Surface Modification of Colloidal Silica Nanoparticles: Controlling the size and Grafting Process

Wentao He,Danhua Wu,Juan Li,Kai Zhang,Yushu Xiang,Lijuan Long,Shuhao Qin,Jie Yu,Qin Zhang 대한화학회 2013 Bulletin of the Korean Chemical Society Vol.34 No.9

Surface modification of colloidal silica nanoparticles without disrupting the electric double layer of nanoparticles is a major challenge. In the work, silane was employed to modify colloidal silica nanoparticles without inducing bridge flocculation obviously. The effect of pH value of the silica sol, the amount of silane in feed, and reaction temperature on the graft amount and the final size of modified particles was investigated. The increased weight loss by TG and the appearance of T2 and T3 except for Q2 and Q3 signals by CP/MAS 29Si NMR of the modified samples verified the successful grafting of silane. The graft amount reached 0.57 mmol/ g, which was slightly lower than theory value, and the particle size remained nearly the same as unmodified particles for acidic silica sol at the optimum condition. For alkaline silica sol after modification, aggregates composed of several nanoparticles connected together with silane moleculars as the bridge appeared.

Influence of Reaction Conditions on the Grafting Pattern of 3-Glycidoxypropyl trimethoxysilane on Montmorillonite

He, Wentao,Yao, Yong,He, Min,Kai, Zhang,Long, Lijuan,Zhang, Minmin,Qin, Shuhao,Yu, Jie Korean Chemical Society 2013 Bulletin of the Korean Chemical Society Vol.34 No.1

Surface modification of montmorillonite (MMT) with 3-glycidoxypropyl trimethoxysilane (3GTO) in mild methanol/water mixture has been investigated in detail. The influence of reaction conditions (including silane concentration in feed, reaction time and reaction temperature) on the grafting amount and yield of silane, and further on the grafting pattern of silanes was studied by thermogravimetric analysis, elemental analysis, X-ray diffraction (XRD) and BET. Higher silane concentration, longer reaction time and higher reaction temperature are all benefit to higher grafting amount. When the grafting reaction was performed with 3 mmol/g silane concentration, at $90^{\circ}C$ for 24 h, the grafted amount and yield of silane reached 1.4443 mmol/g and 30%, respectively. Based on the XRD and BET data analysis, a speculation that the grafting pattern of silanes was concentration dependence was proposed.

Surface Modification of Colloidal Silica Nanoparticles: Controlling the size and Grafting Process

He, Wentao,Wu, Danhua,Li, Juan,Zhang, Kai,Xiang, Yushu,Long, Lijuan,Qin, Shuhao,Yu, Jie,Zhang, Qin Korean Chemical Society 2013 Bulletin of the Korean Chemical Society Vol.34 No.9

Surface modification of colloidal silica nanoparticles without disrupting the electric double layer of nanoparticles is a major challenge. In the work, silane was employed to modify colloidal silica nanoparticles without inducing bridge flocculation obviously. The effect of pH value of the silica sol, the amount of silane in feed, and reaction temperature on the graft amount and the final size of modified particles was investigated. The increased weight loss by TG and the appearance of $T_2$ and $T_3$ except for $Q_2$ and $Q_3$ signals by CP/MAS $^{29}Si$ NMR of the modified samples verified the successful grafting of silane. The graft amount reached 0.57 mmol/g, which was slightly lower than theory value, and the particle size remained nearly the same as unmodified particles for acidic silica sol at the optimum condition. For alkaline silica sol after modification, aggregates composed of several nanoparticles connected together with silane moleculars as the bridge appeared.

Influence of Reaction Conditions on the Grafting Pattern of 3-Glycidoxypropyl trimethoxysilane on Montmorillonite

Wentao He,Yong Yao,Min He,Zhang Kai,Lijuan Long,Minmin Zhang,Shuhao Qin,Jie Yu 대한화학회 2013 Bulletin of the Korean Chemical Society Vol.34 No.1

Surface modification of montmorillonite (MMT) with 3-glycidoxypropyl trimethoxysilane (3GTO) in mild methanol/water mixture has been investigated in detail. The influence of reaction conditions (including silane concentration in feed, reaction time and reaction temperature) on the grafting amount and yield of silane, and further on the grafting pattern of silanes was studied by thermogravimetric analysis, elemental analysis, X-ray diffraction (XRD) and BET. Higher silane concentration, longer reaction time and higher reaction temperature are all benefit to higher grafting amount. When the grafting reaction was performed with 3 mmol/g silane concentration, at 90 oC for 24 h, the grafted amount and yield of silane reached 1.4443 mmol/g and 30%, respectively. Based on the XRD and BET data analysis, a speculation that the grafting pattern of silanes was concentration dependence was proposed.

A novel experimental research on vibration characteristics of the running high-speed motorized spindles

Wentao Shan,Xiaoan Chen,Ye He,Jinming Zhou 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.8

Because of the complicated running condition and many unpredicted factors such as unmodelled dynamics and external disturbances,the fault analysis of the high-speed motorized spindle is proved difficult. In this paper, a novel experimental method is proposed to research the vibration characteristics of the running high-speed motorized spindle. The method consists of four steps. Firstly, the vibration signal measurement and processing system are built according to data collector and signal analysis software, and then, the vibration signal of the spindle extracted from sophisticated experimental environment is studied by using harmonic wavelet transform for its advantages,such as ultra-narrow band, high resolution detection and ability of extracting weak signal. After that, local frequency domain zooming technique of harmonic wavelet packet is employed to study the vibration spectrum of the spindle at eight different rotating speeds. Furthermore, the axis orbit of the rotor is purified successfully, which can serve as verification basis for subsequent on-site fault diagnosis. Finally, a comparative analysis of eight different vibration signals under the same load but different speeds condition is carried out, the spectral components are classified into two types: the repeated ones and the regular ones. The accordance between experimental results and theoretical analysis suggests that the proposed method in this paper is effective.

Isolation and characterization of tick-borne Roseomonas haemaphysalidis sp. nov. and rodent-borne Roseomonas marmotae sp. nov.

Zhu Wentao,Zhou Juan,Lu Shan,Yang Jing,Lai Xin-He,Jin Dong,Pu Ji,Huang Yuyuan,Liu Liyun,Li Zhenjun,Xu Jianguo 한국미생물학회 2022 The journal of microbiology Vol.60 No.2

Four novel Gram-negative, mesophilic, aerobic, motile, and cocci-shaped strains were isolated from tick samples (strains 546T and 573) and respiratory tracts of marmots (strains 1318T and 1311). The 16S rRNA gene sequencing revealed that strains 546T and 573 were 97.8% identical to Roseomonas wenyumeiae Z23T, whereas strains 1311 and 1318T were 98.3% identical to Roseomonas ludipueritiae DSM 14915T. In addition, a 98.0% identity was observed between strains 546T and 1318T. Phylogenetic and phylogenomic analyses revealed that strains 546T and 573 clustered with R. wenyumeiae Z23T, whereas strains 1311 and 1318T grouped with R. ludipueritiae DSM 14915T. The average nucleotide identity between our isolates and members of the genus Roseomonas was below 95%. The genomic G+C content of strains 546T and 1318T was 70.9% and 69.3%, respectively. Diphosphatidylglycerol (DPG) and phosphatidylethanolamine (PE) were the major polar lipids, with Q-10 as the predominant respiratory quinone. According to all genotypic, phenotypic, phylogenetic, and phylogenomic analyses, the four strains represent two novel species of the genus Roseomonas, for which the names Roseomonas haemaphysalidis sp. nov. and Roseomonas marmotae sp. nov. are proposed, with 546T (= GDMCC 1.1780T = JCM 34187T) and 1318T (= GDMCC 1.1781T = JCM 34188T) as type strains, respectively.

Prediction and Identification of an Acid-inducible Promoter from Lactococcus lactis ssp. cremoris MG1363

Hongxian Yu,Wentao Xu,Yunbo Luo,Jing He,Hongtao Tian,Hui Shi,Xiaohong Mei 한국식품과학회 2015 Food Science and Biotechnology Vol.24 No.5

Using a promoter online prediction system, the gene sequence of GroEL protein from Lactococcus lactis ssp. cremoris MG1363 was analysed and a putative promoter, designated as gro, was further studied. Under acidic conditions, gro showed preliminary promoter function by driving the expression of lacZ reporter gene in Escherichia coli DH5α. In addition, gro drove the gene expression of GroEL and green fluorescent protein. In this paper, an acid-inducible promoter was successfully identified. This promoter has a wide prospect in the field of biotechnology.

Production and Optimization of a Kiwi Pectin Methylesterase Inhibitor in Pichia pastoris GS115

Qian Liu,Wentao Xu,Shiwen Han,Dongyan Cao,Xiaoyun He,Kunlun Huang,Xiaohong Mei 한국식품과학회 2014 Food Science and Biotechnology Vol.23 No.6

Gene sequence coding of a kiwi pectin methylesteraseinhibitor was optimized, synthesized, and expressedin Pichia pastoris GS115 based on P. pastoris preferredcodon usage. The expression level of the recombinantprotein (kwPMEI) increased by 89.74% after codonoptimization. Expression conditions of recombinant strainswere optimized. The highest production of kwPMEI wasachieved using 0.8% sorbitol (added every 24 h), 0.05%oleic acid (added at the beginning of induction), and 0.5%methanol (added every 12 h). kwPMEI was purified usingNi2+ chelating affinity chromatography and 17 mg of theprotein was harvested from 60 mL of a culture supernatant. Activity analysis showed that kwPMEI efficiently inhibitedthe activity of different plant PMEs. High expression levelsand purification of kwPMEI will promote applications infruit and vegetable juices.

Broad Activity against Porcine Bacterial Pathogens Displayed by Two Insect Antimicrobial Peptides Moricin and Cecropin B

Han Hu,Qigai He,Chunmei Wang,Xiaozhen Guo,Wentao Li,Yang Wang 한국분자세포생물학회 2013 Molecules and cells Vol.35 No.2

In response to infection, insects produce a variety of antimicrobial peptides (AMPs) to kill the invading patho-gens. To study their physicochemical properties and bioactivities for clinical and commercial use in the porcine industry, we chemically synthesized the mature peptides Bombyx mori moricin and Hyalophora cecropia cecropin B. In this paper, we described the antimicrobial activity of the two AMPs. Moricin exhibited antimicrobial activity on eight strains tested with minimal inhibitory concentration values (MICs) ranging between 8 and 128 g/ml, while cecropin B mainly showed antimicrobial activity against the Gram-negative strains with MICs ranging from 0.5 to 16 g/ml. Compared to the potent antimicrobial activity these two AMPs displayed against most of the bacterial pathogens tested, they exhibited limited hemolytic activity against porcine red blood cells. The activities of moricin and cecropin B against Haemophilus parasuis SH 0165 were studied in further detail. Transmission electron microscopy (TEM) of moricin and cecropin B treated H. parasuis SH 0165 indicated extensive damage to the membranes of the bacteria. Insights into the probable mechanism utilized by moricin and cecropin B to eliminate pathogens are also presented. The observations from this study are important for the future application of AMPs in the porcine industry.

Comprehensive analysis of TCR repertoire of COVID-19 patients in different infected stage

Wang Guangyu,Wang Yongsi,Jiang Shaofeng,Fan Wentao,Mo Chune,Gong Weiwei,Chen Hui,He Dan,Huang Jinqing,Ou Minglin,Hou Xianliang 한국유전학회 2022 Genes & Genomics Vol.44 No.7

Background: The current pandemic of coronavirus disease 2019 (COVID-19), transmitted person-to-person by the severe acute respiratory syndrome of coronavirus 2 (SARS-CoV-2), poses a threat to global public health. Objective: In this study, we performed the comprehensive analysis of the T cell receptor (TCR) repertoire may contribute to a more in-depth understanding of the pathogenesis of COVID-19. Methods: A comprehensive immunological analysis was performed to explore the features of the TCR repertoire and identified TCR sequences correlated with SARS-CoV-2 viral antigens. Results: we analyzed the COVID-19 patients' TCR repertoires in peripheral blood mononuclear cells (PBMC) which obtained before (baseline), during (acute), and after rehabilitation (convalescent) by ImmunoSEQ-technology, and found that repertoire features of TCRβ-chain (TCRβ) complementary-determining region 3 (CDR3) in COVID-19 patients were remarkable difference, including decreased TCR diversity, abnormal CDR3 length, difference of TRBV/J gene usage and higher TCR sequence overlap. Besides, we identified some COVID-19 disease-associated TCRβ clones, and the abundance of them changed with the progression of the disease. Importantly, these disease-associated TCRβ clones could be used to distinguish COVID-19 patients from healthy controls with high accuracy. Conclusions: We provide a clear understanding of the TCR repertoire of COVID-19 patients, which lays the foundation for better diagnosis and treatment of COVID-19 patients.