Experimental Investigation and Finite Element Analysis on Flexural Behavior of PVA Fiber-Reinforced Recycled Concrete Slabs

Yuan Fang,Feng Yu,Jie Song,Yuandi Qian,Qinglin Tao 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.9

This paper presents an experimental study on mechanical behavior of Polyvinyl alcohol (PVA) fiber-recycled reinforced concrete (RC) one-way slabs. 21 specimens including 14 PVA fiber-reinforced recycled concrete slabs and 7 recycled RC slabs are fabricated and tested. The specimens are designed with different variables, such as replacement ratio of recycled coarse aggregate (RCA) γ, reinforcement ratio ρs, content of PVA fibers ρf, and span-to-thickness ratio l/h. The findings demonstrate that yielding of longitudinal reinforcement, breaking or pulling out PVA fibers along crack gaps and crushing of recycled concrete eventually dominate the failures of PVA fiber-reinforced recycled RC one-way slabs. The ultimate carrying capacity enhances as ρf or ρs increases, while decreases as l/h increases. The ultimate carrying capacity decreases with the increment of , while the introduction of PVA fibers can alleviate this weakening effect. The ultimate carrying capacity of RCB and PRCB decreases by 11.96% and 2.15%, respectively when the increases from 0% from 100%. The ultimate deflection first increases and then decreases as ρs increases. Increasing γ, l/h or ρf increases the ultimate deflection. Comparatively, the variation of PVA fiber content has a more prominent effect on the ultimate deflection of PRCB-U. The ultimate deflection of PRCB-U and PRCB increases by 73.03% and 15.15% respectively when the content of PVA fibers increases from 1% to 2%. A verified finite element (FE) model for PVA fiber-reinforced recycled RC one-way slabs under static load is established on account of rational constitutive relationship of materials. Then, the parametric studies are carried out to further reveal stress mechanism and the impacts of five main influence parameters on mechanical behaviors are ulteriorly analyzed. Ultimately, several design recommendations are suggested based on the experimental and FE analysis results. The suggested content of PVA fibers is between 0.5% and 2% and the optimal reinforcement rate ranges from 0.49% to 0.59%.

Genistein Alleviates β-Amyloid-Induced Inflammatory Damage Through Regulating Toll-Like Receptor 4/Nuclear Factor κB

Weiwei Ma,Bingjie Ding,Huanling Yu,Linhong Yuan,Yuandi Xi,Rong Xiao 한국식품영양과학회 2015 Journal of medicinal food Vol.18 No.3

Genistein (GEN), a major soybean isoflavone (SIF), might possess neuroprotective properties through its antiinflammatory activity. We hypothesized that GEN could prevent the inflammatory damage detected in C6 cells induced by β-amyloid peptides 25-35 (Aβ25-35). Accordingly, we evaluated the inflammatory damage induced by Aβ25-35 and the protective effect of GEN against Aβ25-35 in C6 cells. In our study, the C6 glial cells (rats glioma cell lines) were preincubated with or without GEN for 2 h following incubation with Aβ25-35 for another 24 h. Then, methylthiazolyl tetrazolium (MTT) assay was used to assess the cell viability. Immunofluorescence staining was used to identify the C6 cells. Inflammatory factors tumor necrosis factor (TNF)-α and interleukin (IL)-1β were analyzed by using enzyme-linked immunosorbent assay (ELISA). Western blot analysis and reverse transcription-polymerase chain reaction analysis were performed to assess the expression of Toll-like receptors 4 (TLR4), inhibitor of kappaB-alpha (IκB-α). The current results showed that GEN could alleviate Aβ25-35-induced cell apoptosis and prevent Aβ25-35-induced TNF-α and IL-1β release from C6 cells. In addition, GEN prevented Aβ25-35-induced upregulation of the gene and protein expression of TLR4, and GEN significantly upregulated the expression of IκB-α in C6 cells damaged by Aβ25-35. These results suggest that GEN can alleviate the inflammatory stress caused by Aβ25-35 treatment, which might be associated with the neuroprotective effect of GEN regulating the TLR4/NFκB signaling pathway.

Experimental and Numerical Analysis of the Construction Process for the Oblique Cantilevered Steel Reinforced Concrete Structure

Qinglin Tao,Wanyun Yin,Rencai Jin,Feng Yu,Beng Niu,Yi Hu,Zhitao Li,Quanwei Liu,Yuandi Qian,Dongyun Jia 한국강구조학회 2022 International Journal of Steel Structures Vol.22 No.5

The oblique cantilevered steel reinforced concrete structure (OCSRCS) which includes members of oblique beam, upright column, and the oblique column is manly applied in Olympic Sports Center Stadium and has the characteristics of large section, long span, and large inclination angle. For the safe and economical construction of the OCSRCS, a new construction method named Self-balancing and Self-supporting Method is proposed to take place of traditional construction method of Full-space Support. In this method, cables are utilized to transfer the lateral pressure and gravity load of concrete in pouring to the embedded steel in the OCSRCS and the platform. For ensure the safety of this method, the fi nite element method is proposed to predict the mechanical behavior of the OCSRCS in construction, and the strain variation of the embedded steel in the OCSRCS during the construction process has also observed by the in-situ experiment. The stress distribution of steel and cables in the OCSRCS is investigated and validated in this paper. The results show that the Self-balancing and Self-supporting Method for the OCSRCS can eff ectively ensures the safety of the construction, and it provides references for the construction of large-scale OCSRCS in engineering.

Role of soy lecithin combined with soy isoflavone on cerebral blood flow in rats of cognitive impairment and the primary screening of its optimum combination

Li Hongrui,Wang Xianyun,Li Xiaoying,Zhou Xueyang,Wang Xuan,Li Tiantian,Xiao Rong,Xi Yuandi 한국영양학회 2023 Nutrition Research and Practice Vol.17 No.2

BACKGROUND/OBJECTIVES: Soy isoflavone (SIF) and soy lecithin (SL) have beneficial effects on many chronic diseases, including neurodegenerative diseases. Regretfully, there is little evidence to show the combined effects of these soy extractives on the impairment of cognition and abnormal cerebral blood flow (CBF). This study examined the optimal combination dose of SIF + SL to provide evidence for improving CBF and protecting cerebrovascular endothelial cells. MATERIALS/METHODS: In vivo study, SIF50 + SL40, SIF50 + SL80 and SIF50 + SL160 groups were obtained. Morris water maze, laser speckle contrast imaging (LSCI), and hematoxylineosin staining were used to detect learning and memory impairment, CBF, and damage to the cerebrovascular tissue in rat. The 8-hydroxy-2′-deoxyguanosine (8-OHdG) and the oxidized glutathione (GSSG) were detected. The anti-oxidative damage index of superoxide dismutase (SOD) and glutathione (GSH) in the serum of an animal model was also tested. In vitro study, an immortalized mouse brain endothelial cell line (bEND.3 cells) was used to confirm the cerebrovascular endothelial cell protection of SIF + SL. In this study, 50 μM of Gen were used, while the 25, 50, or 100 μM of SL for different incubation times were selected first. The intracellular levels of 8-OHdG, SOD, GSH, and GSSG were also detected in the cells. RESULTS: In vivo study, SIF + SL could increase the target crossing times significantly and shorten the total swimming distance of rats. The CBF in the rats of the SIF50 + SL40 group and SIF50 + SL160 group was enhanced. Pathological changes, such as attenuation of the endothelium in cerebral vessels were much less in the SIF50 + SL40 group and SIF50 + SL160 group. The 8-OHdG was reduced in the SIF50 + SL40 group. The GSSG showed a significant decrease in all SIF + SL pretreatment groups, but the GSH showed an opposite result. SOD was upregulated by SIF + SL pretreatment. Different combinations of Genistein (Gen)+SL, the secondary proof of health benefits found in vivo study, showed they have effective antioxidation and less side reaction on protecting cerebrovascular endothelial cell. SIF50 + SL40 in rats experiment and Gen50 + SL25 in cell test were the optimum joint doses on alleviating cognitive impairment and regulating CBF through protecting cerebrovascular tissue by its antioxidant activity. CONCLUSIONS: SIF+SL could significantly prevent cognitive defect induced by β-Amyloid through regulating CBF. This kind of effect might be attributed to its antioxidant activity on protecting cerebral vessels.

Exploring cognitive trajectories and their association with physical performance: evidence from the China Health and Retirement Longitudinal Study

Jingdong Suo,Xianlei Shen,Jinyu He,Haoran Sun,Yu Shi,Rongxin He,Xiao Zhang,Xijie Wang,Yuandi Xi,Wannian Liang 한국역학회 2023 Epidemiology and Health Vol.45 No.-

OBJECTIVES: The long-term trends of cognitive function and its associations with physical performance remain unclear, particularly in Asian populations. The study objectives were to determine cognitive trajectories in middle-aged and elderly Chinese individuals, as well as to examine differences in physical performance across cognitive trajectory groups. METHODS: Data were extracted from the China Health and Retirement Longitudinal Study. A total of 5,701 participants (47.7% male) with a mean age of 57.8 (standard deviation, 8.4) years at enrollment were included. A group-based trajectory model was used to identify cognitive trajectory groups for each sex. Grip strength, repeated chair stand, and standing balance tests were used to evaluate physical performance. An ordered logistic regression model was employed to analyze differences in physical performance across cognitive trajectory groups. RESULTS: Three cognitive trajectory groups were identified for each sex: low, middle, and high. For both sexes, higher cognitive trajectory groups exhibited smaller declines with age. In the fully adjusted model, relative to the low trajectory group, the odds ratios (ORs) of better physical performance in the middle cognitive group were 1.37 (95% confidence interval [CI], 1.17 to 1.59; p<0.001) during follow-up and 1.40 (95% CI, 1.20 to 1.64; p<0.001) at the endpoint. The ORs in the high trajectory group were 1.94 (95% CI, 1.61 to 2.32; p<0.001) during follow-up and 2.04 (95% CI, 1.69 to 2.45; p<0.001) at the endpoint. CONCLUSIONS: Cognitive function was better preserved in male participants and individuals with higher baseline cognitive function. A higher cognitive trajectory was associated with better physical performance over time.