Gap junction mediated regulation of osteocytes to osteoblastic alkaline phosphatase activity is independent of microgravity

Rui Meng,Li Xie 한국통합생물학회 2014 Animal cells and systems Vol.18 No.1

Decreased bone formation is one of the main causes of bone loss under microgravity. As a mechanical perceiver, osteocyte regulates bone formation by sending mechanical signals to osteoblast. However, the regulation of osteoblastic bone formation by osteocytes is less known so far under the microgravity conditions. The aim of this study was to investigate the regulation of bone formation/loss by detection of the osteocytic regulatory effects on the bone-specific alkaline phosphatase (ALP) activity of osteoblasts under altered gravitational environment. The altered gravitational environment was provided by a large gradient high magnetic field that could produce high magneto-gravitational environment (HMGE) and provided three apparent gravity levels (μg, 1g, and 2g). After the MLO-Y4 and 2T3 cells were cocultured in direct physical contact for 24 h and established gap junction intercellular communication under HMGE, a highly significant rapid increase in ALP activity was observed in μg, 1g, 2g, and control group (p < 0.001). Conversely, application of 50-μM beta-glycyrrhetinic acid gap junction inhibitor or remote coculture significantly decreased the ALP activity. There were no obvious differences of osteoblastic 2T3 ALP activity among μg, 1g, 2g, and control groups. Based on these findings, we interpreted that gap junction was probably the main route of osteoblastic ALP activity regulation by osteocyte. Gravity had no significant impact on the osteoblastic ALP activity regulated by osteocyte in a short period of time.

pH-Sensitive Degradable Hydrophobe Modified 1.8 kDa Branched Polyethylenimine as “Artificial Viruses” for Safe and Efficient Intracellular Gene Transfection

Meng Zheng,Zhiyuan Zhong,Chunmei Yang,Fenghua Meng,Rui Peng 한국고분자학회 2012 Macromolecular Research Vol.20 No.3

1.8 kDa branched polyethylenimine (PEI) was modified with pH-sensitive degradable acetal containing hydrophobe, 2,4,6-trimethoxybenzylidene-tris(hydroxymethyl)ethane (TMB-THME), to enhance its DNA condensation under extracellular conditions as well as to achieve active DNA release inside cells. PEI-(TMBTHME)n conjugates in the amount of 1.8 kDa were prepared with varying degrees of substitution (DS) from 3.0, 5.7 to 10.1. Notably, dynamic light scattering (DLS) measurements showed that all three 1.8 kDa PEI-(TMB-THME)n conjugates could effectively condense DNA into nano-sized particles (189-197 nm) at N/P ratios ranging from 20/1 to 80/1. The surface charges of PEI-(TMB-THME)n polyplexes depending on DS and N/P ratios varied from +22 to +28 mV,which were comparable to or slightly higher than the unmodified 1.8 kDa PEI counterparts (~+22 to +23 mV). Under a mildly acidic condition mimicking that of endosomes, interestingly, 1.8 kDa PEI-(TMB-THME)n polyplexes were quickly unpacked to release DNA because of the pH-induced acetal degradation that transforms hydrophobic modification into hydrophilic modification. MTT assays demonstrated that all PEI-(TMB-THME)n polyplexes displayed low cytotoxicity (>80%) to 293T, and HeLa cells at N/P ratios ranging from 20/1 to 60/1. The in vitro gene transfection studies showed that the transfection activity of 1.8 kDa PEI was significantly enhanced by modifications with TMBTHME,in which transfection efficiencies increased with increasing DS. For example, 1.8 kDa PEI-(TMBTHME)10.1 polyplexes displayed 250-fold and 80-fold higher transfection efficiencies than those of the unmodified 1.8 kDa PEI counterparts in 293T and HeLa cells, respectively, which were approximately 4-fold and 2-fold higher than that of 25 kDa PEI control. The superior transfection activity of 1.8 kDa PEI-(TMB-THME)10.1 polyplexes was also confirmed by confocal laser scanning microscopy (CLSM), which showed efficient delivery of DNA into the nuclei of 293T cells following 4 h transfection. Modification of low molecular weight PEI with pH-sensitive degradable hydrophobe has appeared to be highly promising in the development of “artificial viruses” for safe and efficient gene transfer.

Roadway Engineering Mechanical Properties and Roadway Structural Instability Mechanisms in Deep Wells

Xiang-Rui Meng,Rui Peng,Guang-Ming Zhao,Ying-Ming Li 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.5

We proposed a new classification method for stress-bearing structures in very-deep roadways. We conducted tests for roadwayengineeringmechanical properties, including rock mechanical tests and ground stress measurement of two caverns in very-deepwells. We suggested a classification method for stress-bearing structures based on shear stress. Tests revealed that rock strength in theshear direction was the lowest; the stress distributions of acoustic emission and hollow inclusion were highly similar. Based on theroadway-engineering mechanical properties of two caverns and numerical simulation and in-situ tests, the key bearing structureswere classified based on the concentrated shear stress. In deep caverns, shear stress was more concentrated on the softer surroundingrock, the key bearing structure areas, and the more seriously fractured surrounding rocks. Using the loose circle in-situ test, wecompared the classification method of the key bearing structures with other classification methods. The results revealed agreementwith the classification methods used for the key bearing structures. The deformation in-situ test showed that the strata convergence ofconcentrated shear stress areas developed quickly. Therefore, the phenomena of concentrated shear stress and the expanded range ofkey bearing structures are the structural instability mechanisms of deep roadways.

Case Study of Modified H–B Strength Criterion in Discrimination of Surrounding Rock Loose Circle

Rui Wang,Xianghui Deng,Yaoyao Meng,Dongyang Yuan,Daohong Xia 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.3

Intermediate principal stress is a significant factor when calculate to determine the surrounding rock loose circles. Based on it, this paper is trying to modify the Hoek–Brown strength criterion, and put forwards a theoretical formula of the loose circle radius. The theoretical formula is applied to Shimen Tunnel, and a comparative analysis between theoretical calculations and field test results is conducted. Here are the results as follows: 1) With an increase of intermediate principal stress, the strength of the rock mass increases and the surrounding rock becomes more difficult to break. Consequently, loose circle thickness is gradually reduced and forms a significant negative linear relationship with the Lode parameter. 2) The results indicate that with a decrease of surrounding rock level in a three-lane hard rock tunnel, the radius of the loose circle increases continuously. 3) The results of the field acoustic wave test show that the theoretical calculation values are consistent with the field measurement results. According to above analysis, the deduced formula is feasible.

Synthesis and Electrochemical Characteristics of Fe-P Alloy Prepared by Electrothermal Reduction Method

Meng Zhao,Gui-Xin Wang,Xiu-Li Li,Rui Liu,Kang-Ping Yan 대한금속·재료학회 2010 METALS AND MATERIALS International Vol.16 No.6

Microscale Fe-P alloy was prepared using Ca3(PO4)2 and Fe2O3 in an electrothermal reduction process, and the electrochemical performance was investigated in detail. The initial discharge capacity could reach ~566.8mAh/g at 0.3 C rate, and the fade trend was so slight that the normalized capacities from 1.0 to 2.0 C rate were adjacent. The energy density and the power density could reach ~1133.6 Wh/kg and ~912.4 W/kg,respectively. The rate capability and the cycle performance were comparable to those of the Fe-P alloy synthesized using zerovalent iron and phosphorus. At 0.5 mV/s scan rate, the oxidation peak and the reduction peak for the reaction of lithium ions with P were positioned at ~1.3 and ~0.5 V, respectively. The reaction occurred under diffusion control, and the lithium ion diffusion efficient was ~1.5×10−9 cm2/s.

Arsenic trioxide: applications, mechanisms of action, toxicity and rescue strategies to date

Meng Yan,Hao Wang,Rui Wei,Wenwen Li 대한약학회 2024 Archives of Pharmacal Research Vol.47 No.3

Arsenical medicine has obtained its status in traditional Chinese medicine for more than 2,000 years. In the 1970s, arsenictrioxide was identifi ed to have high effi cacy and potency for the treatment of acute promyelocytic leukemia, which promotedmany studies on the therapeutic eff ects of arsenic trioxide. Currently, arsenic trioxide is widely used to treat acutepromyelocytic leukemia and various solid tumors through various mechanisms of action in clinical practice; however, it isaccompanied by a series of adverse reactions, especially cardiac toxicity. This review presents a comprehensive overviewof arsenic trioxide from preclinical and clinical effi cacy, potential mechanisms of action, toxicities, and rescue strategies fortoxicities to provide guidance or assistance for the clinical application of arsenic trioxide.

Electrochemical enhanced heterogeneous activation of peroxymonosulfate by CoFe2O4 nanoparticles to degrade moxifloxacin

Meng Zhang,Lili Liu,Jianan Li,Rui Zhan,Zhiping Wang,Haosheng Mi,Yunxiao Zhang 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.127 No.-

The catalytic mechanism of CoFe2O4 nanoparticles (NPs) was investigated in the system of electrochemicalenhanced heterogeneous activation of peroxymonosulfate (EC/CoFe2O4/PMS) with moxifloxacin(MOX) as target contaminant. The removal efficiencies of MOX in PMS, CoFe2O4, EC, CoFe2O4/PMS, andEC/CoFe2O4/PMS system were 18.3%, 36.1%, 43.7%, 96.9%, and 98.3%, respectively. Although there wasno synergy effect between EC and heterogeneous catalytic oxidation reaction (HCOR) on MOX removal,the value of apparent rate constant (karc) was much higher in EC/CoFe2O4/PMS system (0.24 min1) comparedwith CoFe2O4/PMS system (0.13 min1). Therefore, EC not only kept the structure of CoFe2O4 NPsstable, but also significantly accelerated the reaction rate of HCOR. Meanwhile, according to electrochemicalimpedance spectra of catalysts synthesized based on ion-substitution strategy and the EC-HCORexperimental results, the decisive role of „Co in PMS activation and the electron transfer between„Co and „Fe were confirmed. The TOC removal efficiency was reached 74.4% as the ratio of PMS toCoFe2O4 NPs being 0.8 mM to 50 mg/L (30 min), and further improved to 87.6% with batch addition(0.25 mM per 30 min) of PMS (120 min, CoFe2O4 = 100 mg/L). The research results could improve theunderstanding of catalytic mechanism of spinel oxide in electrochemical system.

Algicidal Activity of a Dibenzofuran-Degrader Rhodococcus sp

( Meng Hui Wang ),( Peng Peng ),( Yu Mei Liu ),( Rui Bao Jia ),( Li Li ) 한국미생물 · 생명공학회 2013 Journal of microbiology and biotechnology Vol.23 No.2

Rhodococcus sp. strain p52, a previously isolated dibenzofuran degrader, could effectively inhibit the growth of cyanobacteria, including species of Microcystis, Anabaena, and Nodularia. When strain p52 was inoculated at the concentration of 7.7×107 CFU/ml, 93.5% of exponentially growing Microcystis aeruginosa (7.3×106 cells/ml initially) was inhibited after 4 day. The threshold concentration for its algicidal activity against M. aeruginosa was 7.7×106 CFU/ml. Strain p52 exerted algicidal effect by synthesizing extracellular substances, which were identified as trans-3-indoleacrylic acid, DL-pipecolic acid, and L-pyroglutamic acid. The effective concentrations of trans-3-indoleacrylic acid and DL-pipecolic acid against M. aeruginosa were tested to be 0.5 mg/l and 5 mg/l, respectively.

NONLINEAR DYNAMICS STUDY OF A HIGH-TEMPERATURE ROTOR-BEARING-SEAL SYSTEM IN GAS TURBINE

Rui Zhu,Yanru Zhang,Jianxing Ren,Qingkai Han,Hongguang Li,Guang Meng 한국신재생에너지학회 2015 AFORE Vol.2015 No.11

NONLINEAR DYNAMICS STUDY OF A HIGH-TEMPERATURE ROTOR-BEARING-SEAL SYSTEM IN GAS TURBINE

Zhu Rui,Jianxing Ren,Hongguang LI,Meng Guang 한국신재생에너지학회 2014 AFORE Vol.2014 No.-