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Shu-Hua Yang,Kai-Chiang Yang,Chih-Wei Chen,Ting-Chun Huang,Yuanhui Sun,Ming-Hsiao Hu 대한척추외과학회 2019 Asian Spine Journal Vol.13 No.5
Study Design: In vitro cell culture study. Purpose: This study aims to investigate the impact of transforming growth factor-beta1 (TGF-β1) and lovastatin on differentiating human mesenchymal stem cells (MSCs) toward nucleus pulposus (NP)-like phenotype. Overview of Literature: MSCs offer a cell source to the cell-based therapy for intervertebral disc degeneration. TGF-β1 is used to induce MSCs to differentiate into NP-like cells; however, an undesired expression of collagen type I has been reported. Statins reportedly stimulate expression of bone morphogenetic protein-2 (BMP-2) and promote the chondrogenic phenotype to NP cells. However, the effects of statins with or without TGF-β1 on the differentiation of MSCs into NP-like cells remain unclear. Methods: Human MSCs were treated with TGF-β1 alone, lovastatin alone, and simultaneous or sequential treatment with TGF-β1 and lovastatin. After the proposed stimulation, the total RNA was extracted to assess the expression profile of NP cells-specific genes. Hematoxylin–eosin staining was used for examining the microscopic morphology. Furthermore, we detected the syntheses of S-100 protein, aggrecan , and collagen type II in the extracellular matrix using immunohistochemical staining. Results: Simultaneous or sequential treatment of TGF-β1 and lovastatin could further augment the BMP-2 overexpression compared with lovastatin-alone treatment. However, the mRNA expression of aggrecan and collagen type II was not compatible with the expression level of BMP-2 . Immunohistochemical studies revealed compatible production of aggrecan, collagen type II , and S-100 protein in all three groups treated with lovastatin. Cells in groups treated with lovastatin were less populated than that in the group treated with TGF-β1 alone. Conclusions: This study demonstrates a promising role of lovastatin in inducing human MSCs into NP-like cells. However, further optimization of cell density before lovastatin treatment, treatment duration, and combination with TGF-β1 are warranted to attain better stimulatory effects.
A New Triterpenoid from Brucea javanica
Jian Hua Liu,Jiang Jiang Qin,Hui Zi Jin,Xiao Jia Hu,Ming Chen,Yun Heng Shen,Shi Kai Yan,Wei Dong Zhang 대한약학회 2009 Archives of Pharmacal Research Vol.32 No.5
A new triterpenoid, bruceajavanin C (1), together with bruceosides A and B (2 and 3), bruceines D and E (4 and 5), yadanziosides A and G (6 and 7), (20R)-O-(3)-α-L-arabinopyranosylpregn- 5-ene-3β,20-diol (8), and α-D-glucopyranoside, (3β, 20R)-3-hydroxypregn-5-en-20-yl (9) were isolated from the aerial parts of Brucea javanica. The structure of 1 was elucidated on the basis of 2D-NMR spectroscopic analysis. In addition, compounds 1, 3, 4, 5, and 6 exhibited mild inhibitory effect on NO production in LPS-stimulated RAW264.7 cells.
Peng Wanga,Wei Huang,GuangZhi Zhang,Zhi-hua Gao,Yu Tang,Kai Sun,XiaoYu Zhang 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.26 No.-
Modified aluminum alkoxide prepared by alcoholysis was used as an aluminum source in the complete liquid-phase technology for the preparation of slurry catalysts. The use of the modified aluminum alkoxide afforded control over the rate of the hydrolysis/condensation reactions during the preparation of the catalyst precursors, thereby generating catalysts with a fine nano-structured active metal and metallic oxide particles. Four types of Cu–Zn–Al (molar ratio is 2:1:4) catalysts were prepared using different procedures. These catalysts were tested for CO hydrogenation at 553 K, 4.0 MPa and H2/ CO = 1.0 in a kettle with a mechanical agitator. The results indicated that the activity of the catalysts was greatly dependent on the rate of the hydrolysis/condensation reactions, and the catalyst with the best catalytic performance was obtained by controlling the hydrolysis/alcoholysis rate during catalyst synthesis by pre-alcoholysis of AIP as the aluminum source, over which the CO conversion and dimethyl ether selectivity could reach 62.6% and 62.5%, respectively.
Increasing the Lifetime of Ad Hoc Networks Using Hierarchical Cluster-based Power Management
( Tin-yu Wu ),( Kai-hua Kuo ),( Hua-pu Cheng ),( Jen-wen Ding ),( Wei-tsong Lee ) 한국인터넷정보학회 2011 KSII Transactions on Internet and Information Syst Vol.5 No.1
One inevitable problem in Ad Hoc networks is the limited battery capacity, which explains why portable devices might shut down suddenly when the power of hardware is depleted. Hence, how to decrease the power consumption is an important issue in ad hoc networks. With the development of wireless technology, mobile devices can transmit voices, surf the Internet, download entertaining stuffs, and even support some P2P applications, like sharing real-time streaming. In order to keep the quality stable, the transmission must be continuous and it is thus necessary to select some managers to coordinate all nodes in a P2P community. In addition to assigning jobs to the staffs (children) when needed, these managers (ancestors) are able to reappoint jobs in advance when employees retire. This paper proposed a mechanism called Cluster-based Power Management (CPM) to stabilize the transmissions and increase Time to Live (TTL) of mobile hosts. In our new proposed method, we establish the clusters according to every node`s joining order and capability, and adjust their sleep time dynamically through three different mathematical models. Our simulation results reveal that this proposed scheme not only reduces the power consumption efficiently, but also increases the total TTLs evidently.
Bingge Zhao,Yuanfang Wang,Kai Ding,Guanzhi Wu,Tao Wei,Hua Pan,Yulai Gao 한국강구조학회 2023 International Journal of Steel Structures Vol.23 No.4
Among the 3rd generation advanced high strength steels, medium Mn steels receive extensive attention sed in modern automotive industry attributing to their encouraging mechanical performance and lower production cost. Unfortunately, the poor cross-tension property of 7Mn steel, one of the typical medium Mn steels, remains a key challenge to hinder its application in automotive industry. In this study, multiple post-weld heat treatment (MPWHT) consisting of cyclic heat treatment and intercritical annealing was employed to improve the cross-tension property of the resistance spot weld of 7Mn steel. With this method, the diffusion of Mn was significantly enhanced, eliminating their severe segregation along the martensite lath boundaries. Additionally, MPWHT facilitated the structure tailoring: the cyclic heat treatment between room and austenization temperature produced the so-called martensitic transformation induced grain refinement and austenite stability while the intercritical annealing triggered austenite reversion transformation, leading to a mixed structure of refined ferrite and austenite across the weld. With the optimization in composition homogeneity and structure tuning, the cross-tension strength (CTS) of a resistance spot welded 7Mn steel stood at 12.7 kN, which is so far the ultrahigh level to our best knowledge. Moreover, this effort brought on button failure mode, suggesting the dominant ductility deformation during the cross-tension test. In a word, the current study achieved an exceptional trade-off between the outstanding CTS and ductility of the resistance spot weld of 7Mn steel by the MPWHT consisting of cyclic heat treatment and intercritical annealing.
Bingge Zhao,Yuanfang Wang,Kai Ding,Guanzhi Wu,Tao Wei,Hua Pan,Yulai Gao 한국강구조학회 2021 International Journal of Steel Structures Vol.21 No.2
Medium Mn steels, one of the most promising 3rd generation advanced high strength steels (AHSS), achieve an encouraging trade-off between the outstanding mechanical property and the production cost. As a typical medium Mn steel, 7Mn steels have superior mechanical property but their poor cross-tension property becomes the Achilles’ heel, hindering the application in the automotive industry. The current study focuses on the cross-tension property of the resistance spot weld of 7Mn steel. Generally, martensite is produced in the nugget during the resistance spot welding (RSW). However, the microstructure in the weld nugget can be correspondingly tuned by directly optimizing the welding parameters. With post-weld pulses, in situ tempering occurs, which can decrease the segregation of Mn existing along martensite lath boundaries and facilitate the microstructure transition from martensite to tempered martensite. The tuning on the nugget microstructure facilitates the increase of cross-tension strength (CTS) from 1.5 to 3.7 kN. Although both cases fail in an interfacial fracture mode, a partial ductile fracture is demonstrated in the specimen with post-weld treatment, which is attributed to the occurrence of low-carbon α phase and second phase particles. This study elucidates that the decrease of segregation and the microstructure transition in the nugget are the dominant factor determining the CTS. It is therefore demonstrated that the reduction of Mn segregation and the formation of tempered martensite can increase the weldability of RSW joints of the medium Mn steels.
Ginsenoside Rg1 promotes neurite growth of retinal ganglion cells through cAMP/PKA/CREB pathways
Ye-ying Jiang,Rong-yun Wei,Kai Tang,Zhen Wang,Ning-hua Tan The Korean Society of Ginseng 2024 Journal of Ginseng Research Vol.48 No.2
Background: Mechanisms of synaptic plasticity in retinal ganglion cells (RGCs) are complex and the current knowledge cannot explain. Growth and regeneration of dendrites together with synaptic formation are the most important parameters for evaluating the cellular protective effects of various molecules. The effect of ginsenoside Rg1 (Rg1) on the growth of retinal ganglion cell processes has been poorly understood. Therefore, we investigated the effect of ginsenoside Rg1 on the neurite growth of RGCs. Methods: Expression of proteins and mRNA were detected by Western blot and qPCR. cAMP levels were determined by ELISA. In vivo effects of Rg1 on RGCs were evaluated by hematoxylin and eosin, and immunohistochemistry staining. Results: This study found that Rg1 promoted the growth and synaptic plasticity of RGCs neurite by activating the cAMP/PKA/CREB pathways. Meanwhile, Rg1 upregulated the expression of GAP43, Rac1 and PAX6, which are closely related to the growth of neurons. Meantime, H89, an antagonist of PKA, could block this effect of Rg1. In addition, we preliminarily explored the effect of Rg1 on enhancing the glycolysis of RGCs, which could be one of the mechanisms for its neuroprotective effects. Conclusion: Rg1 promoted neurite growth of RGCs through cAMP/PKA/CREB pathways. This study may lay a foundation for its clinical use of optic nerve diseases in the future.