• Biomolecules & Therapeutics
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• 제25권2호
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• pp.186-193
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• 2017

Tetrandrine (Tet), a bisbenzylisoquinoline alkaloid, has been reported to have a radiosensitization effect on tumors. However, its effects on human glioma and the specific molecular mechanisms of these effects remain unknown. In this study, we demonstrated that Tet has a radiosensitization effect on human glioma cells. It has been hypothesized that Tet has a radiosensitization effect on glioma cells by affecting the glioma cell cycle and DNA repair mechanism and that ERK mediates these activities. Therefore, we conducted detailed analyses of the effects of Tet on the cell cycle by performing flow cytometric analysis and on DNA repair by detecting the expression of phosphorylated H2AX by immunofluorescence. We used western blot analysis to investigate the role of ERK in the effect of Tet on the cell cycle and DNA repair. The results revealed that Tet exerts its radiosensitization effect on glioma cells by inhibiting proliferation and decreasing the expression of phosphorylated ERK and its downstream proteins. In summary, our data indicate that ERK is involved in Tet-induced radiosensitization of glioma cells via inhibition of glioma cell proliferation or of the cell cycle at G0/G1 phase.

• Structural Engineering and Mechanics
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• 제72권1호
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• pp.43-60
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• 2019

This paper presents a finite element model which can simulate the axial compression behavior of steel reinforced recycled concrete (SRRC) filled square steel tube columns using the ABAQUS software. The analytical model was established by selecting the reasonable nonlinear analysis theory and the constitutive relationship of material in the columns. The nonlinear analysis of failure modes, deformation characteristics, stress nephogram, and load-strain curves of columns under axial loads was performed in detail. Meanwhile, the influences of recycled coarse aggregate (RCA) replacement percentage, profile steel ratio, width thickness ratio of square steel tube, RAC strength and slenderness ratio on the axial compression behavior of columns were also analyzed carefully. It shows that the results of finite element analysis are in good agreement with the experimental results, which verifies the validity of the analytical model. The axial bearing capacity of columns decreased with the increase of RCA replacement percentage. While the increase of wall thickness of square steel tube, profile steel ratio and RAC strength were all beneficial to improve the bearing capacity of columns. Additionally, the parameter analysis of finite element analysis on the columns was also carried out by using the above numerical model. In general, the SRRC filled square steel tube columns have high bearing capacity and good deformation ability. On the basis of the above analysis, a modified formula based on the American ANSI/AISC 360-10 was proposed to calculate the nominal axial bearing capacity of the columns under axial loads. The research conclusions can provide some references for the engineering application of this kind of columns.

• Geomechanics and Engineering
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• 제18권4호
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• pp.439-448
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• 2019

The bearing capacity of roadside support is the key problem in gob-side entry retaining technology. To study the cooperative bearing characteristics of the roof-roadside support-floor along the gob-side entry retaining, a mechanical model of the composite structure of the roof-roadside support-floor was first established. A method for determining the structural parameters of gob-side entry retaining was then proposed. Based on this model, adaptability analysis of roadside support was carried out. The results showed that the reasonable width of the gob-side entry roadway was inversely proportional to the mining height, and directly proportional to the bearing strength of the roof and floor. And the reasonable width of the "flexible-hard" roadside support was directly proportional to its own strength, and inversely proportional to the width of the gob-side entry retaining. When determining the position and size of the roadside support along the gob-side entry retaining, the surrounding rock environment should be fully considered. Measured results from case study also show the rationality of the model and calculation method.

• Journal of Microbiology and Biotechnology
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• 제28권12호
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• pp.2046-2056
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• 2018

Phospholipase D has great commercial value due to its transphosphatidylation products that can be used in the food and medicine industries. In order to construct a strain for use in the production of PLD, we employed a series of combinatorial strategies to increase PLD expression in Bacillus subtilis WB600. These strategies included screening of signal peptides, selection of different plasmids, and optimization of the sequences of the ribosome-binding site (RBS) and the spacer region. We found that using the signal peptide amyE results in the highest extracellular PLD activity (11.3 U/ml) and in a PLD expression level 5.27-fold higher than when the endogenous signal peptide is used. Furthermore, the strain harboring the recombinant expression plasmid pMA0911-PLD-amyE-his produced PLD with activity enhanced by 69.03% (19.1 U/ml). We then used the online tool \RBS Calculator v2.0 to optimize the sequences of the RBS and the spacer. Using the optimized sequences resulted in an increase in the enzyme activity by about 26.7% (24.2 U/ml). In addition, we found through a transfer experiment that the retention rate of the recombinant plasmid after 5 generations was still 100%. The final product, phosphatidylserine (PS), was successfully detected, with transphosphatidylation selectivity at 74.6%. This is similar to the values for the original producer.

• BMB Reports
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• 제52권8호
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• pp.520-525
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• 2019

Dihydroartemisinin (DHA) has been reported to possess anti-cancer activity against many cancers. However, the pharmacologic effect of DHA on HBV-positive hepatocellular carcinoma (HCC) remains unknown. Thus, the objective of the present study was to determine whether DHA could inhibit the proliferation of HepG2.2.15 cells and uncover the underlying mechanisms involved in the effect of DHA on HepG2.2.15 cells. We found that DHA effectively inhibited HepG2.2.15 HCC cell proliferation both in vivo and in vitro. DHA also reduced the migration and tumorigenicity capacity of HepG2.2.15 cells. Regarding the underlying mechanisms, results showed that DHA induced cellular senescence by up-regulating expression levels of proteins such as p-ATM, p-ATR, ${\gamma}-H_2AX$, P53, and P21 involved in DNA damage response. DHA also induced autophagy (green LC3 puncta gathered together and LC3II/LC3I ratio increased through AKT-mTOR pathway suppression). Results also revealed that DHA-induced autophagy was not linked to senescence or cell death. TPP1 (telomere shelterin) overexpression could not rescue DHA-induced anticancer activity (cell proliferation). Moreover, DHA down-regulated TPP1 expression. Gene knockdown of TPP1 caused similar phenotypes and mechanisms as DHA induced phenotypes and mechanisms in HepG2.2.15 cells. These results demonstrate that DHA might inhibit HepG2.2.15 cells proliferation through inducing cellular senescence and autophagy.

• Journal of the Korean Wood Science and Technology
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• 제47권3호
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• pp.336-343
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• 2019

Effects of a novel mold inhibitor specifically for bamboo, on the properties of composite products have been confirmed in this study. The mechanical and dimensional stability properties of bamboo fiber-based composites (BFBCs) from different bamboo species were also investigated. The results showed that Burmanica Gamble possessed the highest values of modulus of elasticity (MOE) of 33.2 GPa, modulus of rupture (MOR) of 286.9 MPa, compressive strength of 182.6 MPa and shear strength of 24.0 MPa. By contrast, Phyllostochys heterocycla among all of species showed the lowest MOE of 16.3 GPa, MOR of 170.3 MPa and compressive strength of 128.9 MPa were the lowest among all of species. Moreover, there is a remarkable variation in the swelling and water absorption between the samples with 4 h and 28 h water immersion treatment, especially Phyllostachys iridenscens. Overall, the results suggested that TCIT (Tebuconazole and 3(2H)-isothiazolone) had no significant effect on the mechanical properties compared with the control condition, and it would be utilized as an antimould of BFBCs manufacturing.

• Nuclear Engineering and Technology
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• 제54권6호
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• pp.2094-2106
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• 2022

The solid-state core of a heat pipe cooled reactor operates at high temperatures over 1000 K with thermal and irradiation-induced expansion during burnup. The expansion changes the gap thickness between the solid components and the material properties, and may even cause the gap closure, which then significantly influences the thermal and mechanical characteristics of the reactor core. This study developed an irradiation behavior model for HPRTRAN, a heat pipe reactor system analysis code, to introduce the irradiation effects such as swelling and creep. The megawatt heat pipe reactor MegaPower was chosen as an application case. The coupled irradiation-thermal-mechanical model was developed to simulate the irradiation effects on the heat transfer and stresses of the whole reactor core. The results show that the irradiation deformation effect is significant, with the irradiation-induced strains up to 2.82% for fuel and 0.30% for monolith at the end of the reactor lifetime. The peak temperatures during the lifetime are 1027:3 K for the fuel and 956:2 K for monolith. The gap closure enhances the heat transfer but caused high stresses exceeding the yield strength in the monolith.

• Journal of Microbiology and Biotechnology
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• 제32권4호
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• pp.522-530
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• 2022

In this study we aimed to develop novel ZnO-NP/chitosan/β-glycerophosphate (ZnO-NP/CS/β-GP) antibacterial hydrogels for biomedical applications. According to the mass fraction ratio of ZnO-NPs to chitosan, mixtures of 1, 3, and 5% ZnO-NPs/CS/β-GP were prepared. Using the test-tube inversion method, scanning electron microscopy and Fourier-transform infrared spectroscopy, the influence of ZnO-NPs on gelation time, chemical composition, and cross-sectional microstructures were evaluated. Adding ZnO-NPs significantly improved the hydrogel's antibacterial activity as determined by bacteriostatic zone and colony counting. The hydrogel's bacteriostatic mechanism was investigated using live/dead fluorescent staining and scanning electron microscopy. In addition, crystal violet staining and MTT assay demonstrated that ZnO-NPs/CS/β-GP exhibited good antibacterial activity in inhibiting the formation of biofilms and eradicating existing biofilms. CCK-8 and live/dead cell staining methods revealed that the cell viability of gingival fibroblasts (L929) cocultured with hydrogel in each group was above 90% after 24, 48, and 72 h. These results suggest that ZnO-NPs improve the temperature sensitivity and bacteriostatic performance of chitosan/β-glycerophosphate (CS/β-GP), which could be injected into the periodontal pocket in solution form and quickly transformed into hydrogel adhesion on the gingiva, allowing for a straightforward and convenient procedure. In conclusion, ZnO-NP/CS/β-GP thermosensitive hydrogels could be expected to be utilized as adjuvant drugs for clinical prevention and treatment of peri-implant inflammation.

• Journal of Korea Trade
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• 제23권7호
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• pp.128-146
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• 2019

Purpose - The purpose of this paper is to investigate the relationship between internal control, economic policy uncertainty, and performance of cross-border merger and acquisition (M&A) based on the panel data of Chinese listed firms. The authors expected that internal control has a positive moderating effect on the performance of cross-border M&A and that it mainly occurs during periods when economic policies are relatively stable. In addition, the authors tried to find out the mechanism of internal control affecting cross-border M&A and the corporate performance. Design/methodology - The authors tested the hypotheses by a multivariate regression model based on the panel data of Chinese listed firms from 2009 to 2017. The dependent variable is the change value of business performance (DROA_1,2,3) and the explanatory variables are cross-border M&A (MA), China's uncertainty of economic policy (EPU), and internal control level (IC) respectively. Findings - The authors find that internal control has a positive moderating effect on the relationship between cross-border M&A and corporate performance. Further, the authors find that the moderating effect is more significant in state-owned enterprises and that it mainly occurs during periods when economic policies are relatively stable. Originality/value - This paper is the leading study that tries to analyze empirically the relationship between internal control, economic policy uncertainty, and performance of cross-border M&A. It provides a new avenue through which internal control might reasonably mitigate the risks of cross-border M&A and correspondingly improve the performance of cross-border M&A. It also confirms the moderating effect of internal control on the performance of cross-border M&A under the uncertainty of economic policy.

• Animal Bioscience
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• 제34권9호
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• pp.1491-1498
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• 2021

Objective: This research was carried out to investigate the effects of corn particle size on the apparent total tract digestibility (ATTD) of energy and nutrients fed to pigs at four different growth stages and therefore to provide basis for better application of corn in pig feeds. Methods: Eighteen weanling piglets, 18 growing barrows, 24 gestating sows and 24 lactating sows were used in this study. Within each stage, pigs were allotted to 1 of 3 or 4 corn-soybean meal diets which were formulated with different corn particle size in a completely randomized design with 6 replicate pigs per diet. Each stage lasted for 19 days, including 7 days for cages adaptation, 7 days for adaptation to diets and followed by 5 days for total collection of feces and urine. Results: For nursery and growing stages, the results showed that digestible energy content and ATTD of gross energy (GE), dry matter (DM), neutral detergent fiber (NDF), and acid detergent fiber (ADF) was increased (p<0.05) as the corn particle size reduced. Meanwhile, the metabolizable energy content and ATTD of crude protein (CP) tended to increase. For gestating sows, no differences were found in the ATTD of nutrients among dietary treatments. As for lactating sows, there were linear and quadratic increases (p<0.05) in the ATTD of DM, GE, NDF as the corn being finer milled. Quadratic response in ATTD of ADF and CP (p<0.05) were observed as sows fed with four different diets. Conclusion: Reducing corn particle size can increase digestibility of nutrients fed to young pigs and lactating sows. No effects were observed in present experiment when gestating sows were fed with different particle sized corn.