• 대한한의학회지
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• 제31권4호
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• pp.9-19
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• 2010

Objective: To compare the contents and transfer rate of hazardous substances in crude, washing solution, crude after washing, decoction and remnant after boiling. Methods: The heavy metal contents of each step were measured by inductively coupled plasma mass spectrometer (ICP-MS) and mercury analyzer (SP-3DS). In order to analyze pesticides in each sample we used simultaneous multi-residue analysis of pesticides by GC/ECD, which was followed by GC/MSD analysis to confirm the identity of the detected pesticide in each sample. In addition, the contents of sulfur dioxide ($SO_2$) were performed by Monier-Williams distillation method. Results: 1. Contents (mg/kg) of heavy metals were not detected in decoctions of any tested herbal medicine prescriptions. 2. Transfer rates (%) of heavy metals from crude to remnant were as follows: Yijin-tang (As: 46.9, Cd: 50.0 and Pb: 100.0), Oryung-san (As: 80.0, Cd: 100.0 and Pb: 73.8), Hwangryunhaedok-tang (As: 88.9, Cd: 71.4 and Pb: 92.7), Bangpungtongseong-san (As: 100.0, Cd: 17.3 and Pb: 56.1), Oyaksungi-san (As: 47.4, Cd: 175.0 and Pb: 142.4). 3. Contents (mg/kg) of residual pesticides were not detected in any samples. 4. Transfer rate (%) of sulfur dioxide ($SO_2$) from crude to remnant in all samples were as follows: Yijin-tang (25.0), Oryung-san (166.7), Hwangryunhaedok-tang (50.0), Bangpungtongseong-san (181.8), Oyaksungi-san (50.0). Conclusion: Our results showed that the boiled herbal medicine prescriptions which we take are safe from the hazardous substances.

• 농약과학회지
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• 제12권3호
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• pp.229-235
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• 2008

시설재배 딸기에 사용하는 농약이 화분매개를 위해 투입된 꿀벌(Apis mellifera L.)에 미치는 영향을 조사하기 위해 꿀벌에 노출될 가능성이 있는 21종의 농약을 선정하여 꿀벌 급성독성시험과 엽상잔류독성시험을 실시하였다. 표준살포농도로 분무처리한 급성접촉독성시험에서는 24시간 후에 꿀벌치사율이 대조군과 유한 차이를 보인 농약은 dichlofluanid WP 등 6종이었고, 48시간 후에는 fenpropathrin EC 등 7종이었다. 급성 섭식독성시험에서는 fenpropathrin EC만이 꿀벌에 독성을 보여주었으며 milbemectin EC는 배량처리군에서 대조군과 비교하여 유의한 치사율 차이를 보여주었다. 또한 엽상잔류독성시험에서는 fenpropathrin EC만이 10일 이상 장기간 잔류독성을 보였다. 이상의 결과를 종합하여 21종 제품농약에 대한 살포 후 꿀벌안전방사기간을 제안하였다.

• Journal of Applied Biological Chemistry
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• 제63권1호
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• pp.51-60
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• 2020

본 연구는 azoxystrobin 농약을 가지와 상추에 처리한 후 세척 및 조리과정 중 농약의 잔류량 변화를 조사하기 위해 수행하였다. 가지는 흐르는 물 세척, 찜, 볶음으로 가공하였으며, 상추는 담금 물 세척, 흐르는 물 세척, 담금 후 흐르는 물 세척, 초음파세척, 데치기로 가공하였다. Azoxystrobin의 GC분석의 정량 한계는 0.01 mg/kg이었으며, 회수율은 84.7-109.5%이었다. Azoxystrobin을 살포하여 수확한 가지의 농약 잔류량은 0.204 mg/kg, 상추의 잔류량은 12.296 mg/kg이었다. 가지의 흐르는 물 세척, 세척 후 찌기, 세척 후 볶기의 잔류량은 0.059, 0.065, 0.05 mg/kg이었다. 상추의 담금 물 세척, 흐르는 물 세척, 담금 후 흐르는 물 세척, 초음파세척, 데치기의 azoxystrobin의 잔류량은 각각 3.027, 7.513, 3.937, 5.761, 3.241 mg/kg이었다. 가지와 상추의 azoxystrobin 농약의 가공계수 및 감소율을 산출한 결과는 다음과 같았다. 가지의 경우, 흐르는 물 세척의 가공계수 및 감소율은 0.29, 71.1%, 찜 가공한 가지는 0.32, 68.0%, 볶음 가공한 가지는 0.24, 75.7%이었다. 상추의 경우, 담금 물 세척한 상추의 가공계수 및 감소율은 0.25, 75.3%, 흐르는 물 세척은 0.61, 38.9%, 담금 후 흐르는 물 세척은 0.32, 68.0%, 초음파세척은 0.47, 53.1%, 데치기는 0.26, 73.6%이었다. 가지와 상추 중 잔류농약은 세척 및 조리가공을 통해서 잔류농약 감소에 효과가 있는 것을 확인할 수 있었으며, 세척 후 조리과정을 진행할 시, 대부분의 농약이 제거됨을 확인하였다. 따라서, 세척 및 가공 후 azoxystrobin 가공계수를 위해 평가에 기초자료로 제공할 수 있을 것이다.

• 공업화학
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• 제30권3호
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• pp.331-336
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• 2019

본 연구에서는 리튬이차전지의 초기 효율과 율속 특성의 향상을 위해 피치계 소프트 카본 음극재의 요구 물성 및 제조 공정변수에 대한 실험을 진행하였다. 피치는 석유계 잔사유를 사용하여 공정 온도를 변수로 합성하였다. 공정온도를 각각 360, 370, $410^{\circ}C$에서 3 h 진행하여, 86, 98, $152^{\circ}C$의 연화점을 갖는 피치를 제조하였다. 피치의 원소분석과 열적 특성을 EA 분석과 TGA 분석을 통해 고찰한 결과, 높은 연화점을 갖는 경우 낮은 H/C 및 발달된 열적안정성을 관찰할 수 있었다. 얻어진 피치를 $1,200^{\circ}C$에서 1 h 동안 탄화 열처리 공정을 진행하여 소프트 카본계 음극재를 제조하였다. XRD 분석을 통해 결정 구조를 고찰한 결과, 연화점이 높은 피치에서 제조된 소프트 카본은 상대적으로 고비점의 성분들로 구성되어 탄화 열처리공정 시 증발 성분의 감소 및 고리화에 참여하는 성분들의 증가로 인하여 결정성이 증가하였음을 고찰할 수 있었다. 결정성이 향상된 소프트 카본계 음극재에서 향상된 초기 효율과 율속 특성의 결과를 얻을 수 있었다. 향상된 초기 효율 및 율속 특성은 소프트 카본계 음극재의 발달된 결정 구조에서 기인하는 메커니즘에 대하여 논의하였다.

• Advances in nano research
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• 제16권2호
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• pp.127-140
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• 2024

Upon direct/indirect exposure to flame or heat, composite structures may burn or thermally buckle. This issue becomes more important in the natural fiber-based composite structures with higher flammability and lower mechanical properties. The main goal of the present study was to obtain an optimal eco-friendly composite system with low flammability and high thermal buckling resistance. The studied composite consisted of polypropylene (PP) and short abaca fiber (AF) with eggshell powder (ESP) and halloysite clay nanotubes (HNTs) additives. An optimal base composite, consisting of 30 wt.% AF and 70 wt.% PP, abbreviated as OAP, was initially introduced based on burning rate (BR) and the Young's modulus determined by horizontal burning test (HBT) and tensile test, respectively. The effects of adding ESP to the base composite were then investigated with the same experimental tests. The results indicated that though the BR significantly decreased with the increase of ESP content up to 6 wt.%, it had a very destructive influence on the stiffness of the composite. To compensate for the damaging effect of ESP, small amount of HNT was used. The performance of OAP composite with 6 wt.% ESP and 3 wt.% HNT (OAPEH) was explored by conducting HBT, cone calorimeter test (CCT) and tensile test. The experimental results indicated a 9~23 % reduction in almost all flammability parameters such as heat release rate (HRR), total heat released (THR), maximum average rate of heat emission (MARHE), total smoke released (TSR), total smoke production (TSP), and mass loss (ML) during combustion. Furthermore, the combination of 6 wt.% ESP and 3 wt.% HNT reduced the stiffness of OAP to an insignificant amount by maximum 3%. Moreover, the char residue analysis revealed the distinct differences in the formation of char between AF/PP and AF/PP/ESP/HNT composites. Afterward, dilatometry test was carried out to examine the coefficient of thermal expansion (CTE) of OAP and OAPEH samples. The obtained results showed that the CTE of OAPEH composite was about 18% less than that of OAP. Finally, a theoretical model was used based on first-order shear deformation theory (FSDT) to predict the critical bucking temperatures of the OAP and OAPEH composite plates. It was shown that in the absence of mechanical load, the critical buckling temperatures of OAPEH composite plates were higher than those of OAP composites, such that the difference between the buckling temperatures increased with the increase of thickness. On the contrary, the positive effect of CTE reduction on the buckling temperature decreased by raising the axial compressive mechanical load on the composite plates which can be assigned to the reduction of stiffness after the incorporation of ESP. The results of present study generally stated that a suitable combination of AF, PP, ESP, and HNT can result in a relatively optimal and environmentally friendly composite with proper flame and thermal buckling resistance with no significant decline in the stiffness.

• Journal of Photoscience
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• 제9권2호
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• pp.308-310
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• 2002

Bacteriorhodopsin (bR) and halorhodopsin (hR), which exist in the membrane of Halobacterium salinarum, are light-driven ion pumps. In spite of high similarity of primary and tertiary structures between bR and hR, these membrane proteins transport different ions, proton and chloride, in the opposite direction. From alignment of the amino acid sequences, Thr-89 of bR is homologous to Ser-l15 of hR from Halobacterium salinarum (shR). X-ray structure of shR has revealed that OH group of this residue directly interacts with CI$\^$-/ Thus, Ser-lI5 of shR is expected to play an important role in CI$\^$-/ binding and transport. In this study, we expressed wild type hR from Natronobacterium pharaonis (PhR) and Sl30A, which corresponds to Ser-l15 of shR, in E. coli in order to clarify binding affinity of chloride ion and photocycle reactions. From the titration with CI$\^$-/, affinity of Sl30A became quite lower than that of WT (WT 6 mM, Sl30A 89 mM). Furthermore, from the flash photolysis with pulse laser of λ$\_$max/ at 532 nm, the reaction rate of SI30A from 0 intermediate to hR ground state was found to become apparently slower than that of WT. The singular value decomposition (SVD) and global fitting analyses of the photocycles were performed to identify all photointermediates and determine the reaction rates.

• Transactions on Electrical and Electronic Materials
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• 제16권2호
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• pp.90-94
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• 2015

In this study, the characterizations of oxide contact hole etching are investigated with C₄F₈/O₂/Ar and CH₂F₂/C₄F₈/O₂/ Ar plasma. As the percent composition of C₄F₈ in a C₄F₈/O₂/Ar mixture increases, the amount of polymer deposited on the etched surface also increases because the C_xF_y polymer layer retards the reaction of oxygen atoms with PR. Adding CH₂F₂ into the C₄F₈/O₂/Ar plasma increases the etch rate of the oxide and the selectivity of oxide to PR. The profile of contact holes was close to 90°, and no visible residue was seen in the SEM image at a C₄F₈/(C₄F₈+O₂) ratio of 58%. The changes of chemical composition in the chamber were analyzed using optical emission spectroscopy, and the chemical reaction on the etched surface was investigated using X-ray photoelectron spectroscopy.

• 한국축산식품학회지
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• 제36권3호
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• pp.319-325
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• 2016

This study was conducted to determine the residual amount of veterinary drugs such as meloxicam, flunixin, and tulathromycin in animal products (beef, pork, horsemeat, and milk). Veterinary drugs have been widely used in the rearing of livestock to prevent and treat diseases. A total of 152 samples were purchased from markets located in major Korean cities (Seoul, Busan, Incheon, Daegu, Daejeon, Gwangju, Ulsan and Jeju), including Jeju. Veterinary drugs were analyzed by liquid chromatography-tandem mass spectrometry according to the Korean Food Standards Code. The resulting data, which are located within 70-120% of recovery range and less than 20% of relative standard deviations, are in compliance with the criteria of CODEX. A total of five veterinary drugs were detected in 152 samples, giving a detection rate of approximately 3.3%; and no food source violated the guideline values. Our result indicated that most of the veterinary drug residues in animal products were below the maximum residue limits specified in Korea.

• BMB Reports
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• 제40권4호
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• pp.453-458
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• 2007

Bacterial luciferase is a heterodimeric enzyme, which catalyzes the light emission reaction, utilizing reduced FMN (FMNH2), a long chain aliphatic aldehyde and $O_2$, to produce green-blue light. This enzyme can be readily classed as slow or fast decay based on their rate of luminescence decay in a single turnover. Mutation of Glu175 in $\alpha$ subunit to Gly converted slow decay Xenorhabdus Luminescence luciferase to fast decay one. The following studies revealed that changing the luciferase flexibility and lake of Glu-flavin interactions are responsible for the unusual kinetic properties of mutant enzyme. Optical and thermodynamics studies have caused a decrease in free energy and anisotropy of mutant enzyme. Moreover, the role of Glu175 in transition state of folding pathway by use of stopped-flow fluorescence technique has been studied which suggesting that Glu175 is not involved in transition state of folding and appears as surface residue of the nucleus or as a member of one of a few alternative folding nuclei. These results suggest that mutation of Glu175 to Gly extended the structure of Xenorhabdus Luminescence luciferase, locally.

• 한국미생물·생명공학회지
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• 제27권1호
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• pp.8-14
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• 1999

This study was developed to evaluate the growth inhibition effects of cell wall components of Enterococcus faecalis 2B4-1 obtained from feces of neonates against tumor cell lines. Polysaccharide fraction (PS) shown sensitive growth inhibition effect in the cell wall components was isolated and characterized. In growth inhibition effects, residue fractin of whole cell was shown sensitive level of percent survival about 30% when administrated at ehe concentration of 100${\mu}$g/ml, and that was more effective than that of supernatant fraction against the tumor cell lines, SNU-1, 3LL, FARROW and HEC-1-B. Sensitive growth inhibition effects against SNU-1, FARROW and HEC-1-B were performed by whole cell (WC) fraction from Ent. faecalis 2B4-1. Cytoplasm fractin (CP) of WC was shown non-inhibition effect, however, the other part of WC, precipitate of disrupted cell (PD), was sensitive against the tumor cell line mentioned above. Followed by separation to peptidoglycan fraction (PG) and polysaccharide fraction (PS) were all sensitive which the latter was shown more sensitive percent survival than the former. Composed sugars of polysaccharide fraction were determined to D-glucose, L-rhamnose and D-glucosamine, and the rate fo composition was calculated to about 1:1:1 by the data of elemental analysis, IR, TLC and HPLC.