• Korean Journal of Microbiology
• /
• v.32 no.3
• /
• pp.215-221
• /
• 1994

The complete nucleotide sequence of the cloned pga gene encoding the penicillin G acylase of Bacillus megaterium ATCC 14945 and its 5'- and 3'-flanking regions was determined. The sequence revealed only one large open reading frame (2,406 hp) of the penicillin G acylase (pga) gene. Upstream from ATG of the pga gene, there was a putative ribosome binding site, Shine-Dalgarno sequence. The promoter-like structure, - 10 and - 35 sequences, was also found. Following the stop codon, TAG, a structure reminiscent of the E. coli rho-independent transcription terminator was present. The amino acid sequence was deduced from the nucleotide sequence. The molecular mass of the polypeptide was 91,983 Da. There was a potential signal sequence in its amino-terminal region. A comparison of its deduced amino acid sequence with other characterized penicillin G acylases and the result of SDS-polyacrylamide gel electrophoresis of the purified enzyme showed that a precursor polypeptide of 92 kDa was processed into two dissimilar ${\alpha}$ and ${\beta}$-subunits of 25 and 61 kDa.

• Applied Chemistry for Engineering
• /
• v.31 no.4
• /
• pp.398-403
• /
• 2020

In this study, six kinds of rice grown in Cheongwon area were extracted using glycolytic and proteolytic enzymes, and also antioxidant effects and water holding capacity of rice protein extracts were compared and analyzed. Protein contents of rice cultivars protein extract showed that black rice (BR) extract was the highest at 4,900 ㎍/mL, and flavored brown rice (FBR) extract was the lowest at 3,700 ㎍/mL. 2,2-diphenyl-1-picryl-hydrazyl-hydrate free radical scavenging activity was confirmed the superior activity of more than 80.0% at a concentration of 2 mg/mL with BR and red brown rice (RBR) extracts. 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity at a concentration of 2 mg/mL with BR and RBR extracts was more than 70.0% The water holding capacity for extracts using RBR, red-kerneled brown rice (RKBR), BR and FBR was more than 110.0%. Overall, the rice protein extract using BR has excellent antioxidant and water holding capacity which can be used as a potential skin moisturizer and antioxidant functional cosmetic material.

• Korean Journal of Soil Science and Fertilizer
• /
• v.36 no.6
• /
• pp.367-375
• /
• 2003

The aim of this study was to investigate the soil physical properties and the traction characteristics of paddy field before tillage by a computer simulation. Soil physical properties, such as soil moisture content, bulk density, soil hardness, and soil texture were measured in the twelve rice production area. Mathematical model based on dimensional analysis which include soil physical properties and vehicle factors was used for the computer simulation. Most of the soil texture of the investigated area was silty loam, loam and silty clay loam. Soil moisture content ranged between 20 and 40% mostly. Soil bulk density was in the range of 1,500 to $1,700kg\;m^{-3}$. Soil hardness ranged between 2 to $12kg\;cm^{-2}$ mostly. Soil hardness incorporates the effects of many soil physical properties such as moisture content, texture and bulk density, and so the range of soil hardness was greater than that of any other physical properties. The predicted net traction was in the range of 70 to 1,500 kgf depending on the area, but it was above 1,000 kgf for most of the investigated area. Thus it was concluded that 50 HP tractor can pull the four row moldboard plow considering the conventional tillage depth and width. But for the soft soil area such as Andong and Namyang, tractor itself may have mobility problem and show high slip during plowing operation.

• Proceedings of the Korean Vacuum Society Conference
• /
• 1999.07a
• /
• pp.162-162
• /
• 1999

초고주파 집적회로의 핵심소자로 각광을 받고 있는 GaAs MESFET(MEtal-emiconductor)은 게이트 형성 공정이 가장 중요하며, WNx 내화금속을 이용한 planar 게이트 구조의 경우 임계전압(Vth:threshold voltage)의 균일도가 우수할 뿐만 아니라 특히 Side-wall을 이용한 self-align 게이트는 소오스 저항을 줄일 수 있어 고성능의 소자 제작을 가능하게 한다.(1) 본 연구의 핵심이 되는 Side-wall을 형성하기 위하여 PECVD법에 의한 SiOx 박막을 증착하고, 건식식각법을 이용하여 SiOx side-wall을 형성하였다. 이 공정을 이용하여 소오스 저항이 낮고 임계전압의 균일도가 우수한 고성능의 self-aligned gate MESFET을 제작하였다. 3inch GaAs 기판상에 이온주입법에 의한 채널 형성, d.c. 스퍼터링법에 의한 WNx 증착, PECVD법에 의한 SiOx 증착, MERIE(Magnetic Enhanced Reactive Ion Etcing)에 의한 Side-wall 형성, LDD(Lightly Doped Drain)와 N+ 이온주입, 그리고 RTA(Rapid Thermal Annealing)를 사용하여 활성화 공정을 수행하였다. 채널은 40keV, 4312/cm2로, LDD는 50keV, 8e12/cm2로 이온주입하였고, 4000A의 SiOx를 증착한 후 2500A의 Side-wall을 형성하였다. 옴익 접촉은 AuGe/Ni/Au 합금을 이용하였고, 소자의 최종 Passivation은 SiNx 박막을 이용하였다. 제작된 소자의 전기적 특성은 hp4145B parameter analyzer를 이용한 전압-전류 측정을 통하여 평가하였다. Side-wall 형성은 0.3$\mu\textrm{m}$ 이상의 패턴크기에서 수직으로 잘 형성되었고, 본 연궁에서는 게이트 길이가 0.5$\mu\textrm{m}$인 MESFET을 제작하였다. d.c. 특성 측정 결과 Vds=2.0V에서 임계전압은 -0.78V, 트랜스컨덕턴스는 354mS/mm, 그리고 포화전류는 171mA/mm로 평가되었다. 특히 본 연구에서 개발된 트랜지스터의 게이트 전압 변화에 따른 균일한 트랜스 컨덕턴스의 특성은 RF 소자로 사용할 때 마이크로 웨이브의 왜곡특성을 없애주기 때문에 균일한 신호의 전달을 가능하게 한다. 0.5$\mu\textrm{m}$$\times$100$\mu\textrm{m}$ 게이트 MESFET을 이용한 S-parameter 측정과 Curve fitting 으로부터 차단주파수 fT는 40GHz 이상으로 평가되었고, 특히 균일한 트랜스컨덕턴스의 경향과 함께 차단주파수 역시 게이트 바이어스, 즉 소오스-드레스인 전류의 변화에 따라 균일한 값을 보였다. 본 연구에서 개발된 Side-wall 공정은 게이트 길이가 0.3$\mu\textrm{m}$까지 작은 경우에도 사용가능하며, WNx self-align gate MEESFET은 낮은 소오스저항, 균일한 임계전압 특성, 그리고 높고 균일한 트랜스 컨덕턴스 특성으로 HHP(Hend-Held Phone) 및 PCS(Personal communication System)와 같은 이동 통신용 단말기의 MMICs(Monolithic Microwave Integrates Circuits)의 제작에 활용될 것으로 기대된다.

• Preventive Nutrition and Food Science
• /
• v.8 no.4
• /
• pp.356-364
• /
• 2003

A methanol extract from seeds of Paeonia lactiflora (Paeoniaceae, peony) was found to possess different antiproliferative activities against four different human cancer cell lines: Hela, MCF-7, HepG2 and HT-29. Furthermore, five different methanol (20, 40, 60, 80 and 100 % MeOH) fractions obtained by fractionation of the methanol extract of the seeds on a Diaion HP-20 column exhibited differential antiproliferative effects against the above four cancer cell lines. Among five fractions, the 60 % MeOH fraction showed relatively lower antiproliferative activity on MCF-7 estrogen-sensitive breast cancer cell than the other cancer cell lines. Systematic separation of 60% the MeOH fraction by silica gel and Sephadex LH-20 columns led to the isolation of four known stilbenes, trans-resveratrol (1), trans-(+)- $\varepsilon$ -viniferin (2), gnetin H (3) and suffruticosol B (4). The four stilbenes (1∼4) exerted differential biphasic effects on cell proliferation of MCF-7 cells in a similar manner as genistein, a soybean isoflavone used as a positive reference, in the concentration range from 1.0 to 200 $\mu$M. Three stilbenes (1 ∼ 3) weakly stimulated the proliferation of MCF -7 cells at doses below 10 JIM. However, strong antiproliferative effects on MCF-7 cell were exerted by extract 1 at a dose of 200 JIM, and by 2 and 3 at doses above 25 $\mu$M. In contrast, 4 inhibited the proliferation of MCF-7 cell at a dose below 25 $\mu$M, but stimulated cell proliferation at concentrations of 50 and 100 $\mu$M. All four stilbenes (1∼4) stimulated the proliferation of ROS 17/2.8 osteoblast-like cells in the range of 10$^{-10}$ ∼10$^{-1}$ $\mu$M. Compound 1 exhibited especially potent proliferative activity, although its activity was weaker than that of genistein. Additionally, three resveratrol oligomers (2∼4) also exhibited concentration-dependently moderate proliferative activity, but less than that of 1. These results suggest that resveratrol, and its dimer and trimers from the seeds of Paeonia lactiflora may act as a phytoestrogen, but in a somewhat different manner from that of genistein.

• Journal of Food Hygiene and Safety
• /
• v.38 no.4
• /
• pp.193-201
• /
• 2023

Antimicrobials in human medicine are classified by The World Health Organization (WHO) into three groups: critically important antimicrobials (CIA), highly important antimicrobials (HIA), and important antimicrobials (IA). CIA are antibiotic classes that satisfy two main criteria: that they are the sole or the only available limited therapeutic option to effectively treat severe bacterial infections in humans (Criterion 1), and infections where bacteria are transmitted to humans from non-human sources or have the potential to acquire resistance genes from non-human sources (Criterion 2). WHO emphasizes the need for cautious and responsible use of the CIA to mitigate risk and safeguard human health. Specific antimicrobials within the CIA with a high priority for management are reclassified as "highest priority critically important antimicrobials (HP-CIA)" and include the 3^rd generation of cephalosporins and the next generation of macrolides, quinolones, glycopeptides, and polymyxins. The CIA list is the scientific basis for risk assessment and risk management policies that warrant using antimicrobials to reduce antimicrobial resistance in several countries. In addition, the CIA list ensures food safety in the food industry, including for the popular food chain companies McDonald's and KFC. The continuous update of the CIA list reflects the advancement in research and emerging future challenges. Thus, active and deliberate evaluation of antimicrobial resistance and the construction of a list that reflects the specific circumstances of a country are essential to safeguarding food security.

• Journal of Food Hygiene and Safety
• /
• v.38 no.6
• /
• pp.420-429
• /
• 2023

GC-MS/MS using liquid-liquid extraction (LLE) and C18 cartridges was used to identify and quantify levels of chlorpyrifos, chlorpyrifos-methyl, cypermethrin, deltamethrin and permethrin in bulk raw milk. A calibration curve spanning 10 ng/mL to 200 ng/mL was obtained with a satisfactory correlation coefficient of 0.99. The limits of detection (LOD) and limits of quantitation (LOQ) for chlorpyrifos, chlorpyrifos-methyl, cypermethrin, deltamethrin, and permethrin in the matrix ranged from 0.06 to 1.81 ng/mL and 0.19 to 6.04 ng/mL, respectively. The recoveries of 5 pesticides from spiked samples at 37.5-125 ng/mL ranged from 86.1 to 102.1%. The measurement of uncertainty of the GC-MS/MS method for these five pesticides was developed based on the analytical process and quantification. An analysis method that is easier and faster than the method specified in the Korean food standards codes for analyzing these five pesticides in raw material milk was developed. Moreover, the analytical method for chlorpyrifos, chlorpyrifos-methyl, cypermethrin, deltamethrin, and permethrin in bulk raw milk by GC-MS/MS was established.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.22 no.1
• /
• pp.28-34
• /
• 2018

Purpose With regard to the use of radioiodine in domestic medical institution, the case of exceeding the allowance of nuclear safety Act about radioactive concentration in drainage was found. Through understanding the cause of exceeding case and analyzing radioactive concentration in drainage, evaluating the relationship of the public waters in surroundings and usefulness. Materials and Methods From November 1, 2014 to April 30th, 2015, the research is aiming at domestic twenty hospitals for six months. By using a HPGe gamma-ray spectrometer(Canberra DSA-1000) and GENIE-2000 Analysis software for comparative analysis, measuring a radioactive concentration of radioiodine in drainage. Consequently, we confirm the excess of radioactive concentration of radioiodine in seven medical institutions. Results Conducting a survey of twenty hospitals and average radioactive concentration of radioiodine in drainage appears $42,100Bq/m^3$. The features of domestic hospitals where show a high radioactive concentration are a number of medical treatment patient when using radioactive iodine and the absence of private rest room. During I-131 whole body scan, the pretreatment procedure of urinating is considered emission of residual Iodine. In public waters, the cause of exceeding detect on radioactive concentration in drainage suppose a diagnostic radioactive iodine. Conclusion We confirm the importance of enhanced education, providing a safety control instructions and installing a private rest rooms for patients who injected a low capacity radioiodine. Also, constructing institutional and legal management system is considered about the Emission management standard in drainage.

• Biomolecules & Therapeutics
• /
• v.5 no.1
• /
• pp.94-99
• /
• 1997

Capsaicin is known to be an analgesic agent, affecting the synthesis, storage, , transport and release of substance p, the principal neurotransmitter of pain from periphery to the central nervous system(CNS). DA-5018, a newly synthesized capsaicin derivative has shown potent analgesic effect comparable to that of morphine in various rat models of experimentally inducted acute pairs. In this study the mechanism of analgesic actlvity of DA-5018 was examined. First, the electrically-evoked contraction of guinea pig trachea was inhibited by DA-5018 and these inhibition was recovered by incubation with capsafepine(3$\muM$), capsaicin receptor antagonist and this result suggested that DA-5018 has affinity on capsaicin receptor. The correlation between the norciceptive threshold and the release of substance P was evaluated. In vivo perfusion of slices of the rat spinal cord with DA-5018(10, 100$\muM$) produced a significant increase of the release of substance P and this increase was less than that of capsaicin(10$\muM$). The norciceptive threshold of rat treated with DA-5018(1 mg/kg, p.o) in tall pinch test increased from 2.9$\pm$0.3 to 23.5 $\pm$6.61. Tail pinch latency increased to a maximun at 15 min after DA-5018 treatment and then declined to control values by 120 min. The capsaicin-evoked release ot substance P from the spinal cord slices of rat treated with DA-5018 reduced from 2.38$\pm$ 0.79 to 0.69$\pm$ 0.26 pg/mg wet weight. This reduction reached to a minium at 15 min after DA-5018 treatment and then recovered to control value by 120 min. These results mean that analgesic activity of DA-5018 is due to release of substance P The effect of DA-5018 cream on electrically-evoked neurogenic inflammation of rat saphenous nerve was compared with capsaicin (zostrix-HP). DA-5018 showed 34% inhibition of the neurogenic extravasation while capsaicin showed significant 67% inhibition. This result indicates that the potency of DA-5018 in the release of substance P is less than that of capsaicin. These results suggest that the release of substance P is partially involved in the mechanism of analgesic action of DA-50l8.

• Korean Journal of Environmental Agriculture
• /
• v.16 no.2
• /
• pp.193-198
• /
• 1997

The purpose of this study was to find out a suitable resin to remove $NO_3-N$ from groundwater. Four different commercial resins differentiated by type, porosity and nitrate selectivity were used to compare the performance of nitrate removal. Gel type, Type 2 anion exchange resin was preferable when anion concentration of raw water was low. But efficiency of this resin decreased as flow rate increased. However, macroporous type resins were not affected by increasing flow rate. Macroporous resins were preferable when anion concentrations in raw water were high and high flow rate was proposed. And the general type resin showed better efficiency when sulfate concentrations were low. However the nitrate selective resin had better efficiency in treating raw water of high sulfate concentration. From the results, it may be drawn that nitrate selective resins are preferable to general type when a sulfate concentration in groundwater is over 50mg/l.