• 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.

• Korean Chemical Engineering Research
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• v.49 no.4
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• pp.400-404
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• 2011

Many studies on polydiacetylene(PDA) have been investigated to apply to chemical and biological sensors due to their unique optical properties of color change from blue to red and fluorescence change from non-fluorescence to red fluorescence. Especially, high sensitivity against specific molecules is very important to apply polydiacetylenes to various sensors. In this study, we examined the effect of sensitivity enhancement of 10,12-pentacosadynoic acid(PCDA) vesicles in detection ${\alpha}$-cyclodextrin(CD) according to control of vesicle size by filters with different pore sizes and polymerization temperature. Colorimetric response(CR) was calculated using visible spectrometer. In order to investigate the effect of vesicle size on sensitivity of PDA vesicles, two PCDA vesicles were filtered without filtration and with 0.22 ${\mu}m$ filter. The two PCDA vesicles were polymerized at $25^{\circ}C$ and were incubated with ${\alpha}$-CD(5 mM) for 30 min. The CRs of the former and latter vesicles were 31.4% and 74.0%, respectively. Then, two PCDA vesicles filtered with 0.22 ${\mu}m$ filter were polymerized at $25^{\circ}C$ and $5^{\circ}C$ and were reacted with ${\alpha}$-CD(5 mM) for 30 min to examine the effect of polymerization temperature. The CRs of the former and latter vesicles were 74.0 and 99.2%, respectively. This suggests that vesicle sizes and polymerization temperature are key factors in enhancing the sensitivity of PDA vesicles. In addition, these results are expected to be useful to apply the PDA vesicles as biosensors to detect DNA, protein, and cells.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.9
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• pp.835-842
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• 2016

In Korea, urban railway cars are typically maintained using the strategy of predictive maintenance. In an effort to overcome the limitations of the existing strategy, there is increased interest in adopting the condition-based maintenance strategy. In this study, a novel method is proposed to detect faults in the solenoid valves of the braking system in urban railway vehicles. We determined the key component (i.e., solenoid valve) that leads to braking system faults through the analysis of failure modes, effects, and criticality. Then, an equivalent circuit model was developed with the compensation of the temperature effect on solenoid coils. Finally, we presented how to detect faults with the equivalent circuit model and current signal measurements. To demonstrate the performance of the proposed method, we conducted a case study using real solenoid valves taken from urban railway vehicles. In summary, it was shown that the proposed method can be effective to detect faults in solenoid valves. We anticipate the outcome from this study can help secure the safety and reliability of urban railway vehicles.

• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.1
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• pp.13-23
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• 2010

This study was performed to compare the quality of image processing between the newly developed prototype using light emitting diode(LED) and the conventional $DIFOTI^{TM}$ system(EOS Inc., USA). To estimate the optimal light emitting power for the improved images, primary enamel surfaces treated under Carbopol 907 de-mineralizing solution were taken daily during 20 days of experimental periods by both DIFOTI systems. The results of comparative analyses on the images obtained from both systems with polarized image as gold standard can be summarized as follows: 1. Trans-illumination indices of images taken from primary enamel surfaces were decreased with time in both systems. 2. The differences of intensity of luminance between sound and de-mineralized enamel surface in prototype DIFOTI system was shown to be relatively smaller than conventional $DIFOTI^{TM}$ system. 3. From the comparative analysis of images from both DIFOTI system with polarized images as gold standard, the difference between sound and de-mineralized enamel surface of intensity of luminance of $DIFOTI^{TM}$ system was more correlated to polarized images than prototype of DIFOTI system. With the optimal LED emitting power, the control of aperture of digital camera is considered as the another key factor to improve the DIFOTI images. For the best image quality and analysis, the development of the improved image processing software is required.

• The Korean Journal of Pesticide Science
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• v.15 no.1
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• pp.15-21
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• 2011

Monitoring or follow-up surveying pesticide residues in agricultural commodities is the key to meet the international regulations and to enhance international competitiveness of Korean agricultural commodities. Six neonicotinoid insecticides, acctamiprid, clothianidin, dinotefuran, imidacloprid, thiacloprid, and thiamethoxam were monitored in 95 paprika samples collected from Gyeongnam area. Thc pesticide residues were extracted by EN 15662 buffer based on the QuEChERS method, clean-upped with dispersive solid-phase extraction method to remove interfering pigments, and analyzed using UPLC-MS/MS. The neonicotinoid pesticides were detected in 90.5% of the paprika samples. Two or more pesticides were detected in 82.3% of samples. Although detection frequencies were high, all samples complied with the maximum residue limits (MRLs) set by both the Korea Food and Drug Administration (KFDA) and Japanese Ministry of Health, Labour and Welfare.

• The Korean Journal of Nuclear Medicine
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• v.24 no.1
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• pp.37-48
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• 1990

Detection of deep-seated abscesses is sometimes difficult with ultrasonogrpahy or computed tome graphy alone. Indium-111-labeled leukocyte has widely used in the localization of abscesses after introduction by Segal and Thakur in 1976. But there are some difficulties in using indium-111-oxine in our country because of hardness to get the radiopharmaceutical timely and long time for labeling leukocytes. So we peformed the indium-111-labeled leukocyte scan for establishment of the labeling procedure and clinical application. We labeled the mixed leukocytes from 36 ml of patient's blood using 4 ml of ACD solution, 7 ml of 6% hydroxyethyl starch solution $(HESPAN^{(R)})$, 1 mCi of indium-111 oxine, 5 ml of normal saline and centrifuge. It took about 2 hours for the preparation of radiolabeled leukocytes and attention for contamination was needed. The average injected dose of labeled mixed leukocytes was 465 uCi. The average number of injected leukocytes was $2.5\times10^8$ and the labeling ratio was $57{\pm}13%$ (Table 2, Fig. 5). These number and ratio were sufficient for the localization of abscess. About twenty per cent of indium was labeled to red blood cells and platelets (Fig. 6) and the half-life of injected radiolabeled leukocytes was 8.3 hours. Scan was performed in 9 patients who were suspected to have abscesses clinically or radiologically. Three patients were positive, in one patient who had abscess close to lower lumbar vertebrae was surgically drained and another 2 positive cases did not show abscess clearly on computed tomography, so only antibiotics were administrated and treated successfully. The negative 6 patients were improved without specific treatment. In conclusion, the use of indium-111 oxine labeled leukocytes for localization of abscesses were very specific and helpful in the decision of treatment considering its relatively simple labeling method, and could be easily performed providing timely supply of the radiopharmaceutical.

• The Korean Journal of Nuclear Medicine
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• v.21 no.2
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• pp.167-174
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• 1987

Among noninvasive approaches for the evaluation of left ventricular performance, radionuclide ventriculography (RVG) has been shown to be of particular values. Phase analysis, recently introduced as more objective means for evaluating the temporal sequence of systolic ventricular wall motion than cine image of RVG comprises a pixel by pixel Fourier transformation of the time activity curve of a multiple gated acquisition equilibrium blood pool study. To examine the regional wall motion of ventricles in myocardial infarctions, we evaluated the phase image and histogram constructed for each ventricle by total phase angle range and full width of half maximum (FWHM). This study consisted of 7 normal subjects and 23 subjects with acute myocardial infarction. Contrast ventriculography and coronary angiography was performed in all partients with myocardial infarction. And we compared the result of phase analysis with cine image of RVG and examined the interrelationship between phase analysis and contrast ventriculography with coronary angiography. The results were as follows; 1) The total phase angle range and FWHM of LV phase histogram in myocardial infarction ($86^{\circ}\;and\;32^{\circ}$, repectively) were wider than those in normal control ($38^{\circ}\;and\;18^{\circ}$, respectively p<0.01). 2) RV phase angle range and FWHM in patients with right coronary artery (RCA) occlusion ($79^{\circ}\;and\;37^{\circ}$, respectively) were wider than those in normal control ($39^{\circ}\;and\;18^{\circ}$, respectively p<0.001) and the patients without RCA occlusion ($52^{\circ}\;and\;19^{\circ}$, respectively p<0.01). 3) Phase analysis was more sensitive (95%) than cine image of RVG (70%) for the detection of regional wall motion abnormality of LV.

• KIPS Transactions on Software and Data Engineering
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• v.10 no.7
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• pp.279-286
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• 2021

Recently, We are carrying out a policy of physical distancing of at least 1m from each other to prevent the spreading of COVID-19 disease in public places. In this paper, we propose a method for measuring distances between people in real time and an automation system that recognizes objects that are within 1 meter of each other from stereo images acquired by drones or CCTVs according to the estimated distance. A problem with existing methods used to estimate distances between multiple objects is that they do not obtain three-dimensional information of objects using only one CCTV. his is because three-dimensional information is necessary to measure distances between people when they are right next to each other or overlap in two dimensional image. Furthermore, they use only the Bounding Box information to obtain the exact coordinates of human existence. Therefore, in this paper, to obtain the exact two-dimensional coordinate value in which a person exists, we extract a person's key point to detect the location, convert it to a three-dimensional coordinate value using Stereo Vision and Camera Calibration, and estimate the Euclidean distance between people. As a result of performing an experiment for estimating the accuracy of 3D coordinates and the distance between objects (persons), the average error within 0.098m was shown in the estimation of the distance between multiple people within 1m.

• Korean Journal of Remote Sensing
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• v.37 no.3
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• pp.431-447
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• 2021

Recently, the use of high-resolution satellites is increasing in many areas. In order to supply useful satellite images stably, it is necessary to establish automatic precision geometric correction technic. Geometric correction is the process that corrected geometric errors of satellite imagery based on the GCP (Ground Control Point), which is correspondence point between accurate ground coordinates and image coordinates. Therefore, in the automatic geometric correction process, it is the key to acquire high-quality GCPs automatically. In this paper, we proposed iterative precision geometry correction method. we constructed an image pyramid and repeatedly performed GCP chip matching, outlier detection, and precision sensor modeling in each layer of the image pyramid. Through this method, we were able to acquire high-quality GCPs automatically. we then improved the performance of geometric correction of high-resolution satellite images. To analyze the performance of the proposed method, we used KOMPSAT-3 and 3A Level 1R 8 scenes. As a result of the experiment, the proposed method showed the geometric correction accuracy of 1.5 pixels on average and a maximum of 2 pixels.

• Journal of Korean Neurosurgical Society
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• v.65 no.6
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• pp.790-800
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• 2022

Objective : EID3 (EP300-interacting inhibitor of differentiation) was identified as a novel member of EID family and plays a pivotal role in colorectal cancer development. However, its role in glioma remained elusive. In current study, we identified EID3 as a novel oncogenic molecule in human glioma and is critical for glioma cell survival, proliferation and invasion. Methods : A total of five patients with glioma were recruited in present study and fresh glioma samples were removed from patients. Four weeks old male non-obese diabetic severe combined immune deficiency (NOD/SCID) mice were used as transplant recipient models. The subcutaneous tumor size was calculated and recorded every week with vernier caliper. EID3 and AMP-activated protein kinase α1 (AMPKα1) expression levels were confirmed by real-time polymerase chain reaction and Western blot assays. Colony formation assays were performed to evaluate cell proliferation. Methyl thiazolyl tetrazolium (MTT) assays were performed for cell viability assessment. Trypan blue staining approach was applied for cell death assessment. Cell Apoptosis DNA ELISA Detection Kit was used for apoptosis assessment. Results : EID3 was preferentially expressed in glioma tissues/cells, while undetectable in astrocytes, neuronal cells, or normal brain tissues. EID3 knocking down significantly hindered glioma cell proliferation and invasion, as well as induced reduction of cell viability, apoptosis and cell death. EID3 knocking down also greatly inhibited tumor growth in SCID mice. Knocking down of AMPKα1 could effectively rescue glioma cells from apoptosis and cell death caused by EID3 absence, indicating that AMPKα1 acted as a key downstream regulator of EID3 and mediated suppression effects caused by EID3 knocking down inhibition. These findings were confirmed in glioma cells generated patient-derived xenograft models. AMPKα1 protein levels were affected by MG132 treatment in glioma, which suggested EID3 might down regulate AMPKα1 through protein degradation. Conclusion : Collectively, our study demonstrated that EID3 promoted glioma cell proliferation and survival by inhibiting AMPKα1 expression. Targeting EID3 might represent a promising strategy for treating glioma.