Mechanical Study on the Effect of Granular Friction in a Granular System under Biaxial Compression

Fan-Jing Meng,Kun Liu 한국물리학회 2018 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.72 No.10

The in uence of granular friction on the mechanical behaviors of a granular system is a typical research realm that is still not yet fully understood because of the complexities and the discreteness of the granular system. In this study, a two-dimensional model of a granular system with biaxial compression is established by using the discrete element method (DEM). Using this DEM model, we investigate the macroscopic mechanical behaviors, the microscopic mechanical responses and the force chain distributions of a granular system in uenced by granular friction. Simulation results show that the granular friction has a prominent in uence on the stress-strain response, dilatancy behaviors, and peak strength of the granular system. The microscopic mechanical behaviors of the coordination number, the sliding fraction, and the mean mobilized friction coecient of the granular system are also shown to be markedly in uenced by the granular friction. The force chains in the granular system form an inhomogeneous distribution, and their intensities increase with increasing granular friction.

Fire performance of edge and interior circular steel-reinforced concrete-filled steel tubular stub columns

Fan-Qin Meng,Mei-Chun Zhu,G. Charles Clifton,Kingsley U. Ukanwa,James B.P. Lim 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.41 No.1

The steel-reinforced concrete-filled steel tubular column (SRCFT) is a new form of composite columns. Before widely accepted in engineering practice, its fire behaviour shall be fully understood. Four representative circular SRCFT stub columns were built and tested to failure under ISO fire herein. The tests explored the effect of reinforced steel, the internal or external heating condition and load ratios. The experimental results indicated that the inserted section steel significantly improved the fire resistance of circular SRCFT columns. The non-uniform fire condition did not produce a detrimental effect on the fire response of the specimen. The numerical model was developed and validated against the experimental results. Then a parametric study was present to evaluate the effect of load level, eccentricity and heating conditions. A comparison was made to check the accuracy of a widely accepted design method. The comparison indicated the design method was generally 36% conservative for axially loaded condition and 25% un-conservative for eccentrically loaded condition.

Preparation of 5-fluorouracil-loaded Nanoparticles and Study of Interaction with Gastric Cancer Cells

Fan, Yu-Ling,Fan, Bing-Yu,Li, Qiang,Di, Hai-Xiao,Meng, Xiang-Yu,Ling, Na Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.18

Aims: To prepare 5-fluorouracil (5-Fu) nanoparticles with higher encapsulation efficiency and drug loading, and then investigate interaction with the SGC-7901 gastric cancer cell line. Materials and Methods: Prescription was optimized by orthogonal experiments, the encapsulation efficiency and loading capacity were tested by high-performance liquid chromatography, and inhibition of proliferation by 5-Fu nanoparticles and 5-Fu given to cells for 24, 48 and 72 hours was investigated by methyl thiazolyl tetrazolium assay (MTT). In addition, 5-Fu nanoparticles were labeled by fluorescein isothiocyanate (FITC), and absorption into cells was tested by flow cytometry. Results: The optimal conditions for preparation were concentrations of 5-Fu of 5mg/ml, of $CaCl_2$ of 60 mg/ml and of chitosan of 2 mg/ml. With a stirring speed of 1200rpm, encapsulation efficiency of 5-Fu nanoparticles was $55.4{\pm}1.10%$ and loading capacity was $4.22{\pm}0.14%$; gastric cancer cells were significantly inhibited by 5-Fu nanoparticles in a time and concentration dependent manner, and compared to 5-Fu with slower drug release, in a certain concentration range, inhibition with 5-Fu nanoparticles was stronger. 5-Fu nanoparticles were absorbed by the cells in line with the concentration. Conclusions: 5-Fu nanoparticles can inhibit growth of gastric cancer cells in vitro to a greater extent than with 5-Fu with good adsorption characteristics, supporting feasibility as a carrier.

Polarization-Independent Metamaterial Analog of Electromagnetically Induced Transparency for a Refractive-Index-Based Sensor

Fan-Yi Meng,Qun Wu,Erni, D.,Ke Wu,Jong-Chul Lee IEEE 2012 IEEE transactions on microwave theory and techniqu Vol.60 No.10

<P>A polarization-independent metamaterial analog of electromagnetically induced transparency (EIT) at microwave frequencies for normal incidence and linearly polarized waves is experimentally and numerically demonstrated. The metamaterial consists of coupled “bright” split-ring resonators (SRRs) and “dark” spiral resonators (SRs) with virtually equal resonance frequencies. Normally incident plane waves with linear polarization strongly couple to the SRR, but are weakly interacting with the SR, regardless of the polarization state. A sharp transmission peak (i.e., the transparency window) with narrow spectral width and slow wave property is observed for the metamaterial at the resonant frequency of both, the bright SRR and the dark SR. The influence of the coupling strength between the SRR and SR on the frequency, width, magnitude, and quality factor of the metamaterial's transparency window is theoretically predicted by a two-particle model, and numerically validated using full-wave electromagnetic simulation. In addition, it is numerically demonstrated that the EIT-like metamaterial can be employed as a refractive-index-based sensor with a sensitivity of 77.25 mm/RIU, which means that the resonance wavelength of the sensor shifts 77.25 mm per unit change of refractive index of the surrounding medium.</P>

Vitexicarpin Induces Apoptosis in Human Prostate Carcinoma PC-3 Cells through G2/M Phase Arrest

Meng, Fan-Min,Yang, Jing-Bo,Yang, Chun-Hui,Jiang, Yu,Zhou, Yong-Feng,Yu, Bo,Yang, Hong Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.12

Vitexicarpin (3', 5-dihydroxy-3, 4', 6, 7-tetramethoxyflavone), a polymethoxyflavone isolated from Viticis Fructus (Vitex rotundifolia Linne fil.), has long been used as an anti-inflammatory herb in traditional Chinese medicine. It has also been reported that vitexicarpin can inhibit the growth of various cancer cells. However, there is no report elucidating its effect on human prostate carcinoma cells. The aim of the present study was to examine the apoptotic induction activity of vitexicarpin on PC-3 cells and molecular mechanisms involved. MTT studies showed that vitexicarpin dose-dependently inhibited growth of PC-3 cells with an $IC_{50}{\sim}28.8{\mu}M$. Hoechst 33258 staining further revealed that vitexicarpin induced apoptotic cell death. The effect of vitexicarpin on PC-3 cells apoptosis was tested using prodium iodide (PI)/Annexin V-FITC double staining and flow cytometry. The results indicated that vitexicarpin induction of apoptotic cell death in PC-3 cells was accompanied by cell cycle arrest in the G2/M phase. Furthermore, our study demonstrated that vitexicarpin induction of PC-3 cell apoptosis was associated with upregulation of the proapoptotic protein Bax, and downregulation of antiapoptotic protein Bcl-2, release of Cytochrome c from mitochondria and decrease in mitochondrial membrane potential. Our findings suggested that vitexicarpin may become a potential leading drug in the therapy of prostate carcinoma.

Heat-Shock Protein 70 as a Tumor Antigen for in vitro Dendritic Cell Pulsing in Renal Cell Carcinoma Cases

Meng, Fan-Dong,Sui, Cheng-Guang,Tian, Xin,Li, Yan,Yang, Chun-Ming,Ma, Ping,Liu, Yun-Peng,Jiang, You-Hong Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.20

Immunological functions of heat shock proteins (HSPs) have long been recognized. In this study we aimed to efficiently purify HSP70 from renal cell carcinoma and test it as a tumor antigen for pulsing dendritic cells in vitro. HSP70 was purified from renal cell carcinoma specimens by serial column chromatography on Con A-sepharose, PD-10, ADP-agarose and DEAE-cellulose, and finally subjected to fast protein liquid chromatography (FPLC). Dendritic cells derived from the adherent fraction of peripheral blood mononuclear cells were cultured in the presence of IL-4 and GM-CSF and exposed to tumor HSP70. After 24 hours, dendritic cells were phenotypically characterized by flow cytometry. T cells obtained from the non-adherent fraction of peripheral blood mononuclear cells were then co-cultured with HSP70-pulsed dendritic cells and after 3 days T cell cytotoxicity towards primary cultured renal cell carcinoma cells was examined by Cell Counting Kit-8 assay. Dendritic cells pulsed in vitro with tumor-derived HSP70 expressed higher levels of CD83, CD80, CD86 and HLA-DR maturation markers than those pulsed with tumor cell lysate and comparable to that of dendritic cells pulsed with tumor cell lysate plus TNF-${\alpha}$. Concomitantly, cytotoxic T-lymphocytes induced by HSP70-pulsed dendritic cells presented the highest cytotoxic activity. There were no significant differences when using homologous or autologous HSP70 as the tumor antigen. HSP70 can be efficiently purified by chromatography and induces in vitro dendritic cell maturation in the absence of TNF-${\alpha}$. Conspecific HSP70 may effectively be used as a tumor antigen to pulse dendritic cells in vitro.

폴리아스팔트아미드와 폴리(비닐 피롤리돈)의 상용블렌드 및 Semi-IPN 젤 제조

Fan Meng,전영실(Young Sil Jeon),정동준(Dong June Chung),김지흥(Ji Heung Kim) 한국고분자학회 2012 폴리머 Vol.36 No.5

폴리아스팔트아미드[α,β-poly(2-hydroxyethyl-DL-aspartamides), PHEAs]는 폴리아미노산의 일종으로서 잠재적인 의학 및 약학분야에 응용가능한 생분해성 생체적합성 재료로 널리 연구되어 왔다. 본 연구에서는 PHEA와 폴리(비닐 피롤리돈)(PNVP)의 블렌드 및 semi-IPN 젤에 관하여 다루었다. 블렌드 필름은 용액 캐스팅법으로 제조되었다. 제조된 블렌드는 전 조성에서 투명하였으며 DSC를 통해 조성에 따라 단조롭게 변화하는 단일한 유리전이 온도가 관찰됨으로써 두 개 고분자가 서로 상용성이 있음을 확인하였다. 고분자간의 가능한 수소결합 상호작용을 FTIR을 이용하여 설명하였다. 한편, 일정 조성의 PHEA/PNVP 블렌드 용액을 핵사메틸렌디이소시아네이트(HMDI)를 가교제로 사용하여 semi-IPN 타입의 하이브리드 젤을 제조하고, 제조된 젤의 팽윤 물성과 모폴로지를 조사하였다. PHEAs [α,β-poly(2-hydroxyethyl-DL-aspartamides)], a class of poly(amino acid), have been widely studied as biodegradable and biocompatible polymers for potential biomedical and pharmaceutical applications. In this study, we investigated a homogeneous blend of PHEA with poly(N-vinyl pyrrolidone) (PNVP) and its semi-IPN (semi-interpenetrating polymer network) gels. Blend films were prepared by a solution casting method. The resulting blends were totally transparent over the whole composition ranges and the single Tg, changing monotonously with composition, was observed by DSC to confirm the miscibility between these two polymers. FTIR was used to discuss the possible hydrogen-bonding interaction between polymers. In addition, semi-IPN type gels were prepared by chemical crosslinking of PHEA/PNVP blend solution using hexamethylene diisocyanate (HMDI) as a crosslinking reagent. The prepared gel was characterized by their swelling property and morphology.

Comparison of Microbial Diversity and Composition in the Jejunum and Colon of Alcohol-Dependent Rats

( Yang Fan ),( Zhao Ya-e ),( Wei Ji-dong ),( Lu Yu-fan ),( Zhang Ying ),( Sun Ya-lun ),( Ma Meng-yu ),( Zhang Rui-ling ) 한국미생물생명공학회(구 한국산업미생물학회) 2018 Journal of microbiology and biotechnology Vol.28 No.11

Alcohol dependence is a global public health problem, yet the mechanisms of alcohol dependence are incompletely understood. The traditional view has been that ethanol alters various neurotransmitters and their receptors in the brain and causes the addiction. However, an increasing amount of experimental evidence suggests that gut microbiota also influence brain functions via gut-to-brain interactions, and may therefore induce the development of alcohol use disorders. In this study, a rat model of alcohol dependence and withdrawal was employed, the gut microbiota composition was analyzed by high-throughput 16S rRNA gene sequencing, and the metagenome function was predicted by PICRUSt software. The results suggested that chronic alcohol consumption did not significantly alter the diversity and richness of gut microbiota in the jejunum and colon, but rather markedly changed the microbiota composition structure in the colon. The phyla Bacteroidetes and eight genera including Bacteroidales S24-7, Ruminococcaceae, Parabacteroides, Butyricimonas, et al were drastically increased, however the genus Lactobacillus and gauvreauii in the colon were significantly decreased in the alcohol dependence group compared with the withdrawal and control groups. The microbial functional prediction analysis revealed that the proportions of amino acid metabolism, polyketide sugar unit biosynthesis and peroxisome were significantly increased in the AD group. This study demonstrated that chronic alcohol consumption has a dramatic effect on the microbiota composition structure in the colon but few effects on the jejunum. Inducement of colonic microbiota dysbiosis due to alcohol abuse seems to be a factor of alcohol dependence, which suggests that modulating colonic microbiota composition might be a potentially new target for treating alcohol addiction.

Highly Uniform Core/Shell Structured CoFe2O4/MIL-100(Fe) Nanofibers for Efficient Visible Light Photocatalysis

Jun Liu,Meng Sun,Meng-Jie Chang,Si-Meng Fan,Qian Hui,Fu-Rong Ni,Bin Yuan 한국섬유공학회 2021 Fibers and polymers Vol.22 No.2

Novel CoFe2O4/MIL-100(Fe) (CFO/MIL-100(Fe)) core/shell nanofibers were prepared by successive ionic layeradsorption and reaction (SILAR) assembly of MIL-100(Fe) on electrospun CoFe2O4 nanofibers. The MIL-100(Fe) shellswere constructed on the dispersed CoFe2O4 fiber surface with high uniformity, homogeneous thickness and high stability. Due to the inherent porosity of MIL-100(Fe), a higher specific surface area of 225.77 m2/g is achieved for the CFO/MIL-100(Fe)-10 sample. The formed CFO/MIL-100(Fe) catalysts exhibit high catalytic activity towards degradation of rhodamineB (RhB) under visible light irradiation. The photocatalytic activity remains above 77 % within 60 min illumination after fourcycles. Due to the simple synthetic method, highly uniform structure, strong magnetic recoverable, as well as goodphotocatalytic performance, the obtained CFO/MIL-100(Fe) core/shell nanofibers could be promising photocatalysts forpractical application.

Research and Implementation of a Vertical Search Engine in the Financial Domain

Yue Hou-guang,ZhangLing,Meng Fan-jun,Songhong-hao 보안공학연구지원센터 2014 International Journal of u- and e- Service, Scienc Vol.7 No.5

The exponential growth of the data on the web makes it difficult for web users to locate and obtain the interesting information. The general web search engines, such as Google, Baidu, reduce the degree of difficulty to some extent. The rise of vertical search engine provides a promising approach to address the big challenge. A Chinese vertical search engine is urgently needed to provide professional financial information retrieval service for related financial institutions and government agencies. Therefore, in this paper we investigate, design and implement a vertical search engine in the financial domain. Based onNutch plug-in mechanism, we provide and implement the details of a vertical search engine in the financial domain, especially in the finance domain focused crawler. Experimental results show that, the finance domain focused crawler based on Nutch plug-in mechanism has good performance and can satisfy practical requirements of medium search application, and the system runs well.