Comparative study on the structures and properties of organo-montmorillonite and organo-palygorskite in oil-based drilling fluids

Zepeng Zhang,Guanzheng Zhuang,Maguy Jaber,Jiahua Gao,Shanmao Peng 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.56 No.-

This work aims to reveal the differences of structures and properties between organo-montmorillonite(OMt) and organo-palygorskite (OPal) in oil-based drillingfluids. Organoclays are prepared in aqueoussolution and characterized by XRD, SEM and TEM. Surfactants can intercalate into the interlayer space ofMt while they coat only on the palygorskite surface. OMt can form “house of cards” structure while OPalforms “haystack” structure. Temperature rising promotes network structure and rheological properties oforganoclays in oil. The decline of rheological properties at high temperature is mainly caused by thedissolution of surfactants into oil, instead of thermal decomposition.

An improved bearing fault diagnosis method based on variational mode decomposition and adaptive iterative filtering (VMD-AIF)

Lei Fu,Zepeng Ma,Yikun Zhang,Sinian Wang,Libin Zhang 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.4

Rolling bearings are widely applied in rotary machines. Bearing failures can lead to long machine downtime and costly maintenance. To reduce the maintenance time and cost, this article proposes a new denoising approach to remove heavy noise and extract weak bearing fault vibration features. The first step proposes a global variational mode decomposition (VMD) optimization algorithm that adaptively matches the optimal decomposition parameters based on kurtosis. In the second step, an adaptive selection criterion for IMF is developed by kurtosis theory. Meanwhile, an adaptive termination criterion is established based on sample entropy (SampEn), and the fault features are extracted with a Butterworth band-pass filter (BBF). Finally, actual fault-bearing experiments are performed using the proposed denoising approach. The comparison with respect to EEMD and WPD is illustrated in detail. The experimental result shows that the proposed approach is a validated tool for the diagnosis of bearings.

Distinct evolution of toll‑like receptor signaling pathway genes in cetaceans

Ran Tian,Inge Seim,Zepeng Zhang,Ying Yang,Wenhua Ren,Shixia Xu,Guang Yang 한국유전학회 2019 Genes & Genomics Vol.41 No.12

Background The relatively rapid spread and diversity of marine pathogens posed an initial and ongoing challenge for cetaceans (whales, dolphins, and porpoises), descendants of terrestrial mammals that transitioned from land to sea approximately 56 million years ago. Toll-like receptors (TLRs) play important roles in regulating immunity against pathogen infections by detecting specific molecular patterns and activating a wide range of downstream signaling pathways. The ever-increasing catalogue of mammalian genomes offers unprecedented opportunities to reveal genetic changes associated with evolutionary and ecological processes. Objective This study aimed to explore the molecular evolution of TLR signaling pathway genes in cetaceans. Methods Genes involved in the TLR signaling pathway were retrieved by BLAST searches using human coding sequences as queries. We tested each gene for positive selection along the cetacean branches using PAML and Hyphy. Physicochemical property changes of amino acids at all positively selected residues were assessed by TreeSAAP and visualized with WebLogo. Bovine and dolphin TLR4 was assessed using human embryonic kidney cell line HEK293, which lacks TLR4 and its co-receptor MD-2. Results We demonstrate that eight TLR signaling pathway genes are under positive selection in cetaceans. These include key genes in the response to Gram-negative bacteria: TLR4, CD14, and LY96 (MD-2). Moreover, 41 out of 65 positively selected sites were inferred to harbor substitution that dramatically changes the physicochemical properties of amino acids, with most of them situated in or adjacent to functional regions. We also found strong evidence that positive selection occurred in the lineage of the Yangtze finless porpoise, likely reflecting relatively recent adaptions to a freshwater milieu. Species-specific differences in TLR4 response were observed between cetacean and terrestrial species. Cetacean TLR4 was significantly less responsive to lipopolysaccharides from a terrestrial E. coli strain, possibly a reflection of the arms race of host–pathogen co-evolution faced by cetaceans in an aquatic environment. Conclusion This study provides further impetus for studies on the evolution and function of the cetacean immune system.

Energy-harvesting Q-learning secure routing algorithm with authenticated-encryption for WSN

Li Cuiran,Wu Jixuan,Zhang Zepeng,Lv Anqi 한국통신학회 2023 ICT Express Vol.9 No.6

Wireless sensor networks are susceptible to a variety of network attacks. Due to the limited energy of nodes and selfish nodes in the network, the packet delivery rate is lower. To address these issues, we innovatively propose an energy-harvesting Q-learning secure routing algorithm with authenticated-encryption. The algorithm uses physical unclonable functions and optimized Q-learning to ensure that the transmission path is reliable. Meanwhile, we combine the LSTM-based prediction model to predict the energy value that the nodes replenish. In addition, simulations are performed to compare the performances of the proposed algorithm with other algorithms under different attacks. The proposed algorithm has greater improvements in the packet delivery rate, filtering selfish nodes, and reducing node energy consumption.

Ginsenoside compound K protects against cerebral ischemia/ reperfusion injury via Mul1/Mfn2-mediated mitochondrial dynamics and bioenergy

Qingxia Huang,Jing Li,Jinjin Chen,Zepeng Zhang,Peng Xu,Hongyu Qi,Zhaoqiang Chen,Jiaqi Liu,Jing Lu,Mengqi Shi,Yibin Zhang,Ying Ma,Daqing Zhao,Xiangyan Li The Korean Society of Ginseng 2023 Journal of Ginseng Research Vol.47 No.3

Background: Ginsenoside compound K (CK), the main active metabolite in Panax ginseng, has shown good safety and bioavailability in clinical trials and exerts neuroprotective effects in cerebral ischemic stroke. However, its potential role in the prevention of cerebral ischemia/reperfusion (I/R) injury remains unclear. Our study aimed to investigate the molecular mechanism of ginsenoside CK against cerebral I/R injury. Methods: We used a combination of in vitro and in vivo models, including oxygen and glucose deprivation/reperfusion induced PC12 cell model and middle cerebral artery occlusion/reperfusion induced rat model, to mimic I/R injury. Intracellular oxygen consumption and extracellular acidification rate were analyzed by Seahorse multifunctional energy metabolism system; ATP production was detected by luciferase method. The number and size of mitochondria were analyzed by transmission electron microscopy and MitoTracker probe combined with confocal laser microscopy. The potential mechanisms of ginsenoside CK on mitochondrial dynamics and bioenergy were evaluated by RNA interference, pharmacological antagonism combined with co-immunoprecipitation analysis and phenotypic analysis. Results: Ginsenoside CK pretreatment could attenuate mitochondrial translocation of DRP1, mitophagy, mitochondrial apoptosis, and neuronal bioenergy imbalance against cerebral I/R injury in both in vitro and in vivo models. Our data also confirmed that ginsenoside CK administration could reduce the binding affinity of Mul1 and Mfn2 to inhibit the ubiquitination and degradation of Mfn2, thereby elevating the protein level of Mfn2 in cerebral I/R injury. Conclusion: These data provide evidence that ginsenoside CK may be a promising therapeutic agent against cerebral I/R injury via Mul1/Mfn2 mediated mitochondrial dynamics and bioenergy.

Major ginsenosides from Panax ginseng promote aerobic cellular respiration and SIRT1-mediated mitochondrial biosynthesis in cardiomyocytes and neurons

Huang, Qingxia,Lou, Tingting,Lu, Jing,Wang, Manying,Chen, Xuenan,Xue, Linyuan,Tang, Xiaolei,Qi, Wenxiu,Zhang, Zepeng,Su, Hang,Jin, Wenqi,Jing, Chenxu,Zhao, Daqing,Sun, Liwei,Li, Xiangyan The Korean Society of Ginseng 2022 Journal of Ginseng Research Vol.46 No.6

Background: Aerobic cellular respiration provides chemical energy, adenosine triphosphate (ATP), to maintain multiple cellular functions. Sirtuin 1 (SIRT1) can deacetylate peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α) to promote mitochondrial biosynthesis. Targeting energy metabolism is a potential strategy for the prevention and treatment of various diseases, such as cardiac and neurological disorders. Ginsenosides, one of the major bioactive constituents of Panax ginseng, have been extensively used due to their diverse beneficial effects on healthy subjects and patients with different diseases. However, the underlying molecular mechanisms of total ginsenosides (GS) on energy metabolism remain unclear. Methods: In this study, oxygen consumption rate, ATP production, mitochondrial biosynthesis, glucose metabolism, and SIRT1-PGC-1α pathways in untreated and GS-treated different cells, fly, and mouse models were investigated. Results: GS pretreatment enhanced mitochondrial respiration capacity and ATP production in aerobic respiration-dominated cardiomyocytes and neurons, and promoted tricarboxylic acid metabolism in cardiomyocytes. Moreover, GS clearly enhanced NAD⁺-dependent SIRT1 activation to increase mitochondrial biosynthesis in cardiomyocytes and neurons, which was completely abrogated by nicotinamide. Importantly, ginsenoside monomers, such as Rg1, Re, Rf, Rb1, Rc, Rh1, Rb2, and Rb3, were found to activate SIRT1 and promote energy metabolism. Conclusion: This study may provide new insights into the extensive application of ginseng for cardiac and neurological protection in healthy subjects and patients.

Single-cell RNA sequencing analysis of human bone-marrow-derived mesenchymal stem cells and functional subpopulation identification

Xie Zhongyu,Yu Wenhui,Ye Guiwen,Li Jinteng,Zheng Guan,Liu Wenjie,Lin Jiajie,Su Zepeng,Che Yunshu,Ye Feng,Zhang Zhaoqiang,Wang Peng,Wu Yanfeng,Shen Huiyong 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-

Mesenchymal stem cells (MSCs) are a common kind of multipotent cell in vivo, but their heterogeneity limits their further applications. To identify MSC subpopulations and clarify their relationships, we performed cell mapping of bone-marrow-derived MSCs through single-cell RNA (scRNA) sequencing. In our study, three main subpopulations, namely, the stemness subpopulation, functional subpopulation, and proliferative subpopulation, were identified using marker genes and further bioinformatic analyses. Developmental trajectory analysis showed that the stemness subpopulation was the root and then became either the functional subpopulation or the proliferative subpopulation. The functional subpopulation showed stronger immunoregulatory and osteogenic differentiation abilities but lower proliferation and adipogenic differentiation. MSCs at different passages or isolated from different donors exhibited distinct cell mapping profiles, which accounted for their corresponding different functions. This study provides new insight into the biological features and clinical use of MSCs at the single-cell level, which may contribute to expanding their application in the clinic.