• Title/Summary/Keyword: urea method

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An Investigation on Security Management Architecture of Home Gateway (홈 게이트웨이 보안 관리 방식에 관한 연구)

  • Kim, Hyun Cheol;An, Seong Jin;Jung, Jin Wook;Kim, Seung Hae;Ryu, Yoon Sik;Jun, Young Il
    • Convergence Security Journal
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    • v.3 no.3
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    • pp.67-74
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    • 2003
  • Home network technologies which interconnect various wire and wireless home appliances, access network technologies and service offer technologies are continuing growth. To provide secure services in the home, home network environment, access network environment, and various service and contents offer technologies are consist organically. Thesis of administration method of systematic and effective groove network is most urgent and important urea to offer safety and authoritativeness of home networking service in home network that strong certification and security function are required among these technologies. In this paper, we propose home gateway security management architecture and the way to use SNMPv3. Also, we propose structure and function of home network management system to support various home networking security scenarios.

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Hematological and blood chemical findings in hypophysectomized rats (뇌하수체 제거술이 수행된 랫트의 혈액학 및 혈액화학적 소견)

  • Kim, Nam Joong;Kim, Myung-Cheol
    • Korean Journal of Veterinary Research
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    • v.45 no.1
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    • pp.121-125
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    • 2005
  • The present study was carried out to produce the hematological and blood chemical findings after hypophysectomy in rats. Hypophysectomy was performed by the parapharyngeal method and the sham surgery was performed for the control group. Two weeks after the operation, the body weight of the hypophysectomized and control rats was measured daily for 5 days. We deleted the rats the weight gain of which is less than 5 g during 5 days from the hypophysectomy group. The successful operation rate was approximately 40%. In the hypophysectomized and control rats, their blood samples were collected from posterior vena cava after celiotomy under generally anesthesia with ether. Hematological parameters such as erythrocyte count, leukocyte count, hemoglobin concentration, hematocrit level, and platelet count were determined by Animal Blood Counter. The erythrocyte count, hemoglobin concentration, and hematocrit level were lower significantly (p<0.01), and the leukocyte count was lower significantly (p<0.05) in hypophysectomy group compared with control group. But the plate count did not show significant difference (p>0.05) between hypophysectomy group and control group. Also, blood chemical parameters such as glucose, blood urea nitrogen (BUN), aspartate animotransferase, albumin, total protein, cholesterol, calcium, and magnesium in serum were determined. Except BUN concentration, all parameters were not affected by hypophysectomy. But the BUN concentration was higher significantly (p<0.01) in hypophysectomy group compared with control group.

Preparation of Diphtheria Toxin A Chain from Escherichia coli

  • Lee, Jong-Soo;Yoon, Kyoung-Bum;Park, Jong-Won;Choi, Suk-Jung
    • BMB Reports
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    • v.30 no.2
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    • pp.144-149
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    • 1997
  • An expression vector was constructed containing the gene encoding diphtheria toxin A (DTA) which was placed after a T7 promoter. Cytoplasmic expression of the DTA gene resulted in the formation of an insoluble inclusion body. The inclusion body was collected after the complete lysis of the cell, and subsequent washing with 0.1% Triton X-100 released 16~30% of DTA protein from the inclusion body along with other contaminating proteins. The released DTA protein was purified by dialysis. The remaining pellet was dissolved in 8 M urea containing 5% ${\beta}-mercaptoethanol$, and the denatured DTA was renatured by the dilution-dialysis method. The total yield was 35%, and about 5 mg DTA was obtained from 1 L culture. The DTA protein has a free sulfhydryl group exposed to the protein surface, and was shown to have a tendency to dimerize through disulfide formation in the absence of ${\beta}-mercaptoethanol$. The utility of the sulfhydryl group was tested for the construction of recombinant toxins.

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Separate Expression and in vitro Activation of Recombinant Helicobacter pylori Urease Structural Subunits

  • Lee, Kwang-Kook;Son, Joo-Sun;Chang, Yung-Jin;Kim, Soo-Un;Kim, Kyung-Hyun
    • Journal of Microbiology and Biotechnology
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    • v.8 no.6
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    • pp.700-704
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    • 1998
  • Each of the recombinant structural genes of Helicobacter pylori urease, ureA and ureB, was cloned and overexpressed as inclusion bodies. Solubilization and renaturation of the inclusion bodies were carried out, to accelerate the pairing of sulfhydryl groups and the incorporation of nickel ions, which would lead to the native structure with high enzyme activity. Rates of urea hydrolysis were monitored as an indication of in vitro activation of renatured ureases. The activation of the apoprotein using 1 mM nickel ion, 100 mM sodium bicarbonate and a 10:1 ratio of reducing power resulted in a weak urease activity (about 11% of the native urease activity encoded by pTZ 19R/ure-l). When a sparse matrix screen method originally discovered for the crystallization of proteins was used, the activity increased higher than that obtained using glutathione. The effect of polyethylene glycol (PEG) on the activity was noticeable, giving two-fold increase in the specific activity (about 11 U/mg of protein corresponding to 22% of the native urease activity encoded by pTZ19R/ure-1).

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Estimation of In vitro Digestibility of Barley Straw by Using a Homogenized Rumen Fluid and Artificial Saliva Mixed with Nitrogen and Energy Sources

  • Chaudhry, Abdul S.
    • Asian-Australasian Journal of Animal Sciences
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    • v.11 no.1
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    • pp.13-16
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    • 1998
  • A $2{\times}2{\times}4$ factorial study was conducted to examine the possibility of improving estimates of in vitro digestibility, using untreated (UBS) and ammonia-treated (ABS) barley straw, through homogenization of rumen fluid (RF) and by additions of urea (U) and casein (C) as N sources and Xylose + Glucose (XG) as energy sources into artificial saliva. Digestibiltiy of ABS was significantly greater than that of UBS (p < 0.001). There was a significant decrease in digestibility when additions (U, UC, UCXG) were compared with the control (p < 0.001). A 2-way interaction between RF and straw type was significant (p < 0.05) for dry matter digestibility (DMD). Homogenization of RF increased DMD of ABS (p < 0.05) whereas it decreased DMD of UBS (p > 0.05). The study showed that addition of N alone or in combination with energy sources was not better than control, rather the reverse, digestion was inhibited by a combination of U and casein (UC). It was concluded that sufficient N and branched chain fatty acids were supplied in the inoculum from sheep fed high protein grass cubes to support the growth of cellulolytic microbes during in vitro incubation. Further studies are, however, required to explore the potential of homogenization in improving the in vitro method to estimate digestibility of cereal straws.

Characterization of $\beta$-1,4-D-arabinogalactanase from Alkalophilic Bacillus sp. HJ-12 (호알칼리성 Bacillus sp. HJ-12 유래 $\beta$-1,4-D-arabinogalactanase의 특성)

  • 신해헌;변유량
    • Microbiology and Biotechnology Letters
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    • v.23 no.6
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    • pp.710-716
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    • 1995
  • $\beta $-1, 4-D-arabinogalactanase isolated from alkalophilic Bacillus sp. HJ-12, approximate Mw 42 kDa, was generally stable in the range of pH 6-10 and below 50$\circ$C and its highest activity was observed at 60$\circ$C with pH 7-9. The isolated $\beta $-1, 4-D-arabinogalactanase specifically hydrolyzed $\beta $-1, 4-galactosyl linkage that is the major structure of soybean arabinogalactan (SAG) but not $\beta $-1, 3-galactosyl linkage of the other polysaccharides. K. was estimated as 0.67 mg/ml by the method of Hanes-Woolf plot. No metals and chemical reagents inhibited the enzyme activity but urea did. The active site of this enzyme assumed to be tryptophan residue. The hydrolysis products from SAG, assayed by gel chromatography, TLC and HPLC, were predominantly galactotetraose (Gal$_{4}$) and triose (Gal$_{3}$) with a small portion. $\beta $-1, 4-D-arabinogalactanase hydrolyzed ONPG as well as SAG, and the degree of hydrolysis of SAG was 15% which is lower than that by the other $\beta $-1, 4-galactanases from different sources. SAG treated with this enzyme resulted in the reduction of specific viscosity up to 70%.

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Studies on the Presence of all $cis-{\Delta}^{5,11,14}-C_{20:3}$ Fatty Acid in the Seed Oils of Ginkgo (은행종실유의 all $cis-{\Delta}^{5,11,14}-C_{20:3}$ 지방산 존재에 관한 연구)

  • Kim, Seong-Jin;Lee, Kyeng-Hee;Kim, Yeon-Sim;Joh, Yong-Goe
    • Journal of the Korean Applied Science and Technology
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    • v.10 no.1
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    • pp.57-65
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    • 1993
  • The fatty acid, all $cis-{\Delta}^{5,11,14}-C_{20:3}$, in the Gingko nuts oils, was isolated and, purified by urea-adduct method, silver ion silica gel chromatography and HPLC equipped with reversed phase ${\mu}-Bondapak$ $C_{18}$ column. Its structural elucidation was conducted by IR and $^1H$-, $^{13}C$-NMR technique. The fatty acid composition of seed oils mainly consists of linoleic acid(37.73%), vaccenic acid(18.30%), oleic acid(15.18%), palmitic acid(3.37%), palmitoleic acid(3.37%) and ${\Delta}^5$ NMDB fatty acids(8.50%) in which all $cis-{\Delta}^{5,11,14}-C_{20:2}$ predominates.

Preparation and Characteristics of Ceramic Composite Powders Coated with $Al_2O_3$ : (II) Composite Powders of $Al_2O_3$-$TiO_2$ ($Al_2O_3$ 로 피복시킨 세라믹 복합분체의 제조 및 특성 : (II) $Al_2O_3$-$TiO_2$ 복합분체)

  • 현상훈;정형구
    • Journal of the Korean Ceramic Society
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    • v.28 no.4
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    • pp.338-346
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    • 1991
  • The alumina-titania composite powders coated with Al2O3 were prepared by the method of hydrolysis-deposition of mixed aluminium salt solution of Al2(SO)4-Al(NO3)3-Urea. The effects of coating-process parameters on the characteristics of coated composite powders were also investigated. As the content of TiO2 dispersed in deionized water increased, the coated composite powders were found to be more uniform in size and unagglomerated. When TiO2 powders were coated for 30 min, the optimum TiO2 content in the coating process was 400 mg/ι. The size of TiO2 particle was increased approximately from 0.7${\mu}{\textrm}{m}$ to 1.0${\mu}{\textrm}{m}$ through coating of Al2O3. The IEP of coated composite powders was pH=8.3 identical to the value of aluminium hydroxides and the zeta-potential showed nearly similar values each other. When heat treating coated composite powders at 130$0^{\circ}C$, only two phases of TiO2(rutile) and Al2TiO5 were observed. These results showed that the suface of TiO2 could be uniformly coated with the aluminium hydroxide.

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Preparation of Hydrated Basic Aluminum Salts by Homogeneous Precipitation Method and Their Thermal Decomposition (균일침전법에 의한 수화 염기성 알루미늄염의 합성 및 열분해)

  • 박홍채;김주석;이승호;오기동
    • Journal of the Korean Ceramic Society
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    • v.26 no.1
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    • pp.132-138
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    • 1989
  • High purity(99.99%) spherical particles of hydrated Basic Aluminum Salts(BAS) were prepared by a homogeneous precipitation process utilizing the urea decomposition reaction and characterized by XRD, SEM, TG-DTA, IR and PSA methods. Amorphous hydrated BAS was precipitated in the range of pH 4~6. The molar ratio [Al3+]/[SO42-] for the precipitate particles was about 3.7. With increasing the concentration of aluminum sulfate the precipitation of the hydrated BAS occurred slowly and the precipitate particles with a narrow size distribution were fine(1-2${\mu}{\textrm}{m}$ in diameter). At temperatures in the range 400$^{\circ}$to 95$0^{\circ}C$, desulfurization and dehydroxylization resulted in weight loss with 22%. When the precipitate particles were thermally treated, the crystlline ${\gamma}$-Al2O3 was identifited by XRD at 50$0^{\circ}C$ and ${\gamma}$-Al2O3 particles were transformed into $\alpha$-Al2O3 at 100$0^{\circ}C$. A vermicular network was produced by calcining at 125$0^{\circ}C$ for 30min.

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Protected (bypass) Protein and Feed Value of Hazelnut Kernel Oil Meal

  • Saricicek, B.Z.
    • Asian-Australasian Journal of Animal Sciences
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    • v.13 no.3
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    • pp.317-322
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    • 2000
  • In situ and in vivo digestion trials were conducted to determine the degradation of dry matter (DM), crude protein (CP) and effective protein degtadability (EPD), and digestibility of nutrients of Hazelnut kernel oil meal (HKOM), and effects of HKOM on nitrogen (N) balance. In the in situ study, nylon bag were suspended in the rumen of 3 Karayaka rams to estimate protected protein. Protein sources were analyzed for pepsin soluble protein (PSP) using a Pepsin Digestion Method. In the digestion trials, 4 Karayaka rams (36 mo.) were used in a $4{\times}4$ Latin square to evaluate the digestibility of nutrients and N retention to measure effects of diets containing HKOM, soybean meal (SBM) corn gluten meal (CGM) and urea (U). The degradability of DM and CP, and PSP content of HKOM were lower (p>0.05) than that of SBM, but higher (p<0.001) than that of CGM. EPD of HKOM was higher (p<0.01) than that of SBM or CGM. The apparent digestion coefficients of organic matter and CP for HKOM were lower than for SBM, but higher than for CGM. N retention of HKOM was higher than that of SBM and lower than that of CGM (p>0.05). In conclusion, these data may indicate that the HKOM is a high digestible feed source with a value between SBM and CGM.