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Engineering of a Bacillus subtilis Strain Deficient in Cellulase: Application in Degumming of Ramie
Qi Yang,Shengwen Duan,Lifeng Cheng,Xiangyuan Feng,Ke Zheng,Chunliang Xie,Zhiyuan Liu,Yuande Peng 한국섬유공학회 2019 Fibers and polymers Vol.20 No.1
Degumming is the most important step before ramie fibers are used in textile industry. Conventional chemical degumming technology with alkaline treatment at high temperature causes critical problems in environment. In addition to multiple degumming enzymes (e.g. pectinases and xylanases), Bacillus subtilis strain 168 can also produce cellulase which brings irreversible damage to ramie fibers. In this study, a strain deficient in cellulase was constructed by insertional inactivation of gene eglS to make it suitable for microbial degumming. Results showed that the cellulase activity was not detected in strain ΔeglS, after 25 h of incubation with strain ΔeglS, the weight loss of the ramie fibers was 20.20 %. Though the residual gum content of ramie fibers obtained in microbial degumming process was 19.67 %, microbial intervention followed by diluted alkaline solution treatment showed lower residual gum content (2.73 %) than chemical degumming (2.96 %). The single fiber breaking strength value of ramie fibers from bio-chemical degumming process reached 27.19 cN, which was the highest of three samples. Moreover, bio-chemical degumming process resulted in a 75 % decrease of alkali dosage as compared with chemical degumming process. This study provides a suggestion to genetically modify wild-type strain in order to protect ramie fibers from cellulase damage, and indicates a sustainable alternative for the traditional chemical degumming in the textile industry.
Full-scale testing and modeling of the mechanical behavior of shield TBM tunnel joints
Wen-qi Ding,Yi-cheng Peng,Zhi-guo Yan,Bi-wei Shen,He-hua Zhu,Xin-xin Wei 국제구조공학회 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.45 No.3
For shield TBM (Tunnel Boring Machine) tunnel lining, the segment joint is the most critical component for determining the mechanical response of the complete lining ring. To investigate the mechanical behavior of the segment joint in a water conveyance tunnel, which is different from the vehicle tunnel because of the external loads and the high internal water pressure during the tunnel’s service life, full-scale joint tests were conducted. The main advantage of the joint tests over previous ones was the definiteness of the loads applied to the joints using a unique testing facility and the acquisition of the mechanical behavior of actual joints. Furthermore, based on the test results and the theoretical analysis, a mechanical model of segment joints has been proposed, which consists of all important influencing factors,including the elastic-plastic behavior of concrete, the pre-tightening force of the bolts and the deformations of all joint components, i.e., concrete blocks, bolts and cast iron panels. Finally, the proposed mechanical model of segment joints has been verified by the aforementioned full-scale joint tests.
Ma, Peng-Cheng,Liu, Ming-Yang,Zhang, Hao,Wang, Sheng-Qi,Wang, Rui,Wang, Kai,Wong, Yiu-Kei,Tang, Ben-Zhong,Hong, Soon-Hyung,Paik, Kyung-Wook,Kim, Jang-Kyo American Chemical Society 2009 ACS APPLIED MATERIALS & INTERFACES Vol.1 No.5
<P>Nanocomposites reinforced with hybrid fillers of carbon nanotubes (CNTs) and carbon black (CB) are developed, aiming at enhancing the electrical conductivity of composites with balanced mechanical properties while lowering the cost of the final product. Epoxy-based nanocomposites were prepared with varying combinations of CNTs and CB as conducting fillers, and their electrical and mechanical properties were evaluated. It was shown that the addition of CNTs in CB composites enhanced the electrical conductivity of composites: a low percolation threshold was achieved with 0.2 wt % CNTs and 0.2 wt % CB particles. The CB particles also enhanced the ductility and fracture toughness of nanocomposites, confirming the synergistic effect of CB as a multifunctional filler. The novelty of this work lies in the synergy arising from the combination of two conducting fillers with unique geometric shapes and aspect ratios as well as different dispersion characteristics, which have not been specifically considered previously.</P>
Zhang, Cheng-Dong,Li, Hong-Tao,Liu, Kun,Lin, Zhi-Di,Peng, Qi-Liu,Qin, Xue,He, Min,Wu, Hua,Mo, Zeng-Nan,Yang, Xiao-Li Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.18
Background: Despite evidence suggesting roles for caspase-8 (CASP8) -652 6N del and D302H polymorphisms in prostate cancer (PCa), the association of these polymorphisms with PCa risk remains inconclusive. Therefore, a meta-analysis was performed to more precisely estimate the association of CASP8 -652 6N del and D302H polymorphisms with PCa susceptibility. Materials and Methods: A comprehensive literature search was conducted to identify all case-control studies of CASP8 D302H and -652 6N del polymorphisms and PCa risk. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the strength of the association and the precision of the estimate, respectively. Results: Nine -625 6N del studies and 4 D302H studies were included. CASP8 -652 6N del and D302H polymorphisms were not significantly associated with PCa risk in the overall analyses. However, in the subgroup analysis stratified by ethnicity, -625 6N del was significantly associated with PCa risk in the East Asian and Indian populations under the recessive model. Furthermore, the subgroup analysis strongly suggested that D302H was associated with lower PCa risk in the Non-Indian population under the dominant model. Conclusions: In our meta-analysis, ethnic-specific differences were evident in the association of CASP8-625 6N del and D302H polymorphisms with PCa risk.
Photonic Microcavity-Enhanced Magnetic Plasmon Resonance of Metamaterials for Sensing Applications
Chen, Jing,Peng, Cheng,Qi, Shibin,Zhang, Qian,Tang, Chaojun,Shen, Xueyang,Da, Haixia,Wang, Lianhui,Park, Gun-Sik IEEE 2019 IEEE photonics technology letters Vol.31 No.2
<P>We first investigate numerically photonic microcavity-enhanced magnetic plasmon (MP) resonance in metamaterials for high-quality refractive index sensing. The metamaterials consist of a top periodic array of U-shaped metallic split-ring resonators (SRRs), a middle dielectric layer, and a bottom metallic backed plate. The top metallic SRRs that are placed at about Bragg distance above the bottom metallic plate constitute a photonic microcavity. Because the MP resonance excited in metallic SRRs is coupled to the photonic microcavity mode supported by the photonic microcavity, the radiative damping of the MP resonance is strongly reduced, and consequently, its linewidth is decreased dramatically. Benefiting from the narrow linewidth, large modulation depth, and giant magnetic field enhancement at the MP resonance, the cavity-coupled metamaterial sensor has very high sensitivity ( <TEX>$\text {S}= 400$</TEX> nm/RIU and <TEX>$\text {S}^{\ast } = 26$</TEX>/RIU) and figure of merit ( <TEX>$\text {FOM}= 33$</TEX> and FOM* = 4215), which suggests that the proposed metamaterials have potential in applications of plasmonic biosensors.</P>
Xuejin Fan,Qi Peng,Yanhua Chen,Zeke Ma,Xiaoguang He,Biying Deng,Hui Huang,Juan Zeng,Chuyun Cheng,Shaoji Liu,Xiaomei Lu 한국유전학회 2015 Genes & Genomics Vol.37 No.12
The aim of this study was to test the impact of variants rs900400 (located near LEKR1 and CCNL1) and rs9883204 (located in ADCY5) on birth weight in a Chinese population. We conducted a case–control study including 156 low-birth- weight infants as the case group and 100 normal-birth-weight infants as the control group. The rs900400 and rs9883204 variants were analyzed by gene sequencing in all the participants. Our results revealed a significant difference in the genotype distribution (v2 = 10.449, p = 0.005) and allele distribution (v2 = 9.277, p = 0.002) of rs900400 between the case group and the control group. The C allele of rs900400 was associated with lower birth weight (OR 1.771 [95 % CI 1.237–2.535]) in the Chinese population. However, the rs9883204 polymorphism was not informative in the Chinese population. Our study shows that the ‘‘birth weightlowering’’ variant rs900400 located near LEKR1 and CCNL1, which is strongly associated with birth weight in European cohorts, appears to have a similar association in Chinese cohorts. However, the rs9883204 variant located in ADCY5 does not appear to be correlated with low birth weight in the same population. Moreover, we found that the variant rs900400 may also be associated with premature birth, thereby supporting the need for further research in this area.
Full-scale testing and modeling of the mechanical behavior of shield TBM tunnel joints
Ding, Wen-Qi,Peng, Yi-Cheng,Yan, Zhi-Guo,Shen, Bi-Wei,Zhu, He-Hua,Wei, Xin-Xin Techno-Press 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.45 No.3
For shield TBM (Tunnel Boring Machine) tunnel lining, the segment joint is the most critical component for determining the mechanical response of the complete lining ring. To investigate the mechanical behavior of the segment joint in a water conveyance tunnel, which is different from the vehicle tunnel because of the external loads and the high internal water pressure during the tunnel's service life, full-scale joint tests were conducted. The main advantage of the joint tests over previous ones was the definiteness of the loads applied to the joints using a unique testing facility and the acquisition of the mechanical behavior of actual joints. Furthermore, based on the test results and the theoretical analysis, a mechanical model of segment joints has been proposed, which consists of all important influencing factors, including the elastic-plastic behavior of concrete, the pre-tightening force of the bolts and the deformations of all joint components, i.e., concrete blocks, bolts and cast iron panels. Finally, the proposed mechanical model of segment joints has been verified by the aforementioned full-scale joint tests.
Tan Jia-qi,Li Peng-cheng,Li Qian,Tang Jin-tian,Xue Hong-kun 한국응용생명화학회 2020 Applied Biological Chemistry (Appl Biol Chem) Vol.63 No.5
The aim of this study is to assess the cytoprotection and potential molecular mechanisms of procyanidin B2 ( PCB2) on hydrogen peroxide ( H2O2)-induced oxidative damage in MCF-7 cells. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was performed to determine the viability of MCF-7 cell exposure to H2O2 or PCB2. We measured the antioxidant properties of PCB2 by determining the activities of SOD, GSH-Px, LDH and MDA levels, and evaluated apoptosis and intracellular reactive oxygen species (ROS) levels. The related proteins expression levels were monitored by Western blot. MCF-7 cells induced with H2O2 had a remarkable decrease in cell viability that was suppressed when it was interfered with PCB2 (0.1–10.0 μM). PCB2 interference memorably and dose-dependently inhibited H2O2- induced LDH leakage, ROS and MDA overproduction, while PCB2 markedly increased H2O2- induced the activities of SOD and GSH-Px. Eventually, H2O2 prominently down-regulated the ratio of Bcl-2/Bax and the relative proteins expression levels of Nrf2, GCLC, NQO1 and HO-1, and up-regulated the relative proteins expression levels of cytochrome c, caspase-3 and Keap1. However, the relative expression levels of these proteins were reversed in PCB2- interfered MCF-7 cells. This study implied that protective effect of PCB2 on H2O2- induced oxidative damage in MCF-7 cells might be related to inhibition of mitochondria-dependent apoptosis, activation of Keap1/Nrf2/HO-1 signaling pathway and improvement of the antioxidant enzymes activities.
Discrimination of neutrons and gamma-rays in plastic scintillator based on spiking cortical model
Liu Bing-Qi,Liu Hao-Ran,Chang Lan,Cheng Yu-Xin,Zuo Zhuo,Li Peng 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.9
In this study, a spiking cortical model (SCM) based n-g discrimination method is proposed. The SCMbased algorithm is compared with three other methods, namely: (i) the pulse-coupled neural network (PCNN), (ii) the charge comparison, and (iii) the zero-crossing. The objective evaluation criteria used for the comparison are the FoM-value and the time consumption of discrimination. Experimental results demonstrated that our proposed method outperforms the other methods significantly with the highest FoM-value. Specifically, the proposed method exhibits a 34.81% improvement compared with the PCNN, a 50.29% improvement compared with the charge comparison, and a 110.02% improvement compared with the zero-crossing. Additionally, the proposed method features the second-fastest discrimination time, where it is 75.67% faster than the PCNN, 70.65% faster than the charge comparison and 38.4% slower than the zero-crossing. Our study also discusses the role and change pattern of each parameter of the SCM to guide the selection process. It concludes that the SCM's outstanding ability to recognize the dynamic information in the pulse signal, improved accuracy when compared to the PCNN, and better computational complexity enables the SCM to exhibit excellent n-g discrimination performance while consuming less time.