• The Korean Journal of Physiology
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• 제30권1호
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• pp.21-31
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• 1996

To investigate the mechanisms of increased endothelium-dependent contraction by acetylcholine in hypertensive rats, the relationship between endothelium-dependent contraction by acetylcholine and blood pressure was studied in spontaneously hypertensive rats (SHR), one-kidney, one clip Goldblatt hypertension (1K,1C-GBH) rats, and Wistar-Kyoto rats (WKY). SHR were treated orally with enalapril or nicardipine in order to prevent development of hypertension or suppress the developed hypertension. 1K,1C-GBH rats were made by renal artery stenosis with contralateral nephrectomy in 8 week-WKY. 1. Endothelium-dependent contractions by acetylcholine $(10^{-6}{\sim}10^{-5}\;M)$ in SHR were significantly greater than those in WKY. 2. Chronic treatment with enalapril or nicardipine reduced the endothelium-dependent contraction in SHR 3. The degree of reduction of endothelium-dependent contraction was greater in SHR which was prevented from developing hypertension than in SHR of which high blood pressure was suppressed. 4. In aortic rings from 1K,1C-GBH rats, endothelium-dependent contractions by acetylcholine were augmented as compared with WKY. 5. There is good relationship between the value of blood pressure and magnitude of endothelium-dependent contraction. Thus, it is suggested that increased endothelium-dependent contraction in hypertensive rats may he due to the high blood pressure and endothelium-dependent contraction may not be a cause of the initiation of hypertension in SHR.

• 운동과학
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• 제26권3호
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• pp.229-237
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• 2017

PURPOSE: This study was to investigate the Glycolysis mediated sarcoplasmic reticulum (SR) $Ca^{2+}$ signal regulates mitochondria $Ca^{2+}$ during skeletal muscle contraction by using glycolysis inhibitor. METHODS: To examine the effect of Glycolysis inhibitor on SR and mitochondria $Ca^{2+}$ content, we used skeletal muscle fiber from gastrocnemius muscle. 2-deoxy glucose and 3-bromo pyruvate used as glycolysis inhibitor, it applied to electrically stimulated muscle contraction experiment. Intracellular $Ca^{2+}$ content, SR, mitochondria $Ca^{2+}$ level and mitochondria membrane potential (MMP) was detected by confocal microscope. Mitochondrial energy metabolism related enzyme, citric acid synthase activity also examined for mitochondrial function during the muscle contraction. RESULTS: Treatment of 2-DG and 3BP decreased the muscle contraction induced SR $Ca^{2+}$ increase however the mitochondria $Ca^{2+}$ level was increased by treatment of inhibitors and showed and overloading as compared with the control group. Glycolysis inhibitor and thapsigargin treatment showed a significant decrease in MPP of skeletal muscle cells compared to the control group. CS activity significantly decreased after pretreatment of glycolysis inhibitor during skeletal muscle contraction. These results suggest that regulation of mitochondrial $Ca^{2+}$ levels by glycolysis is an important factor in mitochondrial energy production during skeletal muscle contraction CONCLUSIONS: These results suggest that mitochondria $Ca^{2+}$ level can be regulated by SR $Ca^{2+}$ level and glycolytic regulation of intraocular $Ca^{2+}$ signal play pivotal role in regulation of mitochondria energy metabolism during the muscle contraction.

• 대한물리의학회지
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• 제12권1호
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• pp.61-66
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• 2017

PURPOSE: The purpose of this study was to investigate the effects of isometric upper limb contraction on the trunk and lower extremity muscles during the sit-to-stand activity in elderly females. METHODS: Eighteen healthy elderly females performed three directional isometric upper extremity contractions (flexion, extension, and horizontal abduction movements) using an elastic band during sit-to-stand activity. Electromyography signals were collected from the internal oblique, erector spinae, rectus femoris, and biceps femoris muscles. RESULTS: Internal oblique activity was greater in bilateral shoulder flexion and bilateral shoulder horizontal abduction than in neutral position (p<.05). Erector spinae and rectus femoris muscle activities in bilateral shoulder flexion was greater than in neutral position and bilateral shoulder extension (p<.05). Biceps femoris activity was significantly greater in bilateral shoulder flexion than in bilateral shoulder extension and horizontal abduction, and in neutral position compared to bilateral shoulder extension (p<.05). CONCLUSION: These results suggest that incorporating isometric upper limb contraction may be beneficial for enhancing the contribution of trunk and lower extremity muscle activities to trunk stabilization during sit-to-stand activity. Therefore, isometric upper limb contraction during sit-to-stand tasks, especially in flexion, may be used to elicit contraction of the lumbopelvic region muscles within a tolerable range, for developing endurance and strength in the elderly.

• 융합정보논문지
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• 제10권10호
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• pp.109-114
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• 2020

이번 연구는 소화기계 출혈, 궤양 등에 대해 치료와 예방을 목적으로 사용되는 rebamipide에서 농도 의존적 장관 수축성 조절 기전에 대해 조사하고자 한다. 소화기 수축은 근육의 섬유의 조절에 의하여 일어난다. 실험용 쥐의 회장 과 결장을 적출하여 carbachol로 회장 과 결장의 근육수축을 유발하여 연구를 진행하였다. rebamipide 단독으로 장관수축을 억제하지 않고 소폭으로 carbachol 유도 수축을 높이는 것으로 관찰되었다. 소화기계 부작용을 일으키는 indomethacin 과 rebamipide를 흔히 병용하기에, 병용 효과를 관찰하였다. Indomethacin과 병용된 rebamipide는 장관 중 회장의 수축성을 증대시켰다. rebamipide는 장관중 회장에서 수축성을 증대시키고, NSAIDs에 의한 궤양에 대한 항궤양효과 외에 운동성도 일부 조절하는 것으로 생각된다.

• Biomolecules & Therapeutics
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• 제16권3호
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• pp.249-254
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• 2008

The present study was undertaken to determine whether hypoxia influences on the agonist-induced vascular smooth muscle contraction and, if so, to investigate the related mechanism. The measurement of isometric contractions using a computerized data acquisition system was combined with molecular experiments. Hypoxia significantly inhibited fluoride-induced contraction regardless of endothelial function, but there was no relaxation on thromboxane $A_2$ mimetic U-46619-induced contraction suggesting that other pathway such as $Ca^{2+}$ entry or thin filament regulation was not affected. In addition, hypoxia significantly decreased fluoride-induced increase of phospho-myosin-targeting subunit of myosin light chain phosphatase (pMYPT1). Interestingly, hypoxia didn't inhibit significantly phenylephrine-induced contraction suggesting that myosin light chain kinase (MLCK) activity or thin filament regulation is less important on the hypoxia-induced vasorelaxation in the denuded muscle than Rho-kinase activity. In conclusion, this study provides the evidence and possible related mechanism concerning the vasodilation effect of hypoxia on the agonist-specific contraction in rat aortic rings regardless of endothelial function.

• 비교문화연구
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• 제36권
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• pp.211-240
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• 2014

This is a cross-sectional study designed to analyze the correlation between the structural and social variables and the pattern of contraction and deletion of the copula verb in the speech of African American Vernacular English (AAVE) speakers in Athens in Georgia, USA using a questionnaire. The results show that the frequency of copula contraction is higher than that of deletion in all factor groups including the age of the speakers where this study found that younger speakers tend to have higher frequency of contraction and deletion of the copula than older speakers. This study analyzes this as a function of the fact that younger speakers of AAVE are conscious of the linguistic and social differences between AAVE speakers and speakers of Standard American English (SAE) and they consciously make choices regarding which norm to use at which contexts to satisfy their communicative and socio-cultural needs. This sort of conscious social behavior is not likely to disappear with age rather it might increase as a correlate of the perceived physical, socio-cultural and psychological distance between AAVE speakers and speakers of other varieties. This study shows that such perceived linguistic, socio-cultural and psychological distance has negative effects on pedagogy and I proffer the remedy.

• 한국생산제조학회지
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• 제22권4호
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• pp.723-729
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• 2013

The contraction and expansion noise of a refrigerator are investigated, and some effective methods are proposed to reduce the level and occurrence frequency of noise. First, the noise of a refrigerator is measured to estimate the frequency spectrum and occurrence frequency of noise. Second, a sound visualization was conducted using an acoustic camera to determine the location of the noise source. From the results, it was observed that the internal part mainly producing noise was the third shelf in the freezer room. A method to estimate the acceleration on the location of the noise source is introduced to analyze the contraction and expansion noise precisely and accommodate experimental convenience. Noise reduction methods such as the replacement of the existing shelf with glass shelves, adoption of rail slides, and increase of roughness on the contact surface of the shelf are proposed and tested.

• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 1997년도 학술발표회
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• pp.27-27
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• 1997

The effects of $a_1$-adrenoceptor stimulation on intracellular $Ca^{2+}$ ([C $a^{2+}$]$_{i}$ ) transient, contraction, and L-type $Ca^{2＋}$ current ( $I_{Ca,L}$) were studied in single cells isolated from ventricles of guinea pig hearts. Phenylephrine, $\alpha$$_1$-adrenergic agonist, (5$\times$10$^{-5}$ ~10$^{-4}$ M) produced a biphasic pattern of inotropism： transient negative response (decrease in contraction by 23.9$\pm$2.5% of control) followed by a sustained positive response (increase in contraction by 60.0$\pm$3.4%, mean $\pm$ SD, n=12).(omitted)ted)

• Nonlinear Functional Analysis and Applications
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• 제28권2호
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• pp.557-570
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• 2023

The conceptions of generalized b-metric spaces or G_b-metric spaces and a generalized Ω-distance mappings play a key role in proving many important theorems in existence and uniqueness of fixed point theory. In this manuscript, we establish a new type of contraction namely, Ω_b(𝓗, 𝜃, s)-contraction, this contraction based on the concept of a generalized Ω-distance mappings which established by Abodayeh et.al. in 2017 together with the concept of 𝓗-simulation functions which established by Bataihah et.al [10] in 2020. By utilizing this new notion we prove new results in existence and uniqueness of fixed point. On the other hand, examples and application were established to show the importance of our results.

• 한국산학기술학회논문지
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• 제16권3호
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• pp.1904-1919
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• 2015

본 연구는 낙상예방운동 프로그램을 적용 후 효과를 검증하고자 수행되었다. J시 A읍 두 보건진료소의 65세 이상 노인 52명 노인을 대상으로 2014년 6월1일부터 7월14일까지 시행되었다. 대상자는 실험군 31명, 대조군 21명으로 무작위로 분류하였다. 실험군은 주 2회, 6주간 낙상예방운동 프로그램을 실시하였고, 대조군 21명은 교육만 실시하였다. 연구결과 신체적 기능의 TUG에서 두 그룹 간에 유의한 차이를 보였다(p=.032). 정신적 기능의 낙상두려움, 낙상효능감에서는 통계적으로 유의하지 않았다. 하지근육의 초음파 측정은 7항목(RF CSA Contraction, RF DIS Resting, TA Thickness Contraction, TA P-angle Contraction, GCM Thickness Resting, GCM Thickness Contraction, GCM P-angle Contraction)에서 그룹 간 통계적으로 유의한 차이가 있었다(P<.05). 결론적으로 본 프로그램은 낙상예방에 매우 효과적이다.