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Using statistic and bibliometric methods to characterize scientific cooperation between China (excluding Hong Kong, Macao, and Taiwan) and South Korea through their bilateral co-authored papers covered by the Science Citation Index CD-ROM, 1991-2010, in our paper we exploit the feature of their cooperation in four levels: time sequence, academic community, key fields, and institution distribution. From the time sequence we know that collaboration between China and Korea starts in 1991, reaching the first peak during 2004-2007. As for the academic community, the number of Chinese corresponding authors (2414) is slightly lower than that of Korea (2700). Regarding the 27 high yield authors, there are only 4 coming from China. Korea has a higher active level than Chinese authors. China and Korea tend to cooperate with each other on strong disciplines such as physics, chemistry, material science, engineering, mathematics, pharmaceutical, computer science and biology. Furthermore, they also attach great importance to basic research and high-tech cooperation. Besides, Chinese Academy of Sciences ranks at the top 1 among the distribution of institutions. As a majority of the collaborative institutions are universities, the participation of non-university institutions is relatively low. There are 7 Korean universities among the top ten institutions, while Yanbian University and Tsinghua University in China rank respectively as third and fourth. Seoul National University, accompanied by Korea University and Yonsei University as the three top Korean universities, is also among the top among the cooperating institutions.

Under the Castor earthquake, there is a risk of liquefaction instability of saturated tailings, and the evolution of dynamic pore pressure can indirectly reflect its instability process. Before applying dynamic loads, the static stress state of soil is one of the main factors affecting the development of soil dynamic strength and dynamic pore pressure, and there are significant differences in soil dynamic strength under different consolidation ratios. This paper conducted dynamic triaxial tests on saturated tailings silt with different consolidation ratios, and analyzed the dynamic strength variation and liquefaction mechanism of the samples using the discrete element method (PFC3D). The results showed that 1) as the Kc′ gradually increased, and there was a critical consolidation ratio Kc′ during the development of the dynamic strength of the sample. The specific value of Kc′ was related to the properties and stress state of saturated sand. The Kc′ in this research was about 1.9. When Kc < 1.9, dynamic strength was increased with the increase in Kc; when Kc > 1.9, dynamic strength was decreased with the Kc. 2) Under the impact of cyclic load, when samples were normally consolidated (Kc =1), the pore water pressure would tend to be equal to the confining pressure to cause soil liquefaction. In the case of eccentric consolidation (Kc > 1), the pore water pressure would be less than the confining pressure, thus, the soil liquefaction would not be induced, and the pore pressure value would decrease with the increase of consolidation ratio. This paper provides engineering guidance value for the study of dynamic strength and liquefaction mechanism of tailings sand and silt in Castor earthquake prone areas under different consolidation ratios.

The assessment of coal burst risk is a complex and systematic process; the variations among the indicator systems and the stability of the evaluation models used can influence the results. In this study, an index system for the analytic hierarchy process was constructed based on 21 geomechanically influential factors on rock bursts. The multi-weight combination optimization model was used to synthesize the subjective weights derived by the four experts using AHP and the objective weights derived through the inter-criteria correlation method to obtain the unique optimization weights. After normalizing the original evaluation data, the Gram–Schmidt orthogonalization method was employed to eliminate correlations among factors. The optimized factor weights and data were subsequently input into a linearly weighted comprehensive evaluation model to determine the coal burst risk. The proposed method was applied to assess the coal burst risk of a coal seam in the Liang Jia Coal Mine. These results align with those of the actual coal mine scenario. Indeed, the proposed linear weighted comprehensive evaluation model provided enhanced accuracy and reliability with improved practicality compared to previously proposed methods. [ABSTRACT FROM AUTHOR]

Tailings ponds serve as high-potential energy structures designed to store waste tailings and other industrial materials. However, they can give rise to significant environmental pollution and pose a substantial threat to social and economic development, as well as the safety of people's lives and property. Seismic disasters can cause liquefaction of tailings, leading to destabilization and dam failure of tailings ponds, and the evolution of dynamic pore pressure of tailings can indirectly reflect the destabilization process of tailings ponds. Fine grain content is one of the main factors affecting the dynamic strength and pore pressure development of tailings. This article studies the microscopic characteristics of tailings material through microscopic observation, triaxial testing, discrete element simulation, and grain contact state theory, aiming to analyze the influence mechanism of fine grain content on the micromechanics of tailings. Based on the grain contact state theory, the tailings with different fine grain contents are classified into three types: coarse grain tailings, intermediate-size grain tailings, and fine grain tailings, and the grain contact is classified into four different states. In contact state 1, the vibration pore pressure exhibits a "fast-stable" development mode with increasing vibrations. In contact state 2 or 3, the vibration pore pressure develops linearly with vibrations. For contact state 4, the development of vibration pore pressure presents a "fast-stable-sharp" development mode. The effect of fine grain content (FC) on the liquefication of the tailings studied in the present work is as follows. When the fine grain content is F C < 30 % , the liquefaction resistance of the tailings decreases with the increase of FC. When F C > 30 % , the liquefaction resistance increases with the increase of FC. When F C = 30 % , the liquefaction resistance is the lowest, indicating that the critical threshold of the fine grain content of the tailings studied in the present work is F C t h = 30 % . [ABSTRACT FROM AUTHOR]

Purpose: To retrospectively compare the efficacy and safety of combined radiofrequency ablation and percutaneous ethanol injection (RFA-PEI) with repeat hepatectomy for elderly patients with initial recurrent hepatocellular carcinoma (HCC) after hepatic surgery. Methods: From January 2009 to June 2015, 105 elderly patients (≥70 years) who underwent RFA-PEI (n = 57) or repeated hepatectomy (n = 48) for recurrent HCC ≤ 5.0 cm were included in the study. The overall survival (OS) and recurrence-free survival (RFS) were analysed with the Kaplan-Meier method and compared by the log-rank test. Non-tumour-related death, complications and hospital stays were assessed. Univariate and multivariate analyses were performed to identify the prognostic significance of the variables in predicting the OS and RFS. Results: OS rates were 78.2%, 40.8% and 36.7% at 1, 3 and 5 years after RFA-PEI and 76.3%, 52.5% and 42.6% after repeat hepatectomy, respectively (p = 0.413). Correspondingly, the 1-, 3- and 5-year RFS rates after RFA-PEI and repeat hepatectomy were 69.5%, 37.8%, 33.1% and 73.1%, 49.7%, 40.7%, respectively (p = 0.465). Non-tumour-related deaths in the RFA-PEI group (2/57) were significantly fewer than those in the repeat hepatectomy group (10/48) (p = 0.016). RFA-PEI was superior to repeat hepatectomy regarding the major complication rates and length of in-hospital stay (both p < 0.001). Multivariate analysis showed that the tumour number was the significant prognostic factor for the OS (hazard ratio (HR) = 1.961, 95% CI = 1.043-3.686, p = 0.037) and RFS (HR = 1.866, 95% CI = 1.064-3.274, p = 0.030). Conclusion: RFA-PEI provides comparable OS and RFS to repeat hepatectomy for elderly patients with small recurrent HCC after hepatectomy but with fewer non-tumour-related deaths, major complications and shorter hospital stays. [ABSTRACT FROM AUTHOR]

We examined the expression pattern and functional roles of microRNA 15a-5p (miR-15a-5p) in human hepatocellular carcinoma (HCC). Possible miR-15a-5p aberrant expression in HCC cell lines or clinical HCC specimens was examined by quantitative real-time PCR (qRT-PCR). In HCC HepG2 and SNU-182 cells, miR-15a-5p was ectopically overexpressed by lentiviral transduction. Its effect on HCC proliferation, cancer division, and in vivo tumor growth were examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, cell cycle assay, and tumorigenicity assay, respectively. The targeting of miR-15a-5p on its downstream gene, brain-derived neurotrophic factor (BDNF), was examined by dual-luciferase assay, qRT-PCR, and Western blot, respectively. BDNF was then overexpressed in HepG2 and SNU-182 cells to evaluate its selective effect on miR-15a-5p in HCC modulation. MiR-15a-5p is aberrantly downregulated in in vitro HCC cell lines and in vivo HCC clinical specimens. Ectopic overexpression of miR-15a-5p suppressed cancer proliferation, induced cell cycle arrest in HepG2 or SNU-182 cells in vitro, and inhibited HCC tumor growth in vivo. MiR-15a-5p selectively and negatively regulated BDNF at both gene and protein levels in HCC cells. Forced overexpression of BDNF effectively reversed the tumor suppressive functions of miR-15a-5p on HCC proliferation and cell division in vitro. Our study demonstrated that miR-15a-5p is a tumor suppressor in HCC and its regulation is through BDNF in HCC. [ABSTRACT FROM AUTHOR]