• Title/Summary/Keyword: blocking effect

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Influence of Phellodendri Cortex Methanol Extract on the Responses of the Blood Pressure in the Rabbits and Cats (황백(黃柏) Methanol Extract의 가토(家兎) 및 가묘(家猫)의 혈압반응(血壓反應)에 미치는 영향(影響))

  • Lim, Dong-Yoon
    • Journal of Pharmaceutical Investigation
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    • v.9 no.3
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    • pp.27-38
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    • 1979
  • This study was attempted to investigate the pharmacological action, especially depressor action of Phellodendri cortex and to elucidate the mechanism of its action, making use of Phellodendri cortex methanol extract (PCME) because its hypotensive action is not clear. Influence of PCME on the blood pressure of the rabbits and cats were observed in this study. PCME, when given intravenously in the rabbits and cats, elicited the hypotensive action, but intraventricular PCME in the rabbits did not show depressor action. Accumulation and tachyphylaxis by PCME administered into the ear-vein of the rabbits were not shown. Depressor effect of PCME in the rabbits was attenuated significantly by pretreatment with phentolamine, guanethidine, chorisondamine and atropine, but not by propranolol, diphenhydramine, cyproheptadine and vagotomization. The pressor activity of angiotensin was unimpaired after injection of maximal hypotensive doses (100mg/kg) of PCME, but the pressor activity of norepinephrine and carotid occlusion was abolished markedly. In addition, PCME given into jugular vein of the cats weakened norepinephrine pressor responses and caused the reversal of epinephrine pressor responses. These results suggest that the hypotensive action of PCME may be due to dual mechanisms by interference with peripheral sympathetic function, alpha adrenoceptor blocking action, and peripheral parasympathomimetics action, muscarinic action.

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A Robust Preconditioner on the CRAY-T3E for Large Nonsymmetric Sparse Linear Systems

  • Ma, Sangback;Cho, Jaeyoung
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • v.5 no.1
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    • pp.85-100
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    • 2001
  • In this paper we propose a block-type parallel preconditioner for solving large sparse nonsymmetric linear systems, which we expect to be scalable. It is Multi-Color Block SOR preconditioner, combined with direct sparse matrix solver. For the Laplacian matrix the SOR method is known to have a nondeteriorating rate of convergence when used with Multi-Color ordering. Since most of the time is spent on the diagonal inversion, which is done on each processor, we expect it to be a good scalable preconditioner. Finally, due to the blocking effect, it will be effective for ill-conditioned problems. We compared it with four other preconditioners, which are ILU(0)-wavefront ordering, ILU(0)-Multi-Color ordering, SPAI(SParse Approximate Inverse), and SSOR preconditioner. Experiments were conducted for the Finite Difference discretizations of two problems with various meshsizes varying up to 1024 x 1024, and for an ill-conditioned matrix from the shell problem from the Harwell-Boeing collection. CRAY-T3E with 128 nodes was used. MPI library was used for interprocess communications. The results show that Multi-Color Block SOR and ILU(0) with Multi-Color ordering give the best performances for the finite difference matrices and for the shell problem only the Multi-Color Block SOR converges.

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Effectiveness of Silver Thiosulfate Treatment in Reducing Ozone Injury to Tomato Plants (Silver Thiosulfate 처리가 토마토의 오존피해경감에 미치는 효과)

  • 구자형;원동찬;김태일
    • Journal of Korean Society for Atmospheric Environment
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    • v.8 no.1
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    • pp.7-12
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    • 1992
  • This study was conducted to determine the effectiveness of silver thiosulfate(STS) in reducing $O_3$ injury to tomato plants(Lycopersicon esculentm Mill. 'Pink Glory'). Two days prior to $O_3$ fumigation, plants were given a foliar spray of STS solution at concentrations of 0, 0.2, 0.4, 0.6 mM contained with 0.05% Tween-20. STS concentrations below 0.6 mM were significantly effective in providing protection aginst $O_3$ exposure(16 h at 0.3 ppm). STS reduced leaf injury rate, defoliation of cotyledons, ethylene production and degree of epinasty induced by $O_3$ injury. STS slightly increased ethylene production in non-$O_3$-fumigated plants, but changes of chlorophyll content and transpiration rate on a whole plant basis were not observed. In $O_3$-fumigated plants, STS treatment reduced chlorophyll destruction but did not affect transpiration rate. STS treatment seemed not to affect peroxidase(POD) and superoxide dismutase (SOD) activity in non-fumigated plants but reduced increasing activity of POD by $O_3$ fumigation. However, such an effect as above was not found in SOD activity. Even though enzymatic protection effects were not confirmed, the fact that reduction of acute injury rate was attained for 16 h fumigation indicates that the phytoprotective effects of STS are not necessarily related to blocking the action of strees-induced-ethylene as an anti-ethylene agent.

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The Effect of Indole Acetic and Abscisic Acid on Ribonucleic Acid and Ribonuclease (Indole acetic acid 와 Abscisic acid 가 핵산(核酸)과 RNase 에 미치는 영향에 관(關)하여)

  • Jo, D.H.;Lee, C.Y.
    • Applied Biological Chemistry
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    • v.15 no.3
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    • pp.181-186
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    • 1972
  • Wheat coleoptile sections were treated with either $1.5{\times}10^{-5}M$ ABA or $5×10^{-5}M$ IAA in vitro, the results may be summarized as follows, 1. The treatmert of IAA decreased the level of high molecular weight RNA F2 and F3 but that with ABA increased the F4 level. 2. IAA caused an increased activity of G2 isozyme, while ABA suppressed the activity of G3 isozyme. 3. The results may suggest that there may exist common effects of IAA and ABA on RNA and RNase. 4. The latent RNase activity caused by SH blocking reagent (p-hydroxymercury benzoate, Pb et al) was not observed.

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Oridonin Suppresses Proliferation of Human Ovarian Cancer Cells via Blockage of mTOR Signaling

  • Xia, Rong;Chen, Sun-Xiao;Qin, Qin;Chen, Yan;Zhang, Wei-Wei;Zhu, Rong-Rong;Deng, An-Mei
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.2
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    • pp.667-671
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    • 2016
  • Oridonin, an ent-kaurane diterpenoid compound isolated from the traditional Chinese herb Rabdosia rubescens, has shown various pharmacological and physiological effects such as anti-tumor, anti-bacterial, and anti-inflammatory properties. However, the effect of oridonin on human ovarian cancer cell lines has not been determined. In this study, we demonstrated that oridonin inhibited ovarian cancer cell proliferation, migration and invasion in a dose-dependent manner. Furthermore, we showed oridonin inhibited tumor growth of ovarian cancer cells (SKOV3) in vivo. We then assessed mechanisms and found that oridonin specifically abrogated the phosphorylation/activation of mTOR signaling. In summary, our results indicate that oridonin is a potential inhibitor of ovarian cancer by blocking the mTOR signaling pathway.

A Clinical Study of Trigger Point by Blocking Methods (유발점 차단에 의한 임상적 연구)

  • Hur, Yung-Gu
    • Journal of Korean Physical Therapy Science
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    • v.4 no.2
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    • pp.383-390
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    • 1997
  • The purpose of this study is the evaluation of the degree of post injection soreness, symptom duration, factor and autonomic symptoms after trigger point injection in patients with trigger points. We devided the subjects of the study into four groups Such as, only dry needling, needle-TENS, with massage-stretch, massage-stretch only, including 100 patients, and measured the visual analog scale before treatment and after treatment. Before treatment, The VAS mean scores were $6.2{\pm}1.03$ in needle-TENS with massage-stretch group ; $6.2{\pm}1.75$ in needdle-TENS group, and $6.3{\pm}1.85$ in dry needling group, and $6.8{\pm}1.03$ in massage-stretch group. In post injection 3rd day, The VAS mean score were $0.9{\pm}1.78$ in needling-TENS with massage-stretch group, $1.1{\pm}1.52$ in needling-TENS group, $1.7{\pm}1.10$ in dry needling group, and $3.9{\pm}3.01$ in massage-stretch group. As for a causative factor of activities for trigger were overload with 37.0%, overwork with 35.0% and fatigue with 13.0%. Symptoms for trigger were tenderness with 28.0%, numbness and tingling with 24.0%. ROM limit with 17.0% and tightness with 17.0%. As a result, needling-TENS with massage-stretch group showed less soreness and effect than other group.

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Influences of Adrenoreceptor Blockades on the Dose Response to Epinephrine (Epinephrine의 dose-response에 미치는 ${\alpha}-$${\beta}-receptor$ blocking agents의 영향(影響))

  • Cheon, Yun-Sook;Chun, Boe-Gwun;Shin, Man-Ryun
    • The Korean Journal of Pharmacology
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    • v.13 no.2
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    • pp.49-59
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    • 1977
  • Adrenergic receptors are now classified into alpha type and beta type These adrenergic receptors are distributed in various tissue in different patterns. Therefore, the adrenergic response of a certain tissue may be different from those of the other tissues, and such differences may exist among various species of animals. In this paper, the authors attempt to reevaluate the effect of epinephrine on the isolated atria, aortic strips, and vas deferenses of rabbits preincubated with alpha receptor blockades (ergotamine and dibenamine) and beta receptor blockades (propranolol and dichloroisoproterenol) in Locke-Ringer bathing medium. The results obtained were summarized as follows; 1) The dose dependent responses of isolated atria to epinephrine were significantly inhibited by propranolol and dichloroisoproterenol, and slightly inhibited by dibenamine, but not affected by ergotamine. 2) The dose dependent responses of excised aortic strips to epinephrine were significantly inhibited by ergotamine and dibenamine, but the responses were slightly potentiated by propranolol, and significantly by dichloroisoproterenol. 3) The dose dependent responses of isolated vas deferenses to epinephrine were significantly inhibited by ergotamine and dibenamine, but slightly potentiated by propranolol and dichloroisoproterenol.

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A Study on New Materials for Organic Active Devices (유기 능동 소자 제작을 위한 신소재 연구)

  • Lee, Sung-Jae;Lim, Sung-Taek;Shin, Dong-Myung;Choi, Jong-Sun;Lee, Hoo-Sung;Kim, Young-Kwan;Sohn, Byoung-Chung
    • Journal of the Korean Applied Science and Technology
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    • v.17 no.3
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    • pp.174-177
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    • 2000
  • The effect of a-sexithiophene(${\alpha}-6T$) layers on the light emitting diode (LED) were studied. The ${\alpha}-6T$ was used for a buffer layer in electroluminescent (EL) devices. Enhanced carrier (hole) injection and improved emission efficiency were observed. Carrier injection characteristics were investigated as a function of ${\alpha}-6T$ later thickness. The efficiency of the electroluminescence was proportional to the thickness of ${\alpha}-6T$ layer. The highest efficiency was observed 600A of ${\alpha}-6T$ later, which was about 1.5 times higher than that of device without ${\alpha}-6T$ later. The device with a-6T showed an operation voltage lowered by 2V. The ${\alpha}-6T$ layer can substitute hole blocking layer, and control charge injection properties.

Nitric Oxide Modulation of GABAergic Synaptic Transmission in Mechanically Isolated Rat Auditory Cortical Neurons

  • Lee, Jong-Ju
    • The Korean Journal of Physiology and Pharmacology
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    • v.13 no.6
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    • pp.461-467
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    • 2009
  • The auditory cortex (A1) encodes the acquired significance of sound for the perception and interpretation of sound. Nitric oxide (NO) is a gas molecule with free radical properties that functions as a transmitter molecule and can alter neural activity without direct synaptic connections. We used whole-cell recordings under voltage clamp to investigate the effect of NO on spontaneous GABAergic synaptic transmission in mechanically isolated rat auditory cortical neurons preserving functional presynaptic nerve terminals. GABAergic spontaneous inhibitory postsynaptic currents (sIPSCs) in the A1 were completely blocked by bicuculline. The NO donor, S-nitroso-N-acetylpenicillamine (SNAP), reduced the GABAergic sIPSC frequency without affecting the mean current amplitude. The SNAP-induced inhibition of sIPSC frequency was mimicked by 8-bromoguanosine cyclic 3',5'-monophosphate, a membrane permeable cyclic-GMP analogue, and blocked by 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, a specific NO scavenger. Blockade of presynaptic $K^+$ channels by 4-aminopyridine, a $K^+$ channel blocker, increased the frequencies of GABAergic sIPSCs, but did not affect the inhibitory effects of SNAP. However, blocking of presynaptic $Ca^{2+}$ channels by $Cd^{2+}$, a general voltage-dependent $Ca^{2+}$ channel blocker, decreased the frequencies of GABAergic sIPSCs, and blocked SNAP-induced reduction of sIPSC frequency. These findings suggest that NO inhibits spontaneous GABA release by activation of cGMP-dependent signaling and inhibition of presynaptic $Ca^{2+}$ channels in the presynaptic nerve terminals of A1 neurons.

MRI Image Compression by Using Recognition of Region of Disease (질환 영역 인식을 통한 MRI 차등 영상 압축)

  • Kim, Hyun-Soon;Bae, Sung-Ho;Park, Kil-Houm
    • The Transactions of the Korea Information Processing Society
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    • v.5 no.10
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    • pp.2704-2712
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    • 1998
  • In this paper, a MRI image compression technique, which allocates bits effectively by using lossless coding for region having important infommtion to decide disease and lossy coding for the rest, is proposed. In the proposed method, for MHI images needed to rccognize disk disease, we recognizc region having important objects by using the characteristics of c1isease. As the recognized region is imrxlrtant to decide whether disease exists or not, it is compressed by lossless coding and the rest is compressed by lossy coding, Also for the region compressed by lossy coding, we can obtain fine reconstructed images without blocking effect by adopting fractal coding in wavelet transform domain.

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