• ETRI Journal
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• v.28 no.3
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• pp.355-363
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• 2006

This paper presents a low-cost RF parameter estimation technique using a new RF built-in self-test (BIST) circuit and efficient DC measurement for 4.5 to 5.5 GHz low noise amplifiers (LNAs). The BIST circuit measures gain, noise figure, input impedance, and input return loss for an LNA. The BIST circuit is designed using $0.18\;{\mu}m$ SiGe technology. The test technique utilizes input impedance matching and output DC voltage measurements. The technique is simple and inexpensive.

• Journal of Veterinary Clinics
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• v.15 no.1
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• pp.193-195
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• 1998

A one-month old Holstein calf with clinical histories of diarrheal weekness and behavioural abnormality revealed clinical findings of anemia and dehydration. The red blood cells were $1.4{\times} 10^{6}/{\mu}l$ and packed red cell volume was 45%. A blood smear showed a large number of circulating Trypanosoma theileri. To treat Trypanosomiasisi the patient received once a daily oral dosage o$\ulcorner$ 10 mg/kg of the Quinidine sulfate including transfusion (200 ml) for 3 days. After 2 weeks, the calf recovered body condition. These results suggest that Administration of Quinidine sulfate in trypanosomiasis may be a useful treatment approach.

• Bulletin of the Korean Chemical Society
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• v.7 no.1
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• pp.20-23
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• 1986

A reduced condition for liquid-gas phase transition from the singularity of compressibility is derived using diagrammatic approach and is examined in the hard sphere system. The condition turns out that the Percus-Yevick and the Hyper-Netted-Chain approximation never conceive the idea of phase transition, and explains that the liquid-gas transition does not exist in hard sphere system. The solid-fluid transition is considered on the viewpoint of correlation function and diagrammatic analysis.

• Korean Journal of Veterinary Research
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• v.27 no.2
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• pp.361-383
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• 1987

This thesis was designed to find out whether the cadmium content of hair in living animals reflects the status of cadmium accumulation in internal organs or muscles so that this status can be used as a diagnostic method. Forty-five rats were divided into 4 experimental groups and one control group. The control group received a basal diet which contained zinc $100{\mu}g/g$, iron $80{\mu}g/g$ and copper $135{\mu}g/g$. The experimental group received experimental diets sllpplemented with 1, 10, 100 or $1,000{\mu}g/g$ cadmium as cadmium sulfate. Rats were dissected on the 28th or 56th day of experimental periods and tissues, blood and hair samples were taken, dried and burned to ash and analysed. The cadmium, iron zinc and copper concentrations were measured with an atomic absorption spectrophotometer. In addition feed efficiency and hematological changes were observed. The results obtained can be summerized as follows: A marked decrease in feed intake, weight gain and feed efficiency were observed from 1 or 2 weeks of experimental periods, which was in accordance with the dosage and periods. The cadmium contents of kidney, liver, spleen and muscle were significantly increased in all experimental rats; the accumulation was marked in kidney and liver tissues. It was shown that the cadmium contents of hair reflects the cadmium accumulation in internal organs and muscle; the higher the cadmium levels of diet and of rat tissues, the higher the cadmium content of hair. In the $100{\mu}g/g$ group of rats erythrocyte counts and. hemoglobin concentrations were decreased. A significant(p<0.01, p<0.05) increase in iron contents of kidney, liver and muscle was observed in 10, 100, $1,000{\mu}g/g$ groups of rats on the 28th day of experiment. A significant (p<0.01, p<0.05) increase in zinc contents of kidney, liver and muscle was observed in all experimental rats. On the other hand, serum zinc concentration was decreased. A significant(p<0.01) increase in copper contents in the liver was observed on the 28th day in $100{\mu}g/g$ and $1,000{\mu}g/g$ groups of rats. From these results it may be concluded that the analysis of hair for cadmium is a useful diagnostic approach for the cadmium status of internal organs and muscle in living animals.

• International Journal of Highway Engineering
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• v.13 no.4
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• pp.29-40
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• 2011

Warm-Mix Asphalt(WMA) technologies have been developed since 15 years ago, which are internationally and domestically concerned with energy-saving and environmental-friendly technologies in public and private sectors of highway engineering. The performance of asphalt mass is traditionally evaluated by the penetration, viscosity, or Superpave tests. This research, however, is focused more on the properties depending on asphalt film thicknesses instead of evaluating asphalt mass behaviors by those tests. For this approach, a new testing protocol and analysis method are described by the bonding properties on each film thickness. This testing method and analysis tool are borrowed from those of DSR Moisture Damage test and applied by using ARES. The analysis results indicate that there is a limit film thickness between $200{\mu}m$ and $400{\mu}m$, which causes significant changes of the properties. In addition, the results show that the property changes of Hot-Mix Asphalt(HMA) and WMA on the limit film thickness are also different. Therefore, it is suggested that the properties on thin film thicknesses between $200{\mu}m$ and $400{\mu}m$ should be considered in order to evaluate WMA properly.

• Food Science and Preservation
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• v.21 no.1
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• pp.114-120
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• 2014

Zizyphus jujube leaf fractions (ZLFs) showed no cytotoxic effects of up to $100{\mu}g/mL$, while the anti-inflammatory effects of ZLFs were analyzed by checking the productions of nitric oxide (NO), prostaglandin $E_2$ ($PGE_2$), cyclooxygenase-2 (COX-2), and inflammatory cytokines TNF-${\alpha}$, IL-$1{\beta}$, and IL-6 in the lipopolysaccharide (LPS)-stimulated Raw264.7 macrophage up to the concentration of $100{\mu}g/mL$. ZLFs ($100{\mu}g/mL$) demonstrated a strong anti-inflammatory activity that reduced 61~85% of NO and 71~100% of $PGE_2$ production in the LPS-stimulated Raw264.7 macrophage. Even the low ZLFs concentration of $1{\mu}g/mL$ have reduced NO and $PGE_2$ production by 34~64%. Expressions of COX-2 protein were also effectively inhibited by the ZLFs. Furthermore, the TNF-${\alpha}$, IL-$1{\beta}$, and IL-6 production were significantly suppressed through the treatment of ZLFs at concentrations of 1, 10, and $100{\mu}g/mL$. In the order of the Zizyphus jujube leaf water fraction (ZLWF) < buthanol fraction (ZLBF) < ethyl acetate fraction (ZLEF) showed anti-inflammatory activity. In particular, the ethyl acetate fraction ZLEF at $100{\mu}g/mL$ showed an excellent anti-inflammatory activity by reducing the production of NO, $PGE_2$, COX-2, and inflammatory cytokines (TNF-${\alpha}$, IL-$1{\beta}$, IL-6) in the level of Raw264.7 macrophage without LPS-stimulation or even better. The results of our study suggest the potential of ZLEF for use as an excellent ant-inflammatory inhibiting mediator and may be used as a therapeutic approach to various inflammatory diseases.

• Journal of Pharmacopuncture
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• v.19 no.4
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• pp.312-318
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• 2016

Objectives: Bacterial resistant infections have become a global health challenge and threaten the society's health. Thus, an urgent need exists to find ways to combat resistant pathogens. One promising approach to overcoming bacterial resistance is the use of herbal products. Green tea catechins, the major green tea polyphenols, show antimicrobial activity against resistant pathogens. The present study aimed to investigate the effect of catechins, green tea extract, and methylxanthines in combination with gentamicin against standard and clinical isolates of Staphylococcus aureus (S. aureus) and the standard strain of Pseudomonas aeruginosa (P. aeruginosa). Methods: The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) values of different agents against bacterial strains were determined. The interactions of green tea extract, epigallate catechin, epigallocatechin gallate, two types of methylxanthine, caffeine, and theophylline with gentamicin were studied in vitro by using a checkerboard method and calculating the fraction inhibitory concentration index (FICI). Results: The MICs of gentamicin against bacterial strains were in the range of $0.312-320{\mu}g/mL$. The MIC values of both types of catechins were $62.5-250{\mu}g/mL$. Green tea extract showed insufficient antibacterial activity when used alone. Methylxanthines had no intrinsic inhibitory activity against any of the bacterial strains tested. When green tea extract and catechins were combined with gentamicin, the MIC values of gentamicin against the standard strains and a clinical isolate were reduced, and synergistic activities were observed (FICI < 1). A combination of caffeine with gentamicin did not alter the MIC values of gentamicin. Conclusion: The results of the present study revealed that green tea extract and catechins potentiated the antimicrobial action of gentamicin against some clinical isolates of S. aureus and standard P. aeruginosa strains. Therefore, combinations of gentamicin with these natural compounds might be a promising approach to combat microbial resistance.

• Journal of the Korean Society for Nondestructive Testing
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• v.14 no.2
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• pp.112-121
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• 1994

This paper discusses the feasibility of ultrasonic C-scan technique for nondestructive evaluation of spot weld quality. Ultrasonic evaluation for spot weld quality was performed by immersion method with the mechanical and the electronic scanning of point-focussed ultrasonic beam(25 MHz). For the sake of the approach to the quantitative measurement of nugget diameter and the discrimination of the corona bond from nugget, preliminary infinitesimal gap experiment by newton ring is tried in order to set up the optimum ultrasonic test condition. Ultrasonic image data obtained were confirmed and compared by optical microscope and SAM(Scanning Acoustic Microscope) observation of the spot-weld cross section. The results show that the nugget diameter can be measured with the accuracy of 1.0mm, and voids included in nugget can be detected to $10{\mu}m$ extent with simplicity and accuracy. Finally, it was found that it is necessary to make a profound study of definite discrimination of corona bond from nugget and the approach of quantitative evaluation of nugget diameter by utilizing the various image processing techniques.

• Journal of IKEEE
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• v.18 no.1
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• pp.165-171
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• 2014

This paper presents a low complexity QR decomposition (QRD) architecture for MIMO detector. In the proposed approach, various CORDIC-based QRD algorithms are efficiently combined together to reduce the computational complexity of the QRD hardware. Based on the computational complexity analysis on various QRD algorithms, a low complexity approach is selected at each stage of QRD process. The proposed QRD architecture can be applied to any arbitrary dimension of channel matrix, and the complexity reduction grows with the increasing matrix dimension. Our QR decomposition hardware was implemented using Samsung $0.13{\mu}m$ technology. The numerical results show that the proposed architecture achieves 47% increase in the QAR (QRD Rate/Gate count) with 28.1% power savings over the conventional Householder CORDIC-based architecture for the $4{\times}4$ matrix decomposition.

• Journal of Environmental Health Sciences
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• v.37 no.5
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• pp.369-375
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• 2011

Objectives: Exposure to hazardous chemicals during pregnancy may result incritical reproductive health outcomes. Indoor residential levels are significant component of personal exposure. The collection of residential exposure data has been hampered by the cost and participant burden of health studies of indoor air pollution. This study utilized a participant-based approach to collect volatile organic compounds concentration from homes. Methods: Four hundred thirteen women were recruited from three major hospitals in Seoul and Gyeongi Provence and 411 agreed to participate. A passive sampler (OVM 3500, 3M, USA) with instructions were given to the participants, as well as a questionnaire. They were asked to deploy the sampler in their homes for three to five days and return them viapre-stamped envelope. Results: Three hundred forty six participants returned the sampler. Among the returned samplers, three hundred samplers satisfied our monitoring quality criteria. The success rate of the monitoring method was 73%. The geometric mean of TVOC level was 429(2) ${\mu}g/m^3$. The TVOC guideline of 500 ${\mu}g/m^3$ was exceeded in 38% of the houses. The residential VOC levels were significantly associated with remodeling of the house. Conclusions: The results suggested that a participant-based sampling approach may be a feasible and costeffective alternative to exposure assessment involving home visits by a field technician.