Viscoelastic Fatigue Damage Properties of Asphalt Mixture with Different Aging Degrees

Songtao Lv,Chaochao Liu,Jianlong Zheng,Zhanping You,Lingyun You 대한토목학회 2018 KSCE Journal of Civil Engineering Vol.22 No.6

In order to reveal the effects of aging on fatigue damage evolution pattern of asphalt mixture, and to reveal the fatigue damagepatterns of asphalt pavement during its service life more accurately, the viscoelastic fatigue damage model for the aged asphaltmixtures was proposed based on the Burgers viscoelastic model. The dissipation energy was taken as the damage variable, and thedirect tension fatigue tests for asphalt mixture in five different aging degrees were conducted. The viscoelastic parameters of the agedasphalt mixtures were obtained.The calculationmethod of the cumulative fatigue damage was proposed, which considers the agingeffects. Moreover, the critical fatigue damage degree and fatigue life calculation equations were derived by employing the fatiguedamage model, which were calculated and compared. The calculation errors range from 3% to 18%, which was within an acceptableerror range of 30%. The research results show that the aging has a prominent impact on fatigue properties of asphalt mixtures, whichcould be illustrated by the change of the parameters of the viscoelastic fatigue damage model for the aged asphalt mixtures. Theprediction precision of fatigue life is acceptable for using the proposed viscoelastic fatigue damage model.

Distributed parameters modeling for the dynamic stiffness of a spring tube in servo valves

Xinbei Lv,Bijan Krishna Saha,You Wu,Songjing Li 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.75 No.3

The stability and dynamic performance of a flapper-nozzle servo valve depend on several factors, such as the motion of the armature component and the deformation of the spring tube. As the only connection between the armature component and the fixed end, the spring tube plays a decisive role in the dynamic response of the entire system. Aiming at predicting the vibration characteristics of the servo valves to combine them with the control algorithm, an innovative dynamic stiffness based on a distributed parameter model (DPM) is proposed that can reflect the dynamic deformation of the spring tube and a suitable discrete method is applied according to the working condition of the spring tube. With the motion equation derived by DPM, which includes the impact of inertia, damping, and stiffness force, the mathematical model of the spring tube dynamic stiffness is established. Subsequently, a suitable program for this model is confirmed that guarantees the simulation accuracy while controlling the time consumption. Ultimately, the transient response of the spring tube is also evaluated by a finite element method (FEM). The agreement between the simulation results of the two methods shows that dynamic stiffness based on DPM is suitable for predicting the transient response of the spring tube.

Environmentally friendly and non-polluting solvent pretreatment of palm samples for polyphenol analysis using choline chloride deep eutectic solvents

Fu, N.,Lv, R.,Guo, Z.,Guo, Y.,You, X.,Tang, B.,Han, D.,Yan, H.,Row, K.H. Elsevier 2017 Journal of chromatography Vol.1492 No.-

<P>In this work, choline chloride (ChCI) deep eutectic solvents (DESs) were evaluated for the pretreatment of palm samples in the analysis of polyphenols, such as protocatechuic acid, catechins, epicatechin, and caffeic acid. During the enrichment step of the pretreatment, eight DESs comprising ChCI with ethylene glycol (EG), glycerol (Gly), xylitol (Xyl), phenol (Ph), formic acid (FA), citric acid (CiA), oxalic acid (OA), or malonic acid (MA), were prepared and applied to the reflux extraction of polyphenols from palm samples. All the DESs exhibited higher polyphenol extraction efficiency than methanol, and the highest extraction efficiency was obtained using ChCI-FA (1:1, mole ratio). For the purification step of the pretreatment, eight ChCI DES-modified adsorbents were prepared by hydrothermal polymerization and packed into solid phase extraction (SPE) cartridges, and ChCI-Urea, ChCI-Gly, ChCI-FA, and water, were used as eluents. The ChCI DES-modified adsorbents were characterized by Fourier transform infrared spectroscopy, thermal gravimetric analysis, scanning electron microscopy, and Brunauer-Emmett-Teller surface analysis, and the polyphenols were analyzed by mass spectrometry and high-performance liquid chromatographultraviolet detection. The highest purification efficiency was obtained using the ChCI-Ph DES-modified adsorbent as the SPE packing material and ChCI-Urea-H2O (1:1:5, mole ratio), ChCI-Gly (1:1, mole ratio), ChCI-FA-H2O (1:1:5, mole ratio), and H2O as the eluents. Compared to conventional purification processes that employ commercial C-18 or C-8 SPE columns with organic solvents as eluents, the ChCI DES-based SPE purification process successfully avoided the use of expensive commercial SPE columns and organic solvents. Furthermore, it isolated a larger amount of the target compounds under the same experimental conditions, and could be applied over five cycles with good reversibility. This work indicates that DESs as green solvents have great potential for the totally green pretreatment of samples during the enrichment and purification processes. (C) 2017 Elsevier B.V. All rights reserved.</P>

Protective Effect of Polysaccharide Fractions from Radix A. Sinensis against tert-Butylhydroperoxide Induced Oxidative Injury in Murine Peritoneal Macrophages

Yang, Xingbin,Zhao, Yan,Lv, You,Yang, Ying,Ruan, Yun Korean Society for Biochemistry and Molecular Biol 2007 Journal of biochemistry and molecular biology Vol.40 No.6

Three Angelica sinensis polysaccharide fractions (APFs), named APF1, APF2 and APF3, were isolated and purified from Radix A. sinensis and their antioxidant activities were evaluated in isolated mouse peritoneal macrophages by pretreatment with APFs before exposure to 0.2 mM tertbutylhydroperoxide (t-BHP). The results showed that pretreatment of the macrophages with APFs as low as $10{\mu}g$/ml could significantly enhance t-BHP-decreased cell survival, intracellular glutathione (GSH) content and superoxide dismutase (SOD) activity, and also inhibited t-BHP-increased lactate dehydrogenase (LDH) leakage and malondialdehyde (MDA) formation (p < 0.05), and APF3 was the most active fraction, followed by APF2 and APF1 in decreasing order. Furthermore, we found for the first time that the bound-protein in APF3 was associated closely with the protective effects and the polysaccharide inhibited the excess NO release from t-BHP-activated macrophages to protect host cells.

Protective Effect of Polysaccharide Fractions from Radix A. Sinensis against tert-Butylhydroperoxide Induced Oxidative Injury in Murine Peritoneal Macrophages

( Xing Bin Yang ),( Yan Zhao ),( You Lv ),( Ying Yang ),( Yun Ruan ) 생화학분자생물학회 2007 BMB Reports Vol.40 No.6

ACOX1 destabilizes p73 to suppress intrinsic apoptosis pathway and regulates sensitivity to doxorubicin in lymphoma cells

( Fei-meng Zheng ),( Wang-bing Chen ),( Tao Qin ),( Li-na Lv ),( Bi Feng ),( Yan-ling Lu ),( Zuo-quan Li ),( Xiao-chao Wang ),( Li-ju Tao ),( Hong-wen Li ),( Shu-you Li ) 생화학분자생물학회(구 한국생화학분자생물학회) 2019 BMB Reports Vol.52 No.9

Lymphoma is one of the most curable types of cancer. However, drug resistance is the main challenge faced in lymphoma treatment. Peroxisomal acyl-CoA oxidase 1 (ACOX1) is the rate-limiting enzyme in fatty acid β-oxidation. Deregulation of ACOX1 has been linked to peroxisomal disorders and carcinogenesis in the liver. Currently, there is no information about the function of ACOX1 in lymphoma. In this study, we found that upregulation of ACOX1 promoted proliferation in lymphoma cells, while downregulation of ACOX1 inhibited proliferation and induced apoptosis. Additionally, overexpression of ACOX1 increased resistance to doxorubicin, while suppression of ACOX1 expression markedly potentiated doxorubicin-induced apoptosis. Interestingly, downregulation of ACOX1 promoted mitochondrial location of Bad, reduced mitochondrial membrane potential and provoked apoptosis by activating caspase-9 and caspase-3 related apoptotic pathway. Overexpression of ACOX1 alleviated doxorubicin-induced activation of caspase-9 and caspase-3 and decrease of mitochondrial membrane potential. Importantly, downregulation of ACOX1 increased p73, but not p53, expression. p73 expression was critical for apoptosis induction induced by ACOX1 downregulation. Also, overexpression of ACOX1 significantly reduced stability of p73 protein thereby reducing p73 expression. Thus, our study indicated that suppression of ACOX1 could be a novel and effective approach for treatment of lymphoma. [BMB Reports 2019; 52(9): 566-571]

Effect of Trichostatin A on Anti HepG2 Liver Carcinoma Cells: Inhibition of HDAC Activity and Activation of Wnt/β-Catenin Signaling

Shi, Qing-Qiang,Zuo, Guo-Wei,Feng, Zi-Qiang,Zhao, Lv-Cui,Luo, Lian,You, Zhi-Mei,Li, Dang-Yang,Xia, Jing,Li, Jing,Chen, Di-Long Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.18

Purpose: To investigate the effect of deacetylase inhibitory trichostatin A (TSA) on anti HepG2 liver carcinoma cells and explore the underlying mechanisms. Materials and Methods: HepG2 cells exposed to different concentrations of TSA for 24, 48, or 72h were examined for cell growth inhibition using CCK8, changes in cell cycle distribution with flow cytometry, cell apoptosis with annexin V-FTIC/PI double staining, and cell morphology changes under an inverted microscope. Expression of ${\beta}$-catenin, HDAC1, HDAC3, H3K9, CyclinD1 and Bax proteins was tested by Western blotting. Gene expression for ${\beta}$-catenin, HDAC1and HDAC3 was tested by q-PCR. ${\beta}$-catenin and H3K9 proteins were also tested by immunofluorescence. Activity of Renilla luciferase (pTCF/LEF-luc) was assessed using the Luciferase Reporter Assay system reagent. The activity of total HDACs was detected with a HDACs colorimetric kit. Results: Exposure to TSA caused significant dose-and time-dependent inhibition of HepG2 cell proliferation (p<0.05) and resulted in increased cell percentages in G0/G1 and G2/M phases and decrease in the S phase. The apoptotic index in the control group was $6.22{\pm}0.25%$, which increased to $7.17{\pm}0.20%$ and $18.1{\pm}0.42%$ in the treatment group. Exposure to 250 and 500nmol/L TSA also caused cell morphology changes with numerous floating cells. Expression of ${\beta}$-catenin, H3K9and Bax proteins was significantly increased, expression levels of CyclinD1, HDAC1, HDAC3 were decreased. Expression of ${\beta}$-catenin at the genetic level was significantly increased, with no significant difference in HDAC1and HDAC3 genes. In the cytoplasm, expression of ${\beta}$-catenin fluorescence protein was not obvious changed and in the nucleus, small amounts of green fluorescence were observed. H3K9 fluorescence protein were increased. Expression levels of the transcription factor TCF werealso increased in HepG2 cells following induction by TSA, whikle the activity of total HDACs was decreased. Conclusions: TSA inhibits HDAC activity, promotes histone acetylation, and activates Wnt/${\beta}$-catenin signaling to inhibit proliferation of HepG2 cell, arrest cell cycling and induce apoptosis.

Clinical and Pathologic Features of Multifocal and Multicentric Breast Cancer in Chinese Women: A Retrospective Cohort Study

Mei-rong Zhou,Zhong-hua Tang,Jing Li,Jin-Hu Fan,Yi Pang,Hong-jian Yang,Shan Zheng,Jing-qiao Bai,Ning Lv,You-Lin Qiao,Feng Xu,Hai-zhi Qi 한국유방암학회 2013 Journal of breast cancer Vol.16 No.1

Purpose: This study aims to analyze the clinical-pathological characteristics of multifocal and multicentric breast cancer (MMBC) in Chinese women. Methods: Sixty-seven cases with MMBC were randomly collected and reviewed at seven hospitals in representative districts of China during 1999 to 2008. Results: The incidence of MMBC in breast cancer in China was 1.75%. Compared to those with unifocal breast cancer, women with MMBC were more likely to have larger tumor size, lymph node metastasis (59.70% vs. 45.62%) and stage III to IV (46.26% vs. 21.10%). The peak age at onset of MMBC was 40 to 49 years old and has been gradually increasing during 1999 to 2008. Most of the MMBC women were treated with surgery and adjuvant therapy. Conclusion: In China, the incidence of MMBC in breast cancer is significantly lower than that in Western countries. Compared to unifocal breast cancer, MMBC is biologically more aggressive. Most MMBC women underwent mastectomy, instead of breast conservation surgery.