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The Preparation and Characterization of Bismuth Layered Ferroelectric Thin Films by Sol-Gel Process (II. Dielectric Properties of Ferroelectric $Sr_{0.7}/B_{2.3}(Ta_{1-x}Nb_x)_2O_9$ Thin Films Prepared by MOD Process) (솔 - 젤법을 이용한 Bismuth Layered Structure를 가진 강유진성 박막의 제조 및 특성평가에 관한 연구 (II. MOD법으로 제조한 강유전성 $Sr_{0.7}/B_{2.3}(Ta_{1-x}Nb_x)_2O_9$ 박막의 유전특성))

  • 최무용;송석표;정병직;김병호
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.12 no.1
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    • pp.62-68
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    • 1999
  • Ferroelectric $Sr_{0.7}/B_{2.3}(Ta_{1-x}Nb_x)_2O_9$(x=0, 0.1, 0.2, 0.3) thin films were deposited on $Pt/SiO_2/Si$ substrate by MOD(Metalorganic Decomposition) process. Metal carboxylate and metal alkoxide were used as precursors, and 2-methoxyethanol, xylene as solvents. After spin coating, thin films were pre-annealed at $400^{\circ}C$, followed by RTA(Rapid Thermal Annealing) and final annealing at $800^{\circ}C$ in oxygen atmosphere. These procedures were repeated three times to obtain thin films with the thickness of $2000{\AA}$. To enhance the nucleation and growth of layered-perovskite phase, thin films were rapid-thermally annealed above $720^{\circ}C$ in oxygen atmosphere. As RTA temperature increased, fluorite phase was transformed to layered-perovskite phase. And the change of Nb contents affected dielectric / electrical properties and microstructure. The ferroelectric characteristics of $Sr_{0.7}/B_{2.3}(Ta_{1-x}Nb_x)_2O_9$ thin film were Pr=8.67 $\mu{C}/cm^2$, Ec=62.4kV/cm and $I_{L}=1.4\times10^{-7}A/cm^2$ at the applied voltage of 5V, respectively.

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Monitoring for the Resistance of Botrytis cinerea Causing Gingseng Gray Mold to Procymidone and Its Multiple resistance with the Mixture of Carbendazim/Diethofencarb (인삼 잿빛곰팡이병균의 procymidone에 대한 감수성 변화와 carbendazim/diethofencarb 합제와의 다중 저항성)

  • Lee, Seon-Wook;Kim, Joo-Hyung;Min, Ji-Young;Bae, Young-Seok;Kim, Heung-Tae
    • Research in Plant Disease
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    • v.13 no.3
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    • pp.170-176
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    • 2007
  • Effects of fungicides on the mycelial growth of Botrytis cinerea isolated from ginseng leaves were investigated by an agar dilution method. By using a agar dilution method, it was investigated the effect of fungicides, procymidone, carbendazim and the mixture with both of carbendazim and diethofencarb, on the mycelial growth of Botrytis cinerea isolates, which were isolated from infected leaves of ginseng in 2005 and 2006. With MIC (minimum inhibiton concentration) of procymidone against B. cinerea, pathogens were divided into two groups. While one showed the low MIC between 0.8 and $4.0{\mu}g/ml$, the other showed higher MIC above $20{\mu}g/ml$. In terms of the inhibition ratio of mycelial growth at the indicated concentration of procymidone, isolates of B. cinerea were divided into three groups; the sensitive, the intermediate resistant, and the resistant group. Each group was differentiated by $EC_{50}$; the sensitive group showed below $2.0{\mu}g/ml$, the intermediate resistant group between 2.0 to $5.0{\mu}g/ml$, and resistant group above $5.0{\mu}g/ml$. Compared with the ratio of resistant isolates of B. cinerea in 2005, the ratio in 2006 increased from 19.3% to 27.5%. Furthermore, the average $EC_{50}$ value of them increased from $10.0{\mu}g/ml$ in 2005 to $237.3{\mu}g/ml$ in 2006. The ratio of isolates showing the multiple resistance between procymidone and carbendazim was 40.2%, whereas the ratio was 4.0% showing the multiple resistance in the mixture.

Genetic Monitoring of Plant Growth Promoting Rhizobacterium (PGPR), Bacillus subtilis AH18 using Multiplex PCR in Field Soil (Multiplex PCR을 이용한 생물방제균 Bacillus subtilis AH18의 토양내 Genetic Monitoring)

  • Woo, Sang-Min;Lim, Jong-Hui;Jeong, Hee-Young;Kim, Sang-Dal
    • Microbiology and Biotechnology Letters
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    • v.37 no.1
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    • pp.1-9
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    • 2009
  • The genetic monitoring method was developed for the rapid detection of the PGPR and biocontrol agent, B. subtilis AH18 in red-pepper field soil by multiplex PCR using sid, aec and cel gene primers. The monitoring of B. subtilis AH18 in the soil was carried by amplified a 2,3-dihydro-2,3-dihydroxy benzoate dehydrogenase [EC: 1. 3. 1. 28]gene (sid - 794 bp : EF408238) which is a key enzyme of siderophore synthesis, an auxin efflux carrier gene (aec - 1,052 bp : EF408239) and a cellulase gene (cel - 1,582 bp : EF070194). The natural un sterilized soil was inoculated with B. subtilis AH18 to determine the sensitivity ($1.8\times10^5$ cfu/g) of multiplex PCR for the rapid dectection and then the strain was monitored successfully in rhizosphere or non-rhizosphere soil of red-pepper cultural soil. At 3 weeks after the treatment, density of the strain was monitored more abundantly in rhizosphere soil.

Lactate Dehydrogenase and Monocarboxylate Transporters 1, 2, and 4 in Tissues of Micropterus salmoides (큰입우럭(Micropterus salmoides) 조직의 젖산탈수소효소 및 Monocarboxylate 수송체(MCT) 1, 2, 4)

  • Yum, Jung-Joo;Yeon, Jun-Hee
    • Journal of Life Science
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    • v.22 no.1
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    • pp.98-109
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    • 2012
  • The properties of lactate dehydrogenase (EC 1.1.1.27, LDH) and expression of monocarboxylate transporters (MCTs) 1, 2, and 4 were studied in tissues from Micropterus salmoides. Native-PAGE revealed that the LDH $A_4$ isozyme was predominantly located in skeletal muscle. The LDH $A_4$, $A_2B_2$, and $B_4$ isozymes were detected in heart, liver, eye, and brain tissues, while eye-specific $C_4$ isozyme was detected in eye tissue. In September, strong LDH $B_4$ isozyme activity was detected in heart tissue. High $A_4$ isozyme activity was noted in all other tissues except heart tissue. However, in November, strong $A_4$ isozyme activity was detected in heart tissue. The LDH/CS (Citrate synthase, EC 4.1.3.7) ratio in skeletal muscle and heart tissues indicated that anaerobic metabolism was high in those tissues. Native-PAGE after immunoprecipitation showed that eye-specific $C_4$ isozyme was more similar to the $A_4$ than the $B_4$ isozyme. The LDH $A_4$ isozyme was purified by affinity chromatography. The molecular weight of subunit A was 37,200. The LDH activity in tissues was consistently 11.05~28.32% due to inhibition by 10 mM pyruvate. The $K_m^{PYR}$ of LDH in eye tissue was very low. The optimum pH for LDH in tissues was pH 7.5~8.0. The LDH $A_4$ isozyme was detected in mitochondria of skeletal muscle, whereas the $B_4$ and $A_2B_2$ isozymes were detected in heart tissue mitochondria. Western blot analysis indicated that MCTs 1, 2, and 4 were located in the plasma membrane and mitochondria of skeletal muscle and heart tissues. The sizes of MCTs 1, 2, and 4 in skeletal muscle were 60, 54~38, and 63 kDa, while those in heart tissue were 57, 54~38, and 55.5 kDa, respectively. In conclusion, M. salmoides appears to use anaerobic metabolism predominantly when adapted to a hypoxic environment. In highly activated skeletal muscle and heart tissue, energy production is controlled by inward and outward flows of pyruvate and lactate through MCTs 1, 2, and 4 in the plasma membrane and mitochondria, with effective adjustment by LDH isozymes.

The Isolation of Bacillus sphaericus 366M-9 Producing New Cephalosporin-C Deacetylase (CAH) and its Enzymatic Characterization (신규 Cephalosporin-C Deacetylase(CAH) 생산 균주인 Bacillus sphaericus 366M-9의 선발 및 그 효소학적 특성)

  • 이승훈;권태종;이동희
    • Microbiology and Biotechnology Letters
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    • v.32 no.3
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    • pp.224-229
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    • 2004
  • Several microorganisms (esterase-producing group) were isolated by the solid selective media containing-naphtylacetate. Among them, strain 366M-9 having a high activity of cephalosporin-C deacetylase (CAH; EC 3.1.1.41) was selected. The strain 366M-9 was identified as Bacillus sphaericus on the basis of morphological, physiological, and biochemical characteristics. The production of CAH reached at maximum value after 32 hrs, when cultivated in the optimal medium containing dextrin 2.5%, peptone 2.5%, sodium chloride 0.5%, dipotassium phosphate 0.25%, ferrous sulfate 0.02%, and 7-ACA 0.1% at $30^{\circ}C$ with initial pH 6.0. The CAH was purified by 3 steps with ammonium sulfate precipitation, adsorption chromatography on hydroxyapatite column, and Sephadex G-200 gel chromatography. The final enzyme preparation was homogeneous as judged by the analysis of SDS-PAGE and HPLC. Optimum temperature and pH for CAH activity were $50{\circ}C$ and around 7.0, respectively. And the enzyme was stable at pH 6.0~8.0, up to $50^{\circ}C$. The Michaelis-Menten constants ($K_{m}$ ), $V_{max}$ were 0.87 mM and 1.22 unit/ml, respectively.

Purification and Characterization of Cyclodextrin Glycosyltransferase from Bacillus brevis CD162 (Bacillus brevis CD162 Cyclodextrin Glycosyltransferase의 정제 및 특성)

  • Kim, Myung-Hee;Lim, Young-Hee;Oh, Tae-Kwang;Sohn, Cheon-Bae
    • Applied Biological Chemistry
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    • v.40 no.6
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    • pp.465-471
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    • 1997
  • The cyclodextrin glycosyltransferase (CGTase, EC 3.2.1.19) from Bacillus brevis CD162 was purified by precipitating with ammonium sulfate, DEAE-Sepharose CL-6B column chromatography and Sephadex G-150 column chromatography. The molecular mass and pI of the purified enzyme were estimated to be 74,000 and 6.3 by SDS-PAGE and isoelectric focusing, respectively. The purified enzyme was clearly identified as the CGTase by zymogram after SDS-PAGE. The optimum pH and temperature for the enzyme activity were 8.0 and $55^{\circ}C$, respectively. The enzyme was stable at the range of pH $5.5{\sim}9.0$, and up to $50^{\circ}C$. The amino acid sequence from the $NH_2-terminal$ of the purified CGTase was Ser-Val-Thr-Asn-Lys-Val-Asn-Tyr-Ser-Lys-Asp-Val-Ile-Tyr-Gln. The yields of the products from starch as the substrate were 1.3% for ${\alpha}-$, 33.9% for ${\beta}-$, and 9.7% for ${\gamma}-cyclodextrin$.

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A Study on Exposure Indices for Diesel Engine Exhaust in Forklift Operating Areas (지게차 사용 사업장에서 디젤엔진배출물질 노출지표에 관한 연구)

  • Kim, Sangil;Park, Ji Young;Lee, Kyeongmin;Kim, Seung Won
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.26 no.1
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    • pp.38-47
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    • 2016
  • Objectives: The objective of this study was to determine the exposure levels of forklift operators to diesel engine exhaust(DEE) using black carbon(BC), elemental carbon(EC), and nitrogen dioxide($NO_2$) as indicators. Methods: A total of eight forklift operators in six collection companies were assessed over a period of two months from July to September 2015. BC was measured using a real-time monitor and respirable EC samples were analyzed using the NIOSH method 5040. $NO_2$ samples were collected using a passive badge-type sampler. Results: The geometric mean of BC, EC and $NO_2$ were $3.1-19.1{\mu}g/m^3$, $2.1-23.8{\mu}g/m^3$, and 12.5-166.6 ppb at all companies. When forklifts were operating both outside and inside, BC concentrations increased 2.0-5.6 times. The highest increase was observed when forklifts were operating indoors. The increase in BC concentrations varied by company(company A: 2.0 times, B: 3.2 times, C: 5.6 times, D: 2.1 times, E: 5.1 times, F: 2.6 times). The geometric mean of BC, EC, and $NO_2$ for the forklift operators was $9.6{\mu}g/m^3$, $7.9{\mu}g/m^3$, and 48.9 ppb, respectively. The geometric mean of BC, EC, and $NO_2$ for manufacturing workers was $9.3{\mu}g/m^3$, $0.9{\mu}g/m^3$, and 85.2 ppb, respectively. The mean BC and EC exposure levels for the forklift operators were slightly higher than those for manufacturing workers, but $NO_2$ levels for manufacturing workers were higher than those for the forklift operators(p>0.05). Multiple regression analysis revealed that diesel exhaust emissions standard, forklift weight and forklift manufacturer were the most influential factors in determining worker exposure. Conclusions: In the DEE work environment, workers who perform tasks within the workplace as well as inside forklifts as operators are likely to be exposed to a lack of ventilation. Further study of forklift operators' exposure to DEE indicators should be conducted to include a wider range of occupational and environmental situations, such as collection procedures, seasonal situations, types of fuel used, and number of forklifts.

Synthesis and Antiviral Activity of Novel 2′-Methyl and 4′-Phenyl Branched Carbocyclic Nucleosides (2′-메칠 및 4′-페닐 측쇄를 가진 새로운 카보사이클릭 뉴크레오사이드의 합성 및 항바이러스 약효검색)

  • 양선화;홍준희
    • YAKHAK HOEJI
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    • v.48 no.1
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    • pp.88-92
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    • 2004
  • In this study; a series of 2',4'-doubly branched carbocyclic nucleosides (8,9,10) were synthesized from simple acyclic ketone derivative as starting material. The installation of the 4'-quaternary carbon needed was carried out using a 〔3,3〕-sigmatropic rearrangement. In addition, the introduction of a methyl group in the 2'-position was accomplished by Grig-nard reaction. Bis-vinyl was successfully cyclized using a Grubbs' catalyst II. The natural bases (adenine, cytosine, uracil) were efficiently coupled with the use of a Pd(0) catalyst. Although all the synthesized compounds were assayed against several viruses, only cytosine analogue 9 showed weak antiviral viral activity (EC$_{50}$=45.4 $\mu$M) against CoxB3 virus.s.

2'-Spirocyclopropyl-carbocyclic Nucleoside as a Novel Scaffold for Potent Anti-HCV Agents

  • Li, Hua;Yoo, Jin-Cheol;Hong, Joon-Hee
    • Bulletin of the Korean Chemical Society
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    • v.32 no.4
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    • pp.1146-1152
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    • 2011
  • The discovery of 2'-spirocyclopropyl-ribocytidine (J. Med. Chem. 2010, 53, 8150-8160) as a potent inhibitor of RNA synthesis by NS5B ($IC_{50}=7.3{\mu}M$), the RNA polymerase encoded by hepatitis C Virus (HCV), has led to the synthesis and biological evaluation of several carbocyclic versions of 2'-spiropropyl-nucleosides. The cyclopentenol intermediate 7 was successfully constructed via ring-closing metathesis (RCM) from divinyl 6. Spirocyclopropanation of enone 8 was effected by using (2-chloroethyl)-dimethylsulfonium iodide and potassium tert-butoxide to form the desired intermediate 9. The synthesized nucleoside analogues 21-24 were assayed for their ability to inhibit HCV RNA replication in a subgenomic replicon Huh7 cell line. Among them, the cytosine nucleoside analogue 22 exhibited significant anti-HCV activity ($EC_{50}= 8.2{\mu}M$).

Processability and Mechanical Characteristics of Glass Fiber and Carbon Fiber Reinforced PA6 for Reinforcement Content

  • Lee, S.B.;Cho, H.S.;Lyu, M.-Y.
    • Elastomers and Composites
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    • v.50 no.3
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    • pp.184-188
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    • 2015
  • There is a need for light weight and high stiffness characteristics in the building structure as well as aircraft and cars. So fiber reinforced plastic with the addition of reinforcing agent such as glass fiber, carbon fiber, aramid fiber is utilized in this regard. In this study, mechanical strength, flow property and part shrinkage of glass fiber and carbon fiber reinforced PA6 were examined according to reinforcement content such as 10%, 20%, and 30%, and reinforcement type. The mechanical property was measured by a tensile test with specimen fabricated by injection molding and the flow property was measured by spiral test. In addition, we measured the part shrinkage of fiber reinforced PA6 that affects part quality. As glass fiber content increases, mechanical property increased by 75.4 to 182%, and flow property decreased by 18.9 to 39.5%. And part shrinkage decreased by 52.9 to 60.8% in the flow direction, and decreased by 48.2 to 58.1% in the perpendicular to the flow direction. As carbon fiber content increases, mechanical property increased by 180 to 276%, flow property decreased by 26.8 to 42.8%, and part shrinkage decreased by 65.0 to 71.8% and 69.5 to 72.7% in the flow direction and the direction perpendicular to the flow respectively.