• 제목/요약/키워드: retraction

검색결과 490건 처리시간 0.022초

지그재그 포켓 가공에서 공구후퇴 횟수를 줄이기 위한 영역 분할법 (A Partitioning Method Recucing the Number of Tool Retractions in Zigzag Pocket Machining)

  • 서경천;김재정
    • 한국CDE학회논문집
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    • 제6권4호
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    • pp.215-221
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    • 2001
  • In the zigzag milling of a pocket having islands, tool retraction is one of the primary factors that decrease productivity. Therefore, tool path with minimum number of tool retraction has been needed. Most researches about this topic have been concentrated on obtaining the optimum solution formulated through the geometric reasoning off pocket. Recently, several attempts were made to simplify this problem into region partitioning in order to get the numerically expressed minimum solution. In this research, a method reducing the number of tool retractions extended from existing region partitioning is provided. Applying the segment that is normal to the reference direction of zigzag milling, region partitioning is carried out and structural elements of the region are searched via graphs of islands and characteristic points. Through the processes presented, the number of region partitioned is less than that of existing processes.

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Euchrestaflavanone A can attenuate thrombosis through inhibition of collagen-induced platelet activation

  • Shin, Jung-Hae;Kwon, Hyuk-Woo
    • Journal of Applied Biological Chemistry
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    • 제63권4호
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    • pp.339-345
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    • 2020
  • Euchrestaflavanone A (EFA) is a flavonoid found in the root bark of Cudrania tricuspidata. C. tricuspidata extract, widely used throughout Asia in traditional medicine, has been investigated phytochemically and biologically and is known to have anti-obesity, anti-inflammatory, and anti-tumor effects. It has been reported that C. tricuspidata extract also possesses anti-platelet effects; however, the mechanism of its anti-platelet and anti-thrombotic activities is yet to be elucidated. In this study, we investigated the effects of EFA on the modulation of platelet function using collagen-induced human platelets. Our results showed that EFA markedly inhibited platelet aggregation. Furthermore, it downregulated glycoprotein IIb/IIIa (αIIb/β3)-mediated signaling events, including platelet adhesion, granule secretion, thromboxane A2 production, and clot retraction, but upregulated the cyclic adenosine monophosphate-dependent pathway. Taken together, EFA possesses strong anti-platelet and anti-thrombotic properties and is a potential therapeutic drug candidate to prevent platelet-related thrombosis and cardiovascular disease.

콜라겐 유도의 혈소판에서 사이클릭 뉴클레오티드의 조절을 통한 Euchrestaflavone B의 혈전 형성 억제 효과 (Inhibitory Effects of Euchrestaflavone B on Thrombus Formation via Regulation of Cyclic Nucleotides in Collagen-induced Platelets)

  • 권혁우
    • 생약학회지
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    • 제51권4호
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    • pp.231-237
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    • 2020
  • Euchrestaflavanone B (EFB) is a flavonoid that can be found in root bark, particularly in Cudrania tricuspidata (C. tricuspidata). The extract of C. tricuspidata is widespread throughout Asia and used in traditional medicine. In a previous study, we found anti-platelet effects of substances isolated from C. tricuspidata on collagen-induced human platelets. However, the C. tricuspidata still contains numerous substances, thus, we have searched new candidate, EFB isolated from C. tricuspidata for anti-platelet effect. Our results showed that EFA inhibited collagen-induced platelet aggregation and glycoprotein IIb/IIIa (αIIb/β3)-mediated signaling events, including platelet adhesion, granule secretion, thromboxane A2 production and clot retraction. These results suggest that EFA has inhibitory effects on human platelet activities and thrombus formation and has potential value as a natural substance for preventing platelet-induced thrombosis.

ON THE EXISTENCE OF SOLUTIONS OF EXTENDED GENERALIZED VARIATIONAL INEQUALITIES IN BANACH SPACES

  • He, Xin-Feng;Wang, Xian;He, Zhen
    • East Asian mathematical journal
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    • 제25권4호
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    • pp.527-532
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    • 2009
  • In this paper, we study the following extended generalized variational inequality problem, introduced by Noor (for short, EGVI) : Given a closed convex subset K in q-uniformly smooth Banach space B, three nonlinear mappings T : $K\;{\rightarrow}\;B^*$, g : $K\;{\rightarrow}\;K$, h : $K\;{\rightarrow}\;K$ and a vector ${\xi}\;{\in}\;B^*$, find $x\;{\in}\;K$, $h(x)\;{\in}\;K$ such that $\xi$, g(y)-h(x)> $\geq$ 0, for all $y\;{\in}\;K$, $g(y)\;{\in}\;K$. [see [2]: M. Aslam Noor, Extended general variational inequalities, Appl. Math. Lett. 22 (2009) 182-186.] By using sunny nonexpansive retraction $Q_K$ and the well-known Banach's fixed point principle, we prove existence results for solutions of (EGVI). Our results extend some recent results from the literature.

Retraction: Saccharomyces cerevisiae 와 Hanseniaspora uvarum 효모 혼합발효를 이용한 증류식 소주의 휘발성 향기성분 및 아미노산 함량 변화 (Retraction: Changes in the volatile aromatic compounds and amino acid contents of distilled soju using co-fermentation by Saccharomyces cerevisiae and Hanseniaspora uvarum yeasts)

The inhibitory effects of glabridin on human platelet aggregation and thrombus formation

  • Sang-Nam Park;Hyuk-Woo Kwon
    • Journal of Applied Biological Chemistry
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    • 제66권
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    • pp.455-461
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    • 2023
  • Glycyrrhiza glabra is a well-known medicinal herb that grows in various parts of the world and glabridin is a major chemical compound that is found in the root extract of Glycyrrhiza glabra. Glabridin is a natural compound known to have antioxidant, anti-inflammatory, anti-atherogenic, anti-osteoporotic and skin-whitening. In this study, we investigated if glabridin inhibited platelet aggregation and thrombus formation. We observed that glabridin inhibited collagen-induced platelet aggregation and suppressed signal transduction molecules such as phosphatidylinositol-3 kinase (PI3K), Akt, glycogen synthase kinase-3α/β (GSK-3α/β), SYK, cytosolic phospholipase A2, and p38 expression. In addition, glabridin suppressed thromboxane A2 generation and thrombin-induced clot retraction. Taken together, glabridin showed strong antiplatelet effects and may be used to block thrombosis- and platelet-mediated cardiovascular diseases.