• Journal of Pharmaceutical Investigation
• /
• v.30 no.2
• /
• pp.99-105
• /
• 2000

This study compared the permeability of $[^3H]taurine,\;[^3H]phenylalanine,\;and\;[^3H]oxytocin$ through the blood-brain barrier (BBB) in mice and rats with common carotid artery perfusion (CCAP) method that modified internal carotid artery perfusion (ICAP) method. External carotid artery (ECA) was cannulated with coagulating pterygopalatine artery (PPA) in ICAP method, while CCA was cannulated without coagulating PPA in CCAP method. Also, for evaluation of BBB permeability of drugs in mice and rats, we used intravenous injection technique. The results of CCAP method in mice at a perfusion flow-rate of 2 ml/min, the brian volume of distribution $(V_D)$ of $[^{14}C]sucrose,\;[^3H]taurine,\;[^3H]phenylalanine,\;and\;[^3H]oxytocin$ were similar to the result of ICAP method in rats at perfusion flow rate of 4 ml/min. The area under the plasma concentration-time curve and brain uptake of $[^3H]taurine$ by intravenous injection technique, were $65.5{\pm}9.7%ID^*min/ml\;and\;0.515{\pm}0.093%ID/g$, respectively, in mice, and the corresponding values were $8.00{\pm}0.03%ID^*min/ml\;and\;0.052{\pm}0.003%ID/g$ in rats. But the BBB permeability surface-area product of $[^3H]taurine$ was similar between mice and rats. In conclusion, the CCAP method in mice was simple, fast and comparable to ICAP method in rats for drug permeability through the BBB.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2007.11a
• /
• pp.336-337
• /
• 2007

현재 투명전극의 재료로 ITO, ZnO, $SnO_2$등의 재료가 주로 이용되며, 낮은 저항률을 장점으로 가지는 ITO 박막이 가장 널리 이용되고 있으나, 가격이 비싸다는 단점을 가지고 있다. 이 밖에도 ITO 박막보다 가격이 저렴한 ZnO박막에 대한 연구가 많이 진행되고 있으나, 고온에서의 열적 불안정성 등의 문제로 상용화되지는 못하고 있다. 그러나 $SnO_2$ 박막은 ITO와 ZnO 박막보다 저항률이 다소 높지만, 우수한 열적, 화학적 안정성과 저렴한 가격으로 ITO 박막을 대체할 투명전도막 재료로 주목받고 있다. 본 연구에서는 $SnO_2$박막의 저항률 향상을 위하여 ATO(Antimony doped Tin Oxide) 박막을 RF Magnetron Sputtering 법으로 Coming glass위에 증착하였으며, 박막 증착시 산소 유량의 변화가 ATO 박막의 구조적, 전기적 그리고 광학적 특성에 미치는 효과를 연구하였다. 본 실험에서는 동작압력을 10 mTorr, RF power를 250W로 고정하고 $O_2$ 유량을 부분적으로 변화시키면서 증착되어진 ATO 박막을 분석한 결과 Ar:$O_2$의 비가 90:10일 때 최적의 가스비율로써 우수한 구조적, 전기적 그리고 광학적 특성을 보임을 확인하였다.

• Journal of the Semiconductor & Display Technology
• /
• v.17 no.4
• /
• pp.66-69
• /
• 2018

This study was researched the electrical properties of semiconductor devices such as ITO, $SiO_2$, $V_2O_5$ thin films. The films of ITO, $SiO_2$, $V_2O_5$ were deposited by the rf magnetron sputtering system with mixed gases of oxygen and argon to generate the plasma. All samples were cleaned before deposition and prepared the metal electrodes to research the current-voltage properties. The electrical characteristics of semiconductors depends on the interface's properties at the junction. There are two kinds of junctions such as ohmic and schottky contacts in the semiconductors. In this study, the ITO thin film was shown the ohmic contact properties as the linear current-voltage curves, and the electrical characteristics of $SiO_2$ and $V_2O_5$ films were shown the non-linear current-voltage curves as the schottky contacts. It was confirmed that the electronic system with schottky contacts enhanced the electronic flow owing to the increment of efficiency and increased the conductivity. The schottky contact was only defined special characteristics at the semiconductor and the interface depletion layer at the junction made the schottky contact which has the effect of leakage current cutoff. Consequently the semiconductor device with shottky contact increased the electronic current flow, in spite of depletion of carriers.

• Journal of Powder Materials
• /
• v.29 no.2
• /
• pp.99-109
• /
• 2022

Powder flowability is critical in additive manufacturing processes, especially for laser powder bed fusion. Many powder features, such as powder size distribution, particle shape, surface roughness, and chemical composition, simultaneously affect the flow properties of a powder; however, the individual effect of each factor on powder flowability has not been comprehensively evaluated. In this study, the impact of particle shape (sphericity) on the rheological properties of Ti-6Al-4V powder is quantified using an FT4 powder rheometer. Dynamic image analysis is conducted on plasma-atomized (PA) and gas-atomized (GA) powders to evaluate their particle sphericity. PA and GA powders exhibit negligible differences in compressibility and permeability tests, but GA powder shows more cohesive behavior, especially in a dynamic state, because lower particle sphericity facilitates interaction between particles during the powder flow. These results provide guidelines for the manufacturing of advanced metal powders with excellent powder flowability for laser powder bed fusion.

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

• Journal of the Korean Vacuum Society
• /
• v.17 no.1
• /
• pp.16-22
• /
• 2008

We studied plasma etching of polycarbonate in $O_2/SF_6$, $O_2/N_2$ and $O_2/CH_4$. A capacitively coupled plasma system was employed for the research. For patterning, we used a photolithography method with UV exposure after coating a photoresist on the polycarbonate. Main variables in the experiment were the mixing ratio of $O_2$ and other gases, and RF chuck power. Especially, we used only a mechanical pump for in order to operate the system. The chamber pressure was fixed at 100 mTorr. All of surface profilometry, atomic force microscopy and scanning electron microscopy were used for characterization of the etched polycarbonate samples. According to the results, $O_2/SF_6$ plasmas gave the higher etch rate of the polycarbonate than pure $O_2$ and $SF_6$ plasmas. For example, with maintaining 100W RF chuck power and 100 mTorr chamber pressure, 20 sccm $O_2$ plasma provided about $0.4{\mu}m$/min of polycarbonate etch rate and 20 sccm $SF_6$ produced only $0.2{\mu}m$/min. However, the mixed plasma of 60 % $O_2$ and 40 % $SF_6$ gas flow rate generated about $0.56{\mu}m$ with even low -DC bias induced compared to that of $O_2$. More addition of $SF_6$ to the mixture reduced etch of polycarbonate. The surface roughness of etched polycarbonate was roughed about 3 times worse measured by atomic force microscopy. However examination with scanning electron microscopy indicated that the surface was comparable to that of photoresist. Increase of RF chuck power raised -DC bias on the chuck and etch rate of polycarbonate almost linearly. The etch selectivity of polycarbonate to photoresist was about 1:1. The meaning of these results was that the simple capacitively coupled plasma system can be used to make a microstructure on polymer with $O_2/SF_6$ plasmas. This result can be applied to plasma processing of other polymers.

• Journal of Korean Society for Atmospheric Environment
• /
• v.20 no.5
• /
• pp.663-670
• /
• 2004

The catalytic oxidation of benzene, toluene and xylene over a spent industrial catalyst (Pd-based) was investigated in a fixed bed flow reactor system. According to the priming condition, the properties of a spent Pd-based catalyst were characterized by XRD(X-ray diffraction). BET(Brunauer-Emmett-Teller) and ICP(Inductively coupled plasma). When air was used as a primer, optimum priming temperature was found to be 200$^{\circ}C$, and the catalytic activity decreased as the priming temperature increased. When a spent Pd-based catalyst primed with air at 200$^{\circ}C$ was re-treated with hydrogen at 200$^{\circ}C$, 300$^{\circ}C$ or 400$^{\circ}C$, respectively, the catalytic activity increased and thermal effect were negligible. $HNO_3$ aqueous solution priming resulted in slight decrease of the catalytic activity, with little effects on $HNO_3$ concentrations. The activity of a spent Pd-based catalyst with respect to VOC molecule was observed to follow sequence: xylene> toluene> benzene. Benzene. toluene and xylene could be removed to almost 100% by a spent Pd-based catalyst primed with hydrogen.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.11 no.11
• /
• pp.1043-1048
• /
• 1998

The decomposition performance of the Surface induced Plasma Chemical Processing(SPCP) for benzene, toluene, xylene and $NO_2$ were experimentally examined. Discharge exciting frequency range was 5kHz and 10kHz, and low frequency discharge requires high voltage to inject high electric power in gas and to decompose contaminants. The decomposition rate of dioxide nitrogen for 5kHz power in gas and to decompose contaminants. The decomposition rate of dioxide nitrogen for 5kHz power supply is only 85%, but it’s rate for 10kHz power supply is very high, more than 96% when peak voltage is 12kv. Aromatic hydrocarbon vapor of up to 1000ppm is almost throughly decomposed at the flow rate of 1000$\ell$/min or lower rate under the discharge with electric power of several hundred watts. High decomposition rate is shown in every case, that is, for SPCP reactor is necessary to obtain the decomposition rate of more than 80~98%. The decomposition rate of benzene, toluene and xylene were 90~98% and dioxide nitrogen was 45~96%.

• The Korean Journal of Pharmacology
• /
• v.16 no.2 s.27
• /
• pp.9-14
• /
• 1980

The influence of penicillin G infusion(7.5 units/min/kg) on the diuretic action of furosemide$(250{\mu}g/kg)$ in rabbits was studied to investigate the drug interaction between penicillin G and furosemide. The results were as follows: 1) There was no significant change in renal function in the penicillin G infused rabbits compared with the normal ratbit. 2) In comparison with the control group, a significant increase in ${\triangle}U_{flow},\;{\triangle}U_{Na}V,\;{\triangle}U-kV\;and{\triangle}U_{cl}V$ was noted by 30 minutes following the administration of furosemide in the penicillin G infused group. There was no significant difference in ${\triangle}C_{In},\;{\triangle}C_{PAH}$ between the two groups and ${\triangle}Na^+$ reabsorption rate was significantly decreased in the latter. The potentiating effect of penicillin G on the diuretic action of furosemide should be due to the increased luminal concentration of free form of furosemide, and it may be related to the competitive inhibition of plasma protein binding between the two drugs.

• Biomolecules & Therapeutics
• /
• v.9 no.1
• /
• pp.26-32
• /
• 2001

This study was investigated about the effect of glibenclamide (GLY) which is $K^{+}$ channel blocker on renal function in rabbit, GLY, when given into the vein, produced the diuretic action accompanied with the increases of amounts of N $a^{+}$ and $K^{+}$ excreted into urine ( $E_{Na}$ , $E^{K}$), and then osmolar and negative free water clearances ( $C_{osm}$, $T^{C}$$_{H2O}$), fraction excretory rates of filtered N $a^{+}$ and $K^{+}$ ( $F_{Na}$ , $F_{K}$) and ratios of $E_{K}$ against $E_{Na}$ were augmented. Filtration fraction (FF) were reduced because renal plasma flow (RPF) were not changed but glomerular filtration rates (GFR) were diminished. GLY administered into a renal artery exhibited significant reduction of urine volume along with the decreases of GFR and RPF in only experimented kidney whereas changes of renal function was not observed in control kidney. GLY given intracerebroventricularly exhibited diuretic action along with the increase of $E_{Na}$ , $E_{K}$ and $F_{Na}$ , $F_{K}$ by small dose which was not affect on renal function when it given into the vein. Above results suggest that GLY given into the vein in rabbit produce the diuretic action by inhibition of electrolytes reabsorption in renal tubules through central function. function.n. function.ion.