• 제목/요약/키워드: LU10

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THE RICCI CURVATURE ON DIRECTED GRAPHS

  • Yamada, Taiki
    • 대한수학회지
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    • 제56권1호
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    • pp.113-125
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    • 2019
  • In this paper, we consider the Ricci curvature of a directed graph, based on Lin-Lu-Yau's definition. We give some properties of the Ricci curvature, including conditions for a directed regular graph to be Ricci-flat. Moreover, we calculate the Ricci curvature of the cartesian product of directed graphs.

도마 츠카하라 몸 접어 뒤로 두 번 돌기의 운동역학적 분석 (Biomechanical Analysis of Tsukahara Vault with Double Salto Backward Piked)

  • 임규찬
    • 한국운동역학회지
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    • 제14권3호
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    • pp.135-147
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    • 2004
  • This study was conducted to investigate the technical factors of Lu Yu Fu vault actually performed by three men gymnasts participated in artistic gymnastics competition of 2003 summer Universiade in Daegu through the DLT method of three dimensional cinematography. To analyze these vaults, the instant events of Lu Yu Fu were set in the board touchdown(BTD), the board takeoff(BTO), the horse touchdown(HTD), the horse takeoff(HTO), the peak height(PH), the mat touchdown(MTD) respectively and the phases of that vault were set in the board contact(BC), the preflight(PRF), the horse contact(HC), the postflight(POF), the grounding on mat(GM) respectively After calculating the performance times, the CG displacement velocity, the kinetic energy impulse reaction force moment arm torque at the horse, the released angle piked angle addressed angle, the angular momentum angular velocity of whole body in x axis, and the horizontal displacement between the feet and CG, the following conclusions were reached. To perform the better Lu Yu Fu vault, a gymnast must have the large horizontal velocity of whole body with fast run-up, decrease the duration time and the horizontal vertical displacement of whole body in PRF, have the enough time to judge the correct magnitude and direction of force to brake or push the horse so as to lengthen the HC duration time at any cost. Also it is desirable to increase the horizontal vertical displacement of whole body in POF if possible, maintain the adequate piked position to decrease the angular velocity of whole body in x axis, prepare the grounding on mat previously and delay the release of the hand from the body to keep the angular momentum.

Upregulation of HIF-1α by Hypoxia Protect Neuroblastoma Cells from Apoptosis by Promoting Survivin Expression

  • Zhang, Bo;Yin, Cui-Ping;Zhao, Qian;Yue, Shou-Wei
    • Asian Pacific Journal of Cancer Prevention
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    • 제15권19호
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    • pp.8251-8257
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    • 2014
  • Apoptosis is one of main types of neural cell death and is reversible and is a major target of therapeutic interventions. However, detailed apoptotic cascades still need to be recognized. In present study, we determined the promotion of HIF-$1{\alpha}$ and survivin in brain samples of a mouse model of hypoxic-ischemia and in neuroblastoma SH-SY5Y cells post hypoxia treatment. Then gain-of-function and loss-of-function strategies were adopted to manipulate the HIF-$1{\alpha}$ in SH-SY5Y cells, and hypoxia-induced survivin upregulation and cell apoptosis were determined. Results demonstrated that the HIF-$1{\alpha}$ and survivin were significantly promoted in a mouse model of hypoxic-ischemia or in SH-SY5Y cells post hypoxia in vitro. Manually upregulated HIF-$1{\alpha}$ could promote the hypoxia-induced survivin upregulation and improve the hypoxia-induced SH-SY5Y cell apoptosis. On the other hand, the HIF-$1{\alpha}$ knockdown by RNAi reduced the hypoxia-induced survivin upregulation and cell apoptosis. Therefore, the present study confirmed the protective role of HIF-$1{\alpha}$ and survivin in the hypoxia-induced SH-SY5Y cell apoptosis, and the survivin upregulation by hypoxia is HIF-$1{\alpha}$-dependent. Promotion of HIF-$1{\alpha}$ and survivin might be a valuable stragegy for therapeutic intervention for hypoxic-ischemic encephalopathy.