• Journal of the Korea Academia-Industrial cooperation Society
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• v.4 no.4
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• pp.357-360
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• 2003

Methanol extracts from Paeonia lactiflora showed a strong inhibition against platelet aggregation on platelet activation test. Therefore, the bioactive constituents from Paeonia lactiflora were prepared using chromatography methods and were analyzed by NMR and reference data. Compound 1b was confirmed a same structure with henzoyloxypaeoniflorin, compound 2e was a same structure with paeoniflorin; main product of Paeonia lactiflora. Analytical data of compound 3a were not consistent with any known paeoniflorin soucture, but showed the souctural similarity with it. And also the aggregation inhibition activity of compound 3a showed a strong inhibition($\geq$ 90%) induced by collagen. Therefore it suggested that the structure of compound 3a may be the similar structure of benzoyloxypaeoflorin with a functional group in place of benzoyl group and/or a different functional group in stead of Rl. We suggested that benzoyl group of benzoyloxypaeoniflorin substitued instead of 5-carbon OH group on glycoside moiety paeoniflorin played role of the metabolite in case of a platelet aggregation inhibition activity. Paeoniflorin showed more strong inhibition by thrombin than collagen. Therefore, it may be destructed a calcium metabolite as a forming $Ca^2＋$ chelate. Compound 3a may be that other functional group instead of OH group of 5-carbon on glycoside moiety of paeoniflorin and/or OH group of benzoyl moiety of paeoniflorin played role of the metabolite in a platelet aggregation inhibition.

• Journal of the Korean Ceramic Society
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• v.32 no.12
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• pp.1417-1423
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• 1995

α/β sialon based composites containing silicon nitride whisker and silicon carbide platelet were fabricated by hot pressing. Effect of the reinforcing agents on the α to β phase transformation of the sialon as well as on the mechanical properties was investigated. Silicon nitride whisker and silicon carbide platelet promoted the phse transformation. TEM/EDS analysis revealed that the grain containing the whisker had 'core-rim' structure; core being high purity Si3N4 whisker and rim being β-sialon. Flexural strength of the composite decreased with the reinforcement addition which, on the other hand, improved fracture toughness of it. High temperature strength was measured at 1300℃ to be about 130 MPa lower than that measured at RT for the whisker reinforced composites.

• Fisheries and Aquatic Sciences
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• v.12 no.3
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• pp.194-202
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• 2009

Sulfated fucans are known to have both anti-thrombotic and anti-coagulant activities. In this study, the variation in platelet aggregation and anti-coagulant activities was investigated in vitro with regard to administered dose, molecular weight distribution, sulfate content, and sugar composition in two algal fucoidans from Eisenia bicyclis and Undaria pinnatifida sporophylls (Mekabu). The anti-coagulant activity largely correlated with sulfate content and with molecular weight distribution in a dose-dependent manner. However, both fucoidans demonstrated inhibitory responses to ADP-induced platelet aggregation in dose- and structure-dependent manners that contrasted with the anti-coagulant activity. Neither molecular weight distribution nor sulfate content greatly affected platelet-aggregation inhibition (PA-inhibition) by the fucoidan fractions, whereas anti-coagulant activity was sensitive to these structural factors. Interestingly, an E. bicyclis fucoidan fraction exhibited almost complete PA-inhibition at a treatment dose of 500 mg/mL while retaining weak anti-coagulant activity. In conclusion, these observations suggest that fucoidan may be a useful anti-thrombotic or anti-platelet agent in various arterial thrombotic disorders, including post-vascular intervention with controlled bleeding complications, due to its anti-coagulant modulating activity.

• Archives of Pharmacal Research
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• v.20 no.1
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• pp.80-84
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• 1997

Substituted cinnamoyl-tyramine derivatives were synthesized by DCC-coupling of substituted cinnamic acid with tyramine or tyramine methyl-1-ether to evaluate PAF-receptor binding antagonistic activities and inhibitory activities on PAF-induced platelet aggregation with interest on structure-activity relations. The results show that 3,4-dimethoxy-cinnamoyl tyramine-amide or its methyl ether have significant PAF-receptor binding antagonistic activity and platelet anti-aggregatory activities.

• Korean Journal of Pharmacognosy
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• v.25 no.2
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• pp.167-170
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• 1994

The platelet activating factor (PAF) is a newly discovered chemical mediator, the chemical structure of which is 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine. Since PAF has potent and broad activities, its pathophysiological roles have received much attention. To develope a new PAF antagonist from medicinal plants, extracts of twenty medicinal herb were screened using PAF receptor binding, $[^{14}C]$ serotonin release and platelet aggregation.

• Journal of the Korean Society of Visualization
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• v.21 no.1
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• pp.74-79
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• 2023

Thrombogenesis, which is the process of blood clot formation, can be initiated by platelet activation. Excessive formation of blood clot in the bloodstream can lead to thrombosis. Therefore, when dealing with patients with disseminated intravascular coagulation (DIC) or children, it is necessary to use small amounts of blood. Hence, it is important to develop methods for the rapid and accurate measurement of the platelet function using a small amount of blood. In this study, 3D printing technology was utilized to facilitate the production of micro channels. The amount of platelet adhesion in smokers and non-smokers was compared by repeatedly exposing the structure of the channel to adjust the number of blood injections and facilitate thrombosis attachment to simple stenosis structures.

• Journal of Ginseng Research
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• v.41 no.1
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• pp.96-102
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• 2017

Background: Korean ginseng, Panax ginseng Meyer, has been used as a traditional oriental medicine to treat illness and promote health for several thousand years. Ginsenosides are the main constituents for the pharmacological effects of P. ginseng. Since several ginsenosides, including ginsenoside (G)-Rg3 and G-Rp1, have reported antiplatelet activity, here we investigate the ability of G-Rp4 to modulate adenosine diphosphate (ADP)-induced platelet aggregation. The ginsenoside Rp4, a similar chemical structure of G-Rp1, was prepared from G-Rg1 by chemical modification. Methods: To examine the effects of G-Rp4 on platelet activation, we performed several experiments, including antiplatelet ability, the modulation of intracellular calcium concentration, and P-selectin expression. In addition, we examined the activation of integrin ${\alpha}IIb{\beta}_3$ and the phosphorylation of signaling molecules using fibrinogen binding assay and immunoblotting in rat washed platelets. Results: G-Rp4 inhibited ADP-induced platelet aggregation in a dose-dependent manner. We found that G-Rp4 decreased calcium mobilization and P-selectin expression in ADP-activated platelets. Moreover, fibrinogen binding to integrin ${\alpha}IIb{\beta}_3$ by ADP was attenuated in G-Rp4-treated platelets. G-Rp4 significantly attenuated phosphorylation of extracellular signal-regulated protein kinases 1 and 2, p38, and c-Jun N-terminal kinase, as well as protein kinase B, phosphatidylinositol 3-kinase, and phospholipase C-${\gamma}$ phosphorylations. Conclusion: G-Rp4 significantly inhibited ADP-induced platelet aggregation and this is mediated via modulating the intracellular signaling molecules. These results indicate that G-Rp4 could be a potential candidate as a therapeutic agent against platelet-related cardiovascular diseases.

• 한국초전도학회:학술대회논문집
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• v.11
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• pp.53-53
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• 2001

• Geomechanics and Engineering
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• v.35 no.1
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• pp.81-93
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• 2023

Due to the unclear mechanism of the influence of temperature on the resonance problem of doubly curved shells, this article aims to explore this issue. When the ambient temperature rises, the composite structure will expand. If the thermal effects are considered, the resonance response will become more complex. In the design of structure, thermal effect is inevitable. Therefore, it is of significance to study the resonant behavior of doubly curved shell structures in thermal environment. In view of this, this paper extends the previous work (She and Ding 2023) to the case of the nonlinear principal resonance behavior of graphene platelet reinforced metal foams (GPLRMFs) doubly curved shells in thermal environment. The effect of uniform temperature field is taken into consideration in the constitutive equation, and the nonlinear motion control equation considering temperature effect is derived. The modified Lindstedt Poincare (MLP) method is used to obtain the resonance response of doubly curved shells. Finally, we study the effects of temperature changes, shell types, material parameters, initial geometric imperfection and prestress on the forced vibration behaviors. It can be found that, as the temperature goes up, the resonance position can be advanced.

• Structural Engineering and Mechanics
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• v.71 no.1
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• pp.99-107
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• 2019

Wave propagation analysis of a porous graphene platelet reinforced (GPLR) nanocomposite shell is investigated for the first time. The homogenization of the utilized material is procured by extending the Halpin-Tsai relations for the porous nanocomposite. Both symmetric and asymmetric porosity distributions are regarded in this analysis. The equations of the shell's motion are derived according to Hamilton's principle coupled with the kinematic relations of the first-order shear deformation theory of the shells. The obtained governing equations are considered to be solved via an analytical solution which includes two longitudinal and circumferential wave numbers. The accuracy of the presented formulations is examined by comparing the results of this method with those reported by former authors. The simulations reveal a stiffness decrease in the cases which porosity influences are regarded. Also, one must pay attention to the effects of longitudinal wave number on the wave dispersion curves of the nanocomposite structure.