• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2008년도 춘계학술대회
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• pp.135-147
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• 2008

The package loading process of the lumbering industry is an operation that after a pair of workers bind three or six lumbers into one unit and cut both ends of the lumbers, transports the weight cargo of 30-50kg by one meter, pack and load at a height of 1.2 meters. This package loading process causes lots of noise and wood dust when workers carry out the heavy work as the above. Therefore we developed the monolithic both ends cutting package loading equipment in order to prevent from getting musculoskeletal disease. An loading bar working system of this equipment is improved from pneumatic pressure system to oil pressure system, furnished the newly designed flow dividers, and developed the new system that a both end array is loaded identically. Also we developed the safety equipment of loading bar in order to prevent workers mistake and overload from malfunction during the package loading process. The main cause of job evasion on working place could be solved by preventing the musculoskeletal disease and improving the working environments.

• 한국임상수의학회지
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• 제29권3호
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• pp.203-206
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• 2012

심부전의 치료는 심방의 용적 과부하를 줄이기 위한 이뇨제, 심실 압력 과부하를 줄이기 위한 혈관확장제, 심근의 수축력을 향상시키기 위한 강심제 치료로 이루어진다. 이 중 이뇨제가 개의 심부전 조절에서 가장 중요하다. 하지만 장기간의 이뇨제 사용으로 급성 신부전이나 전해질 이상과 같은 부작용이 발생할 수 있다. 따라서 이 연구는 개에서 부작용이 적으면서 더 나은 이뇨효과를 가지는 생약성분의 이뇨제를 찾기 위해 설계되었다. 5마리의 건강한 개를 대상으로 한 예비실험에서 목통(Akebia quinata Decaisne) 추출물은 경도에서 중등도의 이뇨효과(furosemide 2 mg/kg 용량 효과의 0.3-0.5배의 효력)를 보였으며 혈청화학 수치와 전해질 변동은 거의 없었다. 실험 개체 수가 적고 기간이 충분하지 않지만 이 실험을 통해 심부전 환자에서 furosemide의 사용량을 줄이거나 대체할 수 있는 생약성분의 이뇨제 성분을 발굴하였다.

• Reproductive and Developmental Biology
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• 제35권2호
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• pp.159-165
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• 2011

To explore the role of histone deactylase (HDAC) activation in an in vivo model of hypertrophy, we studied the effects of Trichostatin A (TSA). TSA subjected to thoracic aortic banding (TAB)-induced pressure stress in mice. In histological observations, TAB in treated mice showed a significant hypertrophic response, whereas the sham operation remained nearly normal structure with partially blunted hypertrophy. TSA treatment had no effect (measured as HW/BW) on sham-operated animals. TAB animals treated with vehicle manifested a robust ~50% hypertrophic response (p<0.05 vs sham). TAB mice treated with 2 mg/kg/day TSA manifested a blunted growth responses, which was significantly diminished (p<0.05) compared with vehicle-treated TAB mice. TAB mice treated with a lower dose of TSA (0.5 mg/kg/day) manifested a similar blunting of hypertrophic growth (~25% increase in heart mass). Furthermore, to determine activity duration of TSA in vitro, 1 nM TSA was added to H9c2 cells. Histone acetylation was initiated at 4 hr after treatment, and it was peak up to 18 hr, then followed by significantly reduced to 30 hr. We also analyzed the expression of p53 following TSA treatment, wherein p53 expression was elevated at 4 hr, and it was maintained to 24 hr after treatment. ERK was activated at 8 hr, and maintained till 30 hr after treatment suggesting an intracellular signaling interaction between TSA and p53 expression Taken together, it is suggested that HDAC activation is required for pressure-overload growth of the heart. Eventually, these data suggest that histone acetylation may be a novel target for therapeutic intervention in pressure-overloaded cardiac hypertrophy.

• Clinical and Experimental Pediatrics
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• 제52권12호
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• pp.1364-1369
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• 2009

목 적 : 이번 연구에서는 소아기에 흔한 선천성 심장병 환자들을 대상으로 개심술 이후 생긴 반흔과 수술로 인한 용적 또는 압력 과부하 상태의 변화로 초래되는 비정상적인 심실 활성화를 신호 평준화 심전도를 이용하여 분석하고자 하였다. 방 법 : 선천성 심장병으로 개심교정술을 시행한 환자 52명을 대상으로 하였다. 환자군은 우심실 용적 과부하군(심방 중격 결손군, 1군), 좌심실 용적 과부하군(심실 중격 결손군, 2군), 우심실 압력 과부하군(활로씨 4징군, 3군)으로 나누었다. 대상 환자 모두에서 표준 12 유도 심전도와 신호 평준화 심전도 검사를 시행하였고, 평균 QRS 기간, QT와 QTc 간격, f-QRS, HFLA, RMS in terminal 40 ms를 구하였다. 결 과 : 수술 전에는 1군에서 다른 군에 비해 의미 있게 긴 QRS 기간을 보였고(P=0.011), 수술 후에는 3 군에서 다른 군에 비해 QTc 간격이 의미 있는 증가가 있었다(P=0.004). 그러나 신호 평준화 심전도는 수술 전후 환자군 간에 차이가 없었다. 전체 대상 환자 중 신호 평준화 심전도 측정값이 한가지 이상 후전위의 진단 기준에 해당되는 경우가 수술 전 12명(23%)에서 수술 후 21명(40%)로 증가하였다. 특히 2군과 3군에서는 수술 전에 비해 수술 후에 신호 평준화 심전도의 이상 소견을 보이는 경우가 의미있게 많았다(2군: 20% versus 28%, P<0.001, 3군: 14% versus 64%, P<0.001). 결 론 : 비정상적인 신호 평준화 심전도 값은 수술 후 반흔뿐만 아니라 개심술 자체, 심실의 과부하에 의해서도 발생할 수 있다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 지반공학 공동 학술발표회
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• pp.461-468
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• 2005

The D-ROG(Digitalized Restoring of Grouting) Method is the restoring method for structures subjected to differential settlement and tilting by means of high grout injection pressure. This study investigate effect of grouting through in field test which applied D-ROG method in different condition(overload, ground condition).

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.1252-1257
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• 2003

This paper present a procedure of meter-out flow control method for dump valve in full-scale airframe test. Emergency stop, which results in dump state, can be happened during full-scale airframe test by several causes. Because servo valve can't control hydraulics actuator in the dump state, pressure in cylinder chamber may rise abruptly and overload can be acted to the test article. In this paper, the procedure and technology of orifice setting are investigated to protect the test article from unexpected loads by dump. The test results show that the presented methods decrease peak loads and improve unloading characteristics of hydraulic actuators in the dump state.

• Journal of Veterinary Science
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• 제22권5호
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• pp.60.1-60.9
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• 2021

Background: Echocardiography is a primary tool used by veterinarians to evaluate heart diseases. In recent years, various studies have targeted standard echocardiographic values for different breeds. Reference data are currently lacking in Maltese dogs and it is important to fill this gap as this breed is predisposed to myxomatous mitral valve disease, which is a volume overload disease. Objectives: To establish the normal echocardiographic parameters for Maltese dogs. Methods: In total, 23 healthy Maltese dogs were involved in this study. Blood pressure measurements, thoracic radiography, and complete transthoracic echocardiography were performed. The effects of body weight, age and sex were evaluated, and the correlations between weight and linear and volumetric dimensions were calculated by regression analysis. Results: The mean vertebral heart size was 9.1 ± 0.4. Aside from the ejection fraction, fractional shortening, and the left atrial to aorta root ratio, all the other echocardiographic parameters were significantly correlated with weight. Conclusion: This study describes normal echocardiographic parameters that may be useful in the echocardiographic evaluation of Maltese dogs.

• The Korean Journal of Physiology and Pharmacology
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• 제22권6호
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• pp.607-616
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• 2018

The effect of melatonin on juveniles with cardio fibrosis is poorly understood. We investigated whether HDACs participate in the anti-fibrotic processes regulated by melatonin during hypertrophic remodeling. Abdominal aortic constriction (AAC) was employed in juvenile rats resulting in pressure overload-induced ventricular hypertrophy and melatonin was subsequently decreased via continuous light exposure for 5 weeks after surgery. AAC rats displayed an increased cross-sectional area of myocardial fibers and significantly elevated collagen deposition compared to sham-operated rats, as measured by HE and Masson Trichrome staining. Continuous light exposure following surgery exacerbated the increase in the cross-sectional area of myocardial fibers. The expression of HDAC1, HDAC2, HDAC3, HDAC4 and HDAC6 genes were all significantly enhanced in AAC rats with light exposure relative to the other rats. Moreover, the protein level of $TNF-{\alpha}$ was also upregulated in the AAC light exposure groups when compared with the sham. However, Smad4 protein expression was unchanged in the juveniles' hearts. In contrast, beginning 5 weeks after the operation, the AAC rats were treated with melatonin (10 mg/kg, intraperitoneal injection every evening) or vehicle 4 weeks, and sham rats were given vehicle. The changes in the histological measures of cardio fibrosis and the gene expressions of HDAC1, HDAC2, HDAC3, HDAC4 and HDAC6 were attenuated by melatonin administration. The results reveal that melatonin plays a role in the development of cardio fibrosis and the expression of HDAC1, HDAC2, HDAC3, HDAC4 and HDAC6 in cardiomyocytes.

• The Korean Journal of Physiology
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• 제29권2호
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• pp.279-289
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• 1995

This study was designed 1) to develop a hypertensive animal model in which the blood pressures (BPs) of symmetric regions (right and left upper extremities) are significantly different and 2) to test the effect of BP per se on the contractility and endothelium-dependent relaxation of vascular smooth muscle. Rabbits were anesthetized with sodium pentobarbital and ventilated with room air via animal respirator. The transverse aorta was exposed through the left second intercostal space and the lumen of the aorta was narrowed partially by ligation using 3-0 silk and a probe at a point between the origins of the brachiocephalic trunk and the left subclavian artery. Four to eight weeks postoperatively, BPs were measured in the carotid artery as the high BP area (proximal to coactation site) and in the femoral artery as the low BP area (distal to coarctation site). In the animal model, pressure-overload hypertension was developed and the BP of the right subclavian artery was higher than that of the left subclavian artery. The concentrations of circulating epinephrine, norepinephrine, angiotensin I, and angiotensin II were measured. The right and left subclavian arteries and their branches were used for isometric tension recording in organ baths and their responsiveness to phenylephrine, serotonin, acetylcholine, and sodium nitroprusside were examined. The BPs of carotid and femoral artery in control animals were $116{\pm} 12/75{\pm}9\;mmHg (mean ${\pm}SEM$) and $130{\pm}16/68{\pm}9\;mmHg$ respectively, while those of carotid and femoral artery in the hypetensive animals were $172{\pm}6/111{\pm}10\;mmHg$ and 136{\pm} 4/100 {\pm}9\;mmHg$ respectively. There were no significant differences in the concentrations of circulating epinephrine, norepinephrine, angiotensin I, and angiotensin II between controls and the animal models. No significant differences were found in the vascular sensitivities to phenylephrine and serotonin between the high pressure-exposed vessels and the low pressure-exposed vessels. However, the endothelium-dependent relaxation to acetylcholine and nitroprusside-induced relaxation showed significant differences between the high pressure-exposed and the low pressure-exposed subclavian arteries. From the above results, we suggest that the contractility of vascular smooth muscle is unchanged by the elevated pressure per se. However, the endothelium-dependent relaxation to acetylcholine and the nitroprusside-induced relaxation are attenuated by pressure.

• 대한한의학회지
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• 제37권2호
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• pp.23-35
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• 2016

Objectives: The objective of this study is to demonstrate the cardioprotective effects of Salvia Miltiorrhiza Radix (SMR) on the pressure overload (PO)-induced heart failure (HF) by transverse aortic constriction (TAC) in C57BL/6 mice through possible antioxidant effects. Methods: The mortality, body and heart weights, antioxidant defense system of the heart and histopathology of heart were analyzed. The obtained results were compared with resveratrol, in which potent cardioprotective effects on TAC mice model were already proved at a dose level of 10 mg/kg by antioxidant effects, as reference in this experiment. Results: Significant increases of mortalities, heart weights, and hypertrophic, lytic and focal fibrotic histological changes in the left ventricles were found with defects of heart antioxidant defense systems - the increases of heart cortex MDA contents, decreases of GSH contents, SOD and CAT activities in TAC control mice as compared with sham vehicle control mice, respectively. However, these HF signs induced by TAC surgery through PO and destroys heart antioxidant defense systems were significantly and dose-dependently inhibited by 14 days continuous oral treatment of SMR 500, 250 and 125 mg/kg, similar to those of resveratrol 10 mg/kg in SMR 125 mg/kg. Conclusions: The results obtained in this study propose that oral administration of SMR potently alleviates PO-induced HF by TAC, through augmentation of heart antioxidant defense system.