Balancing between "Two Evils"

Yu Lei,Sui Sophia 한국학술연구원 2022 Korea Observer Vol.53 No.2

This paper finds that Pyongyang's nuclear issue is by no means China's "primary contradiction (top priority)" in its international relations. Chinese priority on the Korean peninsula is to keep stability and the status quo of a divided Korea rather than rush to find a resolution to the nuclear issue, which may result in a military imbalance on the Peninsula, or the collapse of the Pyongyang regime and hurt China's interest. To this end, China has adopted the strategy of making a delicate balance between pressuring and sustaining the Pyongyang regime. The paper concludes that from Chinese perspectives, a North Korea at the nuclear threshold contributes to counterbalancing US military presence in the region, maintaining a status quo of divided Koreas and helping China overcome US containment. China aspires to achieve three interconnected objectives with this strategy. This first is to sustain China's economic growth, the second to counterattack US containment, and the third to propel China's rise at the systemic (global) level.

Synergistic effect of novel ionic liquid/graphene complex on the flame retardancy of epoxy nanocomposites

Zhang Chunhong,Xu Zice,Sui Wenbo,Zang Junbo,Ao Yuhui,Wang Lu,Shang Lei 한국탄소학회 2023 Carbon Letters Vol.33 No.2

Epoxy resin (EP) is a thermosetting resin with excellent properties, but its application is limited due to its high brittleness and poor flame retardancy. Therefore, to solve this problem, a dispersion system of imidazole-containing ionic liquid ([Dmim]Es) and graphene in epoxy resin is designed based on the π–π stacking effect between imidazole and graphite layers. The study on the thermal and flame-retardant properties of the composites show that the modified [Dmim]Es–graphene nanosheets improved the flame retardancy, smoke suppression and thermal stability of epoxy resin. With the addition of 5wt% [Dmim]Es and 1% Gra, the exothermic rate (HRR) and total exothermic (THR) of the composites decrease by 35% and 30.2% compared with the untreated epoxy cross-linking, respectively. The limiting oxygen index reaches 33.4%, the UL-94 test rating reaches V-0. The characterization of mechanical properties shows that the tensile properties and impact properties increased by 13% and 30%, respectively. Through SEM observation, the addition of [Dmim]Es improves the dispersion of graphene in the EP collective and changes the mechanical fracture behavior. The results show that ionic liquid [Dmim]Es-modified graphene nanosheets are well dispersed in the matrix, which not only improves the mechanical properties of epoxy resin (EP), but also has a synergistic effect on flame retardancy. This work provides novel flame-retardant and graphene dispersion methods that broaden the range of applications of epoxy resins.

Naturally Occurring Lactic Acid Bacteria Isolated from Tomato Pomace Silage

Wu, Jing-Jing,Du, Rui-Ping,Gao, Min,Sui, Yao-Qiang,Xiu, Lei,Wang, Xiao Asian Australasian Association of Animal Productio 2014 Animal Bioscience Vol.27 No.5

Silage making has become a significant method of forage conservation worldwide. To determine how tomato pomace (TP) may be used effectively as animal feed, it was ensilaged for 90 days and microbiology counts, fermentation characteristics and chemical composition of tomato pomace silage (TPS) were evaluated at the 30th, 60th, and 90th days, respectively. In addition, 103 lactic acid bacteria were isolated from TPS. Based on the phenotypic and chemotaxonomic characteristics, 16S rDNA sequence and carbohydrate fermentation tests, the isolates were identified as 17 species namely: Lactobacillus coryniformis subsp. torquens (0.97%), Lactobacillus pontis (0.97%), Lactobacillus hilgardii (0.97%), Lactobacillus pantheris (0.97%), Lactobacillus amylovorus (1.9%), Lactobacillus panis (1.9%), Lactobacillus vaginalis (1.9%), Lactobacillus rapi (1.9%), Lactobacillus buchneri (2.9%), Lactobacillus parafarraginis (2.9%), Lactobacillus helveticus (3.9%), Lactobacillus camelliae (3.9%), Lactobacillus fermentum (5.8%), Lactobacillus manihotivorans (6.8%), Lactobacillus plantarum (10.7%), Lactobacillus harbinensis (16.5%) and Lactobacillus paracasei subsp. paracasei (35.0%). This study has shown that TP can be well preserved for 90 days by ensilaging and that TPS is not only rich in essential nutrients, but that physiological and biochemical properties of the isolates could provide a platform for future design of lactic acid bacteria (LAB) inoculants aimed at improving the fermentation quality of silage.

Adiponectin Regulates Bone Marrow Mesenchymal Stem Cell Niche Through a Unique Signal Transduction Pathway: An Approach for Treating Bone Disease in Diabetes : Adiponectin Regulates BMSC Niche

Yu, Liming,Tu, Qisheng,Han, Qianqian,Zhang, Lan,Sui, Lei,Zheng, Leilei,Meng, Shu,Tang, Yin,Xuan, Dongying,Zhang, Jin,Murray, Dana,Shen, Qingping,Cheng, Jessica,Kim, Sung-Hoon,Dong, Lily Q.,Valverde, P Wiley (John WileySons) 2015 Stem Cells Vol.33 No.1

<P>Adiponectin (APN) is an adipocyte-secreted adipokine that exerts well-characterized antidiabetic properties. Patients with type 2 diabetes (T2D) are characterized by reduced APN levels in circulation and impaired stem cell and progenitor cell mobilization from the bone marrow for tissue repair and remodeling. In this study, we found that APN regulates the mobilization and recruitment of bone marrow-derived mesenchymal stem cells (BMSCs) to participate in tissue repair and regeneration. APN facilitated BMSCs migrating from the bone marrow into the circulation to regenerate bone by regulating stromal cell-derived factor (SDF)-1 in a mouse bone defect model. More importantly, we found that systemic APN infusion ameliorated diabetic mobilopathy of BMSCs, lowered glucose concentration, and promoted bone regeneration in diet-induced obesity mice. In vitro studies allowed us to identify Smad1/5/8 as a novel signaling mediator of APN receptor (AdipoR)-1 in BMSCs and osteoblasts. APN stimulation of MC3T3-E1 osteoblastic cells led to Smad1/5/8 phosphorylation and nuclear localization and increased SDF1 mRNA expression. Although APN-mediated phosphorylation of Smad1/5/8 occurred independently from adaptor protein, phosphotyrosine interaction, pleckstrin homology domain, and leucine zipper containing 1, it correlated with the disassembly of protein kinase casein kinase 2 and AdipoR1 in immunoprecipitation experiments. Taken together, this study identified APN as a regulator of BMSCs migration in response to bone injury. Therefore, our findings suggest APN signaling could be a potential therapeutic target to improve bone regeneration and homeostasis, especially in obese and T2D patients.</P>

Epigenetically Modified Bone Marrow Stromal Cells in Silk Scaffolds Promote Craniofacial Bone Repair and Wound Healing

Han, Qianqian,Yang, Pishan,Wu, Yuwei,Meng, Shu,Sui, Lei,Zhang, Lan,Yu, Liming,Tang, Yin,Jiang, Hua,Xuan, Dongying,Kaplan, David L.,Kim, Sung Hoon,Tu, Qisheng,Chen, Jake Mary Ann Liebert 2015 Tissue engineering. Part A Vol.21 No.15

<P>Epigenetic regulation of gene expression is a central mechanism that governs cell stemness, determination, commitment, and differentiation. It has been recently found that PHF8, a major H4K20/H3K9 demethylase, plays a critical role in craniofacial and bone development. In this study, we hypothesize that PHF8 promotes osteoblastogenesis by epigenetically regulating the expression of a nuclear matrix protein, special AT-rich sequence-binding protein 2 (SATB2) that plays pivotal roles in skeletal patterning and osteoblast differentiation. Our results showed that expression levels of PHF8 and SATB2 in preosteoblasts and bone marrow stromal cells (BMSCs) increased simultaneously during osteogenic induction. Overexpressing PHF8 in these cells upregulated the expression of SATB2, Runx2, osterix, and bone matrix proteins. Conversely, knockdown of PHF8 reduced the expression of these genes. Furthermore, ChIP assays confirmed that PHF8 specifically bound to the transcription start site (TSS) of the SATB2 promoter, and the expression of H3K9me1 at the TSS region of SATB2 decreased in PHF8 overexpressed group. Implantation of the BMSCs overexpressing PHF8 with silk protein scaffolds promoted bone regeneration in critical-sized defects in mouse calvaria. Taken together, our results demonstrated that PHF8 epigenetically modulates SATB2 activity, triggering BMSCs osteogenic differentiation and facilitating bone formation and regeneration in biodegradable silk scaffolds.</P>

EFFECTS OF ULTRASONIC RADIATION INTENSITY ON THE OXIDATION OF SINGLE-WALLED CARBON NANOTUBES IN A MIXTURE OF SULFURIC AND NITRIC ACIDS

RUI HE,XIBO PEI,LANLAN PAN,LINGYANG TIAN,Feng Luo,LEI SUI,QIANBING WAN,JIAN WANG 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2013 NANO Vol.8 No.4

One of the most commonly used techniques for purification and eventual dispersion of single-wall carbon nanotubes (SWNTs) is oxidation using strong acid and ultrasonication. Literature review reveals that ultrasonication of varying radiation intensities have been used during the acid oxidation, but few have reported whether ultrasonication of different intensities would have different effects on the structure and properties of SWNTs and how the effects are. An investigation of the effects of ultrasonic radiation intensity on SWNTs during oxidation in a mixture of sulfuric and nitric acids was conducted. Ultrasonication using different intensities (50 W, 100 W, 200 W and 300 W) was used. The acid-treated SWNTs were characterized by scanning and transmission electron microscopy, Fourier transform infrared spectroscopy, zeta potential test Boehm titration test and Raman spectrum analysis. Data from these experiments showed that high intensities provided stronger oxidizing conditions than lower ones. As ultrasonic intensity increased, larger number of SWNTs were destroyed and consumed to produce carbonaceous impurities, and more defects appeared in the tube walls.

Serum lipocalin-2 is a potential biomarker for the clinical diagnosis of nonalcoholic steatohepatitis

( Gang Xu ),( Yu-min Wang ),( Miao-miao Ying ),( Sui-dan Chen ),( Zong-rui Li ),( Hong-lei Ma ),( Ming-hua Zheng ),( Jian Wu ),( Chunming Ding ) 대한간학회 2021 Clinical and Molecular Hepatology(대한간학회지) Vol.27 No.2

Background/Aims: Nonalcoholic steatohepatitis (NASH) is a progressive form of nonalcoholic fatty liver disease (NAFLD) characterized by hepatic steatosis, inflammation, hepatocellular injury, and fibrosis. We aimed to investigate the usefulness of a key biomarker, lipocalin-2 (LCN2), for the detection of NASH progression. Methods: A mouse NASH model was established using a high-fat diet and a high-sugar drinking water. Gene expression profile of the NASH model was analyzed using RNA sequencing. Moreover, 360 NAFLD patients (steatosis, 83; NASH, 277), 40 healthy individuals, and 87 patients with alcoholic fatty liver disease were recruited. Results: Inflammatory infiltration, focal necrosis in the leaflets, steatosis, and fibrosis were documented in the mouse liver. In total, 504 genes were differentially expressed in the livers of NASH mice, and showed significant functional enrichment in the inflammation-related category. Upregulated liver LCN2 was found to be significantly interactive with various interleukins and toll-like receptors. Serum LCN2 levels were significantly increased in NAFLD patients. Serum LCN2 levels were correlated with steatosis, intralobular inflammation, semiquantitative fibrosis score, and nonalcoholic fatty liver disease activity score. The area under the curve of serum LCN2 was 0.987 with a specificity of 100% and a sensitivity of 93.5% for NASH diagnosis, and 0.977 with almost the same specificity and sensitivity for steatosis. Conclusions: LCN2 might be involved in the transition from NAFL to NASH by mediating inflammation. Serum LCN2 levels might be a novel biomarker for the diagnosis of NASH. (Clin Mol Hepatol 2021;27:329-345)