Dual-Responsive Shape Memory and Thermally Reconfigurable Reduced Graphene Oxide-Vitrimer Composites

Guo-kang Chen,Kun Wu,Qian Zhang,Yan-cen Shi,Man-geng Lu 한국고분자학회 2019 Macromolecular Research Vol.27 No.6

In this paper, we have prepared shape memory reduced graphene oxidevitrimer composites via in situ reduction of graphene oxide (GO) during the curing reaction. Because of good compatibility between GO and epoxy resin, reduced graphene oxide (rGO) has a good dispersion in the epoxy matrix. Conventional thermoset shape memory polymers can only maintain one permanent shape, while these obtained composites can be randomly reconfigured into other shapes via dynamic covalent transesterification reaction at 200 °C above transesterification temperature (TV). They can recover quickly from fixed shapes to their initial shapes with shape fixity ratio higher than 95% and shape recovery ratio higher than 97%. Besides, the rGO-vitrimers show good mechanical properties and thermal stabilities. In addition, sequent nearinfrared (NIR) irradiation can control the shape recovery, because rGO can serve as an energy convertor to convert NIR irradiation into thermal energy.

Ginsengenin derivatives synthesized from 20(R)-panaxotriol: Synthesis, characterization, and antitumor activity targeting HIF-1 pathway

Guo, Hong-Yan,Xing, Yue,Sun, Yu-Qiao,Liu, Can,Xu, Qian,Shang, Fan-Fan,Zhang, Run-Hui,Jin, Xue-Jun,Chen, Fener,Lee, Jung Joon,Kang, Dongzhou,Shen, Qing-Kun,Quan, Zhe-Shan The Korean Society of Ginseng 2022 Journal of Ginseng Research Vol.46 No.6

Background: Ginseng possesses antitumor effects, and ginsenosides are considered to be one of its main active chemical components. Ginsenosides can further be hydrolyzed to generate secondary saponins, and 20(R)-panaxotriol is an important sapogenin of ginsenosides. We aimed to synthesize a new ginsengenin derivative from 20(R)-panaxotriol and investigate its antitumor activity in vivo and in vitro. Methods: Here, 20(R)-panaxotriol was selected as a precursor and was modified into its derivatives. The new products were characterized by ¹H-NMR, ¹³C-NMR and HR-MS and evaluated by molecular docking, MTT, luciferase reporter assay, western blotting, immunofluorescent staining, colony formation assay, EdU labeling and immunofluorescence, apoptosis assay, cells migration assay, transwell assay and in vivo antitumor activity assay. Results: The derivative with the best antitumor activity was identified as 6,12-dihydroxy-4,4,8,10,14-pentamethyl-17-(2,6,6-trimethyltetrahydro-2H-pyran-2-yl)hexadecahydro-1H-cyclopenta[a]phenanthren-3-yl(tert-butoxycarbonyl)glycinate (A11). The focus of this research was on the antitumor activity of the derivatives. The efficacy of the derivative A11 (IC₅₀ < 0.3 µM) was more than 100 times higher than that of 20(R)- panaxotriol (IC₅₀ > 30 µM). In addition, A11 inhibited the protein expression and nuclear accumulation of the hypoxia-inducible factor HIF-1α in HeLa cells under hypoxic conditions in a dose-dependent manner. Moreover, A11 dose-dependently inhibited the proliferation, migration, and invasion of HeLa cells, while promoting their apoptosis. Notably, the inhibition by A11 was more significant than that by 20(R)-panaxotriol (p < 0.01) in vivo. Conclusion: To our knowledge, this is the first study to report the production of derivative A11 from 20(R)-panaxotriol and its superior antitumor activity compared to its precursor. Moreover, derivative A11 can be used to further study and develop novel antitumor drugs.

Ginsenoside Rb1 exerts neuroprotective effects through regulation of Lactobacillus helveticus abundance and GABA_A receptor expression

Chen, Huimin,Shen, Jiajia,Li, Haofeng,Zheng, Xiao,Kang, Dian,Xu, Yangfan,Chen, Chong,Guo, Huimin,Xie, Lin,Wang, Guangji,Liang, Yan The Korean Society of Ginseng 2020 Journal of Ginseng Research Vol.44 No.1

Background: Ginsenoside Rb1 (Rb1), one of the most abundant protopanaxadiol-type ginsenosides, exerts excellent neuroprotective effects even though it has low intracephalic exposure. Purpose: The present study aimed to elucidate the apparent contradiction between the pharmacokinetics and pharmacodynamics of Rb1 by studying the mechanisms underlying neuroprotective effects of Rb1 based on regulation of microflora. Methods: A pseudo germ-free (PGF) rat model was established, and neuroprotective effects of Rb1 were compared between conventional and PGF rats. The relative abundances of common probiotics were quantified to reveal the authentic probiotics that dominate in the neuroprotection of Rb1. The expressions of the gamma-aminobutyric acid (GABA) receptors, including GABAA receptors (α2, β2, and γ2) and GABAB receptors (1b and 2), in the normal, ischemia/reperfusion (I/R), and I/R+Rb1 rat hippocampus and striatum were assessed to reveal the neuroprotective mechanism of Rb1. Results: The results showed that microbiota plays a key role in neuroprotection of Rb1. The relative abundance of Lactobacillus helveticus (Lac.H) increased 15.26 fold after pretreatment with Rb1. I/R surgery induced effects on infarct size, neurological deficit score, and proinflammatory cytokines (IL-1β, IL-6, and TNF-α) were prevented by colonizing the rat gastrointestinal tract with Lac.H (1 × 10⁹ CFU) by gavage 15 d before I/R surgery. Both Rb1 and Lac.H upregulated expression of GABA receptors in I/R rats. Coadministration of a GABA_A receptor antagonist significantly attenuated neuroprotective effects of Rb1 and Lac.H. Conclusion: In sum, Rb1 exerts neuroprotective effects by regulating Lac.H and GABA receptors rather than through direct distribution to the target sites.

Obstacle-negotiation performance on challenging terrain for a parallel legwheeled robot

Kang Xu,Shou-Kun Wang,Binkai Yue,Jun-Zheng Wang,Fei Guo,Zhihua Chen 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.1

High obstacle-negotiation performance of quadruped robots for the challenging terrain is strongly demanded in some fields, including payload delivery and disaster relief. In this study, a parallel leg-wheeled robot with the high mobility performance on targeted types of rough terrain is proposed. In contrast to other obstacle-negotiating robots, the strength of this robot is that it has adequate over-obstacle capabilities with a horizontal body in terms of different obstacle shapes, which mainly derives from the multi-DOF (degree of freedom) flexible locomotion of legs and the independent actuated wheels as end effectors. Particularly for a steep terrain where a large inertia robot negotiates it with low efficiency and stability, the proposed step-over gait, combined with static gait and wheeled locomotion, improves the overobstacle efficiency and maintains pose stability. Finally, simulations and experiments verify the performance on negotiating the diverse obstacles with level body over challenging terrain.

Association between FGFRs and the susceptibility of digestive and reproductive system cancers in Chinese population

Jia-Kang Wang,Shu-jun Guo,Bao-qing Tian,Chnag-jun Nie,Hai-long Wang,Jia-lang Wang,An Hong,Xiao-jia Chen 대한독성 유전단백체 학회 2017 Molecular & cellular toxicology Vol.13 No.4

Fibroblast growth factors(FGFs) and their receptors (FGFRs) modulate a wide range of biological functions, especially tumor genesis. The aim of this study was to investigate the possible association of FGFR expression with the susceptibility of digestive system and reproductive system cancers in Chinese population. In total, 343 patients with digestive or reproductive system cancers were enrolled in this study. The expression levels of four highly-conserved FGFRs including FGFR1, FGFR2, FGFR3 and FGFR4 were measured by immunohistochemistry (IHC). The expression levels of FGFRs were compared between carcinoma and para-carcinoma tissues. FGFR1 expression significantly differed between carcinoma and para-carcinoma tissues in colon and gastric cancers. FGFR2 expression significantly differed between carcinoma and para-carcinoma tissues in esophageal cancer. FGFR3 expression was significantly different between carcinoma and para-carcinoma tissues in liver and gastric cancers. FGFR2 showed the highest expression probability in all the selected cancers and FGFR4 showed the lowest expression probability. FGFR1 and FGFR3 showed comparable moderate expression probabilities. Our findings have demonstrated significant differences regarding FGFR expression levels between carcinoma and para-carcinoma cells in digestive or reproductive system cancer patients. The data also implicated that FGFR2 and FGFR4 could serve as two prominent factors closely related to the susceptibility of digestive and reproductive system cancers.

Ginsenoside Rb1 exerts neuroprotective effects through regulation of Lactobacillus helveticus abundance and GABAA receptor expression

Huimin Chen,Jiajia Shen,Haofeng Li,Xiao Zheng,Dian Kang,Yangfan Xu,Chong Chen,Huimin Guo,Lin Xie,Guangji Wang,Yan Liang 고려인삼학회 2020 Journal of Ginseng Research Vol.44 No.1

Background: Ginsenoside Rb1 (Rb1), one of the most abundant protopanaxadiol-type ginsenosides, exertsexcellent neuroprotective effects even though it has low intracephalic exposure. Purpose: The present study aimed to elucidate the apparent contradiction between the pharmacokineticsand pharmacodynamics of Rb1 by studying the mechanisms underlying neuroprotective effects ofRb1 based on regulation of microflora. Methods: A pseudo germ-free (PGF) rat model was established, and neuroprotective effects of Rb1 werecompared between conventional and PGF rats. The relative abundances of common probiotics werequantified to reveal the authentic probiotics that dominate in the neuroprotection of Rb1. The expressionsof the gamma-aminobutyric acid (GABA) receptors, including GABAA receptors (a2, b2, and g2) andGABAB receptors (1b and 2), in the normal, ischemia/reperfusion (I/R), and I/RþRb1 rat hippocampus andstriatum were assessed to reveal the neuroprotective mechanism of Rb1. Results: The results showed that microbiota plays a key role in neuroprotection of Rb1. The relativeabundance of Lactobacillus helveticus (Lac.H) increased 15.26 fold after pretreatment with Rb1. I/R surgeryinduced effects on infarct size, neurological deficit score, and proinflammatory cytokines (IL-1b, IL-6, andTNF-a) were prevented by colonizing the rat gastrointestinal tract with Lac.H (1 109 CFU) by gavage 15d before I/R surgery. Both Rb1 and Lac.H upregulated expression of GABA receptors in I/R rats. Coadministrationof a GABAA receptor antagonist significantly attenuated neuroprotective effects of Rb1 and Lac.H. Conclusion: In sum, Rb1 exerts neuroprotective effects by regulating Lac.H and GABA receptors ratherthan through direct distribution to the target sites.

A dual-experience pool deep reinforcement learning method and its application in fault diagnosis of rolling bearing with unbalanced data

Yuxiang Kang,Guo Chen,Wenping Pan,Xunkai Wei,Hao Wang,Zhiyuan He 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.6

A dual-experience pool deep reinforcement learning (DEPDRL) model is proposed for rolling bearing fault diagnosis with unbalanced data. In this method, a dualexperience pool structure is designed to store the sample data of majority and minority classes. A parallel double residual network model is established to extract deep features of the majority and minority input samples, respectively. In the process of training, the proposed balanced cross-sampling technique is used to randomly select samples from dual-experience pool in a certain proportion to realize the training of a double residual network model. We show the effectiveness of our method on three standard data sets, and compared with Resnet18, DCNN, DQN and DQNimb methods, the results show that DEPDRL has the best performance. Finally, with wavelet time-frequency graph as input, DEPDRL is applied to rolling bearing fault diagnosis with unbalanced test data. The results show that on a variety of unbalanced data sets, both the diagnostic accuracy and the G-means value of the DEPDRL are more than 5 % higher than other algorithms, which fully indicates that the DEPDRL has a very high fault diagnosis ability of rolling bearing with unbalanced data.

Genomic and Transcriptomic Characterization Revealed the High Sensitivity of Targeted Therapy and Immunotherapy in a Subset of Endometrial Stromal Sarcoma

Nan Kang,Yinli Zhang,Shichao Guo,Ran Chen,Fangzhou Kong,Shuchun Wang,Mingming Yuan,Rongrong Chen,Danhua Shen,Jianliu Wang 대한암학회 2023 Cancer Research and Treatment Vol.55 No.3

Purpose The unique chromosomal rearrangements of endometrial stromal sarcoma (ESS) make it possible to distinguish high-grade ESS (HGESS) and low-grade ESS (LGESS) from the molecular perspective. Analysis of ESS at the genomic and transcriptomic levels can help us achieve accurate diagnosis of ESS and provide potential therapy options for ESS patients.Materials and Methods A total of 36 ESS patients who conducted DNA- and/or RNA-based next-generation sequencing were retrospectively enrolled in this study. The molecular characteristics of ESS at genomic and transcriptomic levels, including mutational spectrum, fusion profiles, gene expression and pathway enrichment analysis and features about immune microenvironment were comprehensively explored.Results <i>TP53</i> and <i>DNMT3A</i> mutations were the most frequent mutations. The classical fusions frequently found in <i>HGESS</i> (<i>ZC3H7B-BCOR</i> and <i>NUTM2B-YWHAE</i>) and LGESS (<i>JAZF1-SUZ12</i>) were detected in our cohort. <i>CCND1</i> was significantly up-regulated in HGESS, while the expression of <i>GPER1</i> and <i>PGR</i> encoding estrogen receptor (ER) and progesterone receptor (PR) did not differ significantly between HGESS and LGESS. Actionable mutations enriched in homologous recombination repair, cell cycle, and phosphoinositide 3-kinase/AKT/mammalian target of rapamycin pathways were detected in 60% of HGESS patients. Genes with up-regulated expression in HGESS were significantly enriched in five immune-related pathways. Most HGESS patients (85.7%) had positive predictors of immunotherapy efficacy. Moreover, immune microenvironment analysis showed that HGESS had relatively high immune infiltration. The degree of immune infiltration in HGESS patients with <i>ZC3H7B-BCOR</i> fusion was relatively higher than that of those with <i>NUTM2B-YWHAE</i> fusion.Conclusion This study investigated the molecular characteristics of ESS patients at the genomic and transcriptomic levels and revealed the potentially high sensitivity of targeted therapy and immunotherapy in a subset of HGESS with specific molecular features, providing a basis for guiding decision-making of treatment and the design of future clinical trials on precision therapy.

Experimental Study on Waterproofing Properties of Putty-Based Composite Rubber Strip for Underground Post-Tensioned Precast Concrete Structures

Xiang-guo Wu,Xiao-kai Chen,Shi-yan Yu,Seongwon Hong,Thomas H.-K. Kang 한국콘크리트학회 2019 International Journal of Concrete Structures and M Vol.13 No.1

The proper assembly of underground precast concrete structures is often critical in the construction of underground structures. In particular, interfacial waterproofing between precast concrete segments is a key factor influencing use, safety, and life span. Current practice is to incorporate waterproofing rubber strips in the design. During the installation process, compressive stress is applied to the strip by post-tensioning to achieve performance. For this paper, lateral constraint compression tests were carried out on composite rubber seal strips that utilize putty. Special waterproofing and sealing test devices were designed to investigate corresponding relationships between water pressure and compressive stress (or strain). A relationship between water resistance pressure and compression stress and strain of the putty-based composite rubber strip was proposed based on the series tests and the control target of the minimum compression strain of the putty composite rubber strip was then suggested. Finally, full-scale waterproofing tests on tunnel joints were conducted. The experimental results provide a scientific reference for the engineering application and design of composite sealing rubber strips putty for underground post-tensioned precast concrete structures.

Nine facultative endosymbionts in aphids. A review

Jianqing Guo,Séverin Hatta,Kang-lai He,Julian Chen,Frédéric Francis,Zhen-ying Wang 한국응용곤충학회 2017 Journal of Asia-Pacific Entomology Vol.20 No.3

Aphids are frequently engaged in mutualistic associations with endosymbionts. Symbionts are bacterial or fungal microorganisms that can be obligate or facultative to aphids. Research showed facultative (or secondary) symbionts have numerous effects on their host aphids such as resistance to heat shock, parasitoids and fungus etc., which may consequently promote a co-evolution between symbionts and hosts. However, this symbiotic relation may be affected by several factors, such as the ability of symbionts to spread from aphids to others within and across populations, and the cost of infections for hosts. Moreover, aphid-symbionts interactions may be affected by aphid living environment such as its host plant, the presence of natural enemies or the temperature. Here we firstly described the functions of nine facultative symbionts (Serratia symbiotica, Hamiltonella defensa, Regiella insecticola, Rickettsia, Rickettsiella, PAXS (pea aphid X-type symbiont), Spiroplasma, Wolbachia and Arsenophonus) studied in aphids one by one, and discussed the associations between these symbionts and aphids, plants and environment. We aim to have a better knowledge of the roles the facultative symbionts play in aphid biology, ecology and evolution, which we believe can provide new inspirations for aphid control.