• Journal of Biomedical Engineering Research
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• v.28 no.3
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• pp.387-391
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• 2007

An oxygenator is a very important artificial organ and widely used for patients with lung failure or during open heart surgery. Although an oxygenator has been widely studied worldwide to enhance its efficiency, studies on oxygenators, in particular when using a pulsatile blood flow, are domestically limited. Therefore, a new oxygenator was developed in the lab and animal experimental results are described in the paper. The oxygenator is composed of polycarbonate housing and polypropylene hollow fibers. It has a total length of 400 mm and a surface area of $1.7 m^2$. The animal experiment lasted for 4 hours. The blood flow rate was set to 2 L/min and a pulsatile blood pump, T-PLS (Twin-Pulse Life Support), was used. Samples were drawn at the oxygenator's inlet and outlet. The total hemoglobin (Hb), saturation oxygen ($sO_2$), and partial oxygen pressure ($pO_2$), partial $CO_2$ pressure ($pCO_2$), and plasma bicarbonate ion concentration ($HCO_3^-$) were measured. The oxygen and carbon dioxide transfer rates were also calculated based on the experimental data in order to estimate the oxygenator's gas transfer efficiency. The oxygen and carbon dioxide transfer rates were $16.4{\pm}1.58$ and $165.7{\pm}10.96 mL/min$, respectively. The results showed a higher carbon dioxide transfer rate was achieved with the oxygenator. Also, the mean inlet and outlet blood pressures were 162.79 and 137.92 mmHg, respectively. The oxygenator has a low pressure drop between its inlet and outlet. The aim of own preliminary study was to make a new oxygenator and review its performance when applying a pulsatile blood pump thus, confirming the possibility of a new oxygenator suitable for pulsatile flow.

• Membrane and Water Treatment
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• v.14 no.3
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• pp.129-140
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• 2023

The appropriate injection of H₂O₂ is essential to produce hydroxyl radicals (OH·) by mixing H₂O₂ quickly and exposing the resulting H₂O₂ solution to UV irradiation. This study focused on evaluating mixing device of H₂O₂ as a design factor of UV/H₂O₂ AOP pilot plant using a surface water. The experimental investigation involved both experimental and model-based analyses to evaluate the mixing effect of different devices available for the H₂O₂ injection of a tubular hollow pipe, elliptical type of inline mixer, and nozzle-type injection mixer. Computational fluid dynamics analysis was employed to model and simulate the mixing devices. The results showed that the elliptical type of inline mixer showed the highest uniformity of 95%, followed by the nozzle mixer with 83%, and the hollow pipe with only 18%, after passing through each mixing device. These results indicated that the elliptical type of inline mixer was the most effective in mixing H₂O₂ in a bulk. Regarding the pressure drops between the inlet and outlet of pipe, the elliptical-type inline mixer exhibited the highest pressure drop of 15.8 kPa, which was unfavorable for operation. On the other hand, the nozzle mixer and hollow pipe showed similar pressure drops of 0.4 kPa and 0.3 kPa, respectively. Experimental study showed that the elliptical type of inline and nozzle-type injection mixers worked well for low concentration (less than 5mg/L) of H₂O₂ injection within 10% of the input value, indicating that both mixers were appropriate for required H₂O₂ concentration and mixing intensity of UV/ H₂O₂ AOP process. Additionally, the elliptical-type inline mixer proved to be more stable than the nozzle-type injection mixer when dealing with highly concentrated pollutants entering the UV/H₂O₂ AOP process. It is recommended to use a suitable mixing device to meet the desired range of H₂O₂ concentration in AOP process.

• Journal of Chest Surgery
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• v.37 no.1
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• pp.1-10
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• 2004

Background: Currently, the cardiopulmonary machine with non-pulsatile pumps, which are low in internal circuit pressure and cause little damage to blood cells, is widely used. However, a great number of experimental studies shows that pulsatile perfusions are more useful than non-pulsatile counterparts in many areas, such as homodynamic, metabolism, organ functions, and micro-circulation. Yet, many concerns relating to pulsatile cardiopulmonary machines, such as high internal circuit pressure and blood cell damage, have long hindered the development of pulsatile cardiopulmonary machines. Against this backdrop, this study focuses on the safety and effectiveness of the pulsatile cardiopulmonary machines developed by a domestic research lab. Material and Method: The dual-pulsatile cardiopulmonary bypass experiment with total extracorporeal circulation was conducted on six calves, Extracorporeal circulation was provided between superior/inferior vena cava and aorta. The membrane oxygenator, which was placed between the left and right pumps, was used for blood oxygenation. Circulation took four hours. Arterial blood gas analysis and blood tests were also conducted. Plasma hemoglobin levels were calculated, while pulse pressure and internal circuit pressure were carefully observed. Measurement was taken five times; once before the operation of the cardiopulmonary bypass, and after its operation it was taken every hour for four hours. Result: Through the arterial blood gas analysis, PCO2 and pH remained within normal levels. PO2 in arterial blood showed enough oxygenation of over 100 mmHg. The level of plasma hemoglobin, which had total cardiopulmonary circulation, steadily increased to 15.87 $\pm$ 5.63 after four hours passed, but remained below 20 mg/㎗. There was no obvious abnormal findings in blood test. Systolic blood pressure which was at 97.5$\pm$5.7 mmHg during the pre-circulation contraction period, was maintained over 100 mmHg as time passed. Moreover, diastolic blood pressure was 72.2 $\pm$ 7.7 mmHg during the expansion period and well kept at the appropriate level with time passing by. Average blood pressure which was 83$\pm$9.2 mmHg before circulation, increased as time passed, while pump flow was maintained over 3.3 L/min. Blood pressure fluctuation during total extracorporeal circulation showed a similar level of arterial blood pressure of pre-circulation heart. Conclusion: In the experiment mentioned above, pulsatile cardiopulmonary machines using the doual-pulsatile structure provided effective pulsatile blood flow with little damage in blood cells, showing excellence in the aspects of hematology and hemodynamic. Therefore, it is expected that the pulsatile cardiopulmonary machine, if it becomes a standard cardiopulmonary machine in all heart operations, will provide stable blood flow to end-organs.

• The Korean Journal of Pharmacology
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• v.27 no.1
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• pp.33-43
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• 1991

To study the age dependent change of Na, K-ATPase in the erythrocyte of hypertensive rat, 1-kidey 1-clip hypertensive rat was made by the removal of right kidney and partial ligation of left renal artery. After 4 weeks, aged erythrocyte fraction was separated by density gradient centrifugation, and Na, K-ATPase activity and $^3H-ouabain$ binding with ghost cell membrane and ouabain sensitive Rb-uptake with whole cell were measured. 1) In the hypertensive rats, blood pressure was significantly increased to 165.5/119.0 mmHg (systolic/diastolic). Mean corpuscular volume and membrane protein(mg) per $10^9RBC$ were decreased and hemoglobin content was increased in the aged erythrocyte. 2) Na, K-ATPase activity in the solution containing 110 mM NaCl and 10 mM KCI, was decreased in hypertensive rat, and decreased in aged erythrocyte of both group. 3) Ouabain sensitive Rb-uptake by low RbCl concentration(4 mM) was slightly decreased in aged erythrocyte compared to that in young erythrocyte of each group, but slightly increased in young erythrocyte in hypertensive rat compared to that in normotensive rat. 4) Ouabain sensitive Rb-uptake by high RbCl concentration(16 mM) was decreased about 30% to 50 % in aged erythrocyte in both group. And in hypertensive rat, especially in young erythrocyte it was significantly decreased compared to that in normotensive rats. 5) $^3H-ouabain$ binding at 0.13 or $1{\times}10^-6M$ ouabain concentration was slightly decreased in aged erythrocyte of normotensive rat, and significantly decreased in aged erythrocyte of hypertensive rats. 6) $^3H-ouabain$ binding at 6 or $64{\times}10^-6M$ ouabain concentration is slightly decreased in aged erythrocyte of both group, but significantly decreased in young and aged erythrocyte of hypertensive rats compared to that of normotensive rats. The present results suggest that (1) in the young erythrocyte of hypertensive rat, the alterations of Na-pump activity that slightly increased in weak stimulation and inhibited in strong stimulation, may be related to increased molecular activity and the decrease in the number of low affinity site without change in high affinity site, (2) in the aged erythrocyte of normotensive rat, inhibited Na-pump may be related to the change in molecular activity of pump. (3) And in the aged erythrocyte of hypertensive rat, it may be related to the decrease in the number of high and low affinity site as well as the change in molecular activity

• Journal of Chest Surgery
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• v.32 no.8
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• pp.702-708
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• 1999

Background: Surgical closure of the PDA in premature infants with complications or contraindications to indomethacin use, or recurrence of symptomatic PDA is a safe and effective procedure with low operative risk and minimal complications. Material and Method: From April 1996 to August 1998, 11 premature infants with body weight under 1.5 kg at operation underwent operation for a symptomatic PDA (male:5, female: 6). Associated dise ases were congenital heart disease(7), hyaline membrane disease(6), intraventricular hemor rhage(4), pneumonia(4), pneumothorax(3), hyperbilirubinemia(2), necrotizing enterocolitis(2), renal failure(1), epilepsy(1), and hydrocephalus(1). Surgical techniques are hemoclipping(8) and ligation(3). The size of PDA was 3~6 mm (5.0$\pm$1.2). Result: Systolic and diastolic blood pressure rised and heart rates decreased after PDA closure. ABGA improved postoperatively. There were no surgical complications. Six infants with improved ABGA data were weaned from mechanical ventilatory support. The follow-up durations after discharge were 3 month to 12 month. Five deaths were not related to operation. The causes of death were hyaline membrane disease(2), bronchopulmonary dysplasia with pneumonia(1), sepsis(1), and con gestive heart failure with respiratory distress syndrome(1). Conclusion: Early operative closure is the treatment of choice in most premature infants with a hemodynamically significant shunt(PDA), recurrence of symptomatic PDA, complications of Indomethacin, or contraindi cations to Indomethacin.

• Applied Chemistry for Engineering
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• v.24 no.5
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• pp.456-470
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• 2013

Hollow-fiber membranes, is one of the new technologies that is growing rapidly in the past few decades. In addition, separation membranes using polymer materials, have attracted attentions in various fields including gas separation, fuel cells, water treatment, wastewater treatment, and organic separation. Nanofiltration (NF) membranes having the separation characteristics in the intermediate range between ultrafiltration and reverse osmosis (RO) membranes for liquid separation, with relatively low investment cost and operating pressure lower than that of RO membranes, have high permeance and rejection performance of multivalent ions as well as organic compounds of molecular weight between $200{\sim}1000gmol^{-1}$. In this paper, we would like to review the research trends on the various structure control and characterization of NF hollow fiber membranes with respect to materials and the methods of preparation (phase inversion method and interfacial polymerization method). Currently, most of NF membranes have been manufactured by plate and frame types or spiral wound types. But hollow fiber types have delayed in commercial products, because of the weak strength when to produce on the basis of the existing materials, therefore the development of new materials or improvement of existing materials will be needed. If improving manufacturing technology is available, hollow fiber types will replace spiral wound types and gradually show a higher market share.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.11 no.3
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• pp.193-198
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• 2013

In general, boron recovery of 40-90% could be achieved by Reverse Osmosis (RO) membranes in neutral pH condition. As an emerging technology, Forward Osmosis (FO) membrane has attracted growing interest in wastewater treatment and desalination. The objective of this study is to evaluate the possibility of the boron removal in radioactive liquid waste by FO. In this study, the performance of FO was investigated to remove boron in the simulated liquid waste as the factors such as pH, osmotic pressure, ionic strength of solution, etc. The pH of feed solution is a major operating parameter which strongly influences to the permeation of boron and more than 80% of boron content can be separated when conducted at pH values less than 7. The water flux is not influenced but the boron flux and permeation rate tends to decrease in the low salt concentration of 1,000 mg/L. The boron flux increases linearly, but the permeation ratio of reducing boron is nearly constant even with changes in the draw solution concentration.

• YAKHAK HOEJI
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• v.43 no.2
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• pp.237-250
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• 1999

In order to investigate the pharmacologic properties of New Wonbang Woohwangchungsimwon Pill(NSCH), effects of Wonbang Woohwangchungsimwon Pill (SCH) and NSCH were compared using various experimental models. In rat aorta, NSCH and SCH made the relaxation of blood vessels in maximum contractile response to phenylephrine (10-6 M) regardless to endothelium containing or denuded rings of the rat aorta. Furthermore, the presence of the inhibitors of NO synthase and guanylate cyclase did not affect significantly the relaxing effects of NSCH and SCH. NSCH and SCH inhibited the vascular contractions induced by acetylcholine, prostaglandin endoperoxide or peroxide in a dose-dependent manner. In conscious spontaneously hypertensive rats (SHRs), NSCH and SCH decreased significantly heart rate. These, at high doses, had a negative inotropic effects that was a decrease of left ventricular developed pressure and (-dp/dt)/(+dp/dt) in the isolated perfused rat hearts, and also decreased the contractile force and heart rate in the isolated rat right atria. In guinea-pig papillary muscle, these had no effects on parameters of action potential such as action potential amplitude (APA), $V_{max}$ and resting membrane potential (RMP) at low doses, whereas inhibitory the cardiac contractility at high doses. Furthermore, these had a significant inhibitory effects on palpitation of the heart in normotensive rats and SHRs. These had a significant inhibitory effects on palpitation of the heart in normotensive rats and SHRs. These results suggest that NSCH and SCH have weak cardiovascular effects, and that there is no significant differences between cardiovascular effects of two preparations.

• Composites Research
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• v.29 no.5
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• pp.243-248
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• 2016

Although thermoset carbon fiber composite bipolar plates not only have high mechanical properties but also high corrosion resistance in acid environment, high manufacturing cost and low bulk electrical conductivity are the biggest obstacle to overcome. In this research, thermoplastic polymer is employed for the matrix of carbon composite bipolar plate to increase both the manufacturing productivity and bulk electric conductivity of the bipolar plate. In order to increase the electrical conductivity and strength, plain type carbon fabric rather than chopped or unidirectional fibers is used. Also nano particles are embedded in the thermoplastic matrix to increase the bulk resistance of the bipolar plate. The area specific resistance and the mechanical strength of the developed bipolar plate are measured with respect to the environmental temperature and stack compaction pressure.

• Journal of Korean Neurosurgical Society
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• v.30 no.sup2
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• pp.364-367
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• 2001

A 4-month-old female patient admitted because of hydrocephalus. She was premature infant with germinal matrix hemorrhage at gestational period 27 wks. A ventriculoperitoneal shunt with a low-pressure type valve was placed. Follow-up CT scan obtained 3 months after VP shunt placement, revealed a new Lt. middle cranial fossa cyst. The girl was readmitted to hospital at 7 months after VP shunt placement, complaining of lethargy and vomiting. A CT scan was demonstrated a increase in size of a cyst, She subsequently underwent a left-sided pterional craniotomy with partial excision of membrane and cyst fenestration into the basal cisterns. Follow-up CT scan after 18 months revealed reaccumulation of cyst, the girl was reoperated on. After 2 months, the size of cyst was not decreased. Finally, She underwent a cystoperitoneal shunt. Follow-up CT scan after 5 months was demonstrated disappeared cyst and reexpansion of brain parenchyma. We report the development of a symptomatic sylvian fissure arachnoid cyst developed after ventriculoperitoneal shunt.