• Title/Summary/Keyword: Blocker

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Changes of Cytosolic $Ca^{2+}$ by IAA and Zeatin in Protoplasts Isolated from Maize Mesocotyl (옥수수 중배축으로부터 분리한 원형질체에서 IAA와 Aeatin에 의한 세포질 $Ca^{2+}$ 노도의 변화)

  • 송재진
    • Journal of Plant Biology
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    • v.34 no.3
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    • pp.239-244
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    • 1991
  • Ca2+ is implicated as a second messenger in coupling various stimuli such as hormone, gravity and light. The determine whether or not plant hormones mobilize calcium with different action, we investigated the cytosolic Ca2+ changes by IAA and zeatin in the protoplasts isolated from elongating mesocotyl of maize. IAA increased the influx of Ca2+ due to the calcium channel opening, which was confirmed by using verapamil, calcium channel blocker. On the other hand, zeatin increased the cytosolic Ca2+ by promoting the efflux of Ca2+ derived from cellular organelles. These results suggest that different calcium flux induced by IAA and zeatin plays a role in appropriate response resulting in increase of cell elongation or repression cell elongatoin.

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Method Development of Verapamil in Presence of NSAIDs using RP-HPLC Technique

  • Sultana, Najma;Arayne, M. Saeed;Waheed, Abdul
    • Bulletin of the Korean Chemical Society
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    • v.32 no.7
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    • pp.2274-2278
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    • 2011
  • Verapamil is a calcium channel blocker and is classified as a class IV anti-arrhythmic agent. It is used in the control of supra ventricular tachyarrhythmias, and in the management of classical and variant angina pectoris. It is also used in the treatment of hypertension and used as an important therapeutic agent for angina pectoris, ischemic heart disease, hypertension and hypertrophic cardiomyopathy. Verapamil commonly co-administered with NSAIDs (non-steroidal anti-inflammatory drugs) i.e. diclofenac sodium, flurbiprofen, Ibuprofen, mefanamic acid and meloxicam. A simple and rapid RP-HPLC method for simultaneous determination and quantification of verapamil and NSAIDs was developed and validated. The mobile phase constituted of acetonitrile: water (55:45) whose pH was adjusted at 2.7 and pumped at a flow rate of 2.0 mL $min^{-1}$ at 230 nm. The proposed method is simple, precise, accurate, low cost and least time consuming for the simultaneous determination of verapamil and NSAIDs which can be effectively applied for the analysis of human serum.

Development of an Automatic Design System for Axisymmetric Hot Steel Forging (축대칭 열간단조를 위한 자동설계 시스템 개발)

  • 김대영;박종진
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1998.03a
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    • pp.117-125
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    • 1998
  • A hot forging product in general is produced through buster, blocker and finisher processes. Usually the processes including dies are designed by experienced forging engineers. However, due to the lack of such engineers, it is necessary to develop expert systems with which engineers of little experience can perform the design task. In the present study, an expert system is developed for axisyrnmetric hot steel forgings. It is a rule based system written in Fortran and AutoLISP, operating on a personal computer. In this paper, structures of the system are summarized and capabilities of the system are examined through several examples.

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Finite-Element Analysis of a Helical-Gear Blank Hot-Forging (헬리컬기어 블랭크 열간단조의 유한요소해석)

  • 안승우;박종진
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1995.06a
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    • pp.180-187
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    • 1995
  • Helical gears are machined from blanks, which are usually prepared by forging cylindrical billets at high temperatures through buster, blocker and finisher processes. As dimensions of the blank are closer to those of the machined part, machining cost can be more reduced. Therefore, there are a lot of efforts being made to optimize the forging processes in order to produce near-net shaped blanks. In the present investigation, a rigid viscoplastic finite element technique was used to analyze a helical gear blank hot forging processes and deformation, strain and temperature distributions, forging load variations during forging were obtained. In the paper, it is discussed how these results can be utilized to optimize die design, billet dimensions and press usage.

Process Design Molding with Precision Hot Forging of One-Way Clutch Inner Race (원 웨이 클러치 이너 레이스의 정밀 열간 단조 공정설계에 관한 연구)

  • Kim, Hwa-Jeong;Jin, Chul-Kyu
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.17 no.4
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    • pp.83-90
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    • 2018
  • In this research, we developed a process design hot-forging technology that precisely forms an inner race. The inner race transmits power to a one-way clutch of an automatic transmission and minimizes the CNC machining allowance. For a multi-stage hollow shape (inner race), we proposed several shapes of blocker and finisher for the precision hot-forging process and analyzed the forging process using DEFORM. The hot-forging process was optimized for several parameters, such as metal flow pattern, forging defect, and forming load. Blockers and finisher dies in the hot-forging process were designed to select optimal shapes from finite element analysis, and experiments were conducted to optimize the hot-forging process.

Tetrodotoxin Occurrence in Ciliated Protozoa and Possible Bacterial Role in its Toxification

  • Do Hyung Ki;MAEDA Masachika;NOGUCHI Tamao;SIMIDU Usio;KOGURE Kazuhiro
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.29 no.6
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    • pp.856-861
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    • 1996
  • The occurrence of TTX in ciliated protozoa was investigated in order to clarify tetrodotoxin (TTX) accumulation mechanisms in marine organisms. Tissue culture bioassay, HPLC, and GC-MS analyses confirmed the occurrence of TTX in Euplotes mutabilis and also in bacteria isolated from the culture medium. Fluorescently labeled bacteria (FLB) were prepared with those bacteria, and predation by E. mutabilis was observed. The results indicated that TTX in bacteria can be transferred to higher trophic levels through the food chain.

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The Development of Life Prediction Method for Hot Forming Dies (열간단조용 금형형의 수명예측기법 개발)

  • 이진호;김병민
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1998.06b
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    • pp.54-59
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    • 1998
  • In this study, two kinds of life prediction method for hot forming die are developed . One is empirical method requiring some experiment that evaluate thermal softening of die material accoring to operating conditions. The other is analyticl method that calcuate wear quantity of die occuring during the forming process. Wear is a predominant factor as well as plastic deformation and heat checking . And, these methods are applied to prodict tool life real die producting part for automobile. Thus , the applicability and the accuracy of the presented methods are investigated. Using the verified life prediction method above , optimal blocker die design minimizing the finisher die is done.

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Transcutaneous Cardiac Pacing in a Dog with Diltiazem Intoxication (딜티아젬 중독증 이환견에서 경피용 체외심박조절기의 적용 증례)

  • Lee, Seung-Keun;Hyun, Chang-Baig
    • Journal of Veterinary Clinics
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    • v.26 no.2
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    • pp.166-169
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    • 2009
  • An 11-year-old male Beagle, weighing 10.5 kg, was presented with sudden bradyarrhthmia and severe hypotension after incidental ingestion of diltiazem. The dog was treated with intravenous(IV) isotonic crystalloid solution, atropine, calcium gluconate, dobutamine, glucagon and gastric lavage under the aid of temporary transcutaneous cardiac pacing. With the short-term use of transcutaneous cardiac pacing and medical treatment, the heart rhythm and the condition of the patient were stabilized.

Effect of the Concurrent Administration of Banhasasim-tang with Cimetidine on Gastric Ulcer in Rats (반하사심탕과 씨메티딘의 작용투여가 흰쥐의 위궤양에 미치는 영향)

  • Lee Kwang Gyu;Cui Xun;Lim Jong Pil
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.16 no.3
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    • pp.572-576
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    • 2002
  • Banhasasim-tang(半夏瀉心湯), oriental medicine, has been used for the treatment of the gastric diseases and cimetidine, H2-receptor blocker, has been also used as the gastric ulcer remedy but has some side action. Therefore the concurrent administration of these two drugs may increase antiulcer activities and also decrease cimetidine's side action more than administrating one by one. In order to investigate antiulcer activities, some experiments were conducted. The concurrent administration of Banhasasim-tang extract(BS) and cimetidine(CM) given intraperitoneally (CM 50mg/kg + BS 300mg/kg and CM 50mg/kg + BS 500 mg/kg), significantly inhibited Shay, aspirin and indomethacin ulcers in rats.