DHA-enriched phosphatidylcholine suppressed angiogenesis by activating PPARγ and modulating the VEGFR2/Ras/ERK pathway in human umbilical vein endothelial cells

Yuanyuan Liu,Yingying Tian,Yao Guo,Ziyi Yan,Changhu Xue,Jingfeng Wang 한국식품과학회 2021 Food Science and Biotechnology Vol.30 No.12

Docosahexaenoic acid-enriched phosphatidylcholine(DHA-PC) is a new generation of omega-3 lipids,which contains an ester bond linking DHA at the sn-2position of phospholipid. DHA-PC has become the interestrecently as its better bioavailability and anti-oxidationcapacity. In this study, the anti-angiogenic effect of DHAPCwas evaluated. The capacities of proliferation, migration,tube formation of human umbilical vein endothelialcells were significantly declined after DHA-PC treatment. Furthermore, DHA-PC inhibited the neovascularization ofthe chick chorioallantoic membrane in vivo. Mechanismresults indicated that DHA-PC enhances the expression ofperoxisome proliferator-activated receptor c (PPARc) attranscriptional and translational level, subsequently downregulatesthe VEGFR2 expression and VEGFR2-mediateddownstream Ras/ERK pathway, resulting in significantreduction in proliferation and differentiation. Additionally,PPARc-specific antagonist GW9662 partly reversed theinhibition effects of DHA-PC on tube formation and neovascularization,suggesting that DHA-PC exerts anti-angiogenesiseffect through activating PPARc. Thesefindings indicated that DHA-PC has a great prospect ofanti-tumor angiogenesis therapy.

The Unintended Effects of Stock Pledging: A Perspective on the Shareholder–Creditor Conflict

Yuanyuan Liu,Lili Jiu 한국증권학회 2023 Asia-Pacific Journal of Financial Studies Vol.52 No.1

This paper examines whether and how stock pledging by a firm’s largest shareholder affects the conflict of interest between shareholders and creditors. We find such stock pledging is negatively associated with corporate risk-taking. This association is more pronounced for companies with high debt costs before such pledging, with dominant controlling shareholders, and that borrow from small lenders. Further, we find firms subject to such pledging are more likely to be granted new private loans and exhibit greater investment efficiency. Overall, stock pledging by a firm’s largest shareholder unintentionally mitigates the shareholder–creditor conflict by reducing corporations’ pursuit of risky investments.

Oil film stiffness and damping in an elastohydrodynamic lubrication line contact-vibration

Yuanyuan Zhang,Hua iju Liu,Caichao Zhu,Mingyong Liu,Chaosheng Song 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.7

An elastohydrodynamic lubrication line contact-vibration model is proposed to study the stiffness and damping of the oil film existed in the EHL contact region. An initial mutual approach between interacting surfaces, which deviates from the steady-state balanced position, is assumed under the free contact-vibration to predict the response of the mutual approach. An inertia term, which represents the acceleration of the gap motion, is added to the classical force balance equation to form the equation of motion of the mutual approach. Response of the mutual approach is solved based upon the solving of the contact-dynamic model. The oil stiffness is calculated according to the natural frequency of the response under damped and non-damped conditions, the latter of which represents dry contact conditions. The oil film damping is calculated in terms of the principle of the energy conservation which utilizes the whole history of response compared with the log decrement method. Effect of the normal load, the rolling speed and the amplitude of the regular sinusoidal surface waviness on the oil film stiffness, the contact stiffness and the oil film damping are studied. The study provides an insight on the oil film dynamic characteristics of lubricated contact-vibration problems which appear in gears, bearings, etc. The results show that the oil film damping factor decreases with the increasing normal load as well as the increasing rolling speed. The oil film stiffness increases with the normal load and decreases with the rolling speed. Also, compared to the contact stiffness, the oil film stiffness makes less contribution to the total stiffness. The surface waviness amplitude has little effect on the oil film stiffness and the oil film damping.

State of Charge Estimation for Li-Ion Batteries Based on an Unscented H-Infi nity Filter

Yuanyuan Liu,Tiantian Cai,Jingbiao Liu,Mingyu Gao,Zhiwei He 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.6

The state of charge (SOC) of lithium-ion batteries refl ects their remaining capacity. Accurate estimation of SOC helps battery safety and is benefi cial to the effi cient management of batteries. The charging and discharging processes of lithium-Ion batteries are very complicated, and it is diffi cult to obtain accurate SOC estimation results. Therefore, it is important to study improved algorithms for SOC estimation for this nonlinear non-Gaussian battery system. In this paper, we propose an unscented H-infi nity fi lter (UHF) based SOC estimation method, which combines the advantages of both the unscented Kalman fi lter (UKF) and the H-infi nity fi lter (HF). The UKF propagates the sigma points through the nonlinear system and does not need the fi rst-order linear approximation of the system equation, while the HF can suppress the non-Gaussian noise in the system to the greatest extent. The proposed UHF based SOC estimation algorithm is verifi ed and evaluated in the battery management system, and further optimized in practical problems. Experimental results show that the proposed UHF based algorithm can perform accurate SOC estimation for lithium-ion batteries, and is superior to the UKF based SOC estimation.

Residual capacity assessment of in-service concrete box-girder bridges considering traffic growth and structural deterioration

Yuanyuan Liu,Junyong Zhou,Jianxu Su,Junping Zhang 국제구조공학회 2023 Structural Engineering and Mechanics, An Int'l Jou Vol.85 No.4

The existing concrete bridges are time-varying working systems, where the maintenance strategy should be planned according to the time-varying performance of the bridge. This work proposes a time-dependent residual capacity assessment procedure, which considers the non-stationary bridge load effects under growing traffic and non-stationary structural deterioration owing to material degradations. Lifetime bridge load effects under traffic growth are predicated by the nonstationary peaks-over-threshold (POT) method using time-dependent generalized Pareto distribution (GPD) models. The nonstationary structural resistance owing to material degradation is modeled by incorporating the Gamma deterioration process and field inspection data. A three-span continuous box-girder bridge is illustrated as an example to demonstrate the application of the proposed procedure, and the time-varying reliability indexes of the bridge girder are calculated. The accuracy of the proposed non-stationary POT method is verified through numerical examples, where the shape parameter of the time-varying GPD model is constant but the threshold and scale parameters are polynomial functions increasing with time. The case study illustrates that the residual flexural capacities show a degradation trend from a slow decrease to an accelerated decrease under traffic growth and material degradation. The reliability index for the mid-span cross-section reduces from 4.91 to 4.55 after being in service for 100 years, and the value is from 4.96 to 4.75 for the mid-support cross-section. The studied bridge shows no safety risk under traffic growth and structural deterioration owing to its high design safety reserve. However, applying the proposed numerical approach to analyze the degradation of residual bearing capacity for bridge structures with low safety reserves is of great significance for management and maintenance.

Liquid/Liquid Interfacial Fabrication of Thermosensitive and Catalytically Active Ag Nanoparticle-Doped Block Copolymer Composite Foam Films

Liu, Mei,Wang, Qian,Geng, Yuanyuan,Wang, Changwei,Lee, Yong-Ill,Hao, Jingcheng,Liu, Hong-Guo American Chemical Society 2014 Langmuir Vol.30 No.34

<P>An aqueous solution of AgNO<SUB>3</SUB> (upper phase) and a DMF/CHCl<SUB>3</SUB> solution of polystyrene-<I>b</I>-poly(acryl acid)-<I>b</I>-polystyrene (PS-<I>b</I>-PAA-<I>b</I>-PS) or PS-<I>b</I>-PAA-<I>b</I>-PS/1,6-diaminohexane (DAH) (lower phase) constituted a planar liquid/liquid interface. The lower phase gradually transformed to a water-in-oil (W/O) emulsion via spontaneous emulsification due to the “ouzo effect”. Polymer molecules, DAH molecules, and Ag<SUP>+</SUP> ions assembled into microcapsules around emulsion droplets that adsorbed at the planar liquid/liquid interface, resulting in formation of a foam film. DAH acted as a cross-linker during this process. Transmission electron microscopic observations indicated that Ag nanoclusters that were generated through reduction of Ag<SUP>+</SUP> ions by DMF were homogeneously dispersed in the walls of the foam structure. X-ray photoelectron spectroscopic investigations revealed that Ag(I) and Ag(0) coexisted in the film, and Ag(I) transformed to Ag(0) after further treatment. The film formed without DAH was not stable, while the film formed with DAH was very stable due to intermolecular attraction between PAA and DAH and formation of amides, as revealed by FTIR spectra. The film formed with DAH exhibited high and durable catalytic activity for hydrogenation of nitro compounds and, very interestingly, exhibited thermoresponsive catalytic behavior.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/langd5/2014/langd5.2014.30.issue-34/la502738j/production/images/medium/la-2014-02738j_0012.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/la502738j'>ACS Electronic Supporting Info</A></P>

Constrained State Estimation via Projection based Optimized Parameters UKF

Yuanyuan Liu,Jingbiao Liu,Zhiwei He 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.11

The unscented Kalman filter (UKF) has become a popular method for nonlinear state estimation during the last decade. However, the conventional UKF may not be suitable for real-world applications with state constrains that stem from physical definitions, physical laws or model restrictions. A UKF based method with optimized parameters was proposed in this paper to handle state constraints via the projection of sigma points. In the proposed method, the generated sigma points that violate the state constraints were projected onto the constraint boundary first. The three free parameters of the UKF, i.e., α ,β ,κ , were then optimized using a Gaussian process optimization (GPO) method. Simulations indicate that the proposed optimized UKF algorithm with the projection of sigma points can handle constrained state estimation problem effectively and efficiently.

One-step synthesis of hierarchical AuNPs/Cd0.5Zn0.5S nanoarchitectures and their application as an efficient photocatalyst for hydrogen production

Yuanyuan Liu,Cui Du,Chen Zhou,Shengyang Yang 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.72 No.-

The hierarchical AuNPs/Cd0.5Zn0.5S hybrids are directly fabricated via a facile one-step in-situhydrothermal method. The as-prepared AuNPs/Cd0.5Zn0.5S hybrids demonstrate superior photocatalyticperformance toward hydrogen production under visible light irradiation. The hydrogen evolution rate ofthe 5 wt% AuNPs/Cd0.5Zn0.5S synthesized with in-situ hydrothermal method can be 7.1 times greater thanthat of pure Cd0.5Zn0.5S and as much as 2.5 times of 5 wt% AuNPs loaded Cd0.5Zn0.5S synthesized withphotodeposition method. Systematical investigations reveal that the enhanced photocatalyticperformance of the one-step in-situ prepared AuNPs/Zn0.5Cd0.5S can be attributed to the inherentSPR effect and favorable electron transfer properties of AuNPs, as well as the rational hierarchicalnanoarchitectures that allow AuNPs to be uniformly incorporated into Zn0.5Cd0.5S matrix. This one-stepin-situ fabrication method provides a simple and efficient route to synthesize well-definedheterocatalysts.

Sample Entropy Analysis of Heart Rate Variability during Rest and Exercise in Hypoxia

Liu Yuanyuan,Liu Chengyu,Wang Binhua,Yu Mengsun 보안공학연구지원센터 2014 International Journal of Control and Automation Vol.7 No.4

STRESS AND CONSUMER ETHICAL BELIEFS: THE ROLE OF CONSTRUAL LEVEL AND MATERIALISM

Yuanyuan Liu,Yeyi Liu,Xi Zhao 글로벌지식마케팅경영학회 2018 Global Marketing Conference Vol.2018 No.07

Understanding why individuals behave unethically is an important topic for both theory and practice, especially in the current environment where people experience much more stressful events. The current research aims to examine the relationship between peoples’ experienced stress and their attitude towards unethical consumption behavior, as well as the underlying mechanism. Empirical findings from a survey of 451 participants suggest perceived stress serves as an important indicator of people’s tolerance of unethical activities, and that this relationship is mediated by chronic construal level and materialism value. Specifically, stressed individuals tend to develop low-construal mindsets and more materialism values, both of which further increase their tolerance of ethically questionable behaviors. The present research highlights the importance of stress on consumer ethics and contributes to prior literature in three ways. Firstly, the current study adds to the literature on consumer ethics by examining a new predictor of consumers’ ethical beliefs, which enriches the understanding of why some consumers act more ethically than others do. Secondly, to the best of our knowledge, little prior literature has examined the effect stress on ethical beliefs. The current research for the first time examines the effect and the mechanism and reveals the mediating roles of construal level and materialism value. Thirdly, the present research finds that stress increases low-level construal, leading to unethical beliefs. This finding broadens the scope in construal level theory by suggesting that chronic construal level predicts individual ethical judgments.