Tribology Property of Benzoxazine–Bismaleimide Composites with Hyperbranched Polysilane-Grafted Multi-Walled Carbon Nanotubes

YUAN JIA,HONGXIA YAN,Song Li,Tianye Liu 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.6

To reveal the wear mechanism of hyperbranched polysilane (HBPSi) grafted multi-walled carbon nanotubes (HBPSi–MWCNTs) modified benzoxazine–bismaleimide (BOZ–BMI) resin (HBPSi– MWCNTs/BOZ–BMI), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA) were employed. The results indicated that the suitable addition of HBPSi–MWCNTs could largely enhance the tribological properties of BOZ– BMI composites. The worn surface of the composites showed that the severe wear of the BOZ– BMI resin was converted from adhesive wear to abrasive wear with the addition of HBPSi– MWCNTs. The excellent tribological properties can be attributed to the improved interfacial adhesion between HBPSi–MWCNTs and the BOZ–BMI resin matrix. The TGA demonstrated that the composite with 0.8 wt.% HBPSi–MWCNTs exhibits better thermal resistance; thus, it can inhibit adhesive wear during the friction process. The XPS spectra and the surface energy showed that the HBPSi–MWCNTs could be exposed on the worn surface of the composite to improve the anti-wear capacity of the composites further.

Single-Source-Precursor Synthesis of Hafnium-Containing Ultrahigh-Temperature Ceramic Nanocomposites (UHTC-NCs)

Yuan, Jia,Hapis, Stefania,Breitzke, Hergen,Xu, Yeping,Fasel, Claudia,Kleebe, Hans-Joachim,Buntkowsky, Gerd,Riedel, Ralf,Ionescu, Emanuel American Chemical Society 2014 Inorganic chemistry Vol.53 No.19

<P>Amorphous SiHfBCN ceramics were prepared from a commercial polysilazane (HTT 1800, AZ-EM), which was modified upon reactions with Hf(NEt<SUB>2</SUB>)<SUB>4</SUB> and BH<SUB>3</SUB>·SMe<SUB>2</SUB>, and subsequently cross-linked and pyrolyzed. The prepared materials were investigated with respect to their chemical and phase composition, by means of spectroscopy techniques (Fourier transform infrared (FTIR), Raman, magic-angle spinning nuclear magnetic resonance (MAS NMR)), as well as X-ray diffraction (XRD) and transmission electron microscopy (TEM). Annealing experiments of the SiHfBCN samples in an inert gas atmosphere (Ar, N<SUB>2</SUB>) at temperatures in the range of 1300–1700 °C showed the conversion of the amorphous materials into nanostructured UHTC-NCs. Depending on the annealing atmosphere, HfC/HfB<SUB>2</SUB>/SiC (annealing in argon) and HfN/Si<SUB>3</SUB>N<SUB>4</SUB>/SiBCN (annealing in nitrogen) nanocomposites were obtained. The results emphasize that the conversion of the single-phase SiHfBCN into UHTC-NCs is thermodynamically controlled, thus allowing for a knowledge-based preparative path toward nanostructured ultrahigh-temperature stable materials with adjusted compositions.</P><P>Amorphous SiHfBCN ceramics were prepared from a suitable single-source precursor. Annealing experiments of the SiHfBCN samples in an inert gas atmosphere at temperatures of 1300−1700 °C led to their conversion nanostructured UHTC-NCs, such as HfC/HfB<SUB>2</SUB>/SiC nanocomposites (in argon) and HfN/Si<SUB>3</SUB>N<SUB>4</SUB>/SiBCN nanocomposites (in nitrogen), thus revealing a convenient preparative approach to nanostructured ultrahigh-temperature stable materials starting from a greatly flexible single-source precursor.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/inocaj/2014/inocaj.2014.53.issue-19/ic501512p/production/images/medium/ic-2014-01512p_0016.gif'></P>

Enhanced Transfection of Polyplexes Based on Pluronic-Polypropylenimine Dendrimer for Gene Transfer

Junguo Hao,Yuanjia Tang,Xianyi Sha,Ye Jiang,Zhiwen Zhang,Wei Zhang,Yajuan Li,Xiaoling Fang 대한약학회 2009 Archives of Pharmacal Research Vol.32 No.7

Third generation cationic dendritic polymeric polypropyleneimine (PPI) was modified by Pluronic P123 and investigated for gene delivery. The cytotoxicity of P123-PPI was evaluated by the MTT assay and shown to be much lower than that of PPI alone. P123-PPI and PPI can both condense plasmid DNA into nanoparticles with a size of approximately 100 nm and a zeta potential of about 15 mV at the N/P ratio 20:1. The nanoparticles can protect plasmid DNA from being digested by DNase I at a concentration of 0.4 U/μg DNA. The nanoparticles were resistant to dissociation induced by 50% fetal bovine serum and 75 μg/mL sodium heparin. The transfection efficiency of SPC-A1 cells using P123-PPI/DNA nanoparticles was much higher than the transfection utilizing PPI/DNA nanoparticles. The addition of free P123 during the preparation of P123-PPI/DNA nanoparticles could significantly enhance the transfection efficiency in the presence of 10% fetal bovine serum. Therefore, P123-PPI/DNA complex nanoparticles may be a safe, efficient and promising cationic conjugate for gene delivery.

Genotyping of Giardia duodenalis Isolates from Dogs in Guangdong, China Based on Multi-Locus Sequence

Guochao Zheng,Muhamd Alsarakibi,Yuanjia Liu,Wei Hu,Qin Luo,Liping Tan,Guoqing Li 대한기생충학열대의학회 2014 The Korean Journal of Parasitology Vol.52 No.3

Occurrence and Molecular Identification of Giardia duodenalis from Stray Cats in Guangzhou, Southern China

Guochao Zheng,Wei Hu,Yuanjia Liu,Qin Luo,Liping Tan,Guoqing Li 대한기생충학열대의학회 2015 The Korean Journal of Parasitology Vol.53 No.1

The objective of this study was to genetically characterize isolates of Giardia duodenalis and to determine if zoonotic potential of G. duodenalis could be found in stray cats from urban and suburban environments in Guangzhou, China. Among 102 fresh fecal samples of stray cats, 30 samples were collected in Baiyun district (urban) and 72 in Conghua district (suburban). G. duodenalis specimens were examined using light microscopy, then the positive specimens were subjected to PCR amplification and subsequent sequencing at 4 loci such as glutamate dehydrogenase (gdh), triose phosphate isomerase (tpi), β-giardin (bg), and small subunit ribosomal RNA (18S rRNA) genes. The phylogenetic trees were constructed using obtained sequences by MEGA5.2 software. Results show that 9.8% (10/102) feline fecal samples were found to be positive by microscopy, 10% (3/30) in Baiyun district and 9.7% (7/72) in Conghua district. Among the 10 positive samples, 9 were single infection (8 isolates, assemblage A; 1 isolate, assemblage F) and 1 sample was mixed infection with assemblages A and C. Based on tpi, gdh, and bg genes, all sequences of assemblage A showed complete homology with AI except for 1 isolate (CHC83). These findings not only confirmed the occurrence of G. duodenalis in stray cats, but also showed that zoonotic assemblage A was found for the first time in stray cats living in urban and suburban environments in China.

Qualitative and quantitative analysis of the saponins in Panax notoginseng leaves using ultra-performance liquid chromatography coupled with time-of-flight tandem mass spectrometry and high performance liquid chromatography coupled with UV detector

Liu, Fang,Ma, Ni,He, Chengwei,Hu, Yuanjia,Li, Peng,Chen, Meiwan,Su, Huanxing,Wan, Jian-Bo The Korean Society of Ginseng 2018 Journal of Ginseng Research Vol.42 No.2

Background: Panax notoginseng leaves (PNL) exhibit extensive activities, but few analytical methods have been established to exclusively determine the dammarane triterpene saponins in PNL. Methods: Ultra-performance liquid chromatography coupled with time-of-flight mass spectrometry (UPLC/Q-TOF MS) and HPLC-UV methods were developed for the qualitative and quantitative analysis of ginsenosides in PNL, respectively. Results: Extraction conditions, including solvents and extraction methods, were optimized, which showed that ginsenosides Rc and Rb3, the main components of PNL, are transformed to notoginsenosides Fe and Fd, respectively, in the presence of water, by removing a glucose residue from position C-3 via possible enzymatic hydrolysis. A total of 57 saponins were identified in the methanolic extract of PNL by UPLC/Q-TOF MS. Among them, 19 components were unambiguously characterized by their reference substances. Additionally, seven saponins of PNL-ginsenosides Rb1, Rc, Rb2, and Rb3, and notoginsenosides Fc, Fe, and Fd-were quantified using the HPLC-UV method after extraction with methanol. The separation of analytes, particularly the separation of notoginsenoside Fc and ginsenoside Rc, was achieved on a Zorbax ODS C8 column at a temperature of $35^{\circ}C$. This developed HPLC-UV method provides an adequate linearity ($r^2$ > 0.999), repeatability (relative standard deviation, RSD < 2.98%), and inter- and intraday variations (RSD < 4.40%) with recovery (98.7-106.1%) of seven saponins concerned. This validated method was also conducted to determine seven components in 10 batches of PNL. Conclusion: These findings are beneficial to the quality control of PNL and its relevant products.

MiR-125a-5p ameliorates monocrotalineinduced pulmonary arterial hypertension by targeting the TGF-β1 and IL-6/STAT3 signaling pathways

Zongye Cai,Jian Li,Qi Zhuang,Xueming Zhang,Ancai Yuan,Lan Shen,Kang Kang,Bo Qu,Yuanjia Tang,Jun Pu,Deming Gou,Jieyan Shen 생화학분자생물학회 2018 Experimental and molecular medicine Vol.50 No.-

Pulmonary vascular remodeling due to excessive proliferation and resistance to apoptosis of pulmonary artery smooth muscle cells (PASMCs) is the hallmark feature of pulmonary arterial hypertension (PAH). Recent evidence suggests that miR-125a-5p plays a role in a rat model of monocrotaline-induced PAH (MCT-PAH); however, the underlying mechanism is currently unknown. Here, we examined the expression profile of miR-125a-5p in MCT-PAH rats and investigated the putative therapeutic effect of miR-125a-5p using the miR-125a-5p agomir. In addition, the miR-125a- 5p agomir or antagomir was transfected into rat PASMCs, and proliferation and apoptosis were measured. Activity of the miR-125a-5p target STAT3 was measured using a luciferase reporter assay, and the expression of downstream molecules was measured using RT–qPCR and/or western blot analysis. Importantly, inducing miR-125a-5p expression in vivo slowed the progression of MCT-PAH by reducing systolic pulmonary arterial pressure, the Fulton index, and pulmonary vascular remodeling. Moreover, overexpressing miR-125a-5p inhibited the proliferation and promoted the apoptosis of PASMCs. In addition, stimulating PASMCs with TGF-β1 or IL-6 upregulated miR-125a-5p expression, whereas overexpressing miR-125a-5p reduced TGF-β1 and IL-6 production, as well as the expression of their downstream targets STAT3 and Smad2/3; in contrast, downregulating miR-125a-5p increased TGF-β1 and IL-6 production. Finally, a dual-luciferase reporter assay revealed that miR-125a-5p targets the 3′-UTR of STAT3, suppressing the downstream molecules PCNA, Bcl-2, and Survivin. Taken together, these findings suggest that miR-125a-5p ameliorates MCT-PAH in rats, has a negative feedback regulation with TGF-β1 and IL-6, and regulates the proliferation and apoptosis of PASMCs by directly targeting STAT3.