• 제목/요약/키워드: Action Potentials

검색결과 204건 처리시간 0.021초

얼굴마비에서 얼굴근육의 전기생리학적 양상 (Electrophysiologic Pattern of Facial Muscles in Bell's Palsy)

  • 이상수;신동익
    • Annals of Clinical Neurophysiology
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    • 제6권2호
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    • pp.75-79
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    • 2004
  • Backgrounds: Electrodiagnostic tests have been developed to estimate the degree of facial nerve injury during the acute phase. Side-to-side amplitude comparison with the affected side expressed as a percentage of the nonaffected side has been one of the most valuable electrophysiologic methods of assessing facial nerve functioning. This study was designed to know whether there is any difference in the side-to-side comparison of amplitudes and terminal latencies of the compound muscle action potentials (CMAP) of the facial muscles in the patients with Bell's palsy. Methods: Electroneurographic recordings with surface electrodes on the frontalis, orbicularis oculi, nasalis, and orbicularis oris muscles were made within 2 weeks post-onset (mean, day 7) in 39 patients. Results: Of the 39 Bell's palsy patients, 38 patients (97.4%) recovered satisfactorily within 6 months. The amplitude of CMAP in all patients was not reduced to 10% or less of that of the contralateral healthy muscle. The correlation of amplitude change between four facial muscles was relatively strong, but the correlation of latency change was weak. When the electroneurographic values were compared in the four muscle groups, the general linear models procedure did not show any significant difference for CMAP amplitude and latency changes (p=0.62-0.63). Conclusions: This study did not show any significant clinical advantage of electroneurographic recordings in more than one facial muscle at the early stage of Bell's palsy.

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Token's function and role for securing ecosystem

  • Yoo, Soonduck
    • International Journal of Advanced Culture Technology
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    • 제8권1호
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    • pp.128-134
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    • 2020
  • The purpose of this study is to investigate the role and function of tokens to form a healthy blockchain-based ecosystem. Tokens must be constructed in a way that enhances their desired behavior to grow into a healthy token economy. The actions required of ecosystem participants in designing tokens should enable each individual to receive appropriate incentives (rewards) and encourage voluntary participation in taking this action. Also, all ecosystem participants must design to make the token ecosystem self-sustainable by generating profits. For example, in Bitcoin's proof-of-work method, mining is designed as a desirable behavior. Token-based services should be designed to induce multiple engagements, to design penalties for undesirable behavior, and to take into account evolutionary development potentials. Besides, the economic value of the entire token ecosystem will increase if the value that is designed and designed to take into account the revolutionary Innovation Possibility is greater than the reward amount paid to tokens. This study will contribute to presenting relevant service model by presenting how to design tokens and criteria when establishing blockchain-based service model. Future research is needed to discover new facts through a detailed comparative analysis between Tokennomics models.

내분비 장애물질, 환경호르몬이 야생동물의 생식과 발생에 미치는 영향 (The Effects of Endocrine Disrupters on Reproduction and Development of Wild Animals)

  • 윤용달
    • 한국발생생물학회지:발생과생식
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    • 제2권2호
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    • pp.115-133
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    • 1998
  • 지난 반세기 동안내분비 장애물질의 제한없는 생산과 무분별한 소비, 방출, 폐기는 물, 흙, 공기 등 자연을 오염시켜 왔다. 그 결과 생태계의 야생동물이 오염되어, 생식과 발생의 이상이 일어나고, 멸종이 예견되기에 이르렀다. 또한 동물 자신은 물론, 후세대에 내분비계의 교란을 일으켜 정상적인 성생활, 발생과 생식의 기형, 정자수 감소 등의 불임유발, 성행동, 신경계와 면역계의 이상, 암까지 유발하는 것으로 알려지고 있다. 암이 개체의 사멸을 일으키는 반면, 내분비 장애물질은 체내에 잔류되며 대를 이어 전달되고, 사멸하여도 환경의 오염원이 되어 먹이사슬로 축적된다는 의미에서 야생동물은 물론 인간의 미래를 어둡게 만든다고 판단되고 있다. 그러므로 이들이 야생동물의 생식과 발생에 미치는 영향, 먹이사슬내의 이동 및 오염 확산을 개관하고자 하였다. 또한 이에 대처하기 위한 국내외 연구동향을 기술하고, 또 중요한 물질의 생산 현황을 요약하고, 발생과 생식을 전공하는 연구자 제위에게 관심을 유도하고자 하였다.

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Therapeutic potential of traditionally used medicinal plant Andrographis paniculata (Burm. F.) against diabesity: An experimental study in rats

  • Thakur, Ajit Kumar;Chatterjee, Shyam Sunder;Kumar, Vikas
    • 셀메드
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    • 제4권1호
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    • pp.7.1-7.8
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    • 2014
  • Metabolic effects of ten daily doses of standardized extract of Andrographis paniculata leaves (AP) rich in andrographolide were evaluated in a rat model of type-2 diabetes and in diet induced obese rats. AP was administered per-orally as suspension in 0.3% carboxymethylcellulose at doses of 50, 100 and 200 mg/kg/day for 10 consecutive days. Blood glucose, insulin and lipid profile of rats were measured by using enzyme kits. In addition, effects of such treatments on anti-oxidant enzymes activity and histopathological changes in various organs of diabetic rats were assessed. AP treatments reversed body weight losses and increased plasma insulin level in diabetic rats. The anti-oxidant enzymes activity became normal and histopathological changes observed in pancreas, liver, kidney and spleen of diabetic animals were less severe in extract treated groups. On the other hand, hyperinsulinemia and increased body weight gains observed in high fat or fructose fed rats were less severe in the extract treated groups. These observations revealed therapeutic potentials of the extract for treatments of diabesity associated metabolic disorders, and suggest that the effects of the extract on insulin homeostasis depend on the metabolic status of animals. Activation of cytoprotective mechanisms could be involved in its mode of action.

Pharmacological activities of Glehnia littoralis

  • Yoon, Tae-Sook;Choo, Byung-Kil;Cheon, Myeoung-Sook;Lee, Do-Yeon;Choi, Go-Ya;Chae, Sung-Wook;Lee, A-Yeong;Kim, Ho-Kyoung
    • 한국한의학연구원논문집
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    • 제14권1호
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    • pp.123-128
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    • 2008
  • Glehnia littoralis (Umbelliferae), a perennial herb distributed along the coastline of northern Pacific countries, is the medicinal plant used traditionally for treatment of various diseases. This review focuses on the various pharmacological activities of Glehnia littoralis for understanding about its traditional medicinal applications, medicinal uses in the modern society, and potentials for drug development Glehnia littoralis was reported to have anti-oxidant, anti-tumor, anti-amnesic, blood circulation-promoting, immunomodulatory, anti-microbial, and allelopathic activities. However, their mechanisms remain to be clarified. Because Glehnia littoralis has been prescribed in traditional Oriental medicine as a tonic herb, Glehnia littoralis can be better than other chemical drugs and medicines which exert the equal pharmacological activities. Although the activities of Glehnia littoralis are not specifically high-potent with unique mode of action, it may turn out that it can be beneficial to exert multiple pharmacological activities. In view of low toxicity, relative cheapness, presence in the diet, and occurrence in various herbal remedies of Glehnia littoralis, it needs to be prudent to evaluate its properties and applications further.

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파랑하중에 의한 해저지반의 응력변화에 대한 연구 (A Study of Variation of Wave-induced Stresses in a Seabed)

  • 장병욱;박영권;우철웅
    • 한국농공학회지
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    • 제38권1호
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    • pp.79-89
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    • 1996
  • It is expected that the soil hehaviours in the seahed subjected to cyclic wave loads are much different from that on the ground Cyclic shear stresses developed below the ocean bed as a result of a passing wave train may progressively build up pore pressure in certain soils. Such build-up pore pressure may be developed dynamic behaviour such as liquefaction and significant deformation of the seabed. Currently available analytical and testing methods for the seabed subjected to cyclic wave loads are not general. The purpose of the study are to provide a test method in laboratory and to analyse the mechanism of wave-induced stresses and liquefactions potentials of the unsaturated silty marine sand. It is showed that the test set-up made especially for this study delivers exactly oscillatory wave pressures of the form of sine function. Laboratory test results defining the cyclic shear strength of the unsaturated porous medium that is homogenously sedimented. It is understood that the pore water pressure due to induced-waves is not accumulated as the wave number increases but reveals periodical change on the still water surface. The magnitude of the pore water pressure tends to be attenuated radically with a certain time lag under the action of both high and low waves as depth increases.

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Controlling a lamprey-based robot with an electronic nervous system

  • Westphal, A.;Rulkov, N.F.;Ayers, J.;Brady, D.;Hunt, M.
    • Smart Structures and Systems
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    • 제8권1호
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    • pp.39-52
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    • 2011
  • We are developing a biomimetic robot based on the Sea Lamprey. The robot consists of a cylindrical electronics bay propelled by an undulatory body axis. Shape memory alloy (SMA) actuators generate propagating flexion waves in five undulatory segments of a polyurethane strip. The behavior of the robot is controlled by an electronic nervous system (ENS) composed of networks of discrete-time map-based neurons and synapses that execute on a digital signal processing chip. Motor neuron action potentials gate power transistors that apply current to the SMA actuators. The ENS consists of a set of segmental central pattern generators (CPGs), modulated by layered command and coordinating neuron networks, that integrate input from exteroceptive sensors including a compass, accelerometers, inclinometers and a short baseline sonar array (SBA). The CPGs instantiate the 3-element hemi-segmental network model established from physiological studies. Anterior and posterior propagating pathways between CPGs mediate intersegmental coordination to generate flexion waves for forward and backward swimming. The command network mediates layered exteroceptive reflexes for homing, primary orientation, and impediment compensation. The SBA allows homing on a sonar beacon by indicating deviations in azimuth and inclination. Inclinometers actuate a bending segment between the hull and undulator to allow climb and dive. Accelerometers can distinguish collisions from impediment to allow compensatory reflexes. Modulatory commands mediate speed control and turning. A SBA communications interface is being developed to allow supervised reactive autonomy.

파랑하중에 의한 해저지반의 공극수압 변화에 대한 연구 (An Experimental Study on the Variation of Pore Water Pressures in the Seabed Subjected to Waves)

  • 장병욱;강준영
    • 한국농공학회지
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    • 제38권5호
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    • pp.85-94
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    • 1996
  • For the geotechnical analysis in the construction and Deign of the coastal structures, one of the most important factors is the existence of waves. The dynamic behavior and deformation of the seabed subjected to wave load must be considered. It is expected that the soil behavior in the seabed subjected to cyclic wave load is much different from that on the ground subjected to dynamic forces such as earthquake. The purposes of this study are as follows ; Firstly, to provide a testing method to generate wave loads in the laboratory and measuring oscillatory pore water pressures in the unsaturated marine silty sand specimen, Secondly, to analyze the mechanism of wave induced pore water pressures and liquefaction potentials under the conditions in the testing. It is shown that the test set-up manufactured especially for the test is good to generate oscillatory wave pressures to the specimen with sine wave type. From the results of this study, it is understood that the pore water pressure due to induced waves is not accumulated as the wave number increases but is periodically varied with wave passage on still water surface. The magnitude of pore water pressures measured tends to be diminished radically with a certain time lag under the action of both high and low waves as depth increases.

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Distinct Regional and Cellular Localization of Hyperpolarization-activated Cyclic Nucleotide-gated Channel 1 in Cerebellar Cortex of Rat

  • Kwon, Young-Joon;Kim, Tae-Sung
    • Journal of Korean Neurosurgical Society
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    • 제42권3호
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    • pp.205-210
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    • 2007
  • Objective : Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels mediate the hyperpolarization-activated currents (Ih) that participate in regulating neuronal membrane potential and contribute critically to pacemaker activity, promoting synchronization of neuronal networks. However, distinct regional and cellular localization of HCN channels in the brain have not been precisely defined. Aim of this study was to verify the precise cellular location of HCN1 channels in rat cerebellum to better understand the physiological role these channels play in synaptic transmission between CNS neurons. Methods : HCN1 expression in rat brain was analyzed using immunohistochemistry and electron-microscopic observations. Postsynaptic density-95 (PSD-95), otherwise known as locating and clustering protein, was also examined to clarify its role in the subcellular location of HCN1 channels. In addition, to presume the binding of HCN1 channels with PSD-95, putative binding motifs in these channels were investigated using software-searching method. Results : HCN1 channels were locally distributed at the presynaptic terminal of basket cell and exactly corresponded with the location of PSD-95. Moreover, nine putative SH3 domain of PSD-95 binding motifs were discovered in HCN1 channels from motif analysis. Conclusion : Distinct localization of HCN1 channels in rat cerebellum is possible, especially when analyzed in conjunction with the SH3 domain of PSD-95. Considering that HCN1 channels contribute to spontaneous rhythmic action potentials, it is suggested that HCN1 channels located at the presynaptic terminal of neurons may play an important role in synaptic plasticity.

Physical Properties of Mercaptopyruvic-acid Layer Formed on Gold Surfaces

  • Park, Jin-Won
    • Bulletin of the Korean Chemical Society
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    • 제32권8호
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    • pp.2611-2616
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    • 2011
  • We studied the physical properties of the mercaptopyruvic-acid layer formed on gold surfaces, which has the interactions with the titanium dioxide surface for design of gold- titanium dioxide distribution. Surface force measurements were performed, using the atomic force microscope (AFM), between the surfaces as a function of the salt concentration and pH value. The forces were analyzed with the DLVO (Derjaguin-Landau-Verwey-Overbeek) theory, to evaluate the potential and charge density of the surfaces quantitatively for each salt concentration and each pH value. The difference in the properties reflected the effect of the isoelectric point on the surface forces. The forces were interpreted for the evaluation with the law of mass action and the ionizable groups on the surface. The salt concentration dependence of the surface properties, found from the measurement at pH 8.0, was consistent with the prediction from the law. It was found that the mercaptopyruvic-acid layer had higher values for the surface charge densities and potentials than the titanium dioxide surfaces at pH 8, which may be attributed to the ionized-functional-groups of the mercaptopyruvic-acid layer.