• Journal of Biosystems Engineering
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• v.17 no.1
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• pp.55-64
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• 1992

The aim of this study was to develop a phytotron for studying the effects of environmental factors such as temperature and humidity on plant growth. This equipment consists of the growth chamber, and the measurement and control system including control algorithms required for optimum operation. As the first step of the study, a temperature and humidity control system was developed. The results of this study are summarized as follows ; 1. Pt-100 was selected to measure temperature and a linearized op-amp circuit was developed for signal conditioning. 2. Pt-100 wet bulb thermometer based on Asmann's principle was developed to measure relative humidity. 3. Temperature and relative humidity conditions were controlled by ON-OFF and PWM operation using a PID controller. And an autotuning algorithm using the characteristics of step response was developed to determine optimal PID constants which were independent of the size of apparatus and environmental factors. 4. Under the ambient temperature of $20^{\circ}C{\sim}25^{\circ}C$, the temperature was kept within the error of ${\pm}0.3^{\circ}C$ in the range of $10^{\circ}C{\sim}40^{\circ}C$, and the relative humidity was kept within the error of ${\pm}5%$ in the range of ${\pm}50%{\sim}90%$.

• Journal of the Korean Society of Radiology
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• v.82 no.2
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• pp.359-370
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• 2021

Purpose To analyze the findings and serial changes in chest CT lesions in 123 symptomatic patients with coronavirus disease 2019 (COVID-19). Materials and Methods From February 19 to April 7, 2020, a total of 123 confirmed COVID-19 patients (male, 44; female, 79; mean age, 59.2 ± 18.6) were enrolled in this retrospective study. A total of 234 CT scans were reviewed for the following patterns: acute alveolar insult (AAI) patterns: ground-glass opacity (GGO), crazy-paving appearance, mixed pattern, and consolidation; organizing pneumonia (OP) patterns: perilobular patterns, band opacity, curvilinear opacity, reversed halo opacity, and small nodular consolidation; resolving patterns: pure GGO, remnant curvilinear, small nodular consolidation, and serial changes of lung abnormalities. We compared the proportions of AAI pattern, OP pattern, or resolving pattern with time progression and analyzed the association between the patterns and disease severity using Pearson chi-square and Fisher's exact test. Results Predominant CT patterns were AAI pattern (87%) in the early hospital period group (0-10 days, after the onset of symptoms), OP pattern (45.7%) in the later hospital period group (after 10 days), and resolving pattern in discharge and follow-up group (47.2% and 84.8%, respectively). The difference in the proportions of predominant CT patterns with time progression was statistically significant (p < 0.001, Pearson's chi-square test). No statistically significant association was observed between the patterns and disease severity (p = 0.055, Fisher's exact test). No fibrous changes in the lesions were observed on follow-up CT scans. Conclusion The serial CT scans of COVID-19 patients showed the spectrum of COVID pneumonia CT manifestations as different phases of lung injury and repair.

• Journal of Dairy Science and Biotechnology
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• v.26 no.1
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• pp.1-4
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• 2008

Melatonin is one of the functional hormones in the milk and found in all mammalian species. The primary motivation for the use of melatonin as a supplement is as a natural aid to better sleep. Melatonin contents in milk vary according to the naturally occurring factors such as seasons and milking times. As a number of studies indicate melatonin supplementation helps to reduce the age-related decline in hormone production and overall enhancement of health, the more detailed studies are required to know the nature of milk derived hormones and to clarify them as a functional value adaptation. The objectives of this study were to examine the change of melatonin content in bovine milk during different milking times at the two dairy farms and during dairy process including homogenization and pasteurization. Commercial dairy products including night time milking products(night milk) marketed in Japan were also investigated. Melatonin content was determined by radioimmunoassay using 125I. Individual milk was collected from lactating Holstein cows at Kyong-Ki province in Korea. At farm A, the melatonin contents milking at 4 a.m. was higher than those of 7 p.m. and 12 p.m.($6.90{\pm}3.55,\;2.01{\pm}1.47$ and $0.16{\pm}0.04pg/mL$, respectively). At farm B, the mean melatonin contents milked from 24:00 AM to 05:00 AM have shown the highest contents ($4.65{\pm}$0.72pg/mL), and milking samples of the rest time had very little or non-detection of melatonin contents. Melatonin contents of commercial night milk samples were about 5 times higher than those of other common milk products. These results suggested that melatonin might be heat-resistant and commercial dairy process might not affect its contents in the final products.

• Korean Journal of Microbiology
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• v.49 no.1
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• pp.83-89
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• 2013

A bacterium, isolated from a vegetable field in a plastic film house and named strain CY6 was capable of biodegrading chlorpyrifos (CP). Based on the phenotypic features and the phylogenetic similarity of 16S rRNA gene sequences, strain CY6 was identified as a Naxibacter sp.. CP was utilized as the sole source of carbon and phosphorus by Naxibacter sp. CY6. We examined the role of this Naxibacter sp. in the degradation of other OP insecticides under liquid cultures. Parathion, methyl parathion, diazinon, cadusafos, and ethoprop could also be degraded by Naxibacter sp. CY6 when they are provided as the sole sources of carbon and phosphorus. Additionally, Naxibacter sp. CY6 ($10^8$ CFU/g) added to soil with CP (100 mg/kg) resulted in a higher degradation rate of approximately 90% than the rate obtained from uninoculated soils. These results highlight the potential of this bacterium to be used in the cleanup of contaminated pesticide soil.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.6
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• pp.2484-2490
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• 2012

This study reports on the development and performance verification of cell simulation boards of simulator and the embedded program for board control of the battery management system (BMS) of electric vehicle (EV) cars, which manages the next-generation automotive lithium-ion battery pack. Here, we have improved the speed of the simulator by using operational (OP) amplifier and transistors that were connected in series. In addition, using a digital analog converter (DAC) in each channel, we have improved the performance by channel-to-channel isolation (isolation) as compared to the traditional methods. Furthermore, by constructing a current-limiting protection circuit, one can be protected from disturbance and, by utilizing a precision shunt resistor for the current sensor, we have increased the precision of the current control. In order to verify the performance of the developed simulator, we have performed the experiment 10 times, with values ranging from 0.5 V to 5 V, and a voltage drop step of 0.5 V. Significance analysis of experimental data, and repeatability tests were performed, showing an average standard deviation of 0.001~0.004 V, indicating high repeatability and high statistical significance of the current method and system.

• Journal of Periodontal and Implant Science
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• v.35 no.3
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• pp.549-561
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• 2005

이 연구의 목적은 새로이 제작된 chitosan-poly(L-lactic acid)(PLLA) 다층 다공성 차폐막의 생체적합성 및 골세포활성도 및 골재생능을 평가하는 것이다. 제작된 차폐막을 24 well에 넣고 clonal osteoblast-like cell line(MC3T3-E1)을 접종한 군을 실험군으로, 차폐막을 사용하지 않은 대조군으로 하였다. 배양 1일, 7일 및 14일째에 각 well에서 세포수를 측정하였다. 주사전자현미경을 이용하여 차폐막에 부착된 세포의 형태관찰을 시행하였다. RNA 추출 및 RT-PCR을 실시한 후, agarose gel상에서 전기영동하여 조골세포 표식자인 collagen type I(COL), osteopontin(OP) 및 osteocalcin(OC) mRNA의 발현을 관찰하였다. 제작된 매트릭스의 생체적합성 및 골재생능을 관찰하기 위하여 백서의 두개골에 직경 8mm의 원형 결손부를 형성한 후 차폐막을 이식한 군을 실험군으로, 아무 것도 넣지 않은 군을 대조군으로 하여 4주 경과 후 실험동물을 희생시킨 후 조직학적관찰을 시행하였다. 시간경과에 따른 부착세포수 관찰결과, 배양 14일까지 조골세포의 수가 지속적으로 증가하였고, 주사전자현미경으로 세포의 형태 관찰결과, 배양된 세포들은 중층의 형태로 성장하면서 시간경과에 따라 세포가 응집되는 양상을 나타내었다. 관찰 기간동안 COL, OP, 및 OC mRNA의 발현이 관찰되어 배양 전 기간동안 조골세포의 형질이 잘 유지되고 있음을 알 수 있었다. 백서 두개골 결손부에 이식된 차폐막은 염증반응 없이 주위 조직과 우수한 생체적합성을 나타내었으며, 차폐막을 이식하지 하지 않은 대조군에 비해 높은 신생골 형성을 나타내었다. 이상의 관찰결과로 새로이 제작된 chitosan-PLLA 차폐막은 우수한 생체적합성 및 골재생능을 나타냄을 알 수 있었으며, 향후 이를 골조직 재생 및 치주조직유도재생 분야에 응용될 수 있을 것으로 생각된다.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.6
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• pp.523-527
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• 2004

Recombinant Saccharomyces cerevisiae expression systems were developed to pro­duce a novel human anti-angiogenic protein called LK8, an 86 amino-acid kringle fragment pro­tein with three disulfide linkages. Galactose-inducible LK8 expression plasmid was constructed, and LK8 production levels by four S. cerevisiae strains were compared in order to select an op­timal host strain. S. cerevisiae 2805 was the most efficient among the strains tested. Elevating the LK8 gene copy number through multiple integration using 8-sequences as target sites re­sulted in more than a two-fold increase in the LK8 production level compared with the plasmid­based expression system. The maximum LK8 protein concentration of 25 mg/L was obtained from batch cultivation of the yeast transformant that harbors 16 copies of the LK8 gene. In con­clusion, the strain integrated with the multiple LK8 gene secreted the protein with relatively high yield, although, the increased LK8 gene dosage over 11 copies did not lead to further en­hancement in batch cultivations.

• Aerospace Engineering and Technology
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• v.13 no.1
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• pp.86-95
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• 2014

For the accomplishment of satellite's own missions, complicated control procedures and commands are required. Although absolute-Time Command and Command Sequences have been applied for controlling satellite and its operation historically, these command system only has a capability to manage sequential control process and has a limitation that cannot deal with decision and branch for corresponding to the condition of the time. To resolve above limitation, KARI has designed RTCSC which is mainly based on the existing RTCS but adopts a one-byte Op Code for supporting decision making and conditional branch. This paper introduces the design and implementation of RTCSC as On-Board Control System like OBCP, VML and IP.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.5
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• pp.397-407
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• 2004

It is well known that some key parameters, such as evaporating temperature, refrigerant mass flow rate, face velocity and inlet air temperature, have significant influence on the evaporator performance. However performance studies related to a humid environment have been very scarce. It is demonstrated that the refrigerant mass flow rate, heat flux, water condensing rate and air outlet temperature of the evaporator significantly increase with air inlet relative humidity. As the air inlet relative humidity increases, the latent and total heat transfer rates increase, but the sensible heat transfer rate decreases. The purpose of this study is to provide experimental data on the effect of air inlet relative humidity on the air and refrigerant side pressure drop characteristics for a slit fin-tube heat exchanger. Experiments were carried out under the conditions of inlet refrigerant saturation temperature of 7 $^{\circ}C$ and mass flux varied from 150 to 250 kg/$m^2$s. The condition of air was dry bulb temperature of 27$^{\circ}C$, air Velocity Varied from 0.38 to 1.6 m/s. Experiments Showed that air Velocity decreased 8.7% on 50% of relative humidity 40% of that at degree of superheat of 5$^{\circ}C$, which resulted that pressure drop of air and refrigerant was decreased 20.8 and 8.3% for 50% of relative humidity as compared to 40%, respectively.

• Journal of Pharmacopuncture
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• v.10 no.3
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• pp.37-46
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• 2007

Objectives We studied on anti-allergic effects of Ganoderma lucidum herbal acupuncture(GHA) and Ganoderma lucidum extract(GE). Methods In vivo, Animals were herbal-acupunctured GHA at both B13s three times for 5 days. Then, we investigated compound 48/80-induced active systemic anaphylatic shock using ICR mice and anti-DNP IgE-induced passive cutaneous anaphylaxis using Sprague Dawley rat. In vitro, we measured cell viability, b-hexosaminidase release, IL-4 and TNF-a from RBL-2H3 cells, and nitric oxide from Raw264.7 cell after treatment of GE of various concentrations. Results In vivo, GHA pretreatments at both B13s inhibited compound 48/80-induced active systemic anaphylatic shock. Passive cutaneous anaphylaxis were inhibited by GHA10 and OP. In vitro, $0.1\;{\sim}\;2%$ GE treatments were not affect on cell viability and inhibited b-hexosaminidase release, IL-4, TNF-a and nitric oxide. Conclusions These results suggest that GHA and GE may be beneficial in the inhibition of allergic inflammatory response.