[P10-53] The Effects of Acanthopanax Senticosus Extracts on Antioxidant Activity and Cell Proliferation/Alkaline Phosphatase Activity in Human Osteoblast-like MG-63 Cell

Line Soyoung Lim,Yu Jung Jang,Jae-Yoon Leem,Sun Yoon 한국식품영양과학회 2006 한국식품영양과학회 학술대회발표집 Vol.2006 No.10

Inhibition of L-type Ca²⁺ current by ginsenoside Rd in rat ventricular myocytes

Lu, Cheng,Sun, Zhijun,Wang, Line The Korean Society of Ginseng 2015 Journal of Ginseng Research Vol.39 No.2

Background: Ginsenoside Rd (GSRd), one of the most abundant ingredients of Panax ginseng, protects the heart via multiple mechanisms including the inhibition of $Ca^{2+}$ influx.We intended to explore the effects of GSRd on L-type $Ca^{2+}$ current ($I_{Ca,L}$) and define the mechanism of the suppression of $I_{Ca,L}$ by GSRd. Methods: Perforated-patch recording and whole-cell voltage clamp techniques were applied in isolated rat ventricular myocytes. Results: (1) GSRd reduced $I_{Ca,L}$ peak amplitude in a concentration-dependent manner [half-maximal inhibitory concentration $(IC_{50})=32.4{\pm}7.1{\mu}mol/L$] and up-shifted the current-voltage (I-V) curve. (2) GSRd ($30{\mu}mol/L$) significantly changed the steady-state activation curve of $I_{Ca,L}$ ($V_{0.5}:-19.12{\pm}0.68$ vs. $-6.26{\pm}0.38mV$; n = 5, p < 0.05) and slowed down the recovery of $I_{Ca,L}$ from inactivation [the time content (${\zeta}$) from 91 ms to 136 ms, n = 5, p < 0.01]. (3) A more significant inhibitive effect of GSRd ($100{\mu}mol/L$) was identified in perforated-patch recording when compared with whole-cell recording [$65.7{\pm}3.2%$ (n = 10) vs. $31.4{\pm}5.2%$ (n = 5), p < 0.01]. (4) Pertussis toxin ($G_i$ protein inhibitor) completely abolished the $I_{Ca,L}$ inhibition induced by GSRd. There was a significant difference in inhibition potency between the two cyclic adenosine monophosphate elevating agents (isoprenaline and forskolin) prestimulation [$55{\pm}7.8%$ (n = 5) vs. $17.2{\pm}3.5%$ (n = 5), p < 0.01]. (5) 1H-[1,2,4]Oxadiazolo[4,3-a]-quinoxalin-1-one (a guanylate cyclase inhibitor) and N-acetyl-$\small{L}$-cysteine (a nitric oxide scavenger) partly recovered the $I_{Ca,L}$ inhibition induced by GSRd. (6) Phorbol-12-myristate-13-acetate (a protein kinase C activator) and GF109203X (a protein kinase C inhibitor) did not contribute to the inhibition of GSRd. Conclusion: These findings suggest that GSRd could inhibit $I_{Ca,L}$ through pertussis toxin-sensitive G protein ($G_i$) and a nitric oxide-cyclic guanosine monophosphate-dependent mechanism.

Inhibition of L-type Ca<SUP>2+</SUP> current by ginsenoside Rd in rat ventricular myocytes

Cheng Lu,Zhijun Sun,Line Wang 고려인삼학회 2015 Journal of Ginseng Research Vol.39 No.2

Background: Ginsenoside Rd (GSRd), one of the most abundant ingredients of Panax ginseng, protects the heart via multiple mechanisms including the inhibition of Ca<SUP>2+</SUP> influx. We intended to explore the effects of GSRd on L-type Ca2+ current (ICa,L) and define the mechanism of the suppression of ICa,L by GSRd. Methods: Perforated-patch recording and whole-cell voltage clamp techniques were applied in isolated rat ventricular myocytes. Results: (1) GSRd reduced ICa,L peak amplitude in a concentration-dependent manner [half-maximal inhibitory concentration (IC50) = 32.4± 7.1 μmol/L] and up-shifted the currente-voltage (I-V) curve. (2) GSRd (30 μmol/L) significantly changed the steady-state activation curve of ICa,L (V0.5: -19.12± 0.68 vs. -16.26 ± 0.38 mV; n = 5, p < 0.05) and slowed down the recovery of ICa,L from inactivation [the time content (ζ) from 91 ms to 136 ms, n = 5, p < 0.01]. (3) A more significant inhibitive effect of GSRd (100 μmol/L) was identified in perforated-patch recording when compared with whole-cell recording [65.7 ±3.2% (n = 10) vs. 31.4 ± 5.2% (n=5), p < 0.01]. (4) Pertussis toxin (Gi protein inhibitor) completely abolished the ICa,L inhibition induced by GSRd. There was a significant difference in inhibition potency between the two cyclic adenosine monophosphate elevating agents (isoprenaline and forskolin) prestimulation [55± 7.8% (n = 5) vs. 17.2 ± 3.5% (n= 5), p < 0.01]. (5) 1H-[1,2,4]Oxadiazolo[4,3-a]-quinoxalin-1-one (a guanylate cyclase inhibitor) and N-acetyl-L-cysteine (a nitric oxide scavenger) partly recovered the ICa,L inhibition induced by GSRd. (6) Phorbol-12-myristate-13-acetate (a protein kinase Cactivator) and GF109203X (a protein kinase C inhibitor) did not contribute to the inhibition of GSRd. Conclusion: These findings suggest that GSRd could inhibit ICa,L through pertussis toxin-sensitive G protein (Gi) and a nitric oxideecyclic guanosine monophosphate-dependent mechanism.

The JAK/STAT Pathway Is Involved in Synaptic Plasticity

Nicolas, Cé,line ,S.,Peineau, Sté,phane,Amici, Mascia,Csaba, Zsolt,Fafouri, Assia,Javalet, Charlotte,Collett, Valerie ,J.,Hildebrandt, Lars,Seaton, Gillian,Choi, Sun-Lim,Sim, Su-Eo Cell Press 2012 Neuron Vol.73 No.2

<▼1><P><B>Summary</B></P><P>The Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway is involved in many cellular processes, including cell growth and differentiation, immune functions and cancer. It is activated by various cytokines, growth factors, and protein tyrosine kinases (PTKs) and regulates the transcription of many genes. Of the four JAK isoforms and seven STAT isoforms known, JAK2 and STAT3 are highly expressed in the brain where they are present in the postsynaptic density (PSD). Here, we demonstrate a new neuronal function for the JAK/STAT pathway. Using a variety of complementary approaches, we show that the JAK/STAT pathway plays an essential role in the induction of NMDA-receptor dependent long-term depression (NMDAR-LTD) in the hippocampus. Therefore, in addition to established roles in cytokine signaling, the JAK/STAT pathway is involved in synaptic plasticity in the brain.</P></▼1><▼2><P>The authors demonstrate a new neuronal function for the JAK/STAT pathway in the induction of NMDA-receptor-dependent long-term depression (NMDAR-LTD) in the hippocampus.</P></▼2>

A Small Bipedal Trans-Scale Precision Positioning Stage Based on Inertial Stick-Slip Driving

Xi Zhang,Bowen Zhong,Bin Liu,Ziqi Jin,Zhenhua Wang,Lining Sun 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.22 No.3

The small size and high flexibility of the mobile platform is widely used in many fields such as electron scanning microscope (SEM), but the mobile platform still adopts the structure of guide rail at present and has the problem of large volume and poor flexibility, which cannot meet the requirements of SEM for small cavity. Therefore, this paper proposes a small bipedal trans-scale precision positioning stage based on the inertial stick-slip driving to achieve small size and high flexibility. The mobile platform consists of two piezoelectric actuators, a frame structure, two bottom plates, two pre-tightening screws, and magnets, and the volume is 15 mm × 10 mm × 9.5 mm. To investigate the locomotion characteristics of the mobile platform, a prototype is manufactured, and a series of experiments are carried out. The experimental results show that its linear motion velocity can reach 3.553 mm/s and its angular velocity can reach 462.72mrad/s, which means that the mobile platform has good motion performance.

Effect of Scale and Sequence of Surface Textures on the Anti-adhesive Wear Performance of PVD Coated Tool in Dry Machining SLM-Produced Stainless Steel

Kedong Zhang,Xuhong Guo,Chengdong Wang,Xiangfeng Meng,Lining Sun,Youqiang Xing 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.8 No.5

During the dry post-machining processing of selective laser melting (SLM)-produced stainless steel with TiAlN coated tool, the elements of stainless steel chips can diff use and adhere into the coated tool surface, causing serious adhesive wear. In this study, to inhibit the adhesion problem at the tool-chip interface, surface textures with different scales (micro-, nano- and micro/nano-textures) are produced on tool rake face by laser processing before and after physical vapor deposition (PVD) TiAlN coatings deposition. To investigate the cutting performance of these developed coated tools, dry machining tests of the SLM-produced stainless steel are carried out. And, the mechanical properties of textured TiAlN coatings such as the hardness, elastic modulus and critical load are also studied to explain the results from the machining tests. It can be found that the anti-adhesive wear performance of TiAlN coated tool is improved by laser surface texturing. The texture dimension significantly affects the mechanical properties and dry cutting performance of the TiAlN coated tool, and the micro/nanotextures are found to be optimum. Meanwhile, the sequence of surface textures also has an effect on the wear performance of the developed TiAlN coated tools. In the experiment, laser surface texturing before coatings is effective in acting as a barrier against flaking of the TiAlN fi lm, providing a higher active surface for the subsequent TiAlN coatings and presenting a higher compressive residual stress. Thus, the developed cutting tool which is textured before TiAlN coatings deposition presents a milder wear compared to the developed one which is textured after TiAlN coatings deposition.

Electron transport properties of Y-type zigzag branched carbon nanotubes

MaoSheng Ye,HangKong, OuYang,YiNi Lin,Quan Ynag,QingYang Xu,Tao Chen,LiNing Sun,Li Ma Techno-Press 2023 Advances in nano research Vol.15 No.3

The electron transport properties of Y-type zigzag branched carbon nanotubes (CNTs) are of great significance for micro and nano carbon-based electronic devices and their interconnection. Based on the semi-empirical method combining tight-binding density functional theory and non-equilibrium Green's function, the electron transport properties between the branches of Y-type zigzag branched CNT are studied. The results show that the drain-source current of semiconducting Y-type zigzag branched CNT (8, 0)-(4, 0)-(4, 0) is cut-off and not affected by the gate voltage in a bias voltage range [-0.5 V, 0.5 V]. The current presents a nonlinear change in a bias voltage range [-1.5 V, -0.5 V] and [0.5 V, 1.5 V]. The tangent slope of the current-voltage curve can be changed by the gate voltage to realize the regulation of the current. The regulation effect under negative bias voltage is more significant. For the larger diameter semiconducting Y-type zigzag branched CNT (10, 0)-(5, 0)-(5, 0), only the value of drain-source current increases due to the larger diameter. For metallic Y-type zigzag branched CNT (12, 0)-(6, 0)-(6, 0), the drain-source current presents a linear change in a bias voltage range [-1.5 V, 1.5 V] and is symmetrical about (0, 0). The slope of current-voltage line can be changed by the gate voltage to realize the regulation of the current. For three kinds of Y-type zigzag branched CNT with different diameters and different conductivity, the current-voltage curve trend changes from decline to rise when the branch of drain-source is exchanged. The current regulation effect of semiconducting Y-type zigzag branched CNT under negative bias voltage is also more significant.