• Journal of the Korean Crystal Growth and Crystal Technology
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• v.17 no.3
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• pp.121-127
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• 2007

We have applied mechanical alloying (MA) to get $Mg_2Si$ thermoelectric material with nano-sized grains. An optimal milling and heat treatment conditions to obtain the single phase of $Mg_2Si$ compound with fine microstructure were investigated by X-ray diffraction and differential scanning calorimetry (DSC) measurement. The $Mg_{66.7}Si_{33.3}$ MA samples ball-milled for $20{\sim}180\;hrs$ exhibit two broad exothermic heat releases around $220^{\circ}C$ and $570^{\circ}C$. On the other hand, MA sample ball-milled far 260 hrs exhibits only a sharp exothermic peak at $230^{\circ}C$ Single phase Mg2Si powder can be obtained by MA of $Mg_{66.7}Si_{33.3}$ mixture for 60 hours and subsequently heated up to $620^{\circ}C$. Sintering of the MA powders was performed in a spark plasma sintering (SPS) machine using graphite dies at $800{\sim}900^{\circ}C$ under 50 MPa. The shrinkage of sintering sample during SPS was significant at about $200^{\circ}C$. All compact bodies have a high relative density above 94% with metallic glare on the surface.

• The Journal of Pediatrics of Korean Medicine
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• v.18 no.2
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• pp.107-117
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• 2004

Objective : Atopic dermatitis has a close relationship with degranulation of mast cell and separation of Histamine. As there's no experiment with herb, using Arctii Fructus, we investigated experimental influence of Arctii Fructus on degranulation of mast cell and separation of histamine in SD rat. Methods : The SD rats are classified into three groups. One group is normal one treated by normal saline before medical treatment. The other is control group prescribed to Compound 48/80 before normal saline treatment. And the third is experimental group prescribed to compound 48/80 after medical treatment of Arctii Fructus. Then, I investigated the experimental results by measuring the degree of degranulation and separation of histamine. The results of investigation on SD rat group showing the degree of inhibitory effect of degranulation of a mast cell are as follow, the normal group treated by normal saline reflecting the degree of degranulation is $6.10{\pm}0.20\;%$, the control group treated by only compound 48/80 is $87.56{\pm}11.00\;%$, the experimental group which treated by compound 48/80 and Arctii Fructus's medical treatment is $16.26{\pm}4.67\;%$. Results : The normal group treated by only normal saline reflecting the degree of degranulation is $6.10{\pm}0.20\;%$, the control group treated by only compound 48/80 is 87.56=11.00 %, the experimental group treated by compound 48/80 and Arctii Fructus's medical treatment is $16.26{\pm}4.67\;%$. This result indicates that the degree of degranulation of mast cell is obviously inhibited (p<0.0l) in the experimental group in comparison with control one. The analysis of data obtained from plasma, which collected from the experimented SDrats' hearts before their death, and the measurement of quantity of histamine secretion show the following results. The quantity of normal group and control one is $25.34{\pm}4.58$ nM, $348.59{\pm}30.77$ nM respectively, and experimental one prescribed to compound 48/80 after medical treatment of Arctii Fructus is $263.56{\pm}21.34$ nM. This result indicates that separation of histamine isobviously inhibited in the experimental group in comparison with control one (p<0.05). Conclusions : Arctii Fructus does obviously inhibit the degree of degranulation of mast cell (p<0.0l) and separation of histamine in the plasma (p<0.05).

• Restorative Dentistry and Endodontics
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• v.27 no.5
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• pp.488-492
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• 2002

The purpose of this study was to evaluate the effectiveness of plasma arc curing (PAC) unit for composite and compomer curing. To compare its effectiveness with conventional quartz tungsten halogen (QTH) light curing unit, the polymerization shrinkage rates and amounts of three composites (Z100, Z250, Synergy Duo Shade) and one compomer, that had been light cured by PAC unit or QTH unit, was compared using a custome made linometer. The measurement of polymerization shrinkage was peformed after polymerization with either QTH unit or PAC unit. In case of curing with the PAC unit, the composite was light cured with Apollo 95E for 6s, the power density of which was recorded as 1350 mW/$\textrm{cm}^2$ by Coltolux Light Meter. For light curing with QTH unit, the composite was light cured for 30s with the XL2500, the power density of which was recorded as 800 mW/$\textrm{cm}^2$ by Coltolux Light Meter. The amount of linear polymerization shrinkage was recorded in the computer every 0.5s for 60s. Ten measurements were made for each material. The amount of linear polymerization shrinkage for each material in 10s and 60s which were cured with PAC or QTH unit were compared with t test. The amount of polymerization shrinkage in the tested materials were compared with 1way ANOVA with Duncan's multiple range test. As for the amounts of polymerization shrinkage in 60s, there was no difference between PAC unit and QTH unit in Z250 and Synergy Duo Shade. In Z100 and Dyract AP, it was lower when it was cured with PAC unit than when it was cured with QTH unit (p<0.05). As for the amounts of polymerization shrinkage in 10s, there was no difference between PAC unit and QTH unit in Z100 and Dyract AP. The amounts of polymerization shrinkage was significantly higher when it was cured with PAC unit in Z250 and Synergy Duo Shade (p<0.05). The amounts of polymerization shrinkage in the tested materials when they were cured with QTH unit were Z250 (6.6um) < Z100 (9.3um), Dyract AP (9.7um) < Synergy Duo Shade (11.2um) (p<0.05). The amount of polymerization shrinkage when the materials were cured with PAC unit were Dyract AP (5.6um) < Z100 (8.1um), Z250(7.0um) < Synergy Duo Shade (11.2um) (p<0.05).

• Journal of Veterinary Clinics
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• v.15 no.2
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• pp.307-318
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• 1998

Accuracy of rectal palpation and ultrasonography for differential diagnosis of subestrous dairy trows were investigatedl using the result of pIRsma progesterone assay. The ovaries were examined 2 times of 10 days interval in 520 posearom and postinsemination subestroHs dairy cows, using rectal palpation and B-mode transrectal ultrasonography. The results of rectal palpation, ultrasonographic examination and measurement of plasma progesterone profiles in 520 subestrous dairy cows were silent brat or error of estrus detection 303 (58.3%), persistent corpus luteum 59 (11.3%), follicular cyst 37 (7.1%), luteal cyst 16 (3.1%), inactive ovary 9 (1.7%), granulosa tumor 1 (0.2%), hydmsalphinx 1 (0.2%), endomehris 81 (15.6%), pyometra 12 (2.3%) and mummified fetus 1 (0.2%), respectively. Accuncy of rectal palpation and ultrasonography for diagiosing ovarian disordeir based on plasma progesterone profiles were silent heat or error of estrus detection 80.5% and 96.7%$\boxUl$ persistent corpus luteum 57.6% and 94.9%, follicular cyst 62.5% and 91.9%1 luteal cyst 62.5% and 87.5%, maclive ovary 55.6% and 88.9% and granulosa cell tumor 100% and 100%, respectively. Acnuucy of rectal palpation for diagnosing uterine disorders based on ultrasonography was pyometra 75.0%1 endometritis 51.9% and mummified fetus 100%, respectively. Cbaracteristic ultrasonographic appearances of ovaries in subestrous dairy cows were as follows; Silent heat or error of estrus detection: anechoic follicle or hypoechoic corpus luteum than ovarian stroma was alternately present on Day 0 (first examination) and Day 10. Follicular cyst: uniformly nonechogenic ovarian structure $\geq $ 25 mm in diameter with a wall < 3 mm was present in ipsilateral on Day 0 and Day 10. Luteal cyst: luteal cyst was similar to follicular cysts but thickness of cystic wall was $\geq $ 3 mm. Inactive ovary : structures within ovaries was not present on Day 0 Bnd Day 10. Characteristic uthssonograpsc appearances of uterus in subestrous dairy cows were as follows; Endometritis: characterized by uterine lumen containing fluid in which 'snowy'echogenic particles art suspended. Pyometra: ultrasonographic appearance of pyometra was diffuse echogenic particles distributed in fluid within the distended uterus, and a thickened uterine wall. These results indicated that ultrasonography was practical far diagnosing reproductive disorders. To diagnosing ovarian disorders, ultrasonography should be carried out 2 times of 10 days interval and rndometritis should be differentiated with uterus of luteal phase in normal cycling cows.

• Journal of Veterinary Clinics
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• v.21 no.4
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• pp.384-394
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• 2004

This study was carried out to monitor the response of ovaries and cyst according to treatment with GnRH or combination of GnRH and $PGF_2{\alpha}$ in dairy cows with ovarian follicular cysts. Thirty cows were diagnosed as having follicular cysts by rectal palpation, ultrasonography and progesterone (P4) assays. Ten cows were treated with GnRH (control), and the other twenty were treated with $PGF_2{\alpha}$ at 10 days after GnRH treatment. All the animals were re-examined by ultrasonography and blood was collected for the measurement of plasma P4 concentration at day 0 (the day of treatment), day 7, day 10, day 13, day 24 and day 34, respectively. In 30 cows that were diagnosed with follicular cysts, mean plasma P 4 concentrations on day -II and day -I were 0.3 ng/ml and 0.4 ng/ml. On day 10 increased as 2.7$\pm$0.2 ng/ml. Mean cystic wall thickness by ultrasonography on day -11 and day -I were 2.1 mm and 2.2 mm. In 9 cows responded on luteinization of cystic wall, cystic wall thickness was 3.9$\pm$0.5 mm at day 10 after GnRH treatment. The responses of ovaries until day 10 after GnRH treatment included development of corpus luteum in the ovary bearing the cyst or in the contralateral ovary (12 cows), luteinization of cystic wall (6 cows) and clouding of the anechoic antrum of cysts (2 cows). The ovarian responses according to the combination of GnRH and $PGF_2{\alpha}$ included regression of the corpus luteum (12 cows), increase (1 cow) and no change (1 cow) of cyst size until last examination, and complete disappearance on day 13 (6 cows), 23 (6 cows) and 34 (4 cows). Combination treatment group of GnRH and $PGF_2{\alpha}$ showed a higher pregnancy rate within 100 days after initial treatment (40.0 vs 65.0%) and shorter intervals from the treatment to conception (45.4$\pm$25.8 vs 53.5$\pm$31.4 days) compared with control. It was concluded that the administration of $PGF_2{\alpha}$ following GnRH treatment is effective in shortening the interval from treatment to conception in cows with follicular cyst. Also, this study suggested that the response of the cyst according to treatment revealed various types. Therefore, veterinarians should pay attention to monitor of the response of cystic ovaries after treatment, specially no change, slowly decrease or increasement of cyst size after treatment.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.05a
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• pp.139-141
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• 2005

이번 실험에서는 변방전형 교류 PDP에서의 3차원적인 전자온도와 이온밀도의 측정을 마이크로 랑뮈르 탐침법을 통해 실험적으로 연구하였다. 스테핑 모터에 연결된 마이크로 랑뮈르 탐침은 20um씩 움직이며 탐침에 인가하는 플러스와 마이너스의 직류전압을 통해 I-V곡선을 구할 수 있고 이를 통해서 전자온도와 플라스마 밀도를 구할 수 있다. Ne+Xe(4%) 200Torr의 혼합가스에서 전극의 테두리를 따라(X축) 전자온도 및 플라스마 밀도를 측정한 결과 중앙지점에서와 전극의 경계지역에서 이온밀도는 $7.69{\sim}11.1{\times}10^{11}cm^{-3}$ 까지 측정되었다. 또한 전자온도는 플라스마 밀도와 균형적인 관계에 있다는 것은 주목할 만하다. 전자온도는 전극 사이의 중심에서 가장 적게 1.3 ~ 3.15eV까지 측정되었다. Y축으로 측정했을 경우 이온 밀도와 전자온도는 전극 갭 중앙에서부터 약 80um 떨어진 지점에서 서로 교차하며 증가 및 감소였으며 이온밀도는 $8.3{\sim}11.1{\times}10^{11}cm^{-3}$로 측정되었고 전자온도는 이와 균형적인 관계를 가지고 1.2~1.6eV로 측정되었다. 또한 이러한 특성은 AC PDP 에서 나타나는 줄무늬 현상과 관련이 있는 것으로 보인다. Z축으로 측정했을 경우 약 125um높이에서 가장 높게 측정되었으며 $1.1{\times}10^{12}cm^{-3}$정도로 측정되었다.

• Analytical Science and Technology
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• v.21 no.5
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• pp.364-374
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• 2008

Antarctic Environmental Monitoring Handbook' was published by COMNAP/SCAR in 2000. The standardized method described in this handbook is recommended for monitoring of antarctic environment. High pressure bomb technique in this guide was used to decompose soil samples. In compliance with this guide book, high pressure bomb technique was applied to decompose the antarctic soil sampled at the King Sejong Station. An Isotope Dilution-Inductively Coupled Plasma-Mass Spectrometry (ID-ICP-MS) was applied to determine mass concentrations of Pb, Cu and Zn in the soil. The accuracy in this method was verified by the analysis of certified reference materials (CRM) of NIST 2702 (marine sediment). The analytical results agreed with certified value within the range from 99.5~100.8%. Matrix separation was necessitated for the determination of Cu and Zn by Chelex 100 ion exchange resin. As a result, the average mass concentrations of Pb, Cu and Zn which are suspected to be caused by anthropogenic pollution were 332.9 mg/kg, 95.6 mg/kg and 115.3 mg/kg, respectively. Those for the metals sampled in the soils of the remote regions from the station were 28.1 mg/kg, 101.8 mg/kg and 115.6 mg/kg, respectively.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.4
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• pp.405-414
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• 1999

The role of platelet-activating factor (PAF) was investigated in intestinal ischemia/reperfusion (I/R) induced acute lung injury associated with oxidative stress. To induce acute lung injury following intestinal I/R, superior mesenteric arteries were clamped with bulldog clamp for 60 min prior to the 120 min reperfusion in Sprague-Dawley rats. Acute lung injury by intestinal I/R was confirmed by the measurement of lung leak index and protein content in bronchoalveolar lavage (BAL) fluid. Lung leak and protein content in BAL fluid were increased after intestinal I/R, but decreased by WEB 2086, the PAF receptor antagonist. Furthermore, the pulmonary accumulation of neutrophils was evaluated by the measurement of lung myeloperoxidase (MPO) activity and the number of neutrophils in the BAL fluid. Lung MPO activity and the number of neutrophils were increased (p＜0.001) by intestinal I/R and decreased by WEB 2086 significantly. To confirm the oxidative stress induced by neutrophilic respiratory burst, gamma glutamyl transferase (GGT) activity was measured. Lung GGT activity was significantly elevated after intestinal I/R (p<0.001) but decreased to the control level by WEB 2086. On the basis of these experimental results, phospholipase $A_2\;(PLA_2),$ lysoPAF acetyltransferase activity and PAF contents were measured to verify whether PAF is the causative humoral factor to cause neutrophilic chemotaxis and oxidative stress in the lung following intestinal I/R. Intestinal I/R greatly elevated $PLA_2$ activity in the lung as well as intestine (p<0.001), whereas WEB 2086 decreased $PLA_2$ activity significantly (p<0.001) in both organs. LysoPAF acetyltransferase activity, the PAF remodelling enzyme, in the lung and intestine was increased significantly (p<0.05) also by intestinal I/R. Accordingly, the productions of PAF in the lung and intestine were increased (p<0.001) after intestinal I/R compared with sham rats. The level of PAF in plasma was also increased (p<0.05) following intestinal I/R. In cytochemical electron microscopy, the generation of hydrogen peroxide was increased after intestinal I/R in the lung and intestine, but decreased by treatment of WEB 2086 in the lung as well as intestine. Collectively, these experimental results indicate that PAF is the humoral mediator to cause acute inflammatory lung injury induced by intestinal I/R.

• Journal of Astronomy and Space Sciences
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• v.19 no.2
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• pp.123-132
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• 2002

The electron density and temperature in the topside ionosphere are observed by the ionosphere Measurement Sensor (IMS) onboard the KOMPSAT-1, which has the sun-synchronous orbit of the altitude of 685 km and the orbital inclination of $98^{\circ}$ with a descending node at 22:50LT. Observations have been analyzed to determine the seasonal variations of the electron density and temperature in the low-latitude region. Only the night-time (22:50LT) behavior on magnetically quiet days (Kp < 4) has been examined. Observations show a strong longitudinal and seasonal variation. Generally, in the dip equator the density increases and the temperature decreases. In equinox the latitudinal distributions of the electron density and temperature are quite symmetric about the dip equator. However, the local maximum of the density and the local minimum of the temperature shift toward the Northern hemisphere in summer solstice but the Southern hemisphere in winter solstice. Such variations are due to the influences of field-aligned plasma transport induced by F region neutral wind. Compared with the IRI95 model, the observed electron density and temperature show significant differences from those predicted by the IRI95 model.

• Korean Journal of Veterinary Research
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• v.26 no.1
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• pp.175-185
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• 1986

The measurement of angled erythrocyte sedimentation rate (ESR), as a replacement for perpendicular ESR, for cattle blood was scrutinized since it has been well known that perpendicular ESR in cattle is too slow to be adopted as an effective clinical test. Samples of blood were taken from 186 Korean native cattle over 2 years old. The results obtained in the experiment were summarized as follows. 1. Average values of perpendicular ESR/24hrs in 15 apparently healthy cattle, as measured by Wintrobe, Westergren and capillary tubes, were $5.8{\pm}2.2$, $11.1{\pm}3.7$ and $10.4{\pm}4.5%$ respectively, which were found to be similar to the values of perpendicular ESR/hr of normal blood of human. 2. The ESR was determined in the tubes held at 90, 75, 60, 45, 30 and 15-degree angles, using 3 types of tubes. For the diagnostic purposes, the best results were obtained from the tubes held at 45-degree angle. 3. The angled ESR values increased as the diameters of the tube-bores decreased. 4. The tube length did not affect the angled ESR(%). 5. The angled ESR values increased with the increased environmental temperature during the ESR measurement. 6. The storage temperature at $5^{\circ}C$, $20^{\circ}C$ and $35^{\circ}C$, of the blood for 24 hours did not affect the angled ESR. 7. Samples of blood were treated with 4 kinds of anticoagulants (heparin, $K_2$-EDTA, double oxalate and sodium citrate) and the ESR was determined at 45-degree angle, using capillary hematocrit tubes. The ESR values were higher in the blood samples treated with sodium citrate than in those treated with other anticoagulants. 8. By using the autologous plasma, the PCV was adjusted to be 5, 10, 20, 30, 40 and 50ml/100ml and the ESR was determined in the capillary hematocrit and Wintrobe tubes held at 45 degrees. In both of the methods the ESRs increased as the values of PCV decreased. The regressions of ESR to PCV in both 45-degree-angled capillary and Wintrobe tubes were curvilinear. For the capillary hematocrit tubes the second degree polynomial $Y=61.9779-2.3533x+0.0228x^2$ (r=0.9999) fits the data. And in the case of Wintrobe tubes the second degree polynomial $Y=27.9767-1.1314x-0.0117x^2$ (r=0.9998) fits the data. 9. The 45-degree angled ESR was determined in the blood of 71 healthy Korean native cows using capillary hematocrit tubes. The average PCV was $35.4{\pm}3.6ml/100ml$. The observed ESR/hr averaged $7.2{\pm}2.7%$, while the corrected ESR/hr to a PCV of 36ml/100ml averaged $6.6{\pm}1.3%$. From these results it was concluded that to obtain the best results the ESR/hr of Korean native cattle should be determined at 45-degree angle at room temperature($20^{\circ}C$) using capillary hematocrit tubes.