• 동력기계공학회지
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• 제10권3호
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• pp.58-66
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• 2006

The effect of bath composition, plating condition and plating rate on the magnetic properties of electroless Ni-Cu-P deposits were investigated. With increasing $CuSO_4$ concentration in the bath, plating rate increased, while the Br value of deposits decreased Sharply. Plating rate increased up to 34% with the addition of 200ppm of NaF and 0.8ppm of Thiourea to the bath. Plating reaction had been ceased by the increase of pH above 11.3, bath temperature higher than $90^{\circ}C$ and under $70^{\circ}C$. The Br value of deposit was uniform with various concentration of complexing agent (Sodium citrate, Ethylenediamine) in the bath. The Br value of deposit was almost equal to that found by the addition of stabilizer(Thiourea) and accelerator(NaF). The Br value of deposit was uniform in plating time(120 min) and heat treatment temperature(below $200^{\circ}C$), and were confirmed to have adequate bath stability for practical use.

• Clinical and Experimental Pediatrics
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• 제48권6호
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• pp.675-677
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• 2005

가성혈소판감소증은 항응고제인 ethylenediaminetetraacetic acid (EDTA)를 사용 시 주로 발생한다. 이 때 관찰되는 혈소판 응고는 헤파린이나 구연산나트륨 같은 항응고제를 EDTA 대신 사용하면 일어나지 않기도 하여 가성혈소판감소증과 진성혈소판 감소증을 감별할 수 있다. 저자들은 이러한 감별을 위하여 6세된 EDTA 의존성 가성혈소판감소증 남아에서 아미노글리코사이드 계열의 약물인 가나마이신을 채혈 전에 EDTA 용기에 미리 넣거나, EDTA 용기에 이미 채혈된 혈액에 첨가한 후 각각 혈소판수와 혈소판 응고 양상을 조사하여 보았다. 그 결과 가나마이신 채혈 전 혹은 후에 처리한 경우 모두 혈소판응고 없이 정상적인 혈소판수를 나타내어 소아에서도 임상적으로 쉽게 검사 할 수 있는 방법으로 생각되어 보고하는 바이다.

• Mycobiology
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• 제41권4호
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• pp.214-220
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• 2013

This study was conducted in order to perform efficient extraction of lignocellulolytic enzymes amylase (EC 3.2.1.1), cellulase (EC 3.2.1.4), laccase (EC 1.10.3.2), and xylanase (EC 3.2.1.8) from spent mushroom compost (SMC) of Pleurotus ostreatus, P. eryngii, and P. cornucopiae. Optimal enzyme recovery was achieved when SMCs were extracted with 50 mM sodium citrate (pH 4.5) buffer at $4^{\circ}C$ for 2 hr. Amylase, cellulase, and xylanase activities showed high values in extracts from P. ostreatus SMC, with 2.97 U/g, 1.67 U/g, and 91.56 U/g, respectively, whereas laccase activity and filter paper degradation ability were highest in extracts from P. eryngii SMC, with values of 9.01 U/g and 0.21 U/g, respectively. Enzymatic activities varied according to the SMCs released from different mushroom farms. The synthetic dyes remazol brilliant blue R and Congo red were decolorized completely by the SMC extract of P. eryngii within 120 min, and the decolorization ability of the extract was comparable to that of 0.3 U of commercial laccase. In addition, laccase activity of the SMC extract from P. eryngii was compared to that of commercial enzymes or its industrial application in decolorization.

• 한국식품저장유통학회지
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• 제10권4호
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• pp.554-559
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• 2003

동치미로부터 분리된 Latobacillus sp. FF-3의 Bacteriocin 생산에 대한 최적 배양조건과 배양 특성을 조사하였다. Bacteriocin 생산을 위한 최적 생산조건은 MRS(proteose peptone 1%, beef extract 1%, yeast extract 0.5%, glucose 2%, polysorbate 80 0.1%, ammonium citrate 0.2%, sodium acetate 0.5%, magnesium sulfate 0.01%, manganese sulfate 0.005%, dipotassium phosphate 0.2%) 배지를 기본으로 하여 21시간 배양한 결과, 배양온도는 30∼37$^{\circ}C$, 초기 pH는 7.0 으로 확인되었다. 최적 생산배지조성으로 탄소원은 glucose 3%, 질소원은 tryptone 4%, 무기염류는 manganese sulfate 0.005%가 bacteriocin 생성에 최적 조성으로 나타났으며, 최적 배지상에서 항균활성은 최대 484 BUf/mL로 나타났다.

• 한국입자에어로졸학회지
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• 제6권1호
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• pp.21-27
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• 2010

New process consisting of electrospray and epitaxial crystal growth processes was applied to the preparation of c-plane oriented barium ferrite ($BaFe_{12}O_{19}$) thin film for high density magnetic recording media. Sodium citrate aided process was proper to preparation of amorphous $BaFe_{12}O_{19}$ nanoparticles with geometric mean diameter of 3 nm and geometric standard deviation of 1.1. The electrospray was applicable to the prepare of amorphous $BaFe_{12}O_{19}$ thin film on a substrate, and the film thickness could be controlled by adjusting the electrospray deposition time. The c-plane oriented $BaFe_{12}O_{19}$ thin film was successfully prepared by 3 step annealing process of the $BaFe_{12}O_{19}$ amorphous film on a sapphire($Al_2O_3$) substrate; annealing at $350^{\circ}C$ for 30 min, annealing at $500^{\circ}C$ for 30 min, and annealing at $700^{\circ}C$ for 60 min.

• 대한화학회지
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• 제13권3호
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• pp.233-240
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• 1969

The synthesis is described of new pepsin substrates of benzyloxycarbonyl-glycyl-L-tyrosyl-L-phenylalanyl-glycine ethyl ester and benzyloxycarbonyl-glycyl-L-tyrosyl-L-phenylalanyl-glycine for studies on the specificity of pepsin, and thin layer chromatographic examination of the peptides prepared showed the new substrates are homogeneous and also, same examination of the incubation mixtures showed that two synthetic substrates are cleaved by pepsin at the L-tyrosyl-L-phenylalanyl bond and hydrolysis of these substrates by pepsin is achieved without transpeptidation. It is found that synthetic peptides are moderately soluble with the amount of the substrate up to a concentration of 0.7 mM in aqueous sodium citrate buffers (0.04 M) in the pH range 1.8-4.0, thus obviating the necessity for the adding of an organic solvent in the assay mixture. The kinetic parameters for synthetic substrates are tabulated in the following table. The data in the table indicate that the susceptibility of synthetic peptides to peptic hydrolysis are relatively large and the change of the carboxyl-terminal group of synthetic substrate from glycine ethyl ester to glycine causes a small decrease in the susceptibility of the L-tyrosyl-L-phenylalanyl bond.

• 한국식품조리과학회지
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• 제15권4호
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• pp.363-369
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• 1999

The study was carried out to compare the reaction rate of caramel type browning reaction of xylose(XY), glocose(GL), sucrose(SU), glucose+citric acid(GLCA), glucose+sodiumcitrats(GLSC), glucose+glycine(GLGC) heated at 60, 80, 100, 120 and 140$^{\circ}C$ for 24 hours, respectively. 1. The color intensity (absorbance at 490 nm) of the browning reaction mixtures tends to increase as the browning reaction time gets longer and the browning of reaction temperature gets higher. But the degree of the intensity of SU and GLCA changes very little. 2. The reaction rate constant (K) was increased rapidly above 120$^{\circ}C$ and appeared maximum at 140$^{\circ}C$, especially GLGC (140.25) was the highest. The activation energy (Ea) of sugars. XY had the highest value (124.36 J/mol), while SU the lowest(104.68 J/mol). Mixtures of GLGC was shown to have higher activation energy (144.94 J/mol) than the sugar alone and Q$\_$10/ values of GLGC were 1.68-2.85. 3. The residual amount of reactants such as xylose, glucose, sucrose, citric acid, sodium citrate and glycine in each browning mixture were decreased upon the browning reaction temperature increasing. In the GLCA, GLSC and GLGC browning mixtures, respectively, the residual amounts of glucose were less than those with amino acid, organic acid and their salt.

• Journal of Microbiology and Biotechnology
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• 제28권5호
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• pp.718-731
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• 2018

The beneficial effects of lactic acid bacteria (LAB) have been intensively investigated in recent decades with special focus on modulation of the host intestinal microbiota. Numerous discoveries of effective probiotics are driven by a significantly increasing demand for dietary supplements. Consequently, technological advances in the large-scale production and lyophilization are needed by probiotic-related industries for producing probiotic LAB for commercial use. Our study had a dual objective, to determine the optimum growth medium composition and to investigate appropriate cryoprotective additives (CPAs) for Lactobacillus salivarius, and compare its responses with other Lactobacillus species. The one-factor-at-a-time method and central composite design were applied to determine the optimal medium composition for L. salivarius cultivation. The following composition of the medium was established (per liter): 21.64 g maltose, 85 g yeast extract, 1.21 ml Tween 80, 6 g sodium acetate, $0.2g\;MgSO_4{\cdot}7H_2O$, $0.02g\;MnSO_4{\cdot}H_2O$, $1g\;K_2HPO_4$, $1.5g\;KH_2PO_4$, $0.01g\;FeSO_4{\cdot}7H_2O$, and 1 g sodium citrate. A cryoprotective additive combination comprising 10% (w/v) skim milk and 10% (w/v) sucrose supplemented with 2.5% (w/v) sodium glutamate was selected for L. salivarius, and its effectiveness was confirmed using culture-independent methods in the freeze-dried cells of the Lactobacillus strains. In conclusion, the optimized medium enhanced the species-specific cultivation of L. salivarius. On the other hand, the cryoprotective effects of the selected CPA mixture may also be dependent on the bacterial strain. This study highlights the necessity for precise and advanced processing techniques for large-scale production of probiotics in the food and feed industries.

• Journal of Microbiology and Biotechnology
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• 제32권2호
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• pp.187-194
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• 2022

Two α-ʟ-arabinofuranosidases (BfdABF1 and BfdABF3) and a β-ᴅ-xylosidase (BfdXYL2) genes were cloned from Bifidobacterium dentium ATCC 27679, and functionally expressed in E. coli BL21(DE3). BfdABF1 showed the highest activity in 50 mM sodium acetate buffer at pH 5.0 and 25℃. This exo-enzyme could hydrolyze p-nitrophenyl arabinofuranoside, arabino-oligosaccharides (AOS), arabinoxylo-oligosaccharides (AXOS) such as 3²-α-ʟ-arabinofuranosyl-xylobiose (A³X), and 2³-α-ʟ-arabinofuranosyl-xylotriose (A²XX), whereas hardly hydrolyzed polymeric substrates such as debranched arabinan and arabinoxylans. BfdABF1 is a typical exo-ABF with the higher specific activity on the oligomeric substrates than the polymers. It prefers to α-(1,2)-ʟ-arabinofuranosidic linkages compared to α-(1,3)-linkages. Especially, BfdABF1 could slowly hydrolyze 2³,3³-di-α-ʟ-arabinofuranosyl-xylotriose (A²⁺³XX). Meanwhile, BfdABF3 showed the highest activity in sodium acetate at pH 6.0 and 50℃, and it has the exclusively high activities on AXOS such as A³X and A²XX. BfdABF3 mainly catalyzes the removal of ʟ-arabinose side chains from various AXOS. BfdXYL2 exhibited the highest activity in sodium citrate at pH 5.0 and 55℃, and it specifically hydrolyzed p-nitrophenyl xylopyranoside and xylo-oligosaccharides (XOS). Also, BfdXYL2 could slowly hydrolyze AOS and AXOS such as A³X. Based on the detailed hydrolytic modes of action of three exo-hydrolases (BfdABF1, BfdABF3, and BfdXYL2) from Bf. dentium, their probable roles in the hemiceullose-utilization system of Bf. dentium are proposed in the present study. These intracellular exo-hydrolases can synergistically produce ʟ-arabinose and ᴅ-xylose from various AOS, XOS, and AXOS.

• 한국식품과학회지
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• 제31권4호
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• pp.1017-1023
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• 1999

홍합의 천연조미료의 제조를 위하여 홍합 추출시 추출 온도와 pH, 인산염 및 구연산 염의 첨가 그리고 단백질 효소에 의한 분해 효과를 조사하였다. 홍합 추출액은 홍합을 탈각, 마쇄한 다음 열수 추출한 후 여과하여 제조하였다. 추출 온도$(80{\sim}100^{\circ}C)$와 시간($20{\sim}80$분)을 달리하여 열수 추출한 결과 $90^{\circ}C$에서 40분간 추출한 것이 가장 높은 수율을 보여주었으며 비린맛은 감소하고 감칠맛은 높게 나타났다. 인산염 및 구연산염 첨가의 영향은 1.0% $Na_{3}PO_{4}$, 1.0% $Na_{4}P_{2}O_{7}$를 첨가시킨 것이 수율 향상과 감칠맛에서 가장 좋은 효과를 보였다. pH의 영향은 pH 10으로 조절한 것이 높은 수율과 28%이하의 비린맛 감소를 나타내었다. 단백질 분해 효소의 효과는 사용한 효소간에는 큰 차이를 보이지 않았으나 Protamex와 Protease II가 맛에 있어 다른 효소보다 좋은 영향을 보였다. 종합처리의 영향은 선정된 조건들을 모두 처리한 것으로 Protamex로 분해시킨 다음 $Na_{3}PO_{4}$ 1.0%를 첨가한 후 pH 10으로 조절하여 $90^{\circ}C$에서 40분간 추출한 것이 가장 좋았다.