• Title/Summary/Keyword: Center of Pressure (CoP)

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Correlation among triceps surae muscle structure, balance, and gait in persons with stroke

  • Park, Hye-Kang;Yu, Ki-Gon;Shin, Jang-Hoon;Lee, Wan-Hee
    • Physical Therapy Rehabilitation Science
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    • v.9 no.3
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    • pp.155-164
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    • 2020
  • Objective: This study aimed to compare muscle structure, balance, and gait parameters between healthy adults and persons with stroke and to analyze the correlation among these variables. Design: Cross-sectional study. Methods: Twenty persons with stroke (11 male, 9 female) and twenty healthy participants (9 male, 11 female) were included. Ultrasound images of the triceps surae and the tibialis anterior were acquired in sitting resting, sitting co-contraction, and standing resting positions and also during the functional reach test (FRT) and single leg anterior reaching test (SLART). Muscle thickness and fascicle length were measured. Spatiotemporal parameters of gait were measured using a pressure walkway. Gait speed, cadence, step length, stride length, stance time, and swing time were measured. Results: Changes in percent fascicle length were significantly greater in the gastrocnemius and soleus (SOL) muscles of healthy adults in the sitting co-contraction position (p<0.05). The percent fascicle length of the SOL in FRT and SLART were significantly greater in healthy adults (p<0.05). The mid-stance phase of stroke patients was shorter than healthy adults (p<0.05). A negative correlation was observed between percent fascicle length of the SOL in the sitting co-contraction position and the proportion of the mid-stance phase (p<0.05). Conclusions: The function of the triceps surae is affected in persons with stroke when compared with healthy adults. This can lead to difficulty in performing tasks that involve forward transfer of weight. If the triceps surae is not sufficiently secured, the possibility of compensation in the stance phase increases during gait.

The Usefulness of Noninvasive Positive Pressure Ventilation as a New Weaning Method (새로운 이탈방법으로서 비침습적 양압환기법의 유용성)

  • Shim, Tae-Sun;Koh, Youn-Suck;Lee, Sang-Do;Kim, Woo-Sung;Kim, Dong-Soon;Kim, Won-Dong;Lim, Chae-Man
    • Tuberculosis and Respiratory Diseases
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    • v.46 no.4
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    • pp.500-511
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    • 1999
  • Background: Noninvasive positive pressure ventilation (NPPV) using facial or nasal mask have been widely used for several years in stable patients with chronic neuromuscular disease or central alveolar hypoventilation, and recently have been tried in patients with acute respiratory failure. In a few studies, NPPV was also used to rescue the patients with post-extubation respiratory failure. However, yet it has not been adopted as a weaning method in patients on long-term mechanical ventilation. So we performed this prospective clinical study to evaluate the usefulness of NPPV as a weaning method after removing endotracheal tube intentionally in patients on long-term mechanical ventilation. Method: Twelve patients who had been on invasive mechanical ventilation over 10 days were enrolled and 14 trials of NPPV were done. All had failed at least one weaning trial and showed ventilator dependence(pressure support requirement between 8-15cm $H_2O$, and PEEP requirement between 5-10cm $H_2O$), so tracheostomy was being considered. After removing the endotracheal tube, NPPV was applied using facial mask. Respiratory rate, arterial blood gas, pressure support level, and PEEP level were monitored just before intended extubation, at 30 minutes, 1 to 6, 6 to 12, 12 to 24 hours, 2nd day, and 3rd day following initiation of NPPV, and just before weaning from NPPV. The successful weaning was defined as spontaneous breathing off the ventilator for 48 hours or longer without respiratory distress. Results: The weaning through NPPV after intended extubation was successful in 7(50%) of 14 trials, and tracheostomy could be avoided in them. There were no differences in age, sex, APACHE III score, duration of invasive mechanical ventilation, baseline respiratory rate, $PaCO_2$ $PaO_2/FiO_2$, and ventilatory requirement(PS and PEEP) between the success and failure groups. In the success group, respiratory rate, pH, $PaCO_2$, and $PaO_2/FiO_2$ were not different between invasive MV and NPPV period. But in the failure group, pH decreased after 30 minutes of NPPV initiation compared with that of invasive MV($7.40\pm0.08$ vs. $7.34\pm0.06$, p<0.05). The causes of failure were worsening of ABG(n=3), retained tracheal secretion(n=2), mask intolerance(n=1), and flail chest(n=1). Conclusion: NPPV may be worth trying as a bridge method in weaning patients on long-term invasive mechanical ventilation.

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Effect of Kinesiology Taping for Ankle Instability in Stroke Patients

  • Oh, Donghwan;Park, Jaeyoung;Kim, Jinuk
    • Journal of International Academy of Physical Therapy Research
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    • v.11 no.1
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    • pp.1950-1953
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    • 2020
  • Background: Ankle instability usually occurs after stroke, and contributes to unsafe walking and associated risk of falling in the affected patients. Objective: To investigate the effects of kinesiology taping (KT) on gait and balance ability (center of pressure, CoP) in patients with ankle instability after stroke. Design: One group, pre-post design. Methods: A total of 11 patients with ankle instability after stroke were enrolled. In all subjects, the gait and balance ability were assessed under 2 conditions: KT and barefoot. Gait and balance ability was assessed using GAITRite system and FDM-S platform. Results: Comparison between KT and barefoot condition, KT condition was significantly higher in velocity, cadence, step length, and stride length than barefoot condition (P<.05). KT condition was significantly lower in CoP path length and sway speed than barefoot condition (P<.05). Conclusion: KT indicated potential as a helpful method for walking and balancing ability in patients with ankle instability after stroke. Therefore, this study recommends KT as an option applicable to the stroke with ankle instability.

Effect of Vestibular Training Using Ball on Static Balance in Normal Subjects (공을 이용한 안뜰계 훈련이 정상 성인의 정적 균형에 미치는 영향)

  • Choi, Su-Hee;Cho, Hwa-Young;Kang, Yang-Hun;Kwank, Kwang-Il;Kwon, Hye-Min;Seo, Sam-Ki
    • Journal of the Korean Academy of Clinical Electrophysiology
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    • v.9 no.2
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    • pp.13-23
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    • 2011
  • Purpose : The purpose of this study is to investigate the effect on the static balance ability according to vestibular training using ball. Methods : Twenty normal subjects participated and were randomly assigned to either a vestibular training group using ball or a control group. The vestibular training using a ball group exercised 3 times per week over 3 weeks. The static balance was assessed by the center of pressure to the stance position. The participants stood barefoot on a force platform in a normal stance and a one-legged stance with a visual close. Results : In the normal stance, there were no significant differences at CoP surface and CoP speed. However, in a one-legged stance, there were significant differences in the vestibular training group between before and after the program. There was also a significant difference between the vestibular training group and the control group. Conclusion : Vestibular training using ball can be implemented as a therapeutic intervention to improve static balance ability in health adults.

A Comprehensive Review of Geological CO2 Sequestration in Basalt Formations (현무암 CO2 지중저장 해외 연구 사례 조사 및 타당성 분석)

  • Hyunjeong Jeon;Hyung Chul Shin;Tae Kwon Yun;Weon Shik Han;Jaehoon Jeong;Jaehwii Gwag
    • Economic and Environmental Geology
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    • v.56 no.3
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    • pp.311-330
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    • 2023
  • Development of Carbon Capture and Storage (CCS) technique is becoming increasingly important as a method to mitigate the strengthening effects of global warming, generated from the unprecedented increase in released anthropogenic CO2. In the recent years, the characteristics of basaltic rocks (i.e., large volume, high reactivity and surplus of cation components) have been recognized to be potentially favorable in facilitation of CCS; based on this, research on utilization of basaltic formations for underground CO2 storage is currently ongoing in various fields. This study investigated the feasibility of underground storage of CO2 in basalt, based on the examination of the CO2 storage mechanisms in subsurface, assessment of basalt characteristics, and review of the global research on basaltic CO2 storage. The global research examined were classified into experimental/modeling/field demonstration, based on the methods utilized. Experimental conditions used in research demonstrated temperatures ranging from 20 to 250 ℃, pressure ranging from 0.1 to 30 MPa, and the rock-fluid reaction time ranging from several hours to four years. Modeling research on basalt involved construction of models similar to the potential storage sites, with examination of changes in fluid dynamics and geochemical factors before and after CO2-fluid injection. The investigation demonstrated that basalt has large potential for CO2 storage, along with capacity for rapid mineralization reactions; these factors lessens the environmental constraints (i.e., temperature, pressure, and geological structures) generally required for CO2 storage. The success of major field demonstration projects, the CarbFix project and the Wallula project, indicate that basalt is promising geological formation to facilitate CCS. However, usage of basalt as storage formation requires additional conditions which must be carefully considered - mineralization mechanism can vary significantly depending on factors such as the basalt composition and injection zone properties: for instance, precipitation of carbonate and silicate minerals can reduce the injectivity into the formation. In addition, there is a risk of polluting the subsurface environment due to the combination of pressure increase and induced rock-CO2-fluid reactions upon injection. As dissolution of CO2 into fluids is required prior to injection, monitoring techniques different from conventional methods are needed. Hence, in order to facilitate efficient and stable underground storage of CO2 in basalt, it is necessary to select a suitable storage formation, accumulate various database of the field, and conduct systematic research utilizing experiments/modeling/field studies to develop comprehensive understanding of the potential storage site.

Effects of Uwhangchungsim-won(Niuhuangqingxin-yuan) on Systemic Blood Pressure, Pulse Rate, Cerebral Blood Flow, and Cerebrovascular Reactivity in Humans (우황청심원(牛黃淸心元)이 정상인의 혈압(血壓), 맥박수(脈搏數), 뇌혈류(腦血流) 및 뇌혈관반응도(腦血管反應度)에 미치는 영향(影響))

  • Yun, Sang-Pil;Lee, Sang-Ho;Kim, Eun-Ju;Na, Byong-Jo;Jung, Dong-Won;Shin, Won-Jun;Moon, Sang-Kwan;Bae, Hyung-Sup;Kim, Lee-Dong
    • The Journal of Internal Korean Medicine
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    • v.25 no.3
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    • pp.440-450
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    • 2004
  • Objectives: Uwhangchungsim-won(UC) has been used in the treatment of a wide variety of conditions including stroke, hypertension, arterosclerosis, autonomic imbalance, and mental instability, in Korean traditional hospitals. The aim of this study was to evaluate the effect of DC on cerebral hemodynamics and to determine the appropriate dosage. Methods: We studied changes in hyperventilation-induced cerebrovascular reactivity and mean blood flow velocity of the middle cerebral arteries(MCAs) were studied by means of transcranial Doppler ultrasound. Changes in mean blood pressure, pulse rate and expiratory CO2(PECO2) were observed using Cardiocap TM/5. Six healthy young volunteers who were administrated with full doses of DC for group A, and half doses for group B. Six other healthy subjects comprised the control group. The evaluation was performed during basal condition, and repeated at 20, 40, 60, 120, and 180 minutes after administration. Results: Increases of cerebrovascular reactivity and mean blood flow velocity in the middle cerebral artery in group A were significantly different compared with group B and the control group (p<0.1). Mean blood pressure, pulse rate and expiratory CO2 did not change during the observation and were not different among these three groups. We observed that in cerebrovascular reactivity induced hyperventilation, group A was most effective at 40 minutes after administration, and its effectiveness lasted for 120 minutes. Conclusions: This study provides evidence for UC, in full doses, as an agent for dilation of the cerebral arteriols to increase hyperventilation-induced cerebrovascular reactivity as a consequence of faster recovery of blood flow velocity.

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Preparation of p-type transparent semiconductor $SrCu_2O_2$ thin film by RF magnetron sputtering (RF 마그네트론 스퍼터링에 의한 p형 투명 반도체 $SrCu_2O_2$ 박막의 제조)

  • Kim, Sei-Ki;Seok, Hye-Won;Lee, Mi-Jae;Choi, Byung-Hyun;Jeong, Won-Hee
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.06a
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    • pp.47-47
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    • 2008
  • P-type transparent semiconductor $SrCu_2O_2$ thin films have been prepared by RF sputtering using low-alkali glass for LCD and quartz as substrates. Single phase of $SrCu_2O_2$ powder was obtained by heating a stoichiometric mixture of CuO and $SrCO_3$ at 1223K for 96h under N2 gas flow, and target was fabricated at 1243K for 24h. Room temperature conductivity of the sintered body was about 0.02S/cm, and the activation energy in the temperature range of $-50^{\circ}C$~RT and RT~$150^{\circ}C$ were 0.18eV, 0.07eV, respectively. Effects of deposition pressure and post-annealing temperature on the electrical and optical properties of the obtained thin film have been investigated.

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The Respiratory and Hemodynamic Effects of Prone Position According to the Level of PEEP in a Dog Acute Lung Injury Model (잡종견 급성폐손상 모델에서 Prone position 시행시 PEEP 수준에 따른 호흡 및 혈류역학적 효과)

  • Lim, Chae-Man;Chin, Jae-Yong;Koh, Youn-Suck;Shim, Tae-Sun;Lee, Sang-Do;Kim, Woo-Sung;Kim, Dong-Soon;Kim, Won-Dong
    • Tuberculosis and Respiratory Diseases
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    • v.45 no.1
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    • pp.140-152
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    • 1998
  • Background: Prone position improves oxygenation in patients with ARDS probably by reducing shunt Reduction of shunt in prone position is thought to be effected by lowering of the critical opening pressure (COP) of the dorsal lung because the pleural pressure becomes less positive in prone position compared to supine position. It can then be assumed that prone position would bring about greater improvement in oxygenation when PEEP applied in supine position is just beneath COP than when PEEP is above COP. Hemodynamically, prone position is expected to attenuate the lifting of cardiac fossa induced by PEEP. Based on these backgrounds, we investigated whether the effect of prone position on oxygenation differs in magnitude according to the level of PEEP applied in supine position, and whether impaired cardiac output in supine position by PEEP can be restored in prone position. Methods: In seven mongrel dogs, $PaO_2/F_1O_2$(P/F) was measured in supine position and at prone position 30 min. Cardiac output (CO), stroke volume (SV), pulse rate (PR), and pulmonary artery occlusion pressure (PAOP) were measured in supine position, at prone position 5 min, and at prone position 30 min. After ARDS was established with warmed saline lavage(P/F ratio $134{\pm}72$ mm Hg), inflection point was measured by constant flow method($6.6{\pm}1.4cm$ $H_2O$), and the above variables were measured in supine and prone positions under the application of Low PEEP($5.0{\pm}1.2cm$ $H_2O$), and Optimal PEEP($9.0{\pm}1.2cm$ $H_2O$)(2 cm $H_2O$ below and above the inflection point, respectively) consecutively. Results : P/F ratio in supine position was $195{\pm}112$ mm Hg at Low PEEP and $466{\pm}63$ mm Hg at Optimal PEEP(p=0.003). Net increase of P/F ratio at prone position 30 min, however, was far greater at Low PEEP($205{\pm}90$ mm Hg) than at Optimal PEEP($33{\pm}33$ mm Hg)(p=0.009). Compared to CO in supine position at Optimal PEEP($2.4{\pm}0.5$ L/min), CO in prone improved to $3.4{\pm}0.6$ L/min at prone position 5 min (p=0.0180) and $3.6{\pm}0.7$ L/min at prone position 30 min (p=0.0180). Improvement in CO was attributable to the increase in SV: $14{\pm}2$ ml in supine position, $20{\pm}2$ ml at prone position 5 min (p=0.0180), and $21{\pm}2$ ml at prone position 30 min (p=0.0180), but not to change in PR or PAOP. When the dogs were turned to supine position again, MAP ($92{\pm}23$ mm Hg, p=0.009), CO ($2.4{\pm}0.5$ L/min, p=0.0277) and SV ($14{\pm}1$ ml, p=0.0277) were all decreased compared to prone position 30 min. Conclusion: Prone position in a dog with saline-lavaged acute lung injury appeared to augment the effect of relatively low PEEP on oxygenation, and also attenuate the adverse hemodynamic effect of relatively high PEEP. These findings suggest that a PEEP lower than Optimal PEEP can be adopted in prone position to achieve the goal of alveolar recruitment in ARDS avoiding the hemodynamic complications of a higher PEEP at the same time.

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Antihypertensive Effect of Wild Mountain Ginseng Cultured Root Extract in Spontaneously Hypertensive Rats (Spontaneously Hypertensive Rats에 있어서 산삼배양근 추출물의 항고혈압 효과)

  • Yang, Deok-Chun;In, Jun-Gyo;Lee, Bum-Soo;Han, Seung-Ho;Kim, Eun-Jeong;Kim, Kil-Soo
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.22 no.6
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    • pp.1482-1486
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    • 2008
  • The antihypertensive effects of the Wild Mountain Ginseng Cultured Root Extract (WMGCE) were investigated in spontaneously hypertensive rats (SHR). Daily oral administration of the WMGCE (100 and 200 mg/kg) exhibited a significant decrease in blood pressure in SHR rats during for 8 weeks. The systolic blood pressure was dose- and time-dependently decreased significantly from the second weeks (p < 0.05) to the end of WMGCE treatment in SHR. The WMGCE decreased the plasma levels of sodium, potassium, chlorides, urea and osmolarity in SHR rats but no statistically significant change was observed. Furthermore, no significant changes were noted on heart weight, heart rate and diameter of aorta after WMGCE treatment in SHR. Our results suggest that daily oral administration of WMGCE at the dose of 100 and 200 mg/kg for 8 weeks exhibited antihypertensive activities.

Validation of the fuel rod performance analysis code FRIPAC

  • Deng, Yong-Jun;Wei, Jun;Wang, Yang;Zhang, Bin
    • Nuclear Engineering and Technology
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    • v.51 no.6
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    • pp.1596-1609
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    • 2019
  • The fuel rod performance has great importance for the safety and economy of an operating reactor. The fuel rod performance analysis code, which considers the thermal-mechanical response and irradiation effects of fuel rod, is usually developed in order to predict fuel rod performance accurately. The FRIPAC (${\underline{F}}uel$ ${\underline{R}}od$ ${\underline{I}}ntegral$ ${\underline{P}}erformance$ ${\underline{A}}nalysis$ ${\underline{C}}ode$) is such a fuel rod performance analysis code that has been developed recently by China Nuclear Power Technology Research Institute Co. Ltd. The code aims at the computational simulation of the Pressurized Water Reactor fuel rod behavior for both steady-state and power ramp condition. A brief overview of FRIPAC is presented including the computational framework and the main behavioral models. Validation of the code is also presented and it focuses on the fuel rod behavior including fuel center temperature, fission gas release, rod internal pressure/internal void volume, cladding outer diameter and cladding corrosion thickness. The validation is based on experimental data from several international projects. The validation results indicate that FRIPAC is an accurate and reliable fuel rod performance analysis code because of the satisfactory comparison results between the experimental measurements and the code predictions.