• Title/Summary/Keyword: Value

Search Result 80,764, Processing Time 0.102 seconds

Molecular Typing of Staphylococcus aureus Strains from Domestic Animals and Humans by REP-PCR Analysis (REP-PCR을 이용한 국내 사람과 동물유래 Staphylococcus aureus 분리주의 Molecular Typing)

  • Woo Yong-Ku;Kim Shin
    • Korean Journal of Microbiology
    • /
    • v.41 no.1
    • /
    • pp.60-66
    • /
    • 2005
  • To select the rapid and efficient molecular subtyping method for epidemiologic monitoring of Staphylococcus aureus (S. aureus) strains at clinical laboratory levels, a total 116 of S. aureus and MRSA (methicillin-resistant S. aureus) strains from diverse animal species [Korean cattle, goat, pig, dog, chicken, mouse] and also humans were analyzed. To evaluate the discriminatory ability (DA) of individual PCR methods, random amplified polymorphic of DNA [RAPD; 4M & RA primer], repetitive extragenic palindromic sequences PCR (REP-PCR), and enterobacterial repetitive intergenic consensus sequences PCR (ERIC-PCR) methods were conducted and then compared on their Simpson's index of diversity (SID) values based on the dendrogram patterns, which was produced by software program (BiolD2+ & GelCompar II). In first, RAPD using the 4M primer (SID 0.915) was expressed more higher SID value than that of RA primer (SID 0.874). 4M primer was expressed more powerful DA than RA. Both REP-PCR (SID 0.930) and ERIC-PCR (SID 0.929) methods showed much more higher DA than that of RAPD. According to the present results, both REP-PCR and ERIC-PCR among the tested analysis methods were found as the most reliable and discriminative molecular subtyping method, because they expressed the highest DA for the present S. aureus and MRSA strains.

Characterization of Endoglucanase (F-I-III) Purified from Trichoderma sp. C-4 (새로운 섬유소분해 균주 Trichoderma sp. C-4에서 분리한 Endoglucanase (F-I-III)에 대한 연구)

  • Sul Ok Ju;Chung Dae Kyun;Han In Seob;Jeong Choon Soo
    • Korean Journal of Microbiology
    • /
    • v.41 no.1
    • /
    • pp.81-86
    • /
    • 2005
  • One of the endoglucanases, F-I-III, was purified from the culture filtrate of T. sp. C-4 through procedures including chromatography on Sephacryl S-200, DEAE-Sepharose A-50, and Chromatofocusing on Mono-P (FPLC). The molecular weight of the enzyme was determined to be about 56,000 Da by SDS-PAGE, and pI of 4.9 by analytical isoelectric focusing. F-I-III showed the highest enzyme activity at $55^{\circ}C$, and the pH optimum of the enzyme was 5.0. There was no loss of activity when the enzyme was incubated at $50^{\circ}C$ for 24 hours. The specific activity of the enzyme F-I-III toward the CMC was 315.4 U/mg. The Km value for $PNPG_2$ of F-I-III was 2.69 mM. N-terminal sequence of F-I-III was analyzed to be QPGTSTPEVHPKKLTTYK. It showed $95\%$ of homology to that of EGI from T. reesei. The presence of some metal ions (1 mM) had only a little effect on CMCase activity. The treatment of the reducing agents resulted in the increase of endoglucanase activity.

The Detection and a Quantitative Evaluation of Viable but Non-Culturable Soil Bacteria Using a Modified Direct Viable Count Method (변형된 DVC법을 이용한 난배양성 토양세균의 검출 및 정량적 평가)

  • 황경숙;양희찬;염곡효
    • Korean Journal of Microbiology
    • /
    • v.39 no.3
    • /
    • pp.181-186
    • /
    • 2003
  • This study was performed to analyze quantitatively the number of living bacteria in forest soil samples collected from Mt. Keryong using improved direct viable count (DVC) and plate count (PC) methods. The number of living bacteria by DVC comprised 18~44% of the total direct count (TDC), whereas the number of living bacteria by PC was less than 1% of TDC. These results showed that viable but non-culturable (VBNC) bacteria existed in the soil with high percentages. Besides, DVC was proved to make it possible to make a quantitative detection of the VBNC bacteria. On the other hand, upon measuring the value from the conventional nutrient broth (NB) and $10^{-2}$ folded diluted nutrient broth (DNB), the values from the DNB showed 5 to 10 times higher than those from the conventional NB medium. These results indicate that oligotrophic bacterial groups, which could multiply in the low nutrient broth, abundantly exist in the soil ecosystem. It would also be possible to apply this kind of method to other substrate to make a quantitative detection of soil bacterial groups.

Distributions and heterotrophic actibities of bacteria in Lake Paro (파로호 수중생태계에서의 미생물 분포 및 활성도)

  • 안태석;이동훈
    • Korean Journal of Microbiology
    • /
    • v.26 no.3
    • /
    • pp.230-236
    • /
    • 1988
  • The distributions of bacterial numbers and activities were studied bimonthly in 1987, at 3 sites in Lade Paro for elucidating the changes by disturbance of aquatic ecosystem. The total bacterial number was $0.3\times 10^{5}-13.1\times ^{5}$ cells/ml. The geterotrophic bacterial number had the variance from $1.9\times 10^{3}$ CFUs/ml to $3.1\times 10^{4}$CFUs/ml and the variation trend was similar to that of the total bacterial number. The proportions of alpha-glucosidase or beta-glucosidase releasing bacteria showed temporal changes rather than spatial changes. The proportions of phosphatase releasing bacteria had the maximum values, 22.7-83.0%, in July. The electron transpory system activity revealed the variation from $480{\mu}gO_{2}$/l/day to $1696{\mu}gO_{2}$/l/day and hagher values at upper stream and in summer. The degradation fraction by phosphatase was 0.4-9.1%/h and increased with temperature. The maximum value of heterotrophic activity was 8.2%/h in summer. Eventhough the distributions of total bacteria and heterotrophic bacteria were affected by the water disturbance but microbial activities and proportions of the specific enzume releasing bacteria were not affected.

  • PDF

Additive Effects on Magnetic Properties in High Permeability Mn Zn Ferrite (고투자율 Mn-Zn 페라이트의 첨가물 효과에 따른 자기적 특성연)

  • Jeong, Gap-Gyo;Choe, Seung-Cheol
    • Korean Journal of Materials Research
    • /
    • v.3 no.5
    • /
    • pp.497-504
    • /
    • 1993
  • Effects of $Ta_2O_5,ZrO_2$ and $SiO_2$ addition on magnetic properties of 0.02wt%$Bi_2O_3$ and 0 . 0 5 wt%$CaCO_3$ doped Mn-Zn ferrites(58.5mol% $Fe_2O_3$, 25.5 mol% ZnO) were investigated. E:lectrlcal resistivity and magnetic properties such as the initial permeability($\mu_i$), loss factor(tan$\delta$), coercive force Hc(m0c) were measured. With lncreasing $Ta_2O_5$ and $ZrO_2$ addition, the following effects were observed: I ) Decreasing of the average grain size; 2) lncreasing of the electrical resistivity and initial permeability; 3) Ilecreasmg of loss factor values. (very low loss esprcially at high frequency region) ; 4 ) Fine and uniform microsrructures were obtamed at O.lwt% nddecl samples. In case of $SiO_2$ addition, anomalous grain growth and degradation of magnetic properties were observed. The obtained maximum initial permeability value was 6260 at IOkHz. $25^{\circ}C$ from 0.02wt%$Bi_2O_3$. 0.05wt%$CaCO_3$, 0.lwt%$Ta_2O_5$ added sample, the corresponded relative loss factor (tan$\delta /\mu_i$)for the sample was $4.2 \times 10^{-6}$.

  • PDF

The Solubility of Ozone in Deionized Water and its Cleaning Efficiency (초순수내에서의 오존의 용해도와 세정효과)

  • Han, Jeoung-Hoon;Park, Jin-Goo;Kwak, Young-Shin
    • Korean Journal of Materials Research
    • /
    • v.8 no.6
    • /
    • pp.532-537
    • /
    • 1998
  • The purpose of this study was to investigate the behavior of ozone in DI water and the reaction with wafers during the semiconductor wet cleaning process. The solubility of ozone in DI water was not only dependent on the temperature but also directly proportional to the input concentration of ozone. The lower the initial ozone concentration and the temperature, the longer the half-life time of ozone. The reaction order of ozone in DI water was calculated to be around 1.5. The redox potential reached a saturation value in 5min and slightly increased as the input ozone concentrations increased. The completely hydrophilic surface was created in Imin when HF etched silicon wafer was cleaned in ozonized DI water containing higher ozone concentrations than 2ppm. Spectroscopic ellipsometry measurements showed that the chemical oxide formed by ozonized DI water was measured to be thicker than that by piranha solution. The wafers contaminated with a non-ionic surfactant were more effectively cleaned in ozonized DI water than in piranha and ozonized piranha solutions.

  • PDF

Characteristic of Electrical Conductivity in the $\textrm{CuO}-\textrm{Bi}_{2}\textrm{O}_3-\textrm{V}_2\textrm{O}_5$ Glass System with Various Compositions ($\textrm{CuO}-\textrm{Bi}_{2}\textrm{O}_3-\textrm{V}_2\textrm{O}_5$계 글라스에서 조성 변화에 따른 전기 전도도의 특성)

  • Park, S.S.;Jeong, D.J.;Lee, H.;Park, C.Y.;Min, S.K.;Park, H.C.
    • Korean Journal of Materials Research
    • /
    • v.8 no.12
    • /
    • pp.1110-1114
    • /
    • 1998
  • The crystallization behaviors and electrical conductivities of the glasses heat-treated at various times and temperatures in the CuO-Bi$_2$O$_3$-V$_2$O$_{5}$ glass system were investigated. Among glass samples with various compositions, the highest conductivity obtained in the 31CuO-14Bi$_2$O$_3$-55V$_2$O$_{5}$ (mol%) glass sample. The 31CuO-14Bi$_2$O$_3$-55V$_2$O$_{5}$ (mol%) glass sample crystallized by heat treatment at 358$^{\circ}C$ for 8h had 2.67$\times$10$^{-2}$ $\Omega$$^{-1}$ $cm^{-1}$ /, which was much high value as a solid electrolyte. Compared to the glass sample, the heat- treated glass sample was increased in conductivity by an order of 10$^3$-10$^4$due to the formation and growth of BiVO$_4$ and CuVO$_3$crystals.

  • PDF

Effect of Fast Charging Mode on the Degradation of Lithium-Ion Battery: Constant Current vs. Constant Power (정전류/정출력 고속충전 방식에 따른 리튬이온전지의 열화 비교 연구)

  • Park, Sun Ho;Oh, Euntaek;Park, Siyoung;Lim, Jihun;Choi, Jin Hyeok;Lee, Yong Min
    • KEPCO Journal on Electric Power and Energy
    • /
    • v.6 no.2
    • /
    • pp.173-179
    • /
    • 2020
  • Electric vehicles (EVs) using lithium secondary batteries (LIBs) with excellent power and long-term cycle performance are gaining interest as the successors of internal combustion engine (ICE) vehicles. However, there are few systematic researches for fast charging to satisfy customers' needs. In this study, we compare the degradation of LIB where its composition is LiNi0.5Co0.2Mn0.3/Graphite with the constant current and constant power-charging method. The charging speed was set to 1C, 2C, 3C and 4C in the constant current mode and the value of constant power was calculated based on the energy at each charging speed. Therefore, by analyzing the battery degradation based on the same charging energy but different charging method; CP charging method can slow down the battery degradation at a high rate of 3C through the voltage curve, capacity retention and DC-IR. However, when the charging rate was increased by 4C or more, the deviation between the LIBs dominated the degradation than the charging method.

The Environmental Impacts of Seasonal Variation on Characteristics of Geochemical Parameters in Lake Shihwa, Korea (시화호의 계절변화에 따른 지화학적 환경요인 특성 연구)

  • Kim Tae-Ha;Park Yong-Chul;Lee Hyo-Jin;Kim Dong-Hwa;Park Jun-Kun;Kim Sung-Jun;Lee Mi-Yeon
    • Journal of Environmental Science International
    • /
    • v.13 no.12
    • /
    • pp.1089-1102
    • /
    • 2004
  • Seasonal variation of biogeochemical characteristics was determined in Lake Shihwa from October 2002 to August 2003. When the lake was artificially constructed for the freshwater reservoir in 1988, the development of the strong haline density stratification resulted in two-layered system in water column and hypoxic/anoxic environment prevailed in the bottom layer due to oxidation of accumulated organic matters in the lake. Recently, seawater flux to the lake through the sluice has been increased to improve water quality in the lake since 2000, but seasonal stratification and hypoxic bottom layer of the lake still developed in the summer due to the nature of artificially enclosed lake system. As the lake is still receiving tremendous amount of organic matters and other pollutants from neighboring streams during the rainy summer season, limited seawater flux sluicing into the lake may not be enough for the physical and biogeochemical mass balance especially in the summer. The excess of accumulated organic matters in the bottom layer apparently exhausted dissolved oxygen and affected biogeochemical distributions and processes of organic and inorganic compounds in the stratified two-layered environment in the summer. During the summer, ammonia and dissolved organic carbon remarkably increased in the bottom layer due to the hypoxic/anoxic condition in the bottom layer. Phosphate also increased as the result of benthic flux from the bottom sediment. Meanwhile, dissolved organic carbon showed the highest value at the upstream area and decreased along the salinity gradient in the lake. In addition to the sources from the upstream, autochthonous origin of particulate organic carbon from algal bloom in the lake might be more important for sustaining aggravated water quality and development of deteriorated bottom environment in the summer. The removal of trace metals could be attributed to scavenging by strong insoluble metal-sulfide compounds in the hypoxic/anoxic bottom layer in the summer.

A Hashing Scheme using Round Robin in a Wireless Internet Proxy Server Cluster System (무선 인터넷 프록시 서버 클러스터 시스템에서 라운드 로빈을 이용한 해싱 기법)

  • Kwak, Huk-Eun;Chung, Kyu-Sik
    • The KIPS Transactions:PartA
    • /
    • v.13A no.7 s.104
    • /
    • pp.615-622
    • /
    • 2006
  • Caching in a Wireless Internet Proxy Server Cluster Environment has an effect that minimizes the time on the request and response of Internet traffic and Web user As a way to increase the hit ratio of cache, we can use a hash function to make the same request URLs to be assigned to the same cache server. The disadvantage of the hashing scheme is that client requests cannot be well-distributed to all cache servers so that the performance of the whole system can depend on only a few busy servers. In this paper, we propose an improved load balancing scheme using hashing and Round Robin scheme that distributes client requests evenly to cache servers. In the existing hashing scheme, if a hashing value for a request URL is calculated, the server number is statically fixed at compile time while in the proposed scheme it is dynamically fixed at run time using round robin method. We implemented the proposed scheme in a Wireless Internet Proxy Server Cluster Environment and performed experiments using 16 PCs. Experimental results show the even distribution of client requests and the 52% to 112% performance improvement compared to the existing hashing method.