• 제목/요약/키워드: Contraction factor

검색결과 163건 처리시간 0.02초

기능적 전기자극기를 이용한 간헐적 고주파 교대자극과 간헐적 저주파 동시자극의 근 수축력 비교 (A Comparison of Muscle Contraction Using Functional Electrical Stimulation: Intermittent High Frequency Alternating Stimulation Versus Intermittent Low Frequency Synchronous Stimulation)

  • 송영희;조상현;이영희
    • 한국전문물리치료학회지
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    • 제9권2호
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    • pp.115-131
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    • 2002
  • Functional electrical stimulation (FES) training of the knee extensors is a useful way to rehabilitate the ability to stand and walk. However, training using FES has not been able to solve the problem of fatigue; clinical application of FES quickly produces muscle fatigue, due to the continuous activation of the muscles of the lower extremity. Therefore, reduction of muscle fatigue is an important factor in increasing the effectiveness of FES training in paraplegia. Intermittent high frequency alternating stimulation is a method that combines the advantages of high frequency (leading to strong muscle contractions) and alternating stimulation (reducing muscle fatigue), thereby continuously strengthening muscles. It is not known whether low frequency simultaneous stimulation results in stronger muscle contraction than high frequency alternating stimulation. This study compared the effectiveness of high frequency alternating stimulation with low frequency synchronized stimulation. Muscle power using FES on the quadriceps of 20 normal subjects were compared. Intermittent high frequency alternating stimulation did not produce more powerful muscle contraction than intermittent low frequency synchronized stimulation, because the muscle characteristics differed individually. Significant individual variation according to muscle characteristics was founded when applying FES. Accordingly, when physical therapists use FES to treat patients, they must be aware of individual variation in muscle characteristics.

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Glucosamine increases vascular contraction through activation of RhoA/Rho kinase pathway in isolated rat aorta

  • Kim, Do-Hyung;Seok, Young-Mi;Kim, In-Kyeom;Lee, In-Kyu;Jeong, Seong-Yun;Jeoung, Nam-Ho
    • BMB Reports
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    • 제44권6호
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    • pp.415-420
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    • 2011
  • Diabetes is a well-known independent risk factor for vascular disease. However, its underlying mechanism remains unclear. It has been reported that increased influx of the hexosamine biosynthesis pathway (HBP) induces O-GlcNAcylation of proteins, leading to insulin resistance. In this study, we determined whether or not O-GlcNAc modification of proteins could increase vessel contraction. Using an endothelium-denuded aortic ring, we observed that glucosamine induced OGlcNAcylation of proteins and augmented vessel contraction stimulated by U46619, a thromboxane $A_2$ agonist, via augmentation of the phosphorylation of MLC20$MLC_{20}$, MYPT1(Thr855), and CPI17, but not phenylephrine. Pretreatment with OGT inhibitor significantly ameliorated glucosamine-induced vessel constriction. Glucosamine treatment also increased RhoA activity, which was also attenuated by OGT inhibitor. In conclusion, glucosamine, a product of glucose influx via the HBP in a diabetic state, increases vascular contraction, at least in part, through activation of the RhoA/Rho kinase pathway, which may be due to O-GlcNAcylation.

FMM 신경망에서 연관도요소를 이용한 규칙 추출 기법 (A Rule Extraction Method Using Relevance Factor for FMM Neural Networks)

  • 이승강;이재혁;김호준
    • 정보처리학회논문지:소프트웨어 및 데이터공학
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    • 제2권5호
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    • pp.341-346
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    • 2013
  • 본 연구에서는 수정된 구조의 FMM 신경망으로부터 패턴 인식을 위한 규칙 추출 방법을 제안한다. 제안된 방법은 학습데이터에서 특징값에 대한 빈도 요소를 반영하는 하이퍼박스 정의를 기반으로 하는데, 이로부터 특징과 패턴클래스 간의 상호 연관도 요소를 정의 하였다. 이는 기존의 모델에서 사용되는 하이퍼박스 중첩테스트 및 축소(contraction) 기법을 사용하지 않아도 하이퍼박스의 중첩에 의한 분류의 모호성을 해결할 수 있게 한다. 본 연구에서는 패턴 클래스의 각 차원별로 퍼지 분할을 기반으로 하는 수정된 하이퍼박스 멤버쉽 함수와 이를 사용하는 학습방법을 제시한다. 제안된 기법으로부터 특정패턴의 분류를 위한 자극성(excitatory) 특징 및 억제성(inhibitory) 특징을 구분하고 이들 정보는 규칙 생성과정에 적용된다. 수화 인식에 관한 실험에 제안된 방법론을 적용함으로써 제안된 이론의 타당성을 실험적으로 고찰하였다.

Local Silencing of Connective Tissue Growth Factor by siRNA/Peptide Improves Dermal Collagen Arrangements

  • Cho Lee, Ae-Ri;Woo, Inhae
    • Tissue Engineering and Regenerative Medicine
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    • 제15권6호
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    • pp.711-719
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    • 2018
  • BACKGROUND: Collagen organization within tissues has a critical role in wound regeneration. Collagen fibril diameter, arrangements and maturity between connective tissue growth factor (CTGF) small interfering RNA (siRNA) and mismatch scrambled siRNA-treated wound were compared to evaluate the efficacy of CTGF siRNA as a future implement for scar preventive medicine. METHODS: Nanocomplexes of CTGF small interfering RNA (CTGF siRNA) with cell penetrating peptides (KALA and $MPG^{{\Delta}NLS}$) were formulated and their effects on CTGF downregulation, collagen fibril diameter and arrangement were investigated. Various ratios of CTGF siRNA and peptide complexes were prepared and down-regulation were evaluated by immunoblot analysis. Control and CTGF siRNA modified cells-populated collagen lattices were prepared and rates of contraction measured. Collagen organization in rabbit ear 8 mm biopsy punch wound at 1 day to 8 wks post injury time were investigated by transmission electron microscopy and histology was investigated with Olympus System and TS-Auto software. CONCLUSION: CTGF expression was down-regulated to 40% of control by CTGF siRNA/KALA (1:24) complexes (p<0.01) and collagen lattice contraction was inhibited. However, down-regulated of CTGF by CTGF $siRNA/MPG^{{\Delta}NLS}$ complexes was not statistically significant. CTGF KALA-treated wound appeared with well formed-basket weave pattern of collagen fibrils with mean diameter of $128{\pm}22nm$ (n = 821). Mismatch siRNA/KALA-treated wound showed a high frequency of parallel small diameter fibrils (mean $90{\pm}20nm$, n = 563). CONCLUSION: Controlling over-expression of CTGF by peptide-mediated siRNA delivery could improve the collagen orientation and tissue remodeling in full thickness rabbit ear wound.

안면신경마비와 마비성 사시를 병발한 환자의 증례보고 (A Casuistics of a Patient with Facial Palsy and Paralytic Strabismus)

  • 조재훈;김윤범;채병윤
    • 한방안이비인후피부과학회지
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    • 제13권2호
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    • pp.152-164
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    • 2000
  • 1. We experienced one case with facial palsy and paralytic strabismus, which improved under the treatment of Acupuncture, Infrared, Electroacupuncture and Massage. 2. The prognostic factor of facial palsy was affected by On Set and neurodegeneration (such as synkinesis, contraction, spasm and crocodile tear). 3. In facial palsy, Myoneural Excitability Test by Electroacupuncture, which will need the objective clinical standard, was available for the evaluation of therapeutic effect and prognosis.

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등척성 팔굽 굽힘시 최대근지구력시간의 실증적 모델에 적용한 전완길이의 영향 (Effect of forearm length applied on empirical models of maximum endurance time during isometric elbow flexion)

  • 이상식;이기영
    • 한국정보전자통신기술학회논문지
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    • 제16권5호
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    • pp.338-346
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    • 2023
  • 등척성 팔굽 굽힘시 전완길이(florearm length)는 전완에 가해진 힘의 방향이 직각일 때 관절토크 뿐만 아니라 최대근지구력시간(maximum endurance time: MET)을 결정하는 중요한 요소이다. 본 연구의 목표는 전완의 등척성 수축시 MET의 대표적인 두 가지 실증적 모델인 지수모델과 거듭제곱모델에 전완길이를 추가요소로 적용했을 때 미치는 영향을 검토하는 것이다. 30명의 자원자가 실험에 참여하였으며, 요소변수로 사용할 참여자의 상완 및 전완의 둘레 및 길이들과 최대자율수축강도의 백분율(percent of maximum voluntary contraction intensity: %MVC)에 따른 MET를 측정하였다. 실험과정에서 ln(MET)의 다중선형회귀모델에서 유의확률을 산츨한 결과 %MVC와 전완길이가 유의한 독립변수임을 확인하였다 (P<0.05). 또한, 측정 MET와 기존의 두 가지 실증적 모델들 사이의 평균절대편차는 19.4초 였으나 전완길이를 적용한 모델을 이용한 경우 16.2초로 감소하였으며, 상관계수과 급내상관계수는 모두 평균 0.87 이었으나 전완길이를 적용했을 때 평균 0.91로 모두 증가하였다. 실험결과로부터 전완의 길이가 실증적 모델에 유의한 추가 요소임을 확인하였다.

The Absence of Atrial Contraction as a Predictor of Permanent Pacemaker Implantation after Maze Procedure with Cryoablation

  • Jeon, Chang-Seok;Shim, Man-shik;Park, Seung-Jung;Jeong, Dong Seop;Park, Kyoung-Min;On, Young Keun;Kim, June Soo;Park, Pyo Won
    • Journal of Chest Surgery
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    • 제50권3호
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    • pp.163-170
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    • 2017
  • Background: The absence of atrial contraction (AC) after the maze procedure has been reported to cause subsequent annular dilatation and to increase the risk of embolic stroke. We hypothesized that the lack of AC could increase the risk of permanent pacemaker (PPM) implantation in patients undergoing the maze procedure. Methods: In 376 consecutive patients who had undergone a cryo-maze procedure and combined valve operation, recovery of AC was assessed at baseline and at immediate (${\leq}2$ weeks), early (${\leq}1$ year, $4.6{\pm}3.8$ months), and late (>1 year, $3.5{\pm}1.1$ years) postoperative stages. Results: With a median follow-up of 53 months, 10 patients underwent PPM implantation. Seven PPM implants were for sinus node dysfunction (pauses of $9.6{\pm}2.4$ seconds), one was for marked sinus bradycardia, and two were for advanced/complete atrioventricular block. The median (interquartile range) time to PPM implantation was 13.8 (0.5-68.2) months. Our time-varying covariate Cox models showed that the absence of AC was a risk factor for PPM implantation (hazard ratio, 11.92; 95% confidence interval, 2.52 to 56.45; p=0.002). Conclusion: The absence of AC may be associated with a subsequent risk of PPM implantation.

근근막 발통점의 활성도에 따른 초음파 영상구조 및 전기생리학적 특성 (Ultrasound Imaging and Electrophysiological Characteristic According to Activity Levels of Myofascial Trigger Point)

  • 김현진;김수현;박영현;오석;최지호;김태열
    • 대한임상전기생리학회지
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    • 제8권1호
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    • pp.23-29
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    • 2010
  • Purpose : This study is to offer clinical primary data that examines the change of imaging structure and the quantitative evaluation of muscle activity on myofascial trigger points. This study examines neuromuscular physiological characteristic by comparing the differences in physical findings, pressure pain threshold, imaging, and electrophysiological characteristics in latent and active myofascial trigger points muscle and normal muscle through the following experimental procedures. Methods : The participants for the study were thirty-three adults in their twenties. We divided three groups into normal, latent and active myofascial trigger points groups by physical findings. We analyzed the results of measured pressure pain, threshold for pain, ultrasound imaging perform for structure characteristic of muscle, surface EMG according to type of muscle contraction for function of muscle contraction. Results : Significant differences were indicated in pressure pain threshold (p<0.05). Significant differences were discovered in the ultrasound imaging analysis. There were increases in muscle Echogenicity white area index (p<0.001). There were significant differences that decrease in %MVIC (p<0.05), increase in MDF (p<0.05). Conclusion : From these results, active rnyotascial trigger points muscle showed quality deterioration on ultrasound imaging and decreased function of muscle contraction, increased motor unit action potential of II type fiber, and electrophysiologically. Imaging structure and neuromuscular physiological characteristic can be diagnostic and quantitative analytical techniques for myofascial pain syndrome and a primary factor that reflected in physical therapy intervention.

유동교란인자(축소·확대관, Tee관)상하류에 설치된 다회선초음파 유량계의 특성 (Characteristics of Multipath Ultrasonic Flowmeter Installed Upstream and Downstream of Flow Disturbance Factors-Contraction, Expansion, and Tee Pipe)

  • 이동근;조용
    • 대한기계학회논문집B
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    • 제36권8호
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    • pp.877-883
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    • 2012
  • 정확한 유량측정의 목적으로 다회선방식을 이용한 초음파유량계의 설치가 점차 증가하는 추세에 있으나 이에 대한 설치기준이 아직까지는 수립되어 있지 않아 현장설치 시 많은 혼선을 일으키고 있다. 따라서 측정의 정확도 확보에 영향을 주는 유동교란인자 중에서 확대관, 축소관 및 Tee관이 다회선 초음파유량계의 상하류에 설치되어 있는 경우에 필요로 하는 직관거리를 결정하기 위한 실험을 실시하였다. 실험대상으로는 정확도가 ${\pm}0.5%$ 이하인 제품으로 국산 5회선 2개, 외산 2회선 1개, 4회선 1개 등 4개의 제품을 선정하고 유량 즉, 유속과 직관거리별로 반복적인 실험을 통해 허용오차를 만족하는 설치기준을 제시하였다.

Estrogen modulates serotonin effects on vasoconstriction through Src inhibition

  • Kim, Jae Gon;Leem, Young-Eun;Kwon, Ilmin;Kang, Jong-Sun;Bae, Young Min;Cho, Hana
    • Experimental and Molecular Medicine
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    • 제50권12호
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    • pp.11.1-11.9
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    • 2018
  • Estrogen has diverse effects on cardiovascular function, including regulation of the contractile response to vasoactive substances such as serotonin. The serotonin system recently emerged as an important player in the regulation of vascular tone in humans. However, hyperreactivity to serotonin appears to be a critical factor for the pathophysiology of hypertension. In this study, we examined the modulatory mechanisms of estrogen in serotonin-induced vasoconstriction by using a combinatory approach of isometric tension measurements, molecular biology, and patch-clamp techniques. $17{\beta}$-Estradiol (E2) elicited a significant and concentration-dependent relaxation of serotonin-induced contraction in deendothelialized aortic strips isolated from male rats. E2 triggered a relaxation of serotonin-induced contraction even in the presence of tamoxifen, an estrogen receptor antagonist, suggesting that E2-induced changes are not mediated by estrogen receptor. Patch-clamp studies in rat arterial myocytes showed that E2 prevented Kv channel inhibition induced by serotonin. Serotonin increased Src activation in arterial smooth muscle required for contraction, which was significantly inhibited by E2. The estrogen receptor-independent inhibition of Src by E2 was confirmed in HEK293T cells that do not express estrogen receptor. Taken together, these results suggest that estrogen exerts vasodilatory effects on serotonin-precontracted arteries via Src, implying a critical role for estrogen in the prevention of vascular hyperreactivity to serotonin.