exhibit better stability, and possess lower immune rejection rates than stem cells. However, the traditional methods of isolating EVs, such as ultracentrifugation, possess limitations that require a complex process and consume more time. Moreover, it is diffi cult to isolate specifi c EVs that have target surface proteins that aff ect regenerative eff ects. To address these limitations, a new dual-mode horseshoe-shaped orifi ce micromixer (DM-HOMM) chip that can bind antibody-conjugated micromagnetic beads and SC-EVs and sequentially elute specifi c SC-EVs on the beads using an eluent was developed. For eff ective elution from the microbead-SC-EV complex, four types of eluents were used to control pH and ionic strength between antibodies and surface proteins in EVs. In addition, we investigated the reusability of antibody-conjugated micromagnetic beads. The beads indicated identical binding effi ciencies between the antibodies and specifi c SC-EVs for three repeated cycles using the dual-mode chip. CD63 + EVs collected by the chip exhibited higher cell viability and regeneration eff ects than untreated and total EVs. This SC-EVs’ isolation method possesses the potential for targeted therapeutic applications and enhanced regenerative effects.

Microstructure, Thermal Conductivity and Mechanical Properties of the Mg–Zn–Sb Ternary Alloys

Yujian Huang,Xiong Zhou,Jun Du 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.11

A novel Mg alloys of Mg–xZn–ySb (x = 0, 2, 4, 6; y = 0, 0.2, 0.5, 0.8, 1.2) were designed and their microstructure, thermalconductivity and mechanical properties were systematically investigated in the present study. The as-cast Mg–Zn–Sb ternaryalloys consist of α-Mg, Mg4Zn7and Mg3Sb2phases. Sb addition can refine the eutectic structure (α-Mg + Mg4Zn7) by thegrowth of Mg4Zn7on Mg3Sb2phases. The thermal conductivity of Mg–Zn–Sb alloys decreased with increasing Sb content. There existed an interactive effect of Zn/Sb on the thermal conductivity of the Mg–Zn–Sb alloys. The negative effect of Sbaddition on thermal conductivity of alloys was getting smaller with increasing Zn content in alloys. The negative effect ofMg3Sb2phases on the thermal conductivity of alloys could be weakened by the formation of weak-scattering Mg4Zn7coatedon Mg3Sb2phases. The best refinement effect on microstructure could be obtained with 0.8 wt%Sb addition. Mg–4Zn–0.8Sballoy possess the best comprehensive properties with thermal conductivity of over than 120 W/(m·K) and UTS of 185.6 MPa.

Mixture copulas with discrete margins and their application to imbalanced data

Liu Yujian,Xie Dejun,Edwards David A.,Yu Siyi 한국통계학회 2023 Journal of the Korean Statistical Society Vol.52 No.4

This article introduces the approach of using Bayesian sampling to estimate the mixture copula with discrete margins, we further apply our models to solve the class imbalanced problems in data science by oversampling. The methodology makes it possible to learn and sample from the data set with the discrete and continuous features exists simultaneously. On the other hand, the discreetness of factors in a data set are not naturally considered for the classic SMOTE algorithm and classic random oversampling is simply performed by generating the already existing points, which do not give any new information to the classifiers and is easy to overfit. Copula methods enable us to generate new points with the correlation structure memorized by learning from the training set. Hence, the overfitting problems are reduced. Experiments with synthetic and real data are done in the article following the introduction of the methodology. The outcomes shows the validity of the approach when compared with the benchmark methods.

Fuzzy Dynamic Sliding Mode Controller Design for Uncertain Nonlinear Markovian Jump Systems

Wenqiang Ji,Yujian An,Heting Zhang 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.7

This paper investigates the problem of sliding mode control (SMC) for a class of uncertain nonlinearMarkovian jump systems through T-S fuzzy models. By adopting some convexification techniques, new results onstochastic stability analysis of the sliding motion are attained. Then two new SMC design approaches are proposedto force the closed-loop system states onto the sliding surface in finite time. Finally, two simulation examples areshown to verify the effectiveness of the proposed approaches.

Exhaust Gas Recirculation Control in a Spark-Ignition LPG Engine Using Neural Networks

Hongwei Cui,Yifang Liu,Yujian Zhai 제어로봇시스템학회 2002 제어로봇시스템학회 국제학술대회 논문집 Vol.2002 No.10

Fatigue Resistance of a BFRP-Encapsulated Long-Gauge FBG Strain Sensor under Cyclic Train Loads

Bi-tao Wu,Yujian Zhou,Huaxi Lu,Yunhuang Xiao,Zhenwei Zhou 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.9

To verify the performance of a basalt fiber reinforced polymer (BFRP) fiber-encapsulated long-gauge strain sensor in railway bridge health monitoring, this paper studies the fatigue resistance and durability of the BFRP fiber-encapsulated FBG sensor under train loads. First, the influences of the length of the anchorage section and the length ratio of the sensing section on the accuracy of the sensor were studied. Then, the BFRP sensor was applied to a sleeper for 2 million cycles of tension fatigue testing. The strain-time history of the whole fatigue test was monitored and compared. After the test, a calibration test was carried out to verify the accuracy and repeatability of the sensor. Finally, the slip and fatigue cracking of the fiber in the anchorage section of the sensor were observed by electron microscopy. The results show that the gap between the anchoring section and the bare optical fiber was filled with epoxy resin, and there was no slip behavior. No fatigue cracking occurred in the fiber, and the straincoefficient and linearity of the sensor showed no obvious changes after 2 million cycles of loading. The long-gauge strain sensor encapsulated by BFRP fibers exhibited good fatigue resistance and can meet long-term monitoring requirements under train loads.

Output characteristics and experiments of a novel low frequency rotary piezoelectric motor

Kang Liang,Chong Li,Yujian Tong,Jiwen Fang,Wei Zhong,Xiaorui Fu 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.3

In order to improve the output performance of a piezoelectric motor under low driving frequency, a novel rotary piezoelectric motor driven by two piezoelectric actuators is proposed that is actuated based on harmonic and friction driving mechanism. The motor uses two piezoelectric actuators to drive two amplifying mechanisms with π/2 phase difference to produce harmonic motion, and then drives the rotor to rotate through friction force. Based on the driving principle, the electromechanical coupling equations of the motor are established. And a test platform is built to test the output characteristics of the motor. The results show that fluctuation of harmonic force and output torque occurs when the motor operates at different positions. Under the driving voltage and frequency of 150 V and 5 Hz, the actual average output torque of the prototype is 3.08 Nmm. Moreover, fluctuation of harmonic force and output torque occurs when the motor operates at different positions.

Parameter identification and SOC estimation of lithium‑ion batteries based on AGCOA‑ASRCKF

Yunkun Chu,Junhong Li,Juping Gu,Yujian Qiang 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.2

The state of charge (SOC) is an important parameter in battery management systems (BMS), and its accuracy is very important. In this paper, a co-estimation with the adaptive global optimal guided coyote optimization algorithm and the adaptive square root cubature Kalman filter (AGCOA-ASRCKF) is used to perform the parameter identification and SOC estimation of a lithium-ion second-order RC model. The AGCOA effectively solves the problems where traditional heuristic algorithms tend to fall into local optimum and have a slow convergence speed. The AGCOA can accurately identify the parameters of the battery model. At the same time, when compared with the cubature Kalman filter, the ASRCKF introduces a square root filter and adds a residual sequence to adaptively update the covariance of the process noise and measurement noise, which improves the estimation accuracy of the SOC. The method proposed in this paper is verified by intermittent constant current test, dynamic stress test, and the federal urban driving schedule. Simulation results show that a high-precision battery model can be established by AGCOA-ASRCKF. In addition, the predicted value of the terminal voltage is basically consistent with the actual value. At the same time, the SOC estimation error can be controlled to within 1.5%, and the algorithm has good robustness and reliability in the presence of errors in the initial SOC.

ONE-POT SYNTHESIS OF INTERESTING 3D γ-MnOOH NETWORKS

HAIQIU LIU,MINDONG CHEN,FEI TENG,YUJIAN JIN,Na Li,Lili Wang,SUNQI LOU,XIA HUA,KAI WANG,Peng Sun 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2014 NANO Vol.9 No.7

Three-dimensional (3D) γ-MnOOH networks are successfully prepared by one-pot solvothermalmethod without using any catalyst. The samples are characterized by X-ray diffraction (XRD),scanning electron microscopy (SEM) and high-resolution transmission electron microscopy(HRTEM). It is found that the amounts of urea and H2O2 added, reaction temperature and timehave important infuences on the samples. It is interesting that the 3D networks are formed fromthe oriented attachment (OA) of Mn3O4 octahedrons; and that the phase transformation from Mn3O4 to γ-MnOOH occurs via the protonation of Mn3O4. This study is expected to offer a facileapproach to the syntheses of new, intricate nanostructures.

Circular RNA-ZFR Inhibited Cell Proliferation and Promoted Apoptosis in Gastric Cancer by Sponging miR-130a/miR-107 and Modulating PTEN

Tonglei Liu,Shuang Liu,Yu Xu,Ruo Shu,Feng Wang,Cheng Chen,Yujian Zeng,Huayou Luo 대한암학회 2018 Cancer Research and Treatment Vol.50 No.4

Purpose This study aimed to probe into the associations among circular RNA ZFR (circ-ZFR), miR- 130a/miR-107, and PTEN, and to investigate the regulatory mechanism of circ-ZFRmiR- 130a/miR-107PTEN axis in gastric cancer (GC). Materials and Methods GSE89143 microarray data used in the study were acquired from publicly available Gene Expression Omnibus database to identify differentially expressed circular RNAs in GC tissues. The expressions of circ-ZFR, miR-130a, miR-107, and PTEN were examined by real-time reverse transcription polymerase chain reaction, while PTEN protein expression was measured by western blot. The variation of GC cell proliferation and apoptosis was confirmed by cell counting kit-8 assay and flow cytometry analysis. The targeted relationships among circ- ZFR, miR-130a/miR-107, and PTEN were predicted via bioinformatics analysis and demonstrated by dual-luciferase reporter assay and RNA immunoprecipitation assay. The impact of ZFR on gastric tumor was further verified in xenograft mice model experiment. Results Circ-ZFR and PTEN were low-expressed whereas miR-107 and miR-130a were highexpressed in GC tissues and cells. There existed targeted relationships and interactions between miR-130a/miR-107 and ZFR/PTEN. Circ-ZFR inhibited GC cell propagation, cell cycle and promoted apoptosis by sponging miR-107/miR-130a, while miR-107/miR-130a promoted GC cell propagation and impeded apoptosis through targeting PTEN. Circ-ZFR inhibited cell proliferation and facilitated apoptosis in GC by sponging miR-130a/miR-107 and modulating PTEN. Circ-ZFR curbed GC tumor growth and affected p53 protein expression in vivo. Conclusion Circ-ZFR restrained GC cell proliferation, induced cell cycle arrest and promoted apoptosis by sponging miR-130a/miR-107 and regulating PTEN.