• Korean journal of applied entomology
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• v.47 no.4
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• pp.457-465
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• 2008

Eight Bacillus thuringiensis strains activated against mosquito larva were compared their characterization. Spherical-shaped parasporal inclusion of B. thuringiensis subsp. tohokuensis CAB167 was observed by phase-contrast microscopy and scanning electron microscopy. $LC_{50}$ values of B. thuringiensis subsp. tohokuensis CAB167 against Culex pipiens molestus, Culex pipiens pallens, and Aedes aegyti were 173, 190 and 580 ng/ml, respectively. B. thuringiensis subsp. tohokuensis CAB167 had a parasporal inclusion containing 4 major protein components, for example, 135, 80, 49 and 28-kDa by SDS-PAGE. Otherwise, after trypsin digestion of parasporal inclusion, SDS-PAGE was showed new protease-resistant peptides at 72 and 63-kDa. Activated toxins of isolated CAB167 were different from other reference strains on a serological by immuno-diffusion test.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.28 no.5
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• pp.222-227
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• 2018

$Zn_{1-x}Co_x$ Zeolitic Imidazolate Framework (ZIF) (x = 0~0.05) were prepared by the co-precipitation of $Zn^{2+}$ and $Co^{2+}$ using 2-methylimidazole, which were converted into pure and Co-doped ZnO nanoparticles by heat treatment at $600^{\circ}C$ for 2 h. Homogeneous Zn/Co ZIFs were achieved at x < 0.05 owing to the strong coordination of the imidazole linker to $Zn^{2+}$ and $Co^{2+}$, facilitating atomic-scale doping of Co into ZnO via annealing. By contrast, heterogeneous Zn/Co ZIFs were formed at $x{\geq}0.05$, resulting in the formation of $Co_3O_4$ second phase. To investigate the potential as high-performance gas sensors, the gas sensing characteristics of pure and Co-doped ZnO nanoparticles were evaluated. The sensor using 3 at% Co-doped ZnO exhibited an unprecedentedly high response and selectivity to trimethylamine, whereas pure ZnO nanoparticles did not. The facile, bimetallic ZIF derived synthesis of doped-metal oxide nanoparticles can be used to design high-performance gas sensors.

• Korean Journal of Applied Biomechanics
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• v.25 no.2
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• pp.191-198
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• 2015

Objective : The purpose of this study was to conduct biomechanical analysis of varying backpack loads on the lower limb movements during downhill walking over $-20^{\circ}$ ramp. Method : Thirteen male university students (age: $23.5{\pm}2.1yrs$, height: $175.7{\pm}4.6cm$, weight: $651.9{\pm}55.5N$) who have no musculoskeletal disorder were recruited as the subjects. Each subject walked over $20^{\circ}$ ramp with four different backpack weights (0%, 10%, 20% and 30% of body weight) in random order at a speed of $1.0{\pm}0.1m/s$. Five digital camcorders and two force plates were used to obtain 3-d data and kinetics of the lower extremity. For each trial being analyzed, five critical instants were identified from the video recordings. Ground reaction force, loading rate, decay rate, and resultant joint moment of the ankle and the knee were determined by the inverse dynamics analysis. For each dependent variable, one-way ANOVA with repeated measures was used to determine whether there were significant differences among four different backpack weight conditions (p<.05). When a significant difference was found, post hoc analyses were performed using the contrast procedure. Results : The results of this study showed that the medio-lateral GRFs at RHC in 20% and 30% body weight were significantly greater than the corresponding value in 0% of body weight. A consistent increase in the vertical GRFs as backpack loads increased was observed. The valgus joint movement of the knee at RTO in 30% body weight was significantly greater than the corresponding values in 0% and 10% body weight. The increased valgus moment of 30% body weight observed in this phase was associated with decelerating and stabilizing effects on the knee joint. The results also showed that the extension and valgus joint moments of the knee were systematically affected by the backpack load during downhill walking. Conclusion : Since downhill walking while carrying heavy external loads in a backpack may lead to excessive knee joint moment, damage can occur to the joint structures such as joint capsule and ligaments. Therefore, excessive repetitions of downhill walking should be avoided if the lower extremity is subjected to abnormally high levels of load over an extended period of time.

• Journal of Periodontal and Implant Science
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• v.23 no.1
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• pp.109-126
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• 1993

Refractory periodontitis manifest progressive attachment loss in a rapid and unrelenting manner regardless of the type or frequency of therapy applied. The purpose of this study was ta evaluate the relation between the level of cytokines in GCF and periodontopathic microflora with disease activity of refractory periodontitis. Selection of patients with refractory periodontitis (7 males, 3 females) were made by long term clinical observation including conventional clinical history and parameters. Teeth that showed pocket depth greater than 6mm were selected as sample teeth. Subjects were examined at baseline and after 3 months. Prior to baseline test, individual acrylic stent was fabricated. Reference grooves were made on each sample tooth site. Pocket depth and attachment loss were measured by Florida Probe. Gingival index was measured at 4 sites each sample teeth. Disease activity was defined as attachment loss of ${\ge}$ 2.1mm, as determined by sequential probing and tolerance method. The pattern and amount of alveolar bone resorption was observed with quantitative digital subtraction image processing radiography. Morphological analysis of subgingival bacteria was taken by phase contrast microscopy. Predominant cultivable bacterial distribution and frequency were compared between disease-active and disease-inactive site using immunofluorescence microscopy and selective microbial culturing. Levels of $interleukin-l{\beta}$, 2, 4, 6 and $TNF-{\alpha}$ in GCF and blood serum sample were quantified by ELISA. In active sites, P. intermedia was significantly increased to compare with inactive site. $IL-1{\beta}$, IL-2, IL-6 and $TNF-{\alpha}$ in GCF were increased in active sites and IL-2 in serum was increased in active patients significantly. Alveolar bone loss in active site was correlated with $IL-1{\beta}$, IL-2 in GCF. And loss of attachment in active site was correlated with IL-2 in GCF. These results demonstrate that IL-2 in serum, $IL-1{\beta}$, IL-2, IL-6 and $TNF-{\alpha}$ in GCF, P, intermedia might be used as possible predictors of disease activity in refractory periodontitis before it is clinically expressed as attachment loss and quantitative alveolar bone change.

• Journal of the Korean Society of Radiology
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• v.12 no.5
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• pp.631-636
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• 2018

The problem that the existing the magnetic resonance image (MRI) was prone to have not only long readout duration and low bandwidth in the phase-encode direction, but also geometric distortion was pointed out. The purpose of this study is to identify the usefulness of FOCUS-DWI through comparing FOCUS-DWI with the Conventional-DWI on a degree of uniformity and artifacts caused by the distance change in the central axis within the magnetic field. In terms of artifacts, there happened irregular striped artifacts in the Conventional-DWI technique, which in particular, more often arose in the central axis. Also, the overlap of imaging drastically increased. By contrast, there were no irregular striped artifacts in the FOCUS-DWI technique. In conclusion, it was found that the FOCUS-DWI technique was superior to the Conventional-DWI technique in terms of artifacts, the overlap of imaging, and a degree of uniformity. In addition, there was no difference of the change in distance from the central axis between the FOCUS-DWI technique and the Conventional-DWI technique. Thus, it is considered the FOCUS-DWI technique having less imaging distortion and high image quality will be highly clinically used.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.643-646
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• 2005

The gas hydrate exploration using seismic reflection data, the detection of BSR(Bottom Simulating Reflector) on the seismic section is the most important work flow because the BSR have been interpreted as being formed at the base of a gas hydrate zone. Usually, BSR has some dominant qualitative characteristics on seismic section i.e. Wavelet phase reversal compare to sea bottom signal, Parallel layer with sea bottom, Strong amplitude, Masking phenomenon above the BSR, Cross bedding with other geological layer. Even though a BSR can be selected on seismic section with these guidance, it is not enough to conform as being true BSR. Some other available methods for verifying the BSR with reliable analysis quantitatively i.e. Interval velocity analysis, AVO(Amplitude Variation with Offset)analysis etc. Usually, AVO analysis can be divided by three main parts. The first part is AVO analysis, the second is AVO modeling and the last is AVO inversion. AVO analysis is unique method for detecting the free gas zone on seismic section directly. Therefore it can be a kind of useful analysis method for discriminating true BSR, which might arise from an Possion ratio contrast between high velocity layer, partially hydrated sediment and low velocity layer, water saturated gas sediment. During the AVO interpretation, as the AVO response can be changed depend upon the water saturation ratio, it is confused to discriminate the AVO response of gas layer from dry layer. In that case, the AVO modeling is necessary to generate synthetic seismogram comparing with real data. It can be available to make conclusions from correspondence or lack of correspondence between the two seismograms. AVO inversion process is the method for driving a geological model by iterative operation that the result ing synthetic seismogram matches to real data seismogram wi thin some tolerance level. AVO inversion is a topic of current research and for now there is no general consensus on how the process should be done or even whether is valid for standard seismic data. Unfortunately, there are no well log data acquired from gas hydrate exploration area in Korea. Instead of that data, well log data and seismic data acquired from gas sand area located nearby the gas hydrate exploration area is used to AVO analysis, As the results of AVO modeling, type III AVO anomaly confirmed on the gas sand layer. The Castagna's equation constant value for estimating the S-wave velocity are evaluated as A=0.86190, B=-3845.14431 respectively and water saturation ratio is $50\%$. To calculate the reflection coefficient of synthetic seismogram, the Zoeppritz equation is used. For AVO inversion process, the dataset provided by Hampson-Rushell CO. is used.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.21 no.3
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• pp.139-145
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• 2011

Objectives: This investigation is purposed to evaluate the airborne asbestos concentrations in the public buildings having asbestos containing materials(ACMs) in Seoul. Methods: The Seoul Metropolitan Government carried out an asbestos survey to the city-owned public buildings to identify the level of risk exposure, classified into low, moderate and high risk. To evaluate the airborne concentration of asbestos, 11 sampling sites in ten buildings based on the survey were selected. The air samples from the eleven sites were analyzed by Phase Contrast Microscopy(PCM) and Transmission Electron Microscopy (TEM), and compared the analytical results from the both. Results: 1. The airborne fiber concentrations by PCM were less than the detection limit($7f/mm^2$) in 9(82%) out of 11 sampling sites. The highest concentration was 0.0043 f/cc, but it was below the guideline value for indoor air quality(0.01 f/cc), proposed by the Ministry of Environment, Korea. 2. In two sampling sites, having moderate risk level, the chrysotile was identified and showed it's concentrations of 0.0102 s/cc and 0.0058 s/cc, less than $5{\mu}m$ lengths. 3. The ACMs identified in the two sampling sites were a packing material(65% of chrysotile) in mechanical area and a thermal system insulation(5% of chrysotile) in a boiler room. Having more possibility of asbestos emission in the mechanical area, it would be required to set up and carry out the asbestos management plan. Conclusions: Based on the result of this study, the airborne asbestos concentrations in the public buildings with ACMs were generally lower than the guideline value for indoor air quality. There are widespread concerns about the possible health risk resulting from the presence of airborne asbestos fibers in the public buildings. Most of the previous studies about airborne asbestos analysis in Korea were performed based on PCM method that asbestos and non-asbestos fibers are counted together. In the public and commercial buildings, having ACMs, it is suggested that the asbestos be analyzed by TEM method to identify asbestos due to concerns about asbestos exposure to workers and unspecified people.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.4
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• pp.1055-1060
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• 2004

Apoptosis is the ability of cells to self-destruct by the activation of an intrinsic cellular suicide program when the cells are no longer needed or when they are seriously damaged. Morphologically, apoptosis is characterized by the appearance of membrane blebbing, cell shrinkage, chromatin condensation, DNA cleavage, and the fragmentation of the cell membrane-bound apoptotic bodies. Siegesbeckia glabrescens Makino (Siegesbeckiae Herba, SG) has been widely used as treatments for arthritis, and fever, as well as detoxification properties. The present studies were undertaken to evaluate if SG has an anti-apoptotic property. Cell viability was measured by XTT and tryphan blue stain. Morphological characteristic of human aortic smooth muscle cells(HASMC) were visualized with a phase-contrast microscope. SG significantly reduced HASMC, but not human umbilical vein endothelial cell(HUVEC), viability in a dose-dependent manner. Confluent untreated cells at 24hrs showed normal morphology, flat with a uniform polygonal shape. SG-treated cells (0.5㎎/㎖) at 24hrs showed apoptotic morphology. Cells became irregular with elongated lamellipodia, and exhibited condensed chromatin in nuclei with occasional endoucleation. There was an increase in the number of apoptotic cells rounding-up and being detached from the substrate. TUNEL staining of SG-treated cells showed dark-brown stains in nuclei and cytosol. Caspases are central components of the machinery responsible for apoptosis and are generally divided into two categories; the initiator caspases, which include caspases-2,-8,-9, and -10, and the effector caspases, which include caspases-3,-6, and -7. SG decreased anti-caspase-3 protein expression, which means activation of caspases-3 activity. It has been reported that there is a link between NO formation and apoptosis. NO production was accelerated by SG treatment in HASMC. L-NNA, NOS inhibitor, inhibited SG-induced apoptosis. These results, therefore, indicated that both caspases-3 and NO production are involved in apoptosis in smooth muscle cells. According to these results, SG may have a potential effect in the treatment of hypertensive atherosclerosis.

• Korean Journal of Veterinary Research
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• v.32 no.3
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• pp.435-450
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• 1992

To evaluate the fertilizing capacity of domestic animal spermatozoa by hamster test, semen were collected from 15 boars(Duroc, Landrace, and Yorkshire) and 2 mixed dogs which had been proved to be fertile in the past then, the semen were preserved in BWW medium at $4^{\circ}C$ or $18^{\circ}C$ for about 20 hours and coincubated with zona-free hamster ova for 5 hours. The ova were stained by lacmoid and examined under phase contrast microscope to investigate the rates of sperm binding to the ova, penetration and formation of a male pronucleus, and the numbers of both bound and penetrated sperm per ovum. Both the semen preserved at $18^{\circ}C$ for about 20 hours and that treated by swim up procedure showed considerably higher rates of sperm binding and penetration as well as higher number of penetrated sperm than that preserved at $4^{\circ}C$ for about 20 hours, respectively(p<0.01). Motility of boar sperm at insemination was from 40 to 90% and no difference in hamster test was obtained according to different degree of sperm motility. Abnormality in morphology of boar sperm at insemination was from 6 to 45% and no difference in hamster test was obtained according to different degree of sperm abnormality. The sperm concentrations of $7{\times}10^7$ and $7{\times}10^6$ showed considerably higher rates of sperm binding and penetration as well as higher number of bound sperm than that of $7{\times}10^4$ (p<0.01) along with the same higher results than that of $7{\times}10^5$(0<0.05), respectively. Boar sperm showed considerably higher rates of sperm binding and penetration as well as higher numbers of both bound and penetrated sperm than dog sperm, when both semen were treated by BWW＋heparin medium and swim up procedure, respectively. These results indicated that fertile boar sperm showed considerably lower rates in the results of hamster test, when preserved at $4^{\circ}C$ for about 20 hours and in lower concentration of sperm than when preserved at $18^{\circ}C$ for about 20 hours and in higher concentration of sperm, respectively, and at the same time considerably higher results than fertile dog sperm, consequently to prove that hamster test would be of great value in assaying the fertilizing capacity of boar sperm.

• Korean Journal of Materials Research
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• v.21 no.5
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• pp.250-254
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• 2011

We have synthesized bluish-green, highly-efficient $BaSi_2O_2N_2:Eu^{2+}$ and $(Ba,Sr)Si_2O_2N_2:Eu^{2+}$ phosphors through a conventional solid state reaction method using metal carbonate, $Si_3N_4$, and $Eu_2O_3$ as raw materials. The X-ray diffraction (XRD) pattern of these phosphors revealed that a $BaSi_2O_2N_2$ single phase was obtained. The excitation and emission spectra showed typical broadband excitation and emission resulting from the 5d to 4f transition of $Eu^{2+}$. These phosphors absorb blue light at around 450 nm and emit bluish-green luminescence, with a peak wavelength at around 495 nm. From the results of an experiment involving Eu concentration quenching, the relative PL intensity was reduced dramatically for Eu = 0.033. A small substitution of Sr in place of Ba increased the relative emission intensity of the phosphor. We prepared several white LEDs through a combination of $BaSi_2O_2N_2:Eu^{2+}$, YAG:$Ce^{3+}$, and silicone resin with a blue InGaN-based LED. In the case of only the YAG:$Ce^{3+}$-converted LED, the color rendering index was 73.4 and the efficiency was 127 lm/W. In contrast, in the YAG:$Ce^{3+}$ and $BaSi_2O_2N_2:Eu^{2+}$-converted LED, two distinct emission bands from InGaN (450 nm) and the two phosphors (475-750 nm) are observed, and combine to give a spectrum that appears white to the naked eye. The range of the color rendering index and the efficiency were 79.7-81.2 and 117-128 lm/W, respectively. The increased values of the color rendering index indicate that the two phosphor-converted LEDs have improved bluish-green emission compared to the YAG:Ce-converted LED. As such, the $BaSi_2O_2N_2:Eu^{2+}$ phosphor is applicable to white high-rendered LEDs for solid state lighting.