• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.108-109
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• 2013

Mitochondria play key roles in the production of cell's energy. Their dominant function is the synthesis of adenosine 5'-triphosphate (ATP) from adenosine diphosphate (ADP) and phosphate (Pi) through the oxidative phosphorylation. Evaluation of drug-induced mitochondrial toxicity has become increasingly important since mitochondrial dysfunction has recently been implicated in numerous diseases including cancer and diabetes mellitus. Mitochondrial functions have been monitored via oxygen consumption, mitochondrial membrane potential, and more importantly via ATP synthesis since ATP synthesis is the most essential function of mitochondria. Various analytical methods have been employed to investigate ATP synthesis in mitochondria, including high performance liquid chromatography (HPLC), bioluminescence technique, and pH measurement. However, most of these methods are based on destructive analysis or indirect monitoring through the enzymatic reaction. Infrared absorption spectroscopy (IRAS) is one of the useful techniques for real-time, label-free, and direct monitoring of biological reactions [1,2]. However, the strong water absorption requires very short path length in the order of several micrometers. Transmission measurements with thin path length are not suitable for mitochondrial assays because solution handlings necessary for evaluating mitochondrial toxicity, such as rapid mixing of drugs and oxygen supply, are difficult in such a narrow space. On the other hand, IRAS in the multiple internal reflection (MIR) geometry provides an ideal optical configuration to combine solution handling and aqueous-phase measurement. We have recently reportedon a real-time monitoring of drug-induced necrotic and apoptotic cell death using MIR-IRAS [3,4]. Clear discrimination between viable and damaged cells has been demonstrated, showing a promise as a label-free and real-time detection for cell-based assays. In the present study, we have applied our MIR-IRAS system to mitochondria-based assays by monitoring ATP synthesis in isolated mitochondria from rat livers. Mitochondrial ATP synthesis and hydrolysis were in situ monitored with MIR-IRAS, while dissolved oxygen level and solution pH were simultaneously monitored with O2 and pH electrodes, respectively. It is demonstrated that ATP synthesis and hydrolysis can be monitored by the IR spectral changes in phosphate groups in adenine nucleotides and MIR-IRAS is useful for evaluating time-dependent drug effects of mitochondrial toxicants.

• Journal of Applied Biological Chemistry
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• v.56 no.1
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• pp.53-57
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• 2013

In here, we investigated the quantitative analysis method of indole-3-acetic acid (IAA) and indole-3-butyric acid (IBA) with liquid chromatography-mass/mass spectrometry (LC-MS/MS) or gas chromatography-MS. Two ways of clean-up process were investigated for LC-MS/MS instrumental analysis of IAA, but both a simple dilution and hydrophile-lipophile balance (HLB) solid phase extraction (SPE) were not met the optimal recovery rates for quantitative analysis. On the other hand, the clean-up method for GC-MS was finally optimized through HLB-SPE from 250-folds diluted sample and methylation with trimethylsilyl chloride in methanol for 4 h. The limit of detection for methyl ester of IAA and IBA were both 1.4 mg/L, and recovery rates showed 93-107% from the concentrated liquid fertilizer.

• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.4
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• pp.253-258
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• 2016

This paper proposes a method that utilizes optimization approach for localization of an indoor mobile robot. Bayesian filters which have been widely used for localization of a mobile robot use many control parameters to take the uncertainties in measurement and environment into account. The estimation performance depends on the selection of these parameter values. Also, the performance of the Bayesian filters deteriorate as the non-linearity of the motion and measurement increases. On the other hand, the optimization approach uses fewer control parameters and is less influenced by the non-linearity than the Bayesian methods. This paper compares the localization performance of the proposed method with the performance of the extended Kalman filter to verify the feasibility of the proposed method. Measurements of ranges from beacons of ultrasonic satellite to the robot are used for localization. Mahalanobis distance is used for detection and rejection of outlier in the measurements. The optimization method sets performance index as a function of the measured range values, and finds the optimized estimation of the location through iteration. The method can improve the localization performance and reduce the computation time in corporation with Bayesian filter which provides proper initial location for the iteration.

• Journal of the Korean Society of Safety
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• v.24 no.6
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• pp.72-78
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• 2009

Exposure to HDI(hexamethylene di-isocyanate) commonly used in vehicle crash repair workshops remains a leading cause of occupational asthma. Although skin and eye contamination are considered as absorption routes, there are no occupational exposure standards for skin and ocular exposure. This is the reason why there are more empirical data should be provided. Therefore this study was to determine contamination levels of HDI on the skin, eyes, work surfaces, respirators and eye protectors. There was evidence of contamination on a variety of work surfaces, for example, door handles, bench top and spray gun, etc. A high proportion(47~80%) of skin wipe samples from neck, forehead, back hand, palm and wrist was positive for HDI contamination, even though spray time was relatively brief. The contamination levels from spraying inside spray booth were generally higher than outside booth due to poor work practices and inappropriate personal protective use like safety gloves. Apprentices had higher exposure levels than the qualified painters, likely due to lack of the recognition of safety and hygiene. The extent of contamination inside the PPE might provide an indication of the potential for respiratory & skin exposure and ocular exposure. Eye fluid samples from 4 out of 14 workers had the positive detection of HDI contamination, due to poor work practices like no or inappropriate eye protection. Considering the potential for dermal & ocular exposure to contribute to possible health symptoms including respiratory sensitization, the empirical data point to a need for improving work practices and appropriate PPE selection, use and maintenance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.2C
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• pp.192-199
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• 2008

In ultra-wideband (UWB) systems, conventionally, the synchronization is to align time phases of a locally generated template and any of multipath components to within an allowable range. However, the synchronization with a low-power multipath component could incur significant performance degradation in receiver operation (e.g., detection) after the synchronization. On the other hand, the synchronization with a high-power multipath component can improve the performance in receiver operation after the synchronization. Generally, the first one among multipath components has the largest power. Thus, the synchronization with the first path component can make better performance than that with low-power component in receiver operation after the synchronization, Based on which, we first propose an optimal decision rule based on a maximum likelihood (ML) approach, and then, develope a simpler suboptimal decision rule for selecting the first path component. Simulation results show that the system has good demodulation performance, which uses new synchronization definition and the proposed decision rules have better performance than that of the conventional decision rule in UWB multipath channels. Between macroblocks in the previous and the current frame. On video samples with high motion and scene change cases, experimental results show that (1) the proposed algorithm adapts the encoded bitstream to limited channel capacity, while existing algorithms abruptly excess the limit bit rate; (2) the proposed algorithm improves picture quality with $0.4{\sim}0.9$dB in average.

• Journal of the Korean Chemical Society
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• v.40 no.2
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• pp.109-116
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• 1996

A matrix modification was studied for the determination of trace germanium in mineral waters by electrothermal atomic absorption spectrophotometry (ET-AAS). For this, the type and quantity of modifier as well as the use of auxiliary modifier were investigated to realize the efficient modification. Germanium suffers from low sensitivity and poor reproducibility in ET-AAS determination because of the premature loss of germanium via volatile germanium monoxide formation when heated in the presence of carbon. Therefore, the addition of a matrix modifier is necessary to stablize the germanium, thermally and chemically. By the addition of palladium (10 ${\mu}g/mL)$ as a single modifier to the sample containing 500 ng/mL germanium, the charring temperature could be raised from 800 to $1000^{\circ}C$, and its absorbance was also increased, but the atomization temperature was not raised. In this case, the absorbance of germanium was not changed in the range of 10∼70 ${\mu}g/mL$ of palladium added. On the other hand, it was considered that the use of a mixed modifier could modifiy the matrix more effectively than with a single modifier. The best results were obtained by using 1% ammonium hydroxide as an auxiliary modifier together with 10 ${\mu}g/mL$ palladium. The charring temperature could be raised from 800 to $1100^{\circ}C$, without any change of the atomization temperature. With above optimum conditions, the trace amount of germanium in several mineral waters were determined by a calibration curve method, and good recoveries of more than 95% were also obtained in the samples in which a given amount of germanium was spiked. The detection limit of this method was about 6.9 ng/mL.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.6
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• pp.34-51
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• 2008

Today, the Internet is a part of our life. For that reason, we regard revealing characteristics of Internet traffic as an important research theme. However, Internet traffic cannot be easily manipulated because it usually occupy huge capacity. This problem is a serious obstacle to analyze Internet traffic. Many researchers use various sampling techniques to reduce capacity of Internet traffic. In this paper, we compare several famous sampling techniques, and propose efficient sampling scheme. We chose some sampling techniques such as Systematic Sampling, Simple Random Sampling and Stratified Sampling with some sampling intensities such as 1/10, 1/100 and 1/1000. Our observation focused on Traffic Volume, Entropy Analysis and Packet Size Analysis. Both the simple random sampling and the count-based systematic sampling is proper to general case. On the other hand, time-based systematic sampling exhibits relatively bad results. The stratified sampling on Transport Layer Protocols, e.g.. TCP, UDP and so on, shows superior results. Our analysis results suggest that efficient sampling techniques satisfactorily maintain variation of traffic stream according to time change. The entropy analysis endures various sampling techniques well and fits detecting anomalous traffic. We found that a traffic volume diminishment caused by bottleneck could induce wrong results on the entropy analysis. We discovered that Packet Size Distribution perfectly tolerate any packet sampling techniques and intensities.

• Korean Journal of Veterinary Research
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• v.60 no.2
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• pp.61-68
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• 2020

The zoonotic transmission of viral diseases to humans is a serious public health concern. Pigs are frequently a major reservoir for several zoonotic viral diseases. Therefore, periodic surveillance is needed to determine the infection rates of zoonotic diseases in domestic pigs. Hepatitis E virus (HEV), rotavirus, sapovirus (SaV), and norovirus (NoV) are potential zoonotic viruses. In this study, 296 fecal samples were collected from weaned piglets and growing pigs in 13 swine farms, and the viral RNA was extracted. Partial viral genomes were amplified by reverse transcription-polymerase chain reaction (PCR) or nested-PCR using virus-specific primer sets under different PCR conditions. HEV-3, rotavirus A, and SaV genogoup 3 were detected from 11.5, 2.7, and 3.0% of the samples, respectively. On the other hand, NoV was not detected in any of the samples. Genetic analysis indicated that the nucleotide sequences of swine HEV-3 and rotavirus A detected in this study were closely related to those of human isolates. However, swine SaV was distant from the human strains. These results suggest that HEV-3 and rotavirus A can be transmitted from pigs to humans. Therefore, strict preventive measures should be implemented by workers in the swine industry to prevent infections with HEV-3 and rotavirus A excreted from pigs.

• The Journal of Engineering Geology
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• v.16 no.2 s.48
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• pp.145-152
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• 2006

Industry development caused numerical and quantitative increase of noxious chemical substances that contain risk assessment in water resources. For use of efficient water resources a pre-treatment of contaminant source which is flowed in water resources is recognized in essential process. Therefore, the discharged water quality from discharged company began to control contaminant by total amount of pollutant in domestic. However, to estimate closely chemical substances it is not proved up to now, monitoring is very important. This study achieved a monitoring of micro noxious chemical substance by fiber and chemistry industrial wastewater inflow to examine risk assessment of the water system of Nakdong river. Chloroform was measured highest among volatile organic compounds (VOCs) that the results of water quality of influent and effluent are detected from 7 companies of study area. The other side, because measured value of detected chloroform is indefinite detection level in the same company, it is difficulty in management of water quality. However it may not be much effects of the water system of Nakdong river because these company's effluent is high treatment efficiency of chloroform (more than 88%) in sewage treatment plant. On the other hand, in the investigated results for the European Union specified priority substance that is detected to relationship influent and effluent from fiber/chemistry associated industries, these substances were not detected and domestic data was hardly referred. Therefore, data construction of continuous monitoring about this water quality may have to be achieved certainly to utilize as country policy.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.5
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• pp.697-708
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• 2016

As the needs for fast wireless communication technology in various fields, including companies, individuals, etc., grows, many research projects related to the coverage of propagation are being carried out for plaining optimized communication services. On the other hand, there are some limitations in surveying and analyzing propagation in highland areas. To provide a better communication service of a new service, a range of radio environment conditions based on a wide radio bandwidth (selection of propagation model, correction of value in accordance with radio bandwidth, etc.) should be considered. In particular, radio environment conditions are becoming increasingly sophisticated. By the early detection of real-time changes in the radio spectrum, which is based on an examination and research of regional occupied band width condition, proper measures should be established. To make a proper solution of above, the basic real-time analysis of spectrum distribution status by regional groups is necessary. In addition, the establishment of prompt measures should be enable by stored or analyzed radio data. In an attempt to predict reliable propagation coverage, this thesis examines the limited propagation data with HTZ Warfare, which were collected from domestic high land sites faced with limited access. Furthermore, a comparative result value evaluation for an optimized propagation model was performed through testing simulations, and frequency-dependent and propagation model-dependent analysis.