• Fisheries and Aquatic Sciences
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• v.23 no.4
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• pp.10.1-10.10
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• 2020

Background: Butaphosphan (BTP) has recently been introduced into the Korean aquaculture sector as a stressattenuating agent. In this study, a sensitive chemical analytical method was established for the detection of BTP in the olive flounder (Paralichthys olivaceus) tissues. Methods: Utilizing a method employing liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS), detection sensitivity, specificity, and precision were satisfactorily established. Temporal changes in the BTP plasma and muscle concentrations were assessed after a single intramuscular injection of BTP (50 and 150 mg/kg) to the olive flounder maintained at 13 ℃ or 22 ℃. Results: High BTP plasma levels were achieved immediately after the injection, and the drug was rapidly eliminated. Additionally, plasma BTP levels were markedly dependent on the elimination rate, which, in turn, seemed dependent on the water temperature, with the drug elimination half-life and mean residence time significantly shorter at 22 ℃ than 13 ℃. Overall, muscle BTP levels were markedly lower than the plasma levels. Notably, muscle levels were not influenced by water temperatures. Muscle BTP concentrations were used to estimate the necessary withdrawal period for drugs used in food fish, with BTP levels maintained far below the possible hazardous limit. Conclusions: In conclusion, the established LC-MS/MS method can be used for BTP residue detection with high sensitivity and reproducibility.

• Molecules and Cells
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• v.24 no.2
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• pp.210-214
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• 2007

The 90-kDa heat shock protein (HSP90) normally functions as a molecular chaperone participating in folding and stabilizing newly synthesized proteins, and refolding denatured proteins. The HSP90 inhibitor geldanamycin (GA) occupies the ATP/ADP binding pocket of HSP90 so inhibits its chaperone activity and causes subsequent degradation of HSP90 client proteins by proteasomes. Here we show that GA reduces the level of endogenous c-Jun in human embryonic kidney 293 (HEK293) cells in a time and dose dependent manner, and that this decrease can be reversed by transfection of HSP90 plasmids. Transfection of HSP90 plasmids in the absence of GA increases the level of endogenous c-Jun protein, but has no obvious affect on c-Jun mRNA levels. We also showed that HSP90 prolongs the half-life of c-Jun by stabilizing the protein; the proteasome inhibitor N-benzoyloxycarbonyl (Z)-Leu-Leu-leucinal (MG132) blocks the degradation of c-Jun promoted by GA. Transfection of HSP90 plasmids did not obviously alter phosphorylation of c-Jun, and a Jun-2 luciferase activity assay indicated that over-expression of HSP90 elevated the total protein activity of c-Jun in HEK293 cells. All our evidence indicates that HSP90 stabilizes c-Jun protein, and so increases the total activity of c-Jun in HEK293 cells.

• Journal of The Korean Society of Agricultural Engineers
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• v.57 no.3
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• pp.1-7
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• 2015

The objective of this study was to compare fecal microbes survival in soil between compost surface application and soil incorporation. The survival experiment was conducted in six styrofoam beds ($510{\times}325{\times}305(mm)$ in size) filled with sandy loam soil. A half of six boxes were received by compost surface application, while the other half were treated with compost-soil mixture. Duplicated surface and surbsurface soil (20 cm depth) samples were collected at various interval up to 50 days and analyzed for the determination of fecal coliforms and E. coli numbers. As expected, surface applied beds demonstrated two to three magnitudes order greater in both the study microorganisms as compared to soil incorporated beds. Microbial inactivation rate of soil surface was twice as great as subsurface soil condition probably due to exposure to sun light and environmental conditions including moisture loss. When rainfall occurred, microbes on the surface were transported into soil along with water movement. It was concluded that surface compost application may be easier to apply but pose higher risk of human exposure to microbes. Winter compost application may be favorable in alleviating health risk by giving some time for inactivation compared to spring application.

• Korean Journal of Environmental Agriculture
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• v.1 no.2
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• pp.89-92
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• 1982

Persistence of cyanofenphos on Chinese cabbage under the different climate conditions was studied by spraying the insecticide at the rate of 0.5 and 0.75 ㎏ AI/ha at 22 and 36 days after transplanting and monitoring its residues upto 35 days after the final spray. At both spraying rates the degradation patterns of the insecticide, regardless of climate condition, showed similar trends; cyanofenphos residues on Chinese cabbage declined rapidly upto 14 days after the final spray but more slowly thereafter. Half-life for cyanofenphos on Chinese cabbage was $6{\sim}7$ days. The half-life was little affected by the spraying rate and time. Based on the FAO/WHO maximum residue limit of cyanofenphos on common cabbage (2 ppm), it is recommended that the pre-harvest intervels of the insecticide on Chinese cabbage could be 16 and 19 days for 0.5 and 0.75 ㎏ AI/ha, respectively.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.2
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• pp.25-36
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• 2018

Drip irrigation system is a low energy cost method which can efficiently save and supply water by dropping water slowly on the crop's root zone during crop growth. In the drip irrigation system, disk filters take an important role to physically remove impurity (inorganic and suspended organic) particles present in agricultural water which can cause emitter clogging. For the purpose, both top-and-bottom surfaces of the disk are grooved in micron size flowing from outside to inside. However, many congested flow paths in disk filter media incur higher head loss of inflow water resulting in relatively decreasing velocities depending on operation time than sand and mesh filters. Therefore, it is important to optimize the structure of disk filter in micro irrigation system. The head loss of disk filter media takes also charge of more than 60 % of total head loss in whole disk filter. This study is to find the appropriate cross-sectional shape of the disk groove to minimize the head loss by executing the experiment. The experiment used three disk filters that have similar filter body but have a half-elliptic and two kinds of triangular cross sections. The experimental results showed that the disk filter with half-elliptic cross sections of disk grooves have less head loss than the disk filter with regular triangular one.

• Korean Journal of Clinical Pharmacy
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• v.16 no.1
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• pp.1-8
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• 2006

Methotrexate(MTX)는 소아 골육종 환자에서 $12g/m^2$의 고용량을 사용하고 있다. 현재, 소아 골육종 환자에서 신기 능에 따른 고용량 MTX의 임상 약동학은 연구되어 있지 않다. 따라서 본 연구에서는 신기능에 따른 MTX 약동학을 이용하여 구내염을 최소화하는 방법을 제시하고자 하였다. 방법: 환자들의 의무기록지를 후향적 방법으로 검토하였다. 한 병원에서 골육종으로 진단받고, 치료 받은 환자들을 대상으로 정상 신기능군과 비정상 신기능군으로 나누었다. 두 군에 MTX 투여 후 혈중 농도를 각각 비교하였고, 최고 혈중농도도 비교하였다. 혈중 농도와 구내염의 관련성, CL, AUC와 구내염의 상관관계를 분석하였다. 각 군의 terminal half-life, CL, Vss의 평균과 mea residence time(MRT)의 평균을 구하였고, 두 군간 각각을 비교하였다 $({\alpha}=0.05)$. 결과: 환자는 6명이었고, 평가 가능한 총 MTX 투여 회수는 34회였다. MTX 투여 후 최고혈중 농도, 24,48 시간의 혈중농도는 통계적으로 유의성 있는 차이가 있었고, 72,96 시간에서의 농도는 두 군간 유의성이 없었다. 각 군에서 혈중농도와 구내염의 상관관계, 그리고 CL, AUC와 구내염의 상관관계는 발견되지 않았다. Vss를 제외한 모든 파라미터들(terminal half-life, CL, MRT)은 통계적으로 유의성 있는 차이가 있었다. 결론: 비정상 신기능 군에서 MTX 투여 시작 후 24, 48 시간에서의 혈중농도가 더 높고, 변동이 심했다. 또한 MTX의 CL는 감소했고, 혈중농도는 증가하였다. 이러한 사실로 MTX 투여 전 후 혈중 크레아티닌이나 또는 크레아티닌 청소율 모니터링이 필요하다는 것을 알 수 있으며, MTX 투여가 끝난 직후 그리고 그 이후 24 시간 간격으로 혈중 농도를 측정해야함을 알 수 있다.

• Korean Journal of Veterinary Research
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• v.32 no.4
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• pp.677-681
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• 1992

This experiment was carried out to establish a proper method of indocyanine green(ICG) excrection test for a applicable liver function test in three Korean native cattle average weighing about 450kg and dairy cattle parity of 3~5. The results obtained the half life($T^1/_2$), fractional clearance rate(KICG), retention rate and plasma enzyme activities before or after injection of ICG were as follows. 1. The maximum absorbance of ICG in plasma was at 805nm. 2. Average half life and fractional clearance rate following the injection of ICG 0.25mg/kg body weight were $5.53{\pm}1.27$ minute and $0.131{\pm}0.031$/minute in Korean native cattle, $4.55{\pm}0.68$ minute and $0.156{\pm}0.031$/minute in dairy cattle, respectively. The ICG removal rate was exponentially liner for the first 15 minutes after injection both of Korean native cattle and dairy cattle. 3. Average plasma retention rate when 10, 15, 30 minutes after injection was $35.7{\pm}13.9$, $23.2{\pm}7.1$, $10.8{\pm}3.5%$ in Korean native cattle, $26.8{\pm}3.3$, $14.2{\pm}1.2$, $5.5{\pm}2.2%$ in dairy cattle, respectively. 4. Plasma enzyme activities(AST, ALT, r-GTP) were no variation among the before, during and after injection of ICG. From these results, ICG excretion test to cattle is applicable to evaluation of liver funtion in both clinical and research, and adopted the 15 minutes plasma sample as the sample taken at the ideal time for comparative purposes.

• Archives of Pharmacal Research
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• v.27 no.2
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• pp.259-264
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• 2004

The purpose of the present study was to investigate the pharmacokinetics of PEG-hemoglobin SB 1, a modified bovine hemoglobin with polyethylene glycol, after its single and multiple administration in beagle dogs. For this purpose, the analytical method of free hemoglobin in the plasma was developed and validated. Excellent linearity ($r^2$=0.999) was observed in the calibration curve data, with the limit of quantification of 0.005 g/dL. The precision and the deviation of the theoretical values for accuracy were always within $\pm$15％ in both the between-and the within-day results. The method was tested by measuring the plasma concentrations following intravenous administration to beagle dogs and was shown to be suitable for pharmacokinetic studies. In a single dose study, the plasma half-life (t$_{1}$2/) increased and the total body clearance (Cl$_{t}$) decreased with the dose (i.e., 0.017 to 0.75 gHb/kg as PEG-hemoglobin SB1) in both sexes. The volume of distribution at steady-state (Vd$_{ss}$ ) showed no difference with the dose. In contrast, the values of t$_{1}$2/, CL$_{t}$ and the area under the plasma concentration-time curve (AUC) after the multiple dose were significantly different from those of the single dose administration. The values of t$_{1}$2/ in the multiple administration were about two times higher-than that of the single dose. As a result, t$_{1}$2/ of hemoglobin after the administration of PEG-hemoglobin SB1 was about 15-30 h, indicating the PEG modification of the hemoglobin lead to a prolongation of plasma concentration of the protein. Therefore, these observations suggested that the PEG modification of hemoglobin is potentially applicable in the hemoglobin-based therapeutics.tics.

• Korean Journal of Chemical Engineering
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• v.35 no.11
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• pp.2207-2219
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• 2018

Activated carbon (AC) was synthesized from Phoenix dactylifera stones and then modified by $CoFe_2O_4$ magnetic nanocomposite for use as a Cr(VI) adsorbent. Both $AC/CoFe_2O_4$ composite and AC were fully characterized by FTIR, SEM, XRD, TEM, TGA, and VSM techniques. Based on the surface analyses, the addition of $CoFe_2O_4$ nanoparticles had a significant effect on the thermal stability and crystalline structure of AC. Factors affecting chromium removal efficiency like pH, dosage, contact time, temperature, and initial Cr(VI) concentration were investigated. The best pH was found 2 and 3 for Cr adsorption by AC and $AC/CoFe_2O_4$ composite, respectively. The presence of ion sulfate had a greater effect on the chromium sorption efficiency than nitrate and chlorine ions. The results illustrated that both adsorbents can be used up to seven times to adsorb chromium. The adsorption process was examined by three isothermal models, and Freundlich was chosen as the best one. The experimental data were well fitted by pseudo-second-order kinetic model. The half-life ($t_{1/2}$) of hexavalent chromium using AC and $AC/CoFe_2O_4$ magnetic composite was obtained as 5.18 min and 1.52 min, respectively. Cr(VI) adsorption by AC and $AC/CoFe_2O_4$ magnetic composite was spontaneous and exothermic. In general, our study showed that the composition of $CoFe_2O_4$ magnetic nanoparticles with AC can increase the adsorption capacity of AC from 36 mg/L to 70 mg/L.

• Imaging Science in Dentistry
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• v.53 no.3
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• pp.217-220
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• 2023

Purpose: This pilot study was conducted to evaluate half-value layer (HVL) measurements obtained using a semiconductor dosimeter for intraoral radiography. Materials and Methods: This study included 8 aluminum plates, 4 of which were low-purity (less than 99.9%) and 4 high-purity (greater than 99.9%). Intraoral radiography was performed using an intraoral X-ray unit in accordance with the dental protocol at the authors' affiliated hospital: tube voltage, 60 kVp and 70 kVp; tube current, 7 mA; and exposure time, 0.10 s. The accuracy of HVL measurements for intraoral radiography was assessed using a semiconductor dosimeter. A simple regression analysis was performed to compare the aluminum plate thickness and HVL in relation to the tube voltage (60 kVp and 70 kVp) and aluminum purity (low and high). Results: For the low-purity aluminum plates, the HVL at 60 kVp (Y) and 70 kVp (Y) was significantly correlated with the thickness of the aluminum plate (X), with Y=1.708+0.415X (r=0.999, P<0.05) and Y=1.980+0.484X (r=0.999, P<0.05), respectively. Similarly, for the high-purity aluminum plates, the HVL at 60 kVp (Y) and 70 kVp (Y) was significantly correlated with the plate thickness(X), with Y=1.696+0.454X (r=0.999, P<0.05) and Y=1.968+0.515X (r=0.998, P<0.05), respectively. Conclusion: This pilot study examined the relationship between aluminum plate thickness and HVL measurements using a semiconductor dosimeter for intraoral radiography. Semiconductor dosimeters may prove useful in HVL measurement for purposes such as quality assurance in dental X-ray imaging.