• 대한의용생체공학회:의공학회지
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• 제31권4호
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• pp.310-315
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• 2010

Estimation of muscle forces is important in biomechanics, therefore many researchers have tried to build a muscle model. Recently, optimization techniques for adjusting muscle parameters, i.e. EMG-driven model, have been used to estimate muscle forces and predict joint moments. In this study, an EMG-driven model based on the previous studies has been developed and isometric and isokinetic contraction movements were evaluated to validate the developed model. One healthy male participated in this study. The dynamometer tasks were performed for maximum voluntary isometric contractions (MVIC) for ankle dorsi/plantarflexors, isokinetic contraction at both $30^{\circ}/s$ and $60^{\circ}/s$. EMGs were recorded from the tibialis anterior, gastrocnemius medialis, gastrocnemius lateralis and soleus muscles at the sampling rate of 1000 Hz. The MVIC trial was used to customize the EMG-driven model to the specific subject. Once the subject's own model was developed, the model was used to predict the ankle joint moment for the other two dynamic movements. When no optimization was applied to characterize the muscle parameters, weak correlations were observed between the model prediction and the measured joint moment with large RMS error over 100% (r = 0.468 (123%) and r = 0.060 (159%) in $30^{\circ}/s$ and $60^{\circ}/s$ dynamic movements, respectively). However, once optimization was applied to adjust the muscle parameters, the predicted joint moment was highly similar to the measured joint moment with relatively small RMS error below 40% (r = 0.955 (21%) and r = 0.819 (36%) and in $30^{\circ}/s$ and $60^{\circ}/s$ dynamic movements, respectively). We expect that our EMG-driven model will be employed in our future efforts to estimate muscle forces of the elderly.

• Archives of Plastic Surgery
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• 제35권1호
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• pp.7-12
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• 2008

Purpose: Since the report of artificial dermis manufacturing method using collagen by Yannas in 1980, collagen has been effectively used as dermal substitute with its merits such as, lower antigeneicity, controllable biodegradation rate, and minimal inflammatory cytotoxic properties in the dermal tissue engineering field. However, weak mechanical durability was the main drawback of collagen dermal substitute. To improve its stability, mechanical or chemical cross-linking was used. Despite of such process, its clinical use was restricted due to weak durability. To improve the durability of collagen matrix, we designed elastin-incorporated collagen matrix and compared its durability with conventional collagen matrix. Methods: 15mm diameter with 4mm thick collagen dermal matrix was made according to Yannas protocol by mixing 0.5% bovine collagen and chondroitin-6-sulfate followed by degassing, freeze drying, dehydrodermal cross-linking and chemical cross-linking procedure. In elastin incorporated collagen matrix, same procedure was performed by mixing elastin to previous collagen matrix in 4:1 ratio(collagen 80% elastin 20%). In comparison of the two dermal matrix in vitro tests, matrix contracture rate, strain, tensile strength, was measured and stiffness was calculated from comparative analysis. Results: In terms of matrix contracture, the elastin-incorperated added collagen dermis matrix showed 1.2 times more contraction compared to conventional collagen matrix. However, tensile strength showed 1.6 times and stiffness showed 1.6 times increase in elastin-incorporated matrix. Conclusion: Elastin incorperated collagen matrix manufactured by our team showed increased durability due to improvement in tensile strength and stiffness compared to previous collagen matrix($Integra^{(R)}$).

• 한국식품영양학회지
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• 제10권2호
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• pp.151-159
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• 1997

근원섬유단백질의 이온강도에 따른 Ca-ATPase 활성, Mg-ATPase 활성 및 EDTA-ATPase 활성은 오징어와 대합에서 그 차이점이 뚜렷하였으며, activity-pH curve에서 오징어 actomyosin의 Ca-ATPase 활성은 biphasic response가 소실되었고 대합의 actomyosin은 미약한 bipasic response가 나타났다. 또한 저농도의 dioxane에 의하여 오징어의 근원섬유단백질은 급격한 활성의 감소를 보였으나 대합의 근원섬유단백질은 활성이 증가되었다. 그리고 에탄올과 메탄올은 오징어와 대합의 myosin 및 MM에 대하여 저농도에서 활성을 증가시켰다. 한편 NEM으로 근원섬유단백질을 modification시키며 10-6M 이하의 NEM 농도에서는 활성이 증가되었으나 10-5M 이상의 농도가 되면 활성의 급격한 감소가 나타났다.

• Ocean and Polar Research
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• 제25권spc3호
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• pp.399-408
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• 2003

The behavior of Suspended Sediment Concentrations (SSC) around a silt screen in a microtidal coastal area was hydrodynamically measured. The current speed at the mid-layer about 30m downstream of the screen reduces to about half that at the same distance upstream. It was caused by the contraction of the vertical section due to the screen. Even during a relatively weak storm period the SSC increases to that of the value caused by dredging. Section-averaged SSC at the downstream of the screen is higher by about 60% than that at the upstream, suggesting that the silt screen plays an adverse effect rather than a constructive role in the reduction of SSC generated by dredging.

• 약학회지
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• 제45권1호
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• pp.78-84
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• 2001

Heme oxygenase is a rate-limiting enzyme in heme catabolism that cleaves heme to form biliverdin, iron, and carbon monoxide. Heme oxygenase-1 is expressed in many types of cells and tissues and is highly induced in response to oxidative stress. Carbon monoxide, one of the products of heme oxygenase, can stimulate soluble guanylate cyclase and dilate the vascular smooth muscle. So, the induction of heme oxygenase by lipopolysaccharide (LPS)-induced oxydative stress and the effect of the resultant carbon monoxide on aortic contractility were examined in this study. Zinc protoporphyrine IX (ZnPP), a inhibitor of heme oxygenase, elicited weak contraction of thoracic aortic ring, and this effect was more potent in aorta of LPS-treated rats than control and was blocked by methylene blue. The hyperreactivity to ZnPP in LPS-treated group was blocked by co-treatment with aminoguanidine. In the aortic ring of LPS-treated rats, ZnPP didn't change the vasoreactivity to phenylephrine or acetylcholine. ZnPP elicited hyper-tensive effect in concious rats, and pretreatment with LPS did not affect this effect. Prazosin significantly diminished the hypertensive effect of ZnPP. These results indicate that LPS induced heme oxygenase in aotra, and the resultant carbon monoxide diminished the aortic reactivity to vasoconstrictor.

• 대한약리학회지
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• 제32권3호
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• pp.373-380
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• 1996

최근 본 연구실에서는 GS 386인 1-(4'-methoxybenzyl)-6,7-dimethoxy-3,4-dihydroisoquinoline이 적출된 토끼의 심방세포에서 $Ca^{++}$ 채널의 운동성 변화없이 $Ca^{++}$ 채널이 열릴 가능성을 줄임으로써 $Ca^{++}$ 전류의 증폭을 억제한다고 보고하였다. 이번 연구에서는 적출된 쥐의 기관지를 사용하여 GS 386의 작용기전에 대해 연구하였다. GS386은 carbachol $(0.3{\mu}M)$과 높은 농도의 $K^+$ (65.4mM)에 의해 수축된 쥐의 기관지를 용량-의존적으로 이완시켰으며 이때 $IC_{50}$는 5.24와 $5.67\;{\mu}M$이었다. verapamil은 carbachol에 의한 수축시 보다 높은 농도의 $K^+$에 의해 수축된 조직에 더욱 효과적으로 억제하였다. $Ca^{++}$이 없는 상태에서 $Ca^{++}$에 의한 수축은 GS386에 의해 억제되었다. 더욱이 높은 농도의 GS386$(100\;{\mu}M)$은 verapamil과는 다르게 carbachol뿐만 아니라 caffeine에 의한 위상성 수축을 억제 시키므로 GS386은 세포질내로 들어가 sarcoplasmic retuculum과 같은 근육 내부에 2차적인 영향을 나타내었다. 더군다나GS386은 verapamil에 의해 영향을 받지않는 (verapamil-insensitive component)이완을 보였고 쥐 기관지의 평활근에서 cAMP의 양을 증가 시켰다. 이러한 결과는 GS386의 작용기전이 $Ca^{++}$ 길항적인 작용 뿐만 아니라 posphodiesterase억제작용에 기인한다는 사실을 제시한다.

• 대한통합의학회지
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• 제8권1호
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• pp.137-146
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• 2020

Purpose : The enhancement of abdominal muscles increases the activation and contraction of respiratory muscles, including the diaphragm. Generally, diaphragm exercises are applied to increase the breathing ability of patients with respiratory disease. Previous studies have shown that breathing capacity can be increased through abdominal muscle strengthening exercises. However, studies on breathing ability are rare and it is doubtful whether these affect respiratory ability more than diaphragm exercises. Therefore, this study seeks to compare whether abdominal exercises can improve breathing ability and whether any increase is comparable to diaphragm exercises. Methods : After selecting subjects, the place of intervention was separated for blindness. The plank group was allowed to relax for 30 seconds after 30 seconds of planking; this was set at three and increased by one set each week. Subjects in the draw-in group were allowed to relax for 30 seconds after maintaining the draw-in contraction state for 30 seconds and this was done for 15 minutes. Subjects in the control group underwent abdominal dilation for five seconds of inspiration time and expired air for five seconds by exposing the lips; breathing was performed repeatedly for 15 minutes. Subjects in each group measured their respiration function three times before intervention, three weeks after the commencement of intervention and after intervention. Spirovit SP-1 was used to measure respiratory function. In each group, repeated ANOVA was used to compare the respiratory function over time and one-way ANOVA was used to compare the respiratory function between groups. The post hoc was conducted using the LSD method. Results : There was a significant increase in respiratory ability between the forced vital capacity (FVC), forced expiratory volume in one second (FEV₁) and peak expiratory flow (PEF), forced expiratory volume in one second (FEV₁)/forced vital capacity (FVC) according to the six-week period. However, there was no difference between each group. Conclusion : For patients with low respiratory muscle strength, plank exercises and abdominal draw-in are beneficial exercises for improving respiratory function. These are expected to be widely used in clinical practice for patients with weak respiratory muscles.

• 한국산학기술학회논문지
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• 제21권4호
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• pp.285-292
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• 2020

건설산업내 상생을 위한 정부의 중소기업 보호 정책에도 불구하고, 위축되어 가는 건설시장으로 인해 대·중·소기업간 수주양극화, 중소기업 및 지역기업의 수주 경쟁력 약화 및 수익성 약화 등의 문제는 여전히 개선되지 못하고 있는 실정이다. 미국 건설산업내 중소기업 및 지역기업에 대한 발주우대제도, 입찰우대제도, 지역기업 활용을 중심으로 건설산업 생태계 내 상대적 약자인 중소기업, 지역기업, 사회적약자소유기업 등을 위한 미국 연방 및 주정부의 정책 및 제도를 고찰하고, 이를 통해 바람직한 중·소기업 보호 및 경쟁력 강화 정책 방향 재고를 위한 국내 중소기업 보호 관련 정책에 시사하는 바를 도출하였다. 결론적으로 물량 배분을 기반으로 하는 국내 중소기업보호 관련 정책과는 달리 미국의 중소기업 및 지역기업 우대 제도는 해당 기업들을 일정비율이내에서 우대를 하되 공정경쟁 원리를 동시에 수용함으로써, 중소기업 및 지역기업 보호와 동시에 해당 기업들의 경쟁력을 강화 할 수 있는 방향에서 정책을 운용하고 있다. 따라서 향후 국내 중소기업 및 지역기업 보호 및 경쟁력 강화를 위해서는 일정부분 보호하는 동시에 중소기업의 경쟁력을 강화할 수 있는 방향으로 관련 제도를 정비할 필요가 있을 것으로 판단된다.

• The Korean Journal of Physiology and Pharmacology
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• 제18권5호
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• pp.377-381
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• 2014

Propofol is a widely used anesthetic. Many studies have shown that propofol has direct effects on blood vessels, but the precise mechanism is not fully understood. Secondary intrapulmonary artery rings from male rats were prepared and mounted in a Multi Myograph System. The following constrictors were used to induce contractions in isolated artery rings: high $K^+$ solution (60 mmol/L); U46619 solution (100 nmol/L); 5-hydroxytryptamine (5-HT; $3{\mu}mol/L$); or phenylephrine (Phe; $1{\mu}mol/L$). The relaxation effects of propofol were tested on high $K^+$ or U46619 precontracted rings. Propofol also was added to induce relaxation of rings preconstricted by U46619 after pretreatment with the nitric oxide synthase inhibitor $N^G$-nitro-L-arginine methyl ester (L-NAME). The effects of propofol on $Ca^{2+}$ influx via the L-type $Ca^{2+}$ channels were evaluated by examining contraction-dependent responses to $CaCl_2$ in the absence or presence of propofol (10 to $300{\mu}mol/L$). High $K^+$ solution and U46619 induced remarkable contractions of the rings, whereas contractions induced by 5-HT and Phe were weak. Propofol induced dose-dependent relaxation of artery rings precontracted by the high $K^+$ solution. Propofol also induced relaxation of rings precontracted by U46619 in an endothelium-independent way. Propofol at different concentrations significantly inhibited the $Ca^{2+}$-induced contractions of pulmonary rings exposed to high $K^+$-containing and $Ca^{2+}$-free solution in a dose-dependent manner. Propofol relaxed vessels precontracted by the high $K^+$ solution and U46619 in an endothelium-independent way. The mechanism for this effect may involve inhibition of calcium influx through voltage-operated calcium channels (VOCCs) and receptor-operated calcium channels (ROCCs).

• 대한물리치료과학회지
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• 제3권4호
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• pp.207-214
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• 1996

Main cause of low back pain is a poor posture. Most low back pains are due to a poor posture. The poor posture induces muscle tension and finaliy low back pain. The poor posture arehabitually trained from the childhood by the environmetal factors. In general, maintaining good posture during working and sleeping hours are the first line of defence against back pam. (1) Supine posture is the easiest posture that relaxes and fixes muscles. Supine posture is thus a starting position for on exercise. Lying down releases the weight pressures of head and shoulder and thus body can be relaxed and extended which are helpful for treating back pain. However, supine posture can increase the pressure in ribcage posture aspect and disphragram due to visceral oragans. (2) Sitting in one position for a long time results in fatigue and relaxation of spinal muscies. Finally, body strength is weakened and sitting posture will become poor. If this poor posture continues for a longer time, pain will be accompanied due to overelongation of muscle ligaments. The habitual poor posture could induce intervertebral disc distortion. If the intervertebral disc is damaged, sitting in one position or movement causes pain. (3) Abnormal lumbar curve induces the tention of abdominal muscle and paravertebral muscle groups as well as tention of lower limb muscle group connected to pelvis. For a person with weak body strength, muscle relaxation increases curvature in lumbar, chest and cervical regions. This will induce a pelvic anterior tilting of the imaginary line between A. S. I. S. and P. S. I. S. Hip joint extensor muscle acts on releasing the pelvic anterior tilting. Contrections of hamstring muscle and femoral muscle recover the imaginary line between A.S.LS. and P.S.I.S. from pelvic anterior tilting. thus, contraction of rectus abdominis muscle are required to maintain the normal lumbar curve.