• Journal of the Institute of Electronics Engineers of Korea SC
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• v.46 no.2
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• pp.15-21
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• 2009

Hearing loss is one of the most common birth defects among infants. Most of hearing-impaired children are not diagnosed until 1 to 3 years of age - which is too late for the critical period (6 month) for normal speech and language development. If a hearing impairment is identified and treated in its early stage, child's speech and language skills could be comparable to his or her normal-hearing peers. For these reasons, hearing screening at birth and throughout childhood is extremely important. ABR (Auditory brain-stem response) is nowadays one of the most reliable diagnostic tools in the early detection of hearing impairment. In this study, we have developed the system that automatically detects if there is hearing impairment or not for infants or children. For future studies, it will be developed as a portable system to be able to take a measurement not only in sound proof room but also in nursery for neonates.

• Journal of Preventive Medicine and Public Health
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• v.36 no.2
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• pp.101-107
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• 2003

Objectives : Dementia has emerged as a leading public health problem in elderly persons, and its early detection is important for the treatment of curable cases, and in the educational support for other family members. Although dementia screening tests are available, they have not gained widespread use in community or primary care settings. Our goal was to validate the Tine and Change (T&C) Test, -including its validity and reliability in patients, and to assess it as a simple, standardized method for the screening of dementia in the rural elderly. Methods : The participants in this study comprised of 59 patients from an urban hospital and 405 persons from a rural community aged 65 years or older. The time test evaluated the understanding of clock hands indicating 11:10, and the change test the ability to make 1,000 Won from a group of coins, consisting of one 500, seven 100, and seven 50 Won coins. The T&C ratings were validated against a reference standard based on the physician's diagnosis of the patients. The convergent validity in relation to other cognitive measure, test-retest agreement, and inter-observer reliability were assessed. To assess the relationship between the Korean Mini-Mental State Exam (K-MMSE) and the T&C Test, the mean K-MMSE scores were compared with the results of the T&C Test in the elderly from a rural community. Results The T&C Test had a sensitivity and specificity of 73.0, and 90.9%, and positive and negative predictive values of 93.1, and 66.7%, respectively. The test-retest and inter-observer agreement rates were both 95%. The K-MMSE scores and T&C Test were significantly related in the elderly from a rural community (p<0.01), The T&C Test was not influenced by the educational status. The Time and Change Tests took a mean of 6.3 and 12.7 seconds, respectively, to complete Conclusion : The T&C Test is a simple, accurate and reliable, performance-based tool in the screening for dementia. Because it is quick, and easy-to-use, it is hoped the T&C Test will be used for the widespread cognitive screening of aging populations.

• Journal of Periodontal and Implant Science
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• v.38 no.2
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• pp.143-152
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• 2008

Purpose: Specific bacteria are believed to play an important role in chronic periodontitis. Although extensive microbial analyses have been performed from subgingival plaque samples of periodontitis patients, systemic analysis of subingival microbiota has not been carried out in a Korean population so far. The purpose of this study was to investigate the prevalence of 29 putative periodontal pathogens in Korean chronic periodontitis patients and evaluate which pathogens are more associated with Korean chronic periodontitis. Material and Methods: A total of 86 subgingival plaque samples were taken from 15 chronic periodontits(CP) patients and 13 periodontally healthy subjects in Korea. CP samples were obtained from the deepest periodontal pocket (>3 mm probing depth[PD]) and the most shallow periodontal probing site ($\leq$3 mm PD) in anterior tooth and posterior tooth, respectively, of each patient. Samples in healthy subjects were obtained from 1 anterior tooth and 1 posterior tooth. Polymerase chain reaction (PCR) of 16S ribosomal DNA (rDNA) of subgingival plaque bacteria was performed. Detection frequencies(% prevalence) of 29 putative periodontal pathogens were investigated as bacterium-positive sites/total sites. Results: With the exception of Olsenella profuse and Prevotella nigrescens, the sites of diseased patients generally showed higher prevalence than the healthy sites of healthy subjects for all bacteria analyzed. Tanerella forsythensis (B.forsythus), Campylobacter rectus, Filifactor alocis, Fusobacterium nucleatum, Porphyromonas endodontalis and Porphyromonas gingivalis were detected in more than 80% of sites with deep probing depths in CP patients. In comparison between the sites (deep or shallow PD) of CP patients and the healthy sites of healthy subjects, there was statistically significant difference(P<0.05) of prevalence in T.forsythensis (B.forsythus), C.rectus, Dialister invisus, F.alocis, P.gingivalis and Treponema denticola. Conclusion: Our results demonstrate that the four putative periodontal pathogens, T.forsythensis (B.forsythus), C.rectus, P.gingivalis and F.alocis are closely related with CP patients in the Korean population.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.5
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• pp.22-33
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• 2021

In the case of open phase faults caused by the disconnection of distribution feeders interconnected to a PV system, many problems can occur depending on the core type and wiring method of the grid-connected transformers. Moreover, open phase faults are difficult to detect because the open phase voltage of the existing protection relay (Open Phase Relay (47)) can be maintained, even though a disconnection fault occurred, depending on the wiring method and the iron core type of the grid-connected transformer for a PV system. Therefore, this paper proposes a novel algorithm to detect open phase faults by comparing the currents and phases between the primary and secondary sides of a grid-connected transformer. In addition, this paper presents the modeling of a distribution system and protection devices for detecting open phase faults using PSCAD/EMTDC S/W, and implements a test protection device for detecting open phase faults based on the above-mentioned modeling. The simulation and test results confirmed that the proposed algorithm is useful for detecting open phase faults according to the wiring method and iron core type of grid-connected transformer for a PV system because operation slope and unbalance rate of the primary current exceed the setting value (30[%]) of the protection device.

• Journal of Microbiology and Biotechnology
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• v.13 no.6
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• pp.912-918
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• 2003

Mitotic centromere-associated kinesin (MCAK), which is a novel kinesin with a central motor domain, is believed to playa role in mitotic segregation of chromosome during the M phase of the cell cycle. In the present study, it is shown that a rabbit polyclonal antibody has been produced using the N-terminal region (187 aa) of human MCAK expressed in E. coli as the antigen. To express the N-terminal region in E. coli, the MCAK cDNA fragment encoding N-terminal 187 aa was obtained by PCR and was then inserted into the pET 3d expression vector. Molecular mass of the N-terminal region overexpressed in the presence of IPTG was 23.2 kDa on SDS-PAGE, and the protein was insoluble and mainly localized in the inclusion body that could be easily purified from the other cellular proteins. The N-terminal region was purified by electro-elution from the gel after the inclusion body was resolved on the SDS-PAGE. The antiserum obtained after tertiary immunization with the purified protein specifically recognized HsMCAK when subjected to Western blot analysis, and showed a fluctuation of the protein level during the cell cycle of human Jurkat T cells. Synchronization of the cell-cycle progression required for recovery of cells at a specific stage of the cell cycle was performed by either hydroxyurea or nocadazole, and subsequent release from each blocking at 2, 4, and 7 h. Northern and Western analyses revealed that both mRNA and protein of HsMCAK reached a maximum level in the S phase and declined to a basal level in the G1 phase. These results indicate that a polyclonal antibody raised against the N-terminal region (187 aa) of HsMCAK, overexpressed in E. coli, specifically detects HsMCAK (81 kDa), and it can analyze the differential expression of HsMCAK protein during the cell cycle.

• Clinical and Experimental Pediatrics
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• v.46 no.6
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• pp.536-540
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• 2003

Purpose : Aspiration of foreign material into the lungs can cause acute or chronic pulmonary diseases. It is difficult to detect small amounts of aspiration due to the lack of safe, sensitive and specific diagnostic tests. Recently, in animal or human studies, it has been reported that immunochemistry for lactalbumin can be used to detect the minimal aspiration. So, the authors' investigation was designed to determine whether human milk phagocytized alveolar macrophages can be detected in human milk aspirated mice. Methods : Sixty four male mice, 6-8 weeks old and 30-40 gm weighing, were used for this study. About 0.05 mL of human milk or normal saline were given intranasally once per day for 1 day or 3 days. Under anesthesia with ketamine and xylazine, the trachea of each mouse was cannulated with an 18G Jelco needle and then, each mouse's lungs were lavaged three times with 0.5 mL of phosphate buffer solution at 2, 8, 24, and 48 hours after the last milk or normal saline instillation. Cells in bronchoalveolar lavage fluid were stained with Oil Red O and immunocytochemistry for alpha-lactalbumin. Results : Immunocytochemical reactivity for alpha-lactalbumin or lipid-laden alveolar macrophages were not observed in the normal saline aspirated groups. Immunocytochemical reactivity for alpha-lactalbumin were observed in the human milk aspirated groups. They showed a peak at 8 hours and decreased markedly at 24 hours but persisted even at 48 hours after aspiration. Immunocytochemical stain positive alveolar macrophages were noted similarly in number between single and multiple aspiration groups. Conclusion : These observations suggested that alveolar macrophages for lactalbumin could be more easily detected on immunocytochemistry than Oil Red O stain, and immunocytochemistry could be used as a sensitive and specific diagnostic test for the detection of human milk aspiration.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.4
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• pp.11-21
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• 2013

The conventional real-time signal control strategy for oversaturated situation generally requires a number of detectors at the intersection in order to identify the queue length at each approach. Also, existing strategy for the spillback has limited effect due to the temporal spillback control which only reduce the green split at the approach. In this study, a signal control system utilizing the imagery information from ITS roadside equipment is developed for operation of oversaturated intersections. The strategy calculates the saturation ratio based on the queue length extracted from ITS RSE, and designs the signal control variables according to the saturation ratio. The signal control strategy is divided into two phases: oversaturated and supersaturated. In oversaturated conditions, timing plan for main approach is optimized by the queue length. In oversaturated conditions where spillback might occur, the signal timing is designed in order to avoid the spillback. To increase field adaptability, the strategy is designed to adjust the split length, all-red-time, and clearance time, and keep the major signal control variables intact. The result of the simulation shows that in oversaturated conditions, the improvement is similar to the real-time signal control system. In case of, oversaturated conditions, however, the effect of the strategy is superior to that of a real-time system.

• 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 the Korean Institute of Telematics and Electronics C
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• v.35C no.10
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• pp.1-11
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• 1998

This paper presents a new implementation method of the pulsed NMR(nuclear magnetic resonance) apparatus, which contains a single coil in a magnet console, to detect a NMR signal. Applying an RF magnetic field of 5MHz to the magnet console which is designed to have Larmor frequency of 5MHz for hydrogen atom, the hydrogen NMR signal was obtained from the glycerin which was put in the magnet console as a sample. The DC magnetic field in the magnet console was implemented with a permanent magnet of 1168 gauss and the RF magnetic field was generated appling an RF signal with the frequency of 5MHz and the current magnitude of 8A to a coil of 5.73${\mu}$H. The magnitude of the NMR signal was maximum when the RF magnetic field was generated for 2.8 ${\mu}$sec, and the period of generating the RF magnetic field was designed to 100msec for detecting the NMR signal repeatedly. The NMR signal, radiated from the sample in the magnetic console, was appeared as an amplitude-modulated signal with a frequency equal to the Larmor frequency. The signal, induced in the coil, was amplified in the tx/rx separation circuit, preamplifier and intermediate amplifier by a factor of 20.7dB, 36dB and 40dB, respectively, and the signal was detected by a synchronous detection circuits, then the NMR signal was obtained.

• Journal of The Korean Astronomical Society
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• v.55 no.5
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• pp.173-194
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• 2022

We complete the survey for finite-source/point-lens (FSPL) giant-source events in 2016-2019 KMTNet microlensing data. The 30 FSPL events show a clear gap in Einstein radius, 9 𝜇as < 𝜃_E < 26 𝜇as, which is consistent with the gap in Einstein timescales near t_E ~ 0.5 days found by Mróz et al. (2017) in an independent sample of point-source/point-lens (PSPL) events. We demonstrate that the two surveys are consistent. We estimate that the 4 events below this gap are due to a power-law distribution of free-floating planet candidates (FFPs) dN_FFP/d log M = (0.4 ± 0.2) (M/38 M_⊕)^-p/star, with 0.9 ≲ p ≲ 1.2. There are substantially more FFPs than known bound planets, implying that the bound planet power-law index 𝛾 = 0.6 is likely shaped by the ejection process at least as much as by formation. The mass density per decade of FFPs in the Solar neighborhood is of the same order as that of 'Oumuamua-like objects. In particular, if we assume that 'Oumuamua is part of the same process that ejected the FFPs to very wide or unbound orbits, the power-law index is p = 0.89 ± 0.06. If the Solar System's endowment of Neptune-mass objects in Neptune-like orbits is typical, which is consistent with the results of Poleski et al. (2021), then these could account for a substantial fraction of the FFPs in the Neptune-mass range.