Acid-free epoxidation of soybean oil with hydrogen peroxide to epoxidized soybean oil over titanium silicalite-1 zeolite supported cadmium catalysts

Lei Cai,Chao CHEN,Wenjun Wang,Xiu Gao,Xiaoyan Kuang,Yan Jiang,Liang Li,Guoqiang Wu 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.91 No.-

Titanium silicalite-1 (TS-1) zeolite was successfully synthesized by hydrothermal method in the presenceof the tetrapropylammonium hydroxide (TPAOH) template, and a series of TS-1 supported cadmium withdifferent Cd loading (xCd/TS-1) catalysts were carefully prepared to produce epoxidized soybean oil(ESO) through the acid-free catalytic epoxidation of soybean oil (SO) with H2O2. These catalysts were fullycharacterized using various modern techniques and further evaluated systematically in this epoxidationreaction to understand the relationship between catalytic activity and structure of active components. The results show that the highly dispersed Cd species are introduced on the TS-1 support withoutaffecting the coordination environment of tetrahedral Ti (framework Ti). Furthermore, the Cd species arecoordinated with tetrahedral Ti species via O atom resulting in the weakness of the Ti–O bonds and facileattack of the Ti–O bonds by alcohol and H2O2, which can easily form thefive-membered intermediate andpromote the SO epoxidation process. Furthermore, the deactivation and regeneration behaviors of 2%Cd/TS-1 catalyst in SO epoxidation were also investigated, which reveal that the catalyst deactivation of cokedeposition is due to the strong adsorption of the catalysts and SO molecules. But the spent 2%Cd/TS-1 canbe completely regenerated by calcination method.

Modeling and Analyzing Per-flow Throughput in IEEE 802.11 Multi-hop Ad Hoc Networks

( Lei Lei ),( Xinru Zhao ),( Shengsuo Cai ),( Xiaoqin Song ),( Ting Zhang ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.10

In this paper, we focus on the per-flow throughput analysis of IEEE 802.11 multi-hop ad hoc networks. The importance of an accurate saturation throughput model lies in establishing the theoretical foundation for effective protocol performance improvements. We argue that the challenge in modeling the per-flow throughput in IEEE 802.11 multi-hop ad hoc networks lies in the analysis of the freezing process and probability of collisions. We first classify collisions occurring in the whole transmission process into instantaneous collisions and persistent collisions. Then we present a four-dimensional Markov chain model based on the notion of the fixed length channel slot to model the Binary Exponential Backoff (BEB) algorithm performed by a tagged node. We further adopt a continuous time Markov model to analyze the freezing process. Through an iterative way, we derive the per-flow throughput of the network. Finally, we validate the accuracy of our model by comparing the analytical results with that obtained by simulations.

Melatonin Attenuates Noise Stress-induced Gastrointestinal Motility Disorder and Gastric Stress Ulcer: Role of Gastrointestinal Hormones and Oxidative Stress in Rats

( Lei Zhang ),( Ji T Gong ),( Hu Q Zhang ),( Quan H Song ),( Guang H Xu ),( Lei Cai ),( Xiao D Tang ),( Hai F Zhang ),( Fang E Liu ),( Zhan S Jia ),( Hong W Zhang ) 대한소화기기능성질환·운동학회 2015 Journal of Neurogastroenterology and Motility (JNM Vol.21 No.2

Background/Aims There are increasing evidences for gastrointestinal motility disorder (GIMD) and gastric stress ulcer induced by noise stress. The present study was to investigate the reversed effect of melatonin on GIMD and gastric stress ulcer induced by noise stress and potential mechanism. Methods Noise stress was induced on rats, and melatonin (15 mg/kg) was administered to rats by intraperitoneal injection. Differences were assessed in gastric residual rate (GRR), small intestine propulsion rate (SPR), Guth injury score, cortisol, gastrointestinal hormones (calcitonin-gene-related peptide and motilin) and oxidative stress markers (superoxide dismutase and malondialde hyde) in blood plasma as well as gastric mucosa homogenate with or without melatonin. The pathological examination of gastric mucosa was also performed. Results The GRR and SPR were improved by noise stress compared with control (P < 0.05). The pathological examination and Guth injury score revealed gastric stress ulcer. Moreover, the levels of cortisol, motilin and malondialdehyde in blood plasma and malondialdehyde in gastric mucosa homogenate were increased by noise stress (P < 0.05). CGRP and superoxide dismutase activity in both of blood plasma and gastric mucosa homogenate were significantly decreased (P< 0.05). Furthermore, melatonin reversed changes in GRR, SPR, pathological examination, Guth injury score, cortisol, motilin, CGRP, superoxide dismutase activity and malondialdehyde (P < 0.05). Conclusions Melatonin is effective in reversing the GIMD and gastric stress ulcer induced by noise stress. The underlying mechanism may be involved in oxidative stress and gastrointestinal hormones. (J Neurogastroenterol Motil 2015;21:189-199)

Characterization of transcriptional responses mediated by benzo[a] pyrene stress in a new marine fish model of goby, Mugilogobius chulae

Lei Cai,Jianjun Li,Lujun Yu,Yuanzheng Wei,Zongyu Miao,Meili Chen,Ren Huang 한국유전학회 2019 Genes & Genomics Vol.41 No.1

Benzo[a]pyrene (BaP) is one of the most studied targets among polycyclic aromatic hydrocarbons (PAHs). Because of the complexity of the toxicity mechanism in BaP, little is known about the molecular mechanism at the level of transcription of BaP in marine fishes. The primary objective of this study was to investigate the molecular basis of the effects of BaP on marine fish, using Mugilogobius chulae (Smith 1932) as the model. A closed colony of M. chulae was used for the BaP toxicity test. Two fish liver samples per replicate from each group were excised and blended into one sample by pooling an equal amount of liver tissue. Total RNA of all samples was extracted separately. Equal quantities of total RNA from the three replicates of the two groups were pooled for sequencing. The sequencing cDNA libraries were sequenced using Illumina HiSeq 2000 system. Differentially expressed genes were detected with the DEGSeq R package. In total, 52,364,032 and 53,771,748 clean nucleotide reads were obtained in the control and BaP-exposed libraries, respectively, with N50 lengths of 1277 and 1288 bp, respectively. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses revealed a significant enrichment of genes related to detoxification, transportation, and lipid metabolism. We also identified, for the first time, an association between endoplasmic reticulum dysfunction and lipid metabolism resulting from BaP exposure. Using quantitative real-time PCR, some effective molecular biomarkers for monitoring of BaP-polluted seawater were identified. The results demonstrate that BaP enhanced the expression of genes involved in detoxification in M. chulae and inhibited that of genes related to lipid metabolism, possibly by suppressing the expression of numerous ER-related genes involved in fat digestion and absorption.

Tetrazolium Violet Induces Apoptosis via Caspases-8, -9 Activation and Fas/FasL Up-regulation in Rat C6 Glioma Cells

Cheng-fa Cai,Yun-feng Zhao,Lei Feng,Lei Wang,Qing-zhong Kong 대한약학회 2009 Archives of Pharmacal Research Vol.32 No.4

Tetrazolium violet (TV), a tetrazolium salt, was synthesized as a novel and potent anticancer agent with a broad spectrum of anticancer activity against many cancer cells. A previous study showed that tetrazolium violet inhibited cell growth, and induced cell cycle arrest and apoptosis in C6 Rat glioma cells. It also showed that treatment of cells with TV for 24 h resulted in a dramatic up-regulation of p53, and an increase in the activity of caspase-3, accompanied with a significant increase of Bax/Bcl-2 ratio. In this study, we further investigated which Fas/FasL and caspase were activated by TV during the apoptosis. Annexin-V-propidium iodide (PI) binding assay and nucleosome ELISA assay further indicated that TV induced a typical apoptosis, in a time-dose-dependent manner. The data showed that the activity of Fas/FasL and caspase-8 and -9 were significantly enhanced by the compound, which suggested that TV might be used as a Fas/FasL and caspases promoter to initiate brain cancer cell apoptosis.

Polymorphism of the Promoter Region of Hsp70 Gene and Its Relationship with the Expression of HSP70mRNA, HSF1mRNA, Bcl-2mrna and Bax-AMrna in Lymphocytes in Peripheral Blood of Heat Shocked Dairy Cows

Cai, Yafei,Liu, Qinghua,Xing, Guangdong,Zhou, Lei,Yang, Yuanyuan,Zhang, Lijun,Li, Jing,Wang, Genlin Asian Australasian Association of Animal Productio 2005 Animal Bioscience Vol.18 No.5

The blood samples were collected from dairy cows at the same milking stage. The single-strand conformation polymorphism (PCR-SSCP) method was used to analyze for polymorphism at the 5'flanking region of the hsp70 gene. The mRNA expression levels of HSP70, HSF1, Bcl-2 and Bax-$\alpha$ at different daily-mean-temperature were analyzed by relative quantitative RTPCR. The DNA content, cell phase and the ratio of apoptosis of lymphocytes in peripheral blood of dairy cattle at different daily-meantemperature were determined by FCM. The PCR-SSCP products of primer pair 1 showed polymorphisms and could be divided into four genotypes: aa, ab, ac, cc, with the cis-acting element (CCAAT box) included. Mutations in the hsp70 5'flanking region (468-752 bp) had different effects on mRNA expression of HSP70, HSF1, Bcl-2 and Bax-$\alpha$. The ac genotypic cows showed higher expressions of HSP70mRNA, HSF1mRNA and Bcl-2mRNA/Bax-$\alpha$mRNA and lower ratio of apoptosis. These mutation sites can be used as molecular genetic markers to assist selection for anti-heat stress cows.

A Novel Sequence-Based Method of Predicting Protein DNA-Binding Residues, Using a Machine Learning Approach

Cai, Yudong,He, ZhiSong,Shi, Xiaohe,Kong, Xiangying,Gu, Lei,Xie, Lu Korean Society for Molecular and Cellular Biology 2010 Molecules and cells Vol.30 No.2

Protein-DNA interactions play an essential role in transcriptional regulation, DNA repair, and many vital biological processes. The mechanism of protein-DNA binding, however, remains unclear. For the study of many diseases, researchers must improve their understanding of the amino acid motifs that recognize DNA. Because identifying these motifs experimentally is expensive and time-consuming, it is necessary to devise an approach for computational prediction. Some in silico methods have been developed, but there are still considerable limitations. In this study, we used a machine learning approach to develop a new sequence-based method of predicting protein-DNA binding residues. To make these predictions, we used the properties of the micro-environment of each amino acid from the AA Index as well as conservation scores. Testing by the cross-validation method, we obtained an overall accuracy of 94.89%. Our method shows that the amino acid micro-environment is important for DNA binding, and that it is possible to identify the protein-DNA binding sites with it.

Simultaneous removal of sulphide and nickel by the compound of Chitosan Schiff Base from crude oil under microwave irradiation

Lei Wang,Quanming Peng,Shuzhen Li,Liucheng Du,Haijun Cai 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.2

A study has been carried out for simultaneous desulfurization and demetalization by electric desalting from crude oil based on the oxidation of alkyl thiophene and nickel compounds with the compound of Chitosan Schiff Base under the condition of microwave irradiation (SDDM). Besides, an investigation has been made about the influence of Chitosan Schiff Base compound dose, initial temperature, and microwave time on desulfurization and demetalization. By using the optimized conditions for SDDM, up to 56% of sulfur and 82% of nickel removal rates were achieved for model compounds in crude oil samples. With the same conditions but without microwave the removal efficiency was lower than 56%for sulfur model compound and than 82% for nickel porphyrin in crude oil samples. Additionally, in order to develop a fundamental understanding of the SDDM mechanism of sulfides, a molecular simulation of sulfur compounds was performed with both the Hartree–Fock (HF) and second-order Moller–Plesset (MP2) levels of theory for the calculation of reaction kinetic rate by using Gaussian 03 program package. In comparison with conventional desulfurization and demetalization technology, the proposed SDDM process can accomplish the simultaneous removal of sulfur and nickel compounds from crude oil under relatively mild conditions.

Up-regulation of NHE8 by somatostatin ameliorates the diarrhea symptom in infectious colitis mice model

Lei, Xuelian,Cai, Lin,Li, Xiao,Xu, Hua,Geng, Chong,Wang, Chunhui The Korean Society of Pharmacology 2018 The Korean Journal of Physiology & Pharmacology Vol.22 No.3

$Na^+/H^+$ exchangers (NHEs) have been shown to be involved in regulating cell volume and maintaining fluid and electrolyte homeostasis. Pooled evidences have suggested that loss of $Na^+/H^+$ exchanger isoform 8 (NHE8) impairs intestinal mucosa. Whether NHE8 participates in the pathology of infectious colitis is still unknown. Our previous study demonstrated that somatostatin (SST) could stimulate the expression of intestinal NHE8 so as to facilitate $Na^+$ absorption under normal condition. This study further explored whether NHE8 participates in the pathological processes of infectious colitis and the effects of SST on intestinal NHE8 expression in the setting of infectious colitis. Our data showed that NHE8 expression was reduced in Citrobacter rodentium (CR) infected mice. Up-regulation of NHE8 improved diarrhea symptom and mucosal damage induced by CR. In vitro, a similar observation was also seen in Enteropathogenic E. coli (EPEC) infected Caco-2 cells. Seglitide, a SST receptor (SSTR) 2 agonist, partly reversed the inhibiting action of EPEC on NHE8 expression, but SSTR5 agonist (L-817,818) had no effect on the expression of NHE8. Moreover, SST blocked the phosphorylation of p38 in EPEC-infected Caco-2 cells. Taken together, these results suggest that enhancement of intestinal NHE8 expression by SST could ameliorate the symptoms of mice with infectious colitis.

Weighted H∞ Control of Singularly Perturbed Switched Systems with Mode-dependent Average Dwell Time

Lei Ma,Jing Xu,Chenxiao Cai 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.10

In this paper, disturbance attenuation problem of singularly perturbed switched systems is investigated by using a mode-dependent average dwell time (MDADT) approach. By constructing a full-order piecewise Lyapunov function, which depends on the singular perturbation parameter, sufficient conditions to guarantee the exponential stability and weighed H∞ performance are obtained with different singular perturbation parameters and stability bounds of subsystems. Then, theoretical results on the analysis of stability and weighted H∞ performance are derived for a special case that all subsystems have a unified singular perturbation parameter. Thirdly, state feedback controller design methods are proposed. Finally, two examples are given to demonstrate the validity and effectiveness of the proposed methods.