Enhancement of thermal stability and chemical reactivity of phenolic resin ameliorated by nanoSiO2

Yajun Guo,Lihong Hu,Puyou Jia,Baofang Zhang,Yonghong Zhou 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.1

Phenolic resin has unsatisfactory thermal stability owing to the poor anti-oxidation property of methylene and phenol groups. To overcome this defect, a series of phenolic resin modified by nanoSiO2 based on the tetraethoxysilane (TEOS) was successfully prepared via sol-gel method using phenol as solvent. The effect of nanoSiO2 on the structures and properties of phenolic resin/foam was investigated. TGA and DTG indicated that the initial decomposition temperature of PR-0.5 (TEOS accounted for 0.5% of phenolic resin) was 41.8 oC higher than the neat PR-0. DSC revealed that the peak temperature presented a parabolic shape with the dosage of the TEOS, its maximal value resting on the PR-0.5. FT-IR and XRD demonstrated that chemical crosslink was reacted between PR and nanoSiO2 hydrolyzed by the TEOS, forming new chemical bands. Reactivity analysis illustrated that the free phenol content and the hydroxymethyl group content changed sharply in PF-0.5, implying it has highest reactivity.

Rhein lysinate inhibits monocyte adhesion to human umbilical vein endothelial cells by blocking p38 signaling pathway

Yajun Lin,Yongzhan Zhen,Jiang Liu,Jie Wei,Ping Tu,Gang Hu 대한약학회 2013 Archives of Pharmacal Research Vol.36 No.11

The objective of this study was to investigate theeffect of rhein lysinate (RHL) on monocyte adhesion and itsmechanism. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) assay was used to determine thegrowth inhibition by drugs. The monocyte chemoattractantprotein (MCP)-1 levels were assayed using MCP-1 ELISA. The expression of proteins was detected by Western blottinganalysis. The results indicated that RHL inhibited monocyteadhesion in a dose- and time-dependent manner. RHL(\20 lmol/L) and lipopolysaccharide (LPS) had no effecton viability of human umbilical vein endothelial cells. Therefore, 20 lmol/L RHL was selected for this study. RHLinhibited secretion ofMCP-1 induced by LPS and expressionof intercellular adhesion molecule (ICAM)-1 and vascularcell adhesion molecule (VCAM)-1. In the meantime, bothRHL and p38 inhibitor (SB203580) inhibited phosphorylationof p38 and mitogen-activated protein kinase-activatedprotein kinase-2 (MAPKAPK-2) and transcription andexpression of ICAM-1 and VCAM-1. In conclusion, RHLinhibits the transcription and expression of ICAM-1 andVCAM-1 by the p38/MAPKAPK-2 signaling pathway, andthe effect ofRHLon transcription and expression of ICAM-1and VCAM-1 is similar to p38 inhibitor. RHL could be aprophylactic drug for atherosclerosis.

The protection of Rhein lysinate to liver in diabetic mice induced by high-fat diet and streptozotocin

Yajun Lin,Gang Hu,Kai-Ji Li,Yu-Fang Zhao,Jie Wei,Yongzhan Zhen 대한약학회 2015 Archives of Pharmacal Research Vol.38 No.5

Rhein lysinate (RHL) is the salt of lysine andrhein and the objective of this study was to investigate theprotection of RHL to liver in diabetic mice. The model oftype 2 diabetes was established by high-fat diet andstreptozotocin treatment. Malondialdehyde, superoxidedismutase (SOD) and glutathione peroxidase (GSH-Px)were measured using a spectrophotometer. Inflammatoryfactors (TNF-a and IL-6) and related proteins (ERK1/2 andSREBP-1c) were analyzed by Western blot. Tissue profilewas determined by hematoxylin and eosin staining andaccumulation of fat was examined by Nile red staining. The results indicated that plasma glucose levels of type 2diabetic mice were over 13.9 mM. Compared with modelgroup, plasma glucose levels were decreased, howeverinsulin levels were increased in RHL (25 and 50 mg/kg)-treated group. Elevated plasma triglyceride and cholesterolwere also markedly attenuated after RHL treatment. Theactivities of SOD and GSH-Px of livers were increasedafter RHL treatment. Livers of RHL-treated mice had morenormal structure and less steatosis than that of diabeticmice. Moreover, RHL decreased the expression of TNF-aand IL-6 and the phosphorylation of SREBP-1c and ERK1/2. In conclusion, RHL has a noticeable hepatic protectionin diabetic mice.

Genetic Variation and Evolution of the Pi9 Blast Resistance Locus in the AA Genome Oryza Species

Jinling Liu,Yajun Hu,Yuese Ning,Nan Jiang,Jun Wu,전종성,Yinghui Xiao,Xionglun Liu,Liangying Dai,Guo-Liang Wang 한국식물학회 2011 Journal of Plant Biology Vol.54 No.5

The rice nucleotide-binding site–leucine-rich repeat (NBS-LRR)-encoding resistance (R) gene Pi9 confers broad-spectrum resistance to the fungal pathogen Magnaporthe oryzae. The Pi9 locus comprises many NBS-LRR-like genes and is an ancient locus that is highly conserved in cultivated and wild rice species. To understand the genetic variation and molecular evolutionary mechanism of the Pi9 alleles in different rice species, we studied five AA genome Oryza species including two cultivated rice species (Oryza sativa and Oryza glaberrima) and three wild rice species (Oryza nivara, Oryza rufipogon, and Oryza barthii). A 2.9-kb fragment spanning the NBS-LRR core region of the Pi9 gene was amplified and sequenced from 40 accessions. Sequence comparison revealed that the Pi9 alleles had an intermediate-diversified nucleotide polymorphism among the AA genome Oryza species. Sequence variations were more abundant in the LRR region than in the NBS region, indicating that the LRR region has played a more important role for the evolution of the Pi9alleles. Furthermore, positive selection was found to be the main force promoting the divergence of the Pi9 alleles,especially in the LRR region. Our results reveal the characteristics and evolutionary dynamics of the Pi9 alleles among the two cultivated and three wild rice species.

CoMP Transmission for Safeguarding Dense Heterogeneous Networks with Imperfect CSI

( Xu Yunjia ),( Huang Kaizhi ),( Hu Xin ),( Zou Yi ),( Chen Yajun ),( Jiang Wenyu ) 한국인터넷정보학회 2019 KSII Transactions on Internet and Information Syst Vol.13 No.1

To ensure reliable and secure communication in heterogeneous cellular network (HCN) with imperfect channel state information (CSI), we proposed a coordinated multipoint (CoMP) transmission scheme based on dual-threshold optimization, in which only base stations (BSs) with good channel conditions are selected for transmission. First, we present a candidate BSs formation policy to increase access efficiency, which provides a candidate region of serving BSs. Then, we design a CoMP networking strategy to select serving BSs from the set of candidate BSs, which degrades the influence of channel estimation errors and guarantees qualities of communication links. Finally, we analyze the performance of the proposed scheme, and present a dual-threshold optimization model to further support the performance. Numerical results are presented to verify our theoretical analysis, which draw a conclusion that the CoMP transmission scheme can ensure reliable and secure communication in dense HCNs with imperfect CSI.

Role of Ubiquitination in Plant Innate Immunity and Pathogen Virulence

Gautam Shirsekar,Liangying Dai,Yajun Hu,Xuejun Wang,Lirong Zeng,Guo-Liang Wang 한국식물학회 2010 Journal of Plant Biology Vol.53 No.1

Plant diseases are a major constraint for stable crop production in the world. Plants are constantly threatened by different pathogens and have developed an array of mechanisms to defend themselves. A growing body of evidence indicates that ubiquitination, which is one of the most important cellular processes for protein modification in eukaryotic organisms, is involved in the regulation of host defense signaling. Pathogens also exploit ubiquitination to block or interfere with plant defenses. Recent studies in a few model plants have demonstrated that ubiquitination plays a critical role in plant–pathogen interactions that lead either to plant resistance or to successful pathogen invasion of the plant host. This review discusses recent findings about the functions of ubiquitination in host defense and pathogen invasion.

Secured Green Communication Scheme for Interference Alignment Based Networks

Zhibin Xie,Xinquan Geng,Yunfei Chen,Kening Song,Benjamin Panful,Yajun Wang,Yinjie Su,Zhenkai Zhang,Ying Hu 한국통신학회 2020 Journal of communications and networks Vol.22 No.1

In this paper, a new security and green communicationscheme is proposed to the interference-alignment (IA) based networks. To achieve a secured communication, full-duplex receiversare utilized to transmit artificial noise (AN). Both the signals andthe ANs are used to harvest energy to realize green communication. For these reasons, the feasible conditions of this scheme areanalyzed first. Secondly, the average transmission rate, the secrecyperformance and the harvested energy are investigated. Thirdly,an optimization scheme of simultaneous wireless information andpower transfer (SWIPT) is given to optimize the information transmissionand the energy harvesting efficiency. Meanwhile, an improvedIA iteration algorithm is designed to eliminate both the ANand the interference. Furthermore, relay cooperation is consideredand its system performance is analyzed. The simulations show thatthe target average transmission rate is not affected by AN, whilethe secrecy performance can be greatly improved. The energy harvestingefficiency is also better than the traditional schemes. Asexpected, the average transmission rate further is improved withthe relay cooperation.

Rhein lysinate decreases inflammation and adipose infiltration in KK/HlJ diabetic mice with non-alcoholic fatty liver disease

Jie Wei,Yong-Zhan Zhen,Ju Cui,Fa-Lin He,Tao Shen,Gang Hu,Xiao-Hong Ren,Yajun Lin 대한약학회 2016 Archives of Pharmacal Research Vol.39 No.7

The objective of this study was to investigate the protective effects of rhein lysinate (RHL) on the liver. Mice were divided into four groups: C57BL/J control, the KK/HlJ diabetic model, and 25 and 50 mg/kg/day RHLtreated KK/HlJ groups. The KK/HlJ diabetic mouse model was made by injecting STZ and feeding mice diabetic food. At 16 weeks, mice were sacrificed and their livers were harvested. The results indicated that compared with the C57BL/J control group, the body weights, liver weights and liver weight-to-body weight ratio were increased in KK/HlJ diabetic mice; however, these values were decreased following treatment with RHL. Compared with the C57BL/J control, KK/HlJ diabetic mice had a significantly lower level of SOD and GSH-px in their livers, but had a significantly higher level of MDA. However, these effects were ameliorated by RHL. Hepatic adipose infiltration was observed in KK/HlJ mice, but not in C57BL/J mice. RHL decreased the incidence of hepatic adipose infiltration and significantly decreased the expression of TNF-a, IL-6, NF-jB, SREBP-1c, and Fas, as well as the phosphorylation of NF-jB in the liver. In conclusion, RHL can improve hepatic function by decreasing hepatic adipose infiltration and the expression of inflammatory factors.