• Journal of Chest Surgery
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• v.31 no.12
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• pp.1222-1225
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• 1998

Aortic valve replacement in young patients has its problems. Biologic prosthetic valves degenerate and need replacement. Metalic prosthetic valves are more durable, however, anticoagulation which has its inherent problems is inevitable. The use of Ross procedure in young patients is gaining wider acceptance. The need of foreign pulmonary valve in right ventricular outflow tract(RVOT) will require reoperation due to RVOT obstruction, later. To overcome this problem, we reimplanted the native aortic valve in the pulmonary position in 21 year old female patient operated on utilizing the Ross procedure for aortic insufficiency. We experienced that the diseased aortic valve worked well in the pulmoanry position because of low pulmonary artery pressure and resistance.

• Journal of The Korean Society of Clinical Toxicology
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• v.9 no.2
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• pp.105-108
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• 2011

Aconitine is an anti-inflammatory agent with therapeutic uses in oriental medicine as an analgesic and for treatment of stroke. Because of its sodium channel effect, aconitine can promote undesirable, wide complex tachyarrhythmia. If tachycardia develops during use of aconitine, class Ia and class III anti arrhythmic drugs can be utilized for treatment. However there are no single anti-arrhythmia agents which are uniformly effective. We report a case, characterized by wide complex tachyarrhythmia and severe hypotension, which was successfully treated by simultaneous injections of amiodarone and lidocaine. A 59-year-old woman exhibiting clinical signs of drowsiness as a result of ingesting 6 g of aconitine, was admitted to the emergency department. Initially, wide complex tachyarrhythmia (ventricular tachycardia and pulse rate of 180 beats/min) and severe hypotension (blood pressure of 53/26 mmHg) was observed. After simultaneous injection of amiodarone and lidocaine, the patient's rhythm pattern changed to an accelerated junctional rhythm with ventricular premature complex. Two hours later, the patient's heart pattern became a sinus rhythm. As demonstrated by this case, simultaneous injections of amiodarone and lidocaine can be useful in treating ventricular arrhythmia induced by aconitine.

• Journal of International Academy of Physical Therapy Research
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• v.4 no.2
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• pp.562-565
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• 2013

The fact that flip-flops, one of many different types of unstable shoes, are light and relatively easy to put on, accounts for their popularity among people. But because flip-flops rely heavily on the support of a single thong between your first and second toes, they impose a huge amount of pressure onto lower leg. Thus in the following experiment we tried to examine the different effects of flip-flops and running shoes in terms of their effect on muscle activity and fatigue of tibialis anterior and gastrocnemius during walking. In order to measure an electromyogram we used Free EMG system. 10 men and 10 women in running shoes ran on treadmills for 15 minutes at 4.8km/h, 2 days later the same experiment was carried out, but this time, in flip-flops. p value turned out to be greater than .05 and thus there was no considerable difference between the effects of flip-flops and running shoes on muscle activity and fatigue during walking. Therefore we conclude that despite the fact that flip-flops are considered unstable, their effects on muscle activity and fatigue of tibialis anterior and gastrocnemius are negligible.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.3
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• pp.390-401
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• 2000

In this study, numerical calculation is carried out to investigate the influence of injection timing, fuel amount, intake $O_2$ concentration, and EGR on Nitric Oxide(NO) formation using a two-zone model in a diesel engine. Results can be summarized as follows. The NO formation is very sensitive to the burned gas temperature, so multi-zone model must be applied to combustion process to predict the burned gas temperature exactly. Since the burned gas temperature increases rapidly during the premixed combustion, most NO is formed within 20 crank angle degrees after ignition. As the injection timing is retarded, the combustion occurs later in the expansion process which causes the decrease of burned gas temperature and, as a result, NO formation decrease. The increase of fuel amount results in the increase of earlier formation of NO in the engine. As the intake $O_2$ concentration increases, the maximum pressure and burned gas temperature increase due to activate combustion. And, [O] mole fraction of equilibrium combustion products also increase. Therefore NO exponentially increases. If exhaust gas is recirculated, the burned gas temperature decreases which results in NO decrease. If exhaust gas is cooled, more NO can be decreased.

• Membrane and Water Treatment
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• v.1 no.2
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• pp.121-137
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• 2010

This work presents inexpensive inorganic precursor formulations to yield submicron range symmetric ceramic microfiltration (MF) membranes whose average pore sizes were between 0.1 and $0.4{\mu}m$. Incidentally, the sintering temperature used in this work was about 800 to $950^{\circ}C$ instead of higher sintering temperatures ($1100^{\circ}C$) that are usually deployed for membrane fabrication. Thermogravimetric (TGA) and X-Ray diffraction (XRD) analysis were carried out to evaluate the effect of temperature on various phase transformations during sintering process. The effect of sintering temperature on structural integrity of the membrane as well as pore size distribution and average pore size were evaluated using scanning electron microscopy (SEM) analysis. The average pore sizes of the membranes were increased from 0.185 to $0.332{\mu}m$ with an increase in sintering temperature from 800 to $950^{\circ}C$. However, a subsequent reduction in membrane porosity (from 34.4 to 19.6%) was observed for these membranes. Permeation experiments with both water and air were carried out to evaluate various membrane morphological parameters such as hydraulic pore diameter, hydraulic permeability, air permeance and effective porosity. Later, the membrane prepared with a sintering temperature of $950^{\circ}C$ was tested for the treatment of synthetic oily waste water to verify its real time applicability. The membrane exhibited 98.8% oil rejection efficiency and $5.36{\times}10^{-6}\;m^3/m^2.s$ permeate flux after 60 minutes of experimental run at 68.95 kPa trans-membrane pressure and 250 mg/L oil concentration. Based on retail and bulk prices of the inorganic precursors, the membrane cost was estimated to be $220 /$m^2$ and $1.53 /$m^2$, respectively.

• Journal of Yeungnam Medical Science
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• v.29 no.2
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• pp.113-117
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• 2012

Primary aldosteronism is characterized by hypertension, hypokalemia, and metabolic alkalosis, associated with excessive aldosterone production and suppressed plasma renin activity. Hypokalemia-induced rhabdomyolysis has been rarely reported in primary aldosteronism patients. This paper reports a case of primary aldosteronism presented with rhabdomyolysis due to severe hypokalemia. A 48-year-old male with a three-year history of hypertension presented himself at the authors' hospital with generalized weakness and myalgia in both legs over a period of several days. His laboratory findings showed hypokalemia (1.8 mEq/L) with elevations of his serum creatine phosphokinase and serum myoglobin. His plasma aldosterone level was also elevated, and his plasma renin activity was reduced. An abdominal computed tomography revealed a 2.0 cm hypodense mass in the left adrenal gland, which suggested adrenal adenoma. The accordingly underwent laparoscopic adrenalectomy. Three months later, his plasma potassium level and blood pressure became normal without the use of medications.

• Sleep Medicine and Psychophysiology
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• v.3 no.2
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• pp.65-76
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• 1996

Natural sleep pattern and its physiology in childhood are much different from those in adulthood. Several aspects of clinical evaluation for sleepiness in childhood are more difficult than in adulthood. These difficulties are due to several factors. First, excessive sleepiness in childhood do not always develop functional impairments. Second, objective test such as MSLT may not be reliable since it is hard to be certain that the child understand instructions. Third, sleepiness in children is often obscured by irritability. paradoxical hyperactivity, or behavioral disturbances. Anseguently, careful clinical evaluation is needed for the sleepy children. Usual causes of sleepiness in children are the disorders that induce insufficient sleep such as sleep apnea syndrome, schedule disorder, underlying medical and psychiatric disorder, and so forth. After excluding such factors, we can diagnose the hypersomnic disorders such as narcolepsy, Kleine-Levin syndrome, and idiopathic central nervous system hypersomnia. Among the variety of those causes of sleepiness, I reviewed the clinical difference of narcolepsy and obstructive sleep apnea syndrome in childhood compared with in adulthood. Recognition of the childhood narcolepsy is difficult because even severely sleepy children often do not develop pathognomic cataplexy and associated REM phenomena until much later. Since childhood narcolepsy give srise to many psychological, academical problem. Practicers should be concerned about these aspects. Childhood obstructive sleep apnea syndrome is different from adult obstructive sleep apnea syndrome too. Several aspects such as pathophysiology. clinical feature, diagnostic criteria, complication, management, and prognosis differ from those in the adult syndrome. An important feature of childhood obstructive sleep apnea syndrome is the variety of severe complications such as behavioral disorders, cognitive impairment, cardiovascular symptoms, developmental delay, and ever death. Fortunately, surgical interventions like adenotosillectomy or UPPP are more effective for Childhood OSA than adult form. CPAP is a "safe, effective, and well-tolerated" treatment modality too. So if early detection and proper management of childhood OSA were done, the severe complication would be prevented or ever cured.

• Journal of Yeungnam Medical Science
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• v.34 no.2
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• pp.279-284
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• 2017

Pulmonary artery sarcoma (PAS) is a rare and fatal disease that often mimics chronic thromboembolic pulmonary hypertension (CTEPH); therefore, diagnosis of PAS is often delayed. Herein, a healthy 74-year-old man was presented with a 4-month history of dyspnea. Chest computed tomography showed wall thickening and stenosis in the main pulmonary artery as well as in both proximal pulmonary arteries. In order to differentiate between unusual CTEPH, vasculitis, and PAS, we performed right heart catheterization and pulmonary angiography. The mean pulmonary arterial pressure was 21 mmHg, and there was severe pulmonary artery stenosis. Thrombi on the pulmonary arterial wall lesions were observed in intravascular ultrasound and optical coherence tomography. Furthermore, the patient had a history of deep vein thrombosis. Therefore, we diagnosed unusual CTEPH. After 6 months of rivaroxaban anticoagulation therapy, a chest X-ray revealed a left lower lobe lung mass, and a positron emission tomography later showed hypermetabolic lesions in the main pulmonary artery wall, in both pulmonary arteries walls, in the lung parenchyma, and in the bones. A biopsy of the right proximal humerus lesion revealed undifferentiated intimal sarcoma. Pulmonary sarcoma is rare, but should be considered when differentially diagnosing main pulmonary artery wall thickening and stenosis. A positron emission tomography may aid in this diagnosis.

• The Journal of the Acoustical Society of Korea
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• v.14 no.6
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• pp.13-20
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• 1995

In this paper, the thermoacoustic refrigerating system was implemented and its operation was experimentally verified. The system is composed of several parts ,4 inch midrange speaker, speaker housing, chamber, stack housing, stack of plates, heat exchangers, thin pipe and cavity. The system is filled with He gas at 10 bar and contains T-type thermocouples and condenser microphone for measuring the temperature and pressure inside, respectively. In addition, cooling water is used for protecting speaker from thermal destruction and cooling down the hot heat exchanger. For the experimental verification of the implemented refigerating system, electrical impedance and resonance characteristics were measured. The results showed that it was most efficient to drive the system at 340 Hz. When operated at 340 Hz, $30^\circ{C}$ environments and 50 electical watts, the temperature of the cold region decreased by $16^\circ{C}$. The dissatisfaction mainly comes from the incomplete thermal insulation of the cold region. We also pointed out some guidelines to improve the performance for later study.

• The Korean Journal of Pain
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• v.9 no.1
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• pp.46-56
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• 1996

Many surgeons and anesthesiologists prefer using vasoconstrictor mixed with local anesthetic agent to reduce the incidence of side effects and prolong the duration of analgesia because most local anesthetic agents, except cocaine, were believed to possess vasodilating effect. However, some investigators recently reported vasoconstricting effect of local anesthetic agents. There is still controversy on the vasoactive effect of local anesthetic agents. So this study is aimed to clarify the vasoactive effect of local anesthetics in the animal model resembling clinical settings. Rabbits were anesthesized with ketamine and haloghane, and respirations were controlled with Harvard animal ventilator. Lidocaine (0.5%, 1.0%, 1.5%) and bupivacaine (0.125%, 0.25% and 0.5%) with or without 1:100,000 epinephrine were subdermaly injected on the femoral bupivacaine of the femoral artery were measured with Doppler flow meter in vivo. The mean arterial pressure, pulse rate, arterial blood gases, pH and level of serum electrolytes were measured at every 2 minute interval for 30 minutes. Results were as follows: 1) There was no significant vasoconstriction with 0.5% lidocaine and 0.125% bupivacaine. 2) Statistically significant (p<0.05) vasodilations were observed with lidocaine (1.0~2.0%) and bupivacaine (0.25~0.5%). 3) There were no changes on the duration of vasodilation induced by local anesthetic agents of various concentrations. 4) Onset of vasodilation induced by local anesthetic agents of high concentration were faster than that of lower concentrations. 5) In the mixed injection group of epinephrine and local anesthetic agent, the vasoconstriction induced by epinephrine was completely reversed by local anesthetics, approximately 5 minutes later. In conclusion, local anesthetic agents at dose exceeding 1.0% lidocaine and 0.25% bupivacaine increase local blood flow significantly in animal study in vivo which is applicable in human clinical settings. The increase blood flow may be due to dilatation of blood vessel. Further study on the analysis of association between amount of absorbed local anesthetics in blood vessels and dilatation of blood vessels is needed.