Effects of Submicron Metakaolin on Hydration and Compressive Strength of Portland Cement Slurry

Yao Yu Wang,Lihua Zhao,Jing Zhao 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.7

Submicron metakaolin (SMK) is an ultrafine aluminosilicate material, which was used for improving properties of cement slurry in this paper. SMK was added to the slurry mix as a partial substitute for Portland cement in proportions of 1%, 3%, 5% and 7%. To explore the influence of SMK on hydration of cement slurry, the heat flow and pH measurement was used to indicate that SMK significantly increased the rate of heat release and total heat release,increase the rate of calcium hydroxide (CH) generation in the pore solution at initial stage of hydration. The hardened specimens at different ages (3 – 28 days) were measured by X–ray diffraction, Differential Thermal Analysis and Compressive strength. The results showed that:SMK displayed pozzolanic effect which reduced CH content and increased the generation of Calcium Silicate Hydrate (C-S-H) gel at later stages of hydration. The compressive strength tests showed that SMK highest increased compressive strength of the slurry by 67% and 19% at 3d and 28d over plain cement slurry. It was concluded that SMK could improve manyproperties of cement slurry and has the use potential on actual projects.

Multibody contact dynamics on mechanisms with deep groove ball bearing joints

Tingqiang Yao,Liguo Xian,Lihua Wang,Xiaobao Liu 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.9

The dynamics of ball bearings are important to fatigue breakage, dynamic performance and motion precision of mechanisms connected by ball bearings joints with multi-clearances. In this study, a new method is proposed for multibody dynamics analysis on mechanisms under the effects of radial internal clearances and impact of balls/cage pockets interactions of ball bearings. Including balls/rings interactions and balls/cage pockets interactions, the three dimensional dynamics models of the crank slider mechanism are established and calculated by generalized-α algorithms on the basis of Hertzian contact theory and penalty function method. The rules of eccentric trajectories of inner and outer ring center for one ball bearing joint are verified with the results calculated by XU’s references. The results of dynamic errors, motion trajectories, dynamic forces are achieved under different speeds, radial clearances and number of ball bearings. The speeds and radial clearances are critical to the dynamic performances and motion precision of mechanisms, especially the number of ball bearings. The number of ball bearings is important to impact force and motion stability of the mechanism.

Optimization of Ultrasonic-assisted Extraction of Flavonoid from Portulaca oleracea L. by Response Surface Methodology and Chemical Composition Analysis

Wang, Chenxi,Li, Yuping,Yao, Lihua,Wu, Guangjie,Chang, Jun,Shu, Chengchuang,Chen, Meiqin 한국응용생명화학회 2014 Applied Biological Chemistry (Appl Biol Chem) Vol.57 No.5

Optimization of ultrasonic extraction of Portulaca oleracea L. flavonoids (POF) was investigated using single-factor experimentation combined with response surface methodology. The optimal conditions for the highest yield (16.25 mg RE/g DW) of POF was 39.01% ethanol, $55.25^{\circ}C$ extraction temperature, 15 min extraction time, and 23.92 (v/m) liquid-to-solid ratio. The crude extract of POF was purified on the polyamide resin. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, a yellow tetrazole assays of the flavonoids were evaluated, which suggested the concentrations of the flavonoids (0-1 mg/mL) and quercetin (0-1 mg/mL). Quercetin was identified in the extract by comparing relative retention time of the reference standard.

Probiotics Increase Intramuscular Fat and Improve the Composition of Fatty Acids in Sunit Sheep through the Adenosine 5′-Monophosphate-Activated Protein Kinase (AMPK) Signaling Pathway

Yue Zhang,Duo Yao,Huan Huang,Min Zhang,Lina Sun,Lin Su,LiHua Zhao,Yueying Guo,Ye Jin 한국축산식품학회 2023 한국축산식품학회지 Vol.43 No.5

This experiment aims to investigate the impact of probiotic feed on growth performance, carcass traits, plasma lipid biochemical parameters, intramuscular fat and triglyceride content, fatty acid composition, mRNA expression levels of genes related to lipid metabolism, and the activity of the enzyme in Sunit sheep. In this experiment, 12 of 96 randomly selected Sunit sheep were assigned to receive the basic diet or the basic diet supplemented with probiotics. The results showed that supplementation with probiotics significantly increased the loin eye area, and decreased plasma triglycerides and free fatty acids, increasing the content of intramuscular fat and triglycerides in the muscle and improving the composition of the fatty acids. The inclusion of probiotics in the diet reduced the expression of adenosine 5’-monophosphate-activated protein kinase alpha 2 (AMPKα2) mRNA and carnitine palmitoyltransferase 1B (CPT1B) mRNA, while increasing the expression of acetyl-CoA carboxylase alpha (ACCα) mRNA, sterol regulatory elementbinding protein-1c (SREBP-1c) mRNA, fatty acid synthase mRNA, and stearoyl-CoA desaturase 1 mRNA. The results of this study indicate that supplementation with probiotics can regulate fat deposition and improves the composition of fatty acids in Sunit sheep through the signaling pathways AMPK-ACC-CPT1B and AMPK-SREBP-1c. This regulatory mechanism leads to an increase in intramuscular fat content, a restructuring of muscle composition of the fatty acids, and an enhancement of the nutritional value of meat. These findings contribute to a better understanding of the food science of animal resources and provide valuable references for the production of meat of higher nutritional value.

Facile Synthesis, Morphology Evolution and Tunable Luminescence of NaGdF4:Yb,Er Nanorods with Various Aspect Ratios

Shasha Gai,Jiqing Jiao,Wei Wei,Yao Li,Lihua Liu,Yi Liu,Baize Lv,Yao Wang,Laurence A. Bel¯ore,Jianguo Tang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.08

The well-defined NaGdF4:Yb,Er nanorods (NRs) with various aspect ratios were synthesized using a facile hydrothermal method. The morphology and crystal phase of NRs could be controlled by reaction conditions. NaGdF4:Yb,Er NRs with various aspect ratios could be synthesized and their upconversion (UC) luminescence was tuned. It is displayed that the NRs with aspect ratios about 5 exhibited the strongest UC luminescence among samples. The growth mechanism and morphology transition of NRs had been deduced by schematic diagram. And UC mechanism had been determined by energy level diagrams. Compared with previous reports, the work provided a facial method for UCNRs with various aspect ratios at lower temperature.

Dihydroartemisinin inhibits HepG2.2.15 proliferation by inducing cellular senescence and autophagy

( Jiang Zou ),( Qiang Ma ),( Ru Sun ),( Jiajing Cai ),( Hebin Liao ),( Lei Xu ),( Jingruo Xia ),( Guangcheng Huang ),( Lihua Yao ),( Yan Cai ),( Xiaowu Zhong ),( Xiaolan Guo ) 생화학분자생물학회(구 한국생화학분자생물학회) 2019 BMB Reports Vol.52 No.8

Dihydroartemisinin (DHA) has been reported to possess anti-cancer activity against many cancers. However, the pharmacologic effect of DHA on HBV-positive hepatocellular carcinoma (HCC) remains unknown. Thus, the objective of the present study was to determine whether DHA could inhibit the proliferation of HepG2.2.15 cells and uncover the underlying mechanisms involved in the effect of DHA on HepG2.2.15 cells. We found that DHA effectively inhibited HepG2.2.15 HCC cell proliferation both in vivo and in vitro. DHA also reduced the migration and tumorigenicity capacity of HepG2.2.15 cells. Regarding the underlying mechanisms, results showed that DHA induced cellular senescence by up-regulating expression levels of proteins such as p-ATM, p-ATR, γ-H₂AX, P53, and P21 involved in DNA damage response. DHA also induced autophagy (green LC3 puncta gathered together and LC3II/LC3I ratio increased through AKT-mTOR pathway suppression). Results also revealed that DHA-induced autophagy was not linked to senescence or cell death. TPP1 (telomere shelterin) overexpression could not rescue DHA-induced anticancer activity (cell proliferation). Moreover, DHA down-regulated TPP1 expression. Gene knockdown of TPP1 caused similar phenotypes and mechanisms as DHA induced phenotypes and mechanisms in HepG2.2.15 cells. These results demonstrate that DHA might inhibit HepG2.2.15 cells proliferation through inducing cellular senescence and autophagy. [BMB Reports 2019; 52(8): 520-525]