Assessment and Control of Construction Risk for a Super-Sized Quasi-Rectangular Pipe-Jacking Tunnel Adjacently to High-Speed Railways: A case study

Jianfei Ma,Guangyao Cui,Shaohui He,Xiaokang Ling 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.10

Constructing super-sized quasi-rectangular pipe-jacking tunnels beneath high-speed railways presents a significant risk to both the railways and the tunnels. This paper uses expert inquiry, numerical simulation, fuzzy comprehensive evaluation, and on-site monitoring to assess and control risks for constructing a super-sized quasi-rectangular pipe-jacking tunnel project beneath high-speed railways. An assessment system including 18 factors from 6 aspects is built by integrating existing literature, expert consultation, and causality analysis. As the insufficient number of projects, the Analytic Hierarchy Process (AHP), Fuzzy Comprehensive Evaluation Method (FCEM), Delphi method, and numerical simulation are employed to establish a risk assessment model. The pre-support roof construction (P-SRC) technology is proposed to control tunnel construction risks. The actual scenario on site examines the validity and practicality of the evaluation model and control measures. The results indicate that the super-sized quasi-rectangular pipe-jacking tunnel sections for planned and operational high-speed railways belong to the level I risk, requiring risk reduction measures. The artificial borehole piles + D-shaped beams scheme and pile-plate structure scheme decrease the construction risk from level I to IV, and the evaluated risk results and control effect are in good agreement with actual construction conditions. The proposed risk assessment method and control technology are reasonable and reliable, providing a scientific reference for similar projects.

Gas-phase dehydration of glycerol to acrolein over different metal phosphate catalysts

Tianlin Ma,Jianfei Ding,Xueli Liu,Gangling Chen,Jiandong Zheng 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.6

We conducted a comparative study of gas phase dehydration of glycerol to acrolein over aluminium phosphate, iron phosphate and nickel phosphate catalysts prepared by a simple replacement reaction method (AlP, FeP and NiP). The textural properties, acid amounts, acid types, and coke contents of the samples were studied. The results showed that all metal phosphate catalysts remained in an amorphous state. The glycerol conversion was proportional to the acid amount of metal phosphate catalyst in the glycerol dehydration reaction. Higher value of B/L was more likely to produce acrolein. Among the metal phosphate catalysts, FeP showed superior performance due to its suitable textural and acid properties. After 2 h on stream, high glycerol conversion (96%), acrolein selectivity (82%) and acrolein yield (79%) were achieved on the FeP catalyst at 280 oC. The catalyst deactivation was ascribed to carbon deposition on the catalyst surface blocking the active sites during the glycerol dehydration reaction.

Relationships Among Character Strengths, Self-efficacy, Social Support, Depression, and Psychological Well-being of Hospital Nurses

Xie Jianfei,Liu Min,Zhong Zhuqing,Zhang Qiuxiang,Zhou Jianda,Wang Lu,Ma Keke,Ding Siqing,Zhang Xiaohong,Sun Qian,Cheng Andy S.K. 한국간호과학회 2020 Asian Nursing Research Vol.14 No.3

Purpose: From the perspective of positive psychology, our study aimed to explore depressive symptoms and psychological well-being among Chinese nurses, as well as analyze the impacts of character strengths, self-efficacy and social support on the mental health of nurses. Methods: A cross-sectional and descriptive design using five self-reported questionnaires was used to investigate a cohort of 4238 nurses during 2018. A structural equation modeling analysis was used to verify a hypothetical model linking character strengths, self-efficacy, social support, depressive symptoms, and psychological well-being. Results: The prevalence of depression among this cohort of Chinese nurses was 58.1%. The mean scores for caring, inquisitiveness, and self-control were 19.93 (SD ¼ 2.82), 15.94 (SD ¼ 3.00), and 16.34 (SD ¼ 2.95), respectively. The hypothesized model was a good fit of the data (c2/df ¼ 1.77, p ¼ .183, root mean square error of approximation ¼ 0.04, goodness of fit index ¼ 1.00, comparative fit index ¼ 1.00, TuckereLewis index ¼ 1.00). Except for the path from self-control to depression, the other hypothetical paths investigated were statistically significant. Conclusion: Character strengths were directly and positively associated with psychological well-being. Inquisitiveness was the strongest direct protective factor for depression. In addition, character strengths indirectly alleviated depression and increased psychological well-being through mediating variables of social support and self-efficacy. This study should alert nurse managers that more attention should be paid to the character strengths and mental health of nurses. This study provides evidence for interventions based on character strengths as a management strategy to support the mental health of nurses.

Transparent Fluorinated Poly(imide siloxane) Copolymers with Good Adhesivity

Linshuang Li,Yong Xu,Jianfei Che,Xu Su,Chaoran Song,Xiuping Ma 한국고분자학회 2017 Macromolecular Research Vol.25 No.11

A series of fluorinated poly(imide siloxane) (PIS) copolymers were prepared with fluorine dianhydride 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) and two kinds of functional diamine, 2,2'-bis(trifluoromethyl)-[ 1,1'-biphenyl]-4,4'-diamine (TFMB) and 1,3-bis(3-aminopropyl) tetramethyldisiloxane (GAPD) via a conventional two-stage process with thermal imidization. The soft and hard segments in the copolymer chain were composed of 6FDA-GAPD and 6FDA-TFMB, respectively. The structure of the resulting copolymers was determined by Fourier transform infrared (FT-IR) and 1H nuclear magnetic resonance (1H NMR) spectroscopy. Optical, adhesion, mechanical, and thermal properties of these PIS copolymers have been evaluated with respect to real siloxane loading kept to 0, 1.4, 2.6, 4.1, and 5.5wt% in the copolymers, which is lower than the theoretical content of siloxane loading due to a disproportionation reaction of the siloxane chain. The resulting PIS copolymers showed excellent optical transparency in the UV-visible range and good adhesion property. The cutoff absorption wavelength (λ0) of the resulting PIS copolymers films was less than 345 nm and the maximum transmittance (λmax) was up to 91%. The introduction of siloxane segment dramatically improved the adhesion property of PIS copolymers from 1.29 to 2.26MPa (measured by means of shear strength) compared to the fluorinated homopolyimide (6FDA-TFMB) synthesized without siloxane moiety. The thermal and mechanical properties of the resulting PIS copolymers decreased slightly with the increase in siloxane loading but still remain a good level. Due to the addition of trifluoromethyl (-CF3) group and siloxane moiety, the solubility of PIS films was greatly enhanced and they were able to be dissolved in polar aprotic solvents, such as DMAC, DMF, and NMP. The contact angle, surface energy and water absorption were also studied in order to discuss their hydrophobic property.

Treatment of bladder cancer by geoinspired synthetic chrysotile nanocarrier-delivered circPRMT5 siRNA

Chunping Yu,Yi Zhang,Ning Wang,Wensu Wei,Ke Cao,Qun Zhang,Peiying Ma,Dan Xie,Pei Wu,Biao Liu,Jiahao Liu,Wei Xiang,Xing Hu,Xuewen Liu,Jianfei Xie,Jin Tang,Zhi Long,Long Wang,Hongliang Zeng,Jianye Liu 한국생체재료학회 2022 생체재료학회지 Vol.26 No.1

Background: Circular RNAs (circRNAs) have important functions in many fields of cancer biology. In particular, we previously reported that the oncogenic circRNA, circPRMT5, has a major role in bladder cancer progression. Therapy based on circRNAs have good prospects as anticancer strategies. While anti-circRNAs are emerging as therapeutics, the specific in vivo delivery of anti-circRNAs into cancer cells has not been reported and remains challenging. Methods: Synthesized chrysotile nanotubes (SCNTs) with a relatively uniform length (~ 200 nm) have been designed to deliver an siRNA against the oncogenic circPRMT5 (si-circPRMT5) inhibit circPRMT5. In addition, the antitumor effects and safety evaluation of SCNTs/si-circPRMT5 was assessed with a series of in vitro and in vivo assays. Results: The results showed that SCNTs/si-circPRMT5 nanomaterials prolong si-circPRMT5’s half-life in circulation, enhance its specific uptake by tumor cells, and maximize the silencing efficiency of circPRMT5. In vitro, SCNTs encapsulating si-circPRMT5 could inhibit bladder cancer cell growth and progression. In vivo, SCNTs/si-circPRMT5 inhibited growth and metastasis in three bladder tumor models (a subcutaneous model, a tail vein injection lung metastatic model, and an in situ model) without obvious toxicities. Mechanistic study showed that SCNTs/sicircPRMT5 regulated the miR-30c/SNAIL1/E-adherin axis, inhibiting bladder cancer growth and progression. Conclusion: The results highlight the potential therapeutic utility of SCNTs/si-circPRMT5 to deliver si-circPRMT5 to treat bladder cancer.