• Korean Journal of Veterinary Service
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• v.29 no.4
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• pp.493-496
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• 2006

This study investigated cases of progressively necrotizing limbs in Korean indigenous calves. The recent case (Case 1) involved a 3-month old, male calf in Jeonbuk province that presented a visibly dry form of gangrene affecting joints of the forelimbs and the hind limbs. Radiograph revealed osteoarthritis possibly resulting from pressure of disrupted joint skin, fasciae, deeper underlying musculatures and tendon. Histopathology of affected tissue showed necrotizing; severely thrombosed dilated blood vessels with rechanneling microvasculatures. The lack of substantial infectious inflammatory exudates in the vital organs and the inability to respond to antimicrobial treatment bolstered the notion that the observed thromboembolic and vascular lesion was attributed to possible vasoconstrictive effects of ergot alkaloids. Case 2: A previously encountered similar case in a 4-month old, male calf showing gangrene of hind limbs and posterior ataxia was likewise presented. These two cases were impressed as probable ergotism. Ergotism may be uncommon or underreported in Korea. Future isolation of ergot alkaloids in feeds or in pasture is highly suggested.

• Structural Engineering and Mechanics
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• v.49 no.6
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• pp.705-726
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• 2014

In general, cylindrically curved plates are used in ships and offshore structures such as wind towers, spa structures, fore and aft side shell plating, and bilge circle parts in merchant vessels. In a number of studies, it has been shown that curvature increases the buckling strength of a plate under compressive loading, and the ultimate load-carrying capacity is also expected to increase. In the present paper, a series of elastic and elastoplastic large deflection analyses were performed using the commercial finite element analysis program (MSC.NASTRAN/PATRAN) in order to clarify and examine the fundamental buckling and collapse behaviors of curved plates subjected to combined axial compression and lateral pressure. On the basis of the numerical results, the effects of curvature, the magnitude of the initial deflection, the slenderness ratio, and the aspect ratio on the characteristics of the buckling and collapse behavior of the curved plates are discussed. On the basis of the calculated results, the design formula was developed to predict the buckling and ultimate strengths of curved plates subjected to combined loads in an analytical manner. The buckling strength behaviors were simulated by performing elastic large deflection analyses. The newly developed formulations were applied in order to perform verification analyses for the curved plates by comparing the numerical results, and then, the usefulness of the proposed method was demonstrated.

• The Journal of Korean Obstetrics and Gynecology
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• v.31 no.1
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• pp.43-56
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• 2018

Objectives: This study was designed to investigate the basis for developing the herbal decoction that may help promote healthy blood vessels in accordance with the basic principles of Korean medicinal materials. Methods: In this study, we investigated the vascular relaxation effects of fifty herbal decoctions on vascular response in isolated thoracic aorta of phenylephrine-preconracted rats. Results: The results of identify the vascular relaxation effect of fifty herbal decoctions provided by Korea Institute of Korean Medicine, twenty-one herbal decoctions showed vascular relaxation effects. Among them, four herbal decoctions, Mahwang-tang (麻黃湯), Samchulgeonbi-tang (參朮健脾湯), Cheonwangbosim-dan (天王補心丹), and Socheonglyong-tang (小靑龍湯), with showed significantly concentration-dependent vasodilation was examined. Vascular relaxation level are $84.02{\pm}4.70$, $79.39{\pm}13.9$, $51.26{\pm}12.56$, and $54.73{\pm}15.8%$, respectively (P<0.05, 0.01, and 0.001). Conclusions: Thus these results provide a basic data for the treatment of the impairment of vascular function and blood pressure in traditional Oriental medicine.

• The Korean Journal of Physiology and Pharmacology
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• v.4 no.1
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• pp.55-61
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• 2000

The present study was conducted to investigate the possible role of the sympathetic nervous system in two-kidney, one clip (2K1C) and deoxycorticosterone acetate (DOCA)-salt hypertension. 2K1C and DOCA- salt hypertension were made in Sprague-Dawley rats. Four weeks after induction of hypertension, systolic blood pressure measured in conscious state was significantly higher in 2K1C $(216{\pm}18\;mmHg)$ and DOCA-salt $(205{\pm}29\;mmHg)$ groups than that in control $(128{\pm}4\;mmHg).$ The third branches (＜300 ${\mu}m$ in outer diameter) of the mesenteric artery were isolated and cut into ring segments of $2{\sim}3$ mm in length. Each ring segment was mounted in tissue bath and connected to a force displacement transducer for measurement of isometric tension. The arterial rings were contracted by application of norepinephrine (NE) in a dose-dependent manner. The amplitude of the NE-induced contraction of the vessels was significantly larger in hypertension than in control. The NE-induced contraction was significantly enhanced by neuropeptide Y (NPY) in hypertension. Reciprocally, NPY-elicited vasocontraction was increased by NE in hypertension. These results suggest that the sympathetic nervous system contributes to the development of 2K1C and DOCA-salt hypertension.

• Journal of Physiology & Pathology in Korean Medicine
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• v.29 no.1
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• pp.1-10
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• 2015

This article is a study on palpitation of which disease cause, disease mechanism and formulas were analyzed with reference to annotations on "Shanghanlun" and "Jinkuiyaolue". And the scope of modern diseases related with palpitation was drawn by research on clinical papers. The source books are "Zhujieshanghanlun" and "Jinkuiyaoluefanglun" and the clinical papers are searched in China Academic Journals(CAJ) of China National Knowledge Infrastructure(CNKI). 13 clauses in "Shanghanlun" and 9 clauses in "Jinkuiyaolue" and 12 formulas are related with palpitation. Disease mechanisms of palpitation were classified as yang deficiency, yin deficiency, qi deficiency, blood deficiency, retained fluid, cold, etc and these days, qi stagnation, phlegm turbidity, blood stasis and fire heat are also considered as disease mechanisms. Modern diseases related with palpitation are arrhythmia(extrasystole, atrial fibrillation, bradycardia, tachycardia, sick sinus syndrome, atrioventricular block), vascular diseases(arterial occlusion, phlebothrombosis, Buerger's disease, coronary artery disease, vasculitis), blood pressure disorder(hypertension, hypotension) and heart diseases such as heart failure, angina pectoris, myocardial infarction, myocarditis, cardiomyopathy, pericardial effusion. And diseases related with psychological change(cardiac neurosis, anxiety neurosis, neurosis, depression, hyperthyroidism, hypothyroidism), pyrexia, anemia, drug intoxication, etc are also related with palpitation. Zhen Wu Tang showing an efficacy in dilating blood vessels and strengthening cardiac function, Wuling Powder with diuretic effect and Fried Glycyrrhizae Decoction acting on the ${\beta}$ receptor are applied to heart failure in different ways. Fried Glycyrrhizae Decoction(308 cases), Zhen Wu Tang(154), Wuling Powder(54), Xiao Chaihu Tang(34), Sini San(20) are reported to have been clinically applied to cardiovascular diseases and Zhen Wu Tang and Wuling Powder mainly applied to heart failure, Fried Glycyrrhizae Decoction, Lizhong Wan, Sini San and Zhen Wu Tang chiefly applied to arrhythmia related diseases. This study focuses on the general research and consideration on clinical applications and is a preliminary study to understand relations between Korean Medicine's symptoms and categories of modern diseases.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.3
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• pp.88-93
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• 2021

SAW (Submerged Arc Welding) is often used for ship construction or welding pressure vessels and involves spraying a flux in a powder form to a welding site to a certain thickness and continuously supplying electrode wires therein. This welding method enables high current welding up to 1,500 to 3,000 A. Arc efficiency is higher than 95% and the technique allows clean work as it creates less welding fume, which is composed of fine metal oxide particles, and the arc beam is not exposed. In this study, SM490C-TMC thick plates were heterogeneously welded by SAW. Mechanical properties of welds were measured, and welds were assessed macroscopically and for adhering magnetic particles. The following conclusions were drawn. Bending tests showed no spots exploded on sample surfaces or any other defect, and plastic deformation testing confirmed sufficient weld toughness. These results showed the 1F welding method has no shortcomings in terms of bending performance.

• Journal of the Korean Society of Propulsion Engineers
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• v.26 no.3
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• pp.54-65
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• 2022

We are developing a compact ignition device that can provide a multi-ignition capability for an upper stage methane engine of a two staged small satellite launch vehicle. Firstly, the multi-ignition device is designed and built as an integral part of an additively manufactured mixing head. Secondly, the ignition device requires no separate high-pressure vessels to store ignition propellants as they are branched out from the main feed lines for the mixing head. We performed experiments at various levels, including igniter autonomous tests, thrust chamber ignition and combustion tests on the new compact ignition device which is integrated in the thrust chamber of one-tonf class liquid oxygen/liquid methane engine, and confirmed stable ignition performance.

• Journal of Korean Neurosurgical Society
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• v.66 no.3
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• pp.228-238
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• 2023

Intraventricular hemorrhage (IVH) is a serious concern for preterm infants and can predispose such infants to brain injury and poor neurodevelopmental outcomes. IVH is particularly common in preterm infants. Although advances in obstetric management and neonatal care have led to a lower mortality rate for preterm infants with IVH, the IVH-related morbidity rate in this population remains high. Therefore, the present review investigated the pathophysiology of IVH and the evidence related to interventions for prevention. The analysis of the pathophysiology of IVH was conducted with a focus on the factors associated with cerebral hemodynamics, vulnerabilities in the structure of cerebral vessels, and host or genetic predisposing factors. The findings presented in the literature indicate that fluctuations in cerebral blood flow, the presence of hemodynamic significant patent ductus arteriosus, arterial carbon dioxide tension, and impaired cerebral venous drainage; a vulnerable or fragile capillary network; and a genetic variant associated with a mechanism underlying IVH development may lead to preterm infants developing IVH. Therefore, strategies focused on antenatal management, such as routine corticosteroid administration and magnesium sulfate use; perinatal management, such as maternal transfer to a specialized center; and postnatal management, including pharmacological agent administration and circulatory management involving prevention of extreme blood pressure, hemodynamic significant patent ductus arteriosus management, and optimization of cardiac function, can lower the likelihood of IVH development in preterm infants. Incorporating neuroprotective care bundles into routine care for such infants may also reduce the likelihood of IVH development. The findings regarding the pathogenesis of IVH further indicate that cerebrovascular status and systemic hemodynamic changes must be analyzed and monitored in preterm infants and that individualized management strategies must be developed with consideration of the risk factors for and physiological status of each preterm infant.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1982.05a
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• pp.10.3-11
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• 1982

Recently through the advancement of medical and surgical managements and the development of low pressure cuffed endotracheal tube, incidence of tracheal stenosis was decreased significantly. Though its incidence was decreased markedly, stenosis was developted unfortunately in the situations such as long term use of respirator, heavy infection, trauma of the trachea and long term intubation etc. Tracheal stenosis had been handled with various methods such as mechanical dilatation, tissue graft techniques, luminal augumentation and end to end anastomosis due to their individual advantages but their effects were not satisfactory. In 1959 Lester had been found the regenerated cartilage from the perichondrium of the rib incidentaly. Since then Skoog, Sohn and Ohlsen were reported chondrogenic potential of perichondrium through the animal experiments. Though many different materials have been tried to rebuild stenosis and gaping defect of trachea, tracheal reconstruction has been a perplexing clinical problems. We choose the perichondrium as the graft material because cartilage is the normal supporting matrix of that structure and it will be an obvious advantage to be able to position perichondrium over a defect and obtain new cartilage there. The young rabbits, which were selected as our experimental animals, were sacrified from two to eight weeks after surgery. The results of our experiment were as follows; 1) In control group, the defect site of trachea was covered with fibrosis and vessels but graft site was covered with hypertrophied perichondrium and vessels. 2) Respiratory mucosa was completely regenerated in defect sites both control and grafted groups. 3) The histologic changes of the grafted sites were as follows: 2 weeks- microvessel dilatation, inflammatory reaction, initiation of fibrosis 4 weeks- decreased microvessel engorgement, submucosal fibrosis, decreased inflammatory reaction immatured cartilage island was noted in the grafted perichondrium (one specimen) 6 weeks- mild degree vascular engorgement submucosal fibrosis. chronic inflamatory reaction cartilage island and endochondrial ossification was noted in the grafted perichondrium (Two specimens) 8 weeks- minute vascular engorgement dense submucosal fibrosis. loss of inflammatory reaction. cartilage island was noted in the grafted perichondrium (two specimens) 4) There was no significant differences in regeneration between active surface in and out groups. 5) We observed immatured cartilage islands and endochondrial ossification in the perichondrial grafted groups where as such findings were not noted in control groups except fibrosis. We concluded that perichondrium was the adequate material for the reconstruction of defected trachea but our results was not sufficient in the aspect of chondrogenic potential of perichondrium. So further research has indicated possibility of chondrogenic potential of perichondrium.

• Journal of Biomedical Engineering Research
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• v.38 no.2
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• pp.62-73
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• 2017

To identify a solution for the restricted availability of healthy lungs and the high risk of immune rejections following organ transplantation, tissue engineering techniques for culturing lungs have been studied by many research groups. The most promising method for culturing lungs is the utilization of a bio-scaffold that was prepared using harvested organs from human donors or other animals by removing their original cells. In this study, a pulsatile perfusion pump was used to alleviate the cell removal effect with the high fluid-dynamic power of the perfusion stream during the decellularization process, while other conventional studies focused on chemical methods to identify efficient detergents. The purpose of this study was to analyze the developed device by using energy equivalent pressure (EEP), which is an indicator of pulsatility, to understand the characteristics of pulsatile energy transmitted according to the load size by using the artificial model and compare it with the measured EEP. The pulsatility of the device can be estimated with the concept of fluid-dynamic energy during a particular constant time period or fluid-dynamic power represented as EEP and EEP increment. Because the measured EEP of perfusion flow during decellularization can be changed by the amount of fluid leakage and the degree of clogging in the capillary vessels, EEP should be measured to determine whether the decellularization is progressing without problems. The decrement of EEP caused by the high perfusion resistance was observed from some experimental results that were obtained with artificial models. EEP can be used to monitor the decellularization process after analyzing the varying EEP according to the amount of load. It was confirmed that the EEP was maintained at a high level in the experiment using the harvested lungs from 12-13-week-old rats. In addition, it was confirmed that the cell removal time was faster than when continuous perfusion was performed. In this study, pulsatile power delivered to the lungs was measured to monitor the process of cell removal, and it serve as the evidence for efficient decellularization.