Study and Design of High Strength and Low Heat Generation Polymer Composites by Molecular Dynamics Simulation

Rui-Rui Zhang,Bin Wu,Peng Chen,Jia-Sheng Qian 한국고분자학회 2020 폴리머 Vol.44 No.6

The molecular dynamics simulation was used to study and design a polymer composites system with excellent mechanical strength and less heat generation in a dynamic process. A series of system factors such as filler loading, surface modification onto filler, and network of cross-linking filler particles on mechanical and heat generation of polymer composites are systematically considered. It is found that the surface grafting onto fillers can restrain the heat generation of polymer composite in the dynamic process, while it shows less effect on the mechanical property. A network of cross-linking filler particles can be fabricated by a combination of grafting chains onto fillers. By filling such a network into the polymer, the mechanical and heat generation properties of polymer composites are significantly improved. Simulation results can help experimental fabrication of polymer composites with excellent mechanical and heat generation properties.

Tri-stimuli responsive carbon nanotubes covered by mesoporous silica graft copolymer multifunctional materials for intracellular drug delivery

Rui-Qian Zhang,Zhan-Qing Liu,Yan-Ling Luo,Feng Xu,Ya-Shao Chen 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.80 No.-

To overcome premature drug leakage and instability in drug delivery systems, we designed tri-stimuliresponsive multiwalled carbon nanotubes covered by mesoporous silica graft poly(N-isopropylacryla-mide-block-poly(2-(4-formylbenzoyloxy) ethyl methacrylate) multifunctional materials via disulfidelinkages (MWCNTs@MSN-s-s-g-PNIPAM-b-PFBEMA). The multifunctional materials could covalentlybind and physically load anticancer drug doxorubicin (DOX), and exhibited pH-, temperature- andreductant-induced multi-stimuli responsiveness, significantly enhancing drug loading capacity andimproving the release dynamics of drug. The DOX-loaded multifunctional materials exhibited theoptimal release behavior in cancer environments compared with in normal cells upon simultaneouslytriggered by these stimuli. It meant that the MWCNTs@MSN-s-s-g-PNIPAM-b-PFBEMA could serve asefficient gatekeepers to control the mesopore on–off and thus to modulate drug release. Themultifunctional materials were proved to be low toxic, whereas the DOX-loaded counterparts had almostthe same toxicity as free DOX to cancer cells. Therefore, the developed multifunctional materials can beused as promising drug controlled delivery platforms for cancer therapy.

Historical Long-term Exposure to Pentachlorophenol Causing Risk of Cancer - A Community Study

Zheng, Rui-Zhi,Zhang, Qing-He,He, Yi-Xin,Zhang, Qian,Yang, Lin-Shen,Zhang, Zhi-Hua,Zhang, Xiu-Jun,Hu, Jing-Ting,Huang, Fen Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.2

Background: Pervious studies suggested occupational workers exposure to pentachlorophenol (PCP) might contribute to increased risk of cancer. However, few studies have focused on associations between PCP and cancer risk at the community level. Objective: The present study was to explore the cancer risk for the community population living long-term in a PCP contaminated area. Methods: All the cancer cases diagnosed in 2009-2011 in Tongling City were collected. The cancer patients' residencies were geo-referenced in each district. The historical PCP usage for each district of Tongling was calculated as the PCP pollution index, which was further used to divide into PCP exposure categories. Standardized rate ratios (SRRs) of cancer incidence were applied to detect the cancer risk as exposure grade elevated. Correlation analysis was performed to analyze the relationship between PCP pollution and cancer incidence. Results: A total of 5,288 cancer cases (3,451 male and 1,837 female) were identified. PCP usage was correlated with the incidence of leukemia (r=0.88, P=0.002) for males, and with cancer of the esophagus for males (r=0.83, P=0.008) and females (r=0.71, P=0.020). Compared with the low exposure category, significant SRRs for total cancer sites was obtained for high PCP exposure category (SRR=1.61, 95%CI=1.59-1.62). Most SRR values of the cancer sites were significantly increased as exposure grade elevated and exposure time extended. Conclusion: The present study found that community residents living in the PCP contaminated area had increased risk of cancers. Leukemias, lymphomas and nasopharyngeal and esophageal cancers are most possibly associated with PCP exposure.

Genome-wide identification of microRNAs and phased siRNAs in soybean roots under long-term salt stress

Qian Wang,Yingxia Yang,Guoqing Lu,Xianjun Sun,Youren Feng,Shuangyong Yan,Huiyuan Zhang,Qiyan Jiang,Hui Zhang,Zheng Hu,Rui Chen 한국유전학회 2020 Genes & Genomics Vol.42 No.11

Background Salinity stress, as the key limiting factor for agricultural productivity, can activate a series of molecular responses and alter gene expression in plants. Endogenous regulatory small RNAs, such as microRNAs (miRNAs) and phased siRNAs (phasiRNAs), play crucial roles during stress adaptation and prevent the injury from environmental circumstances. Objective To identify long-term salt stress responsive miRNAs and phasiRNAs as well as their associated genes and pathways in soybean roots. Methods Small RNA and degradome sequencing strategies were applied to genome widely investigate miRNAs and phasiRNAs in soybean roots under control and long-term salt stress conditions. Results In this study, stringent bioinformatic analysis led to the identifcation of 253 conserved and 38 novel miRNA candidates. Results of expression profling, target and endogenous target mimics predictions provided valuable clues to their functional roles. Furthermore, 156 genes were identifed to be capable of generating 21 nt and 24 nt phasiRNAs, in which 37 candidates were confrmed by degradome data for miRNA-directed cleavage. Approximately 90% of these phasiRNA loci were protein coding genes. And GO enrichment analysis pointed to “signal transduction” and “ADP binding” entries and refected the functional roles of identifed phasiRNA genes. Conclusion Taken together, our fndings extended the knowledge of salt responsive miRNAs and phasiRNAs in soybean roots, and provided valuable information for a better understanding of the regulatory events caused by small RNAs underlying plant adaptations to long-term salt stress.

Prospective comparison of hybrid capture 2 and SPF10-LiPA for carcinogenic human papillomavirus detection and risk prediction of cervical cancer: a population-based cohort study in China

Li Dong,Rui-Mei Feng,Li Zhang,Xiao-qian Xu,Xue-Lian Zhao,Margaret Zhuoer Wang,You-Lin Qiao,Fang-Hui Zhao 대한부인종양학회 2017 Journal of Gynecologic Oncology Vol.28 No.5

Objective: To investigate the extent of the cross-reactivity of hybrid capture 2 (HC2) assay andevaluate the potential effect of cross-reactivity on the long-term risk for cervical cancer andprecancers. Methods: Based on the Shanxi Province Cervical Cancer Screening Study-I (SPOCCS-I)cohort from 2005 to 2014 in Shanxi, China, SPF10-line probe assay (LiPA) was performedin all 598 HC2 positive and 300 random-selected HC2 negative cervical specimens. Tenyearcumulative incidence rate (CIR) of cervical intraepithelial neoplasia grade 2 or worse(CIN2+) of these two tests was evaluated using Kaplan-Meier methods. Possible humanpapillomavirus (HPV) types to be cross-reacted by HC2 were also analyzed. Results: The overall agreement between HC2 and SPF10-LiPA for detecting carcinogenic HPVwas 73.27%. The highest 10-year cumulative risk of CIN2+ was observed in both HC2 positiveand LiPA-carcinogenic HPV positive women (25.70%; 95% confidence interval [CI]=23.55%–27.91%), followed by HC2 positive but LiPA-non-carcinogenic HPV positive women (9.97%;95% CI=8.57%–11.50%), HC2 negative but LiPA-carcinogenic HPV positive (2.56%; 95%CI=2.44%–2.70%) and HC2 positive but LiPA-HPV negative (1.85%; 95% CI=1.78%–1.92%)women. The proportion of cross-reactivity of HC2 with untargeted carcinogenic types was8.9%, most of which were attributable to HPV26, 73, 82, 69, 71, 53, 11, 43, and 54. Conclusion: The noticeable high risk of CIN2+ in women infected with cross-reacted noncarcinogenicHPV and low risk in those with miss-to-detective carcinogenic HPV supportedan overall good clinical performance of HC2 for a general cervical cancer screening.

Performance of the R-way Colposcopic Evaluation System in Cervical Cancer Screening

Zhao, Jian,Zhang, Xi,Chen, Rui,Zhao, Yu-Qian,Wang, Ting-Ting,He, Shan,Qiao, You-Lin Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.10

Objective: To investigate the diagnostic value of the R-way colposcopic evaluation system (R-way system) in cervical cancer screening. Materials and Methods: Between August 2013 and August 2014, a total of 1,059 cases referred to colposcopy in Peking University First Hospital were studied using both the R-way system and conventional colposcopy. Our study evaluated and compared the diagnostic ability of the two methods in detecting high-grade lesions and cervical cancer (hereinafter called CIN2+). Evaluation indicators including sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), Youden index and the area under the curve (AUC) of the receiver operating characteristic (ROC) were calculated. Results: The R-way system had a slightly lower specificity (94.5%) than conventional colposcopy (96.0%) for CIN2+ detection (P=0.181). However, the sensitivity (77.8%) was significantly higher than with the conventional colposcopic method (46.6%) (${\chi}^2=64.351$, P<0.001). In addition, the AUC of the ROC for CIN2+ detection using the R-way system (0.839) was larger than that with conventional colposcopy (0.731) (Z=4.348, P<0.001). If preliminary result had been drawn from cervical exfoliated cytology before colposcopy referral, combination of the R-way system with cytology could increase the sensitivity to 93.9% for CIN2+ detection (excluding ASCUS\LSIL), confirmed by multipoint biopsy or ECC. Conclusions: The diagnostic value of the R-way evaluation system is higher than that of conventional colposcopic evaluation in cervical cancer screening. Moreover, taking the ease of use and standardized quality control management into account, the R-way system is highly preferable.

Aerostatic instability mode analysis of three-tower suspension bridges via strain energy and dynamic characteristics

Wen-ming Zhang,Kai-rui Qian,Li Wang,Yao-jun Ge 한국풍공학회 2019 Wind and Structures, An International Journal (WAS Vol.29 No.3

Multispan suspension bridges make a good alternative to single-span ones if the crossed strait or river width exceeds 2-3 km. However, multispan three-tower suspension bridges are found to be very sensitive to the wind load due to the lack of effective longitudinal constraint at their central tower. Moreover, at certain critical wind speed values, the aerostatic instability with sharply deteriorating dynamic characteristics may occur with catastrophic consequences. An attempt of an in-depth study on the aerostatic stability mode and damage mechanism of three-tower suspension bridges is made in this paper based on the assessment of strain energy and dynamic characteristics of three particular three-tower suspension bridges in China under different wind speeds and their further integration into the aerostatic stability analysis. The results obtained on the three bridges under study strongly suggest that their aerostatic instability mode is controlled by the coupled action of the anti-symmetric torsion and vertical bending of the two main-spans’ deck, together with the longitudinal bending of the towers, which can be regarded as the first-order torsion vibration mode coupled with the first-order vertical bending vibration mode. The growth rates of the torsional and vertical bending strain energy of the deck after the aerostatic instability are higher than those of the lateral bending. The bending and torsion frequencies decrease rapidly when the wind speed approaches the critical value, while the frequencies of the anti-symmetric vibration modes drop more sharply than those of the symmetric ones. The obtained dependences between the critical wind speed, strain energy, and dynamic characteristics of the bridge components under the aerostatic instability modes are considered instrumental in strength and integrity calculation of three-tower suspension bridges.

A mathematical description of thermal decomposition and spontaneous ignition of wood slab under a truncated-cone heater

Dekui Shen,Qian Liu,Rui Xiao,Huiyan Zhang,Mengxiang Fang 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.3

A mathematical model of thermal decomposition together with the flammability limit is proposed to describe the pyrolysis and spontaneous ignition of wood slab subjected to the radiation from a truncated-cone heater. The prominent physical and chemical phenomena were considered in the model, involving heat transfer in a solid, heat consumed by thermal decomposition reactions, the evaporation of moisture, re-radiation from pore surfaces inside a solid and so on. The numerical solution allows the prediction of in-depth temperature profiles, evolution of volatiles,variation of thermal conductivity, apparent mass loss (solid conversion) and ignition time. The different densities for wood species and effect of moisture content and grain orientation on thermal conductivity are also considered in the model, producing a good prediction of surface temperatures. This gives birth to the reasonable prediction on ignition time of wood by employing fixed surface temperature (400 oC) as ignition criterion. However, the analysis of constituent fractions for the species associated with the multi-components kinetic scheme should be included in the mathematical model to give a more precise prediction on the apparent mass loss of solid.

An iterative approach for time-domain flutter analysis of bridges based on restart technique

Wen-ming Zhang,Kai-rui Qian,Lian Xie,Lian Xie,Yao-jun Ge 한국풍공학회 2019 Wind and Structures, An International Journal (WAS Vol.28 No.3

This paper presents a restart iterative approach for time-domain flutter analysis of long-span bridges using the commercial FE package ANSYS. This approach utilizes the recursive formats of impulse-response-function expressions for bridge's aeroelastic forces. Nonlinear dynamic equilibrium equations are iteratively solved by using the restart technique in ANSYS, which enable the equilibrium state of system to get back to last moment absolutely during iterations. The condition for the onset of flutter instability becomes that, at a certain wind velocity, the amplitude of vibration is invariant with time. A long-span suspension bridge was taken as a numerical example to verify the applicability and accuracy of the proposed method by comparing calculated results with wind tunnel tests. The proposed method enables the bridge designers and engineering practitioners to carry out time-domain flutter analysis of bridges in commercial FE package ANSYS.

Mast Cell-dependent Mesenteric Afferent Activation by Mucosal Supernatant From Different Bowel Segments of Guinea Pigs With Post-infectious Irritable Bowel Syndrome

( Jun Song ),( Lei Zhang ),( Tao Bai ),( Wei Qian ),( Rui Li ),( Xiaohua Hou ) 대한소화기기능성질환·운동학회 2015 Journal of Neurogastroenterology and Motility (JNM Vol.21 No.2

Background/Aims Mesenteric afferent nerves (MANs) play a pivotal role in the visceral-nociceptive perception. Inappropriate activation of MANs may be involved in the pathogenesis of post-infectious irritable bowel syndrome (PI-IBS). However, the underlying mechanisms remain unclear. We assessed the effects of mucosal mediators from different bowel segments of guinea pigs with PI-IBS on MAN firing and the role of mast cells. Methods PI-IBS was induced in guinea pigs by Trichinella spiralis infection. Inflammation in terminal ileum, proximal and distal colon was scored with hematoxylin-eosin staining, and mast cell infiltration was assessed with immunofluorescence. We determined the effects of supernatant extracted from the mucosa of different bowel segments of PI-IBS on MANs activity, and assessed the role of mast cells in this process. Results Eight weeks after infection, intestinal inflammation resolved, whereas mast cell numbers increased significantly in terminal ileum and proximal colon (P < 0.05) compared with findings in controls. Mucosal supernatant from different bowel segments of PI-IBS models, but not from controls, significantly enhanced the frequency of MAN firing (terminal ileum 41.01 ± 7.60 Hz vs. 26.55 ± 0.67 Hz, P = 0.001; proximal colon 45.90 ± 11.20 Hz vs. 30.88 ± 6.92 Hz, P = 0.002; distal colon 48.25 ± 9.70 Hz vs. 29.47 ± 6.13 Hz, P < 0.001). In addition, the excitatory effects were inhibited by mast cell stabilizer Nasmil (terminal ileum, 32.71 ± 2.52 Hz, P = 0.030; proximal colon, 30.94 ± 4.44 Hz, P = 0.002; distal colon, 27.15 ± 5.83 Hz, P < 0.001). Conclusions Supernatant from the intestinal mucosa of different bowel segments of PI-IBS models markedly enhanced the MAN firing in a mast cell-dependent manner, indicating that mast cell-mediated MAN activation plays an important role in the pathogenesis of PI-IBS. (J Neurogastroenterol Motil 2015;21:236-246)