• Tuberculosis and Respiratory Diseases
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• v.59 no.1
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• pp.39-46
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• 2005

Background : Even though it has been suggested that low-colony, scotochromogen nontuberculous mycobacteria (NTM) are usually contaminants and not true pathogens, evidence for this hypothesis has not been provided. This study investigated the colony characteristics, organism identification, and clinical significance of low-colony scotochromogen. Methods : The laboratory cultured 6,898 respiratory clinical specimens for an examination of mycobacteria over a three-month period. A low-colony count was arbitrarily defined as ${\leq}20$ colonies. This study analyzed the recovery rate of the mycobacteria, the number of colonies and their gross characteristics, and their clinical significance. PCR-restriction fragment length polymorphism analysis was carried out to identify the NTM species. NTM pulmonary disease was defined according to the American Thoracic Society. Results : A total of 6,898 respiratory specimens for mycobacterium were cultured. Of these, 263 (3.8%) grew NTM, and 382 (5.5%) grew M. tuberculosis. Of the 263 cultured NTM specimens, 124 (47.1%) were scotochromogens. The smear-positive rate was significantly lower in these scotochromogens (4.8%) than in the non-scotochromogens (23.7%) (p<0.05). The most common isolates were M. gordonae (83/102, 81.4%) in the scotochromogens, and MAC (52/121, 43.0%) in the non-scotochromogens. Even though three out of 113 patients with a low-colony scotochromogen has been diagnosed with NTM pulmonary disease, the isolated scotochromogen was not considered to be the cause of the NTM disease but was just a contaminant. Conclusion : In this study, the most common isolate of a low-colony count scotochromogen was M. gordonae, which appeared to be contaminants and not true pathogens. Greater efforts in the quality control of a mycobacterium laboratory are needed in cases where there is a high recovery rate of low-colony count scotochromogen.

• Korean Journal of Optics and Photonics
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• v.6 no.4
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• pp.331-336
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• 1995

The steady-state absorption saturation of the photodarkend SDG was investigated. The absorption saturation intensity was observed to increase for the photodarkened sample. The diffraction efficiency of the permanent grating due to photodarkening was also measured using the backward DFWM technique. For the low backward pump intensity, the diffraction efficiency was proportional to the intensity of the pump beam. The origin of increasing diffraction efficiency is attributed to the difference in absorption between the permanent gratings created by photodarkening. ening.

• Korean Journal of Ichthyology
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• v.27 no.1
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• pp.39-44
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• 2015

Based on the 14 specimens collected from the Korean waters, we described the external morphology of Ocynectes maschalis in detail to provide morphological characteristics for species identification. The species from Korea is characterized by having a low first dorsal fin with a dark spot posteriorly, no dark blotches ventrally, three saddle-like blotches on dorsal midline posterior to the second dorsal fin, and two occipital cirri on head.

• Proceedings of the Optical Society of Korea Conference
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• 2003.07a
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• pp.264-265
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• 2003

광 회절한계를 극복한 기록밀도 향상 기술로 대두된 근접장 응용 정보저장기술은 차세대 광 정보저장의 핵심기술로 간주되고 있다. 근접장을 응용한 기술에는, 근접장 헤드구조의 관점에서, 근접장 효과 렌즈(SIL), 탐침형, 미소구멍레이저, 안테나 구조 등 나노크기 Aperture를 가지는 구조 등이 있다. 그러나 각각의 근접장 헤드구조에 적합한 특히, 탐침형 근접장 방식에 적합한 근접장 매체에 대한 활발한 연구는 아직 진행되고 있지 않다. (중략)

• Economic and Environmental Geology
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• v.37 no.3
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• pp.347-354
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• 2004

We report the petrographic and petrochemical results on the rocks which have been classified as hornfelsic sandstones or mudstones of the Gyeongsang Group in Wolseong Area, part of Choyang Geologic Sheet (Tateiwa, 1924) and discuss its origin. The rocks consist of alternating layers with dark. fine-grained and bright, coarse-grained but don't have any clues of thermal alteration such as hornfels. The rocks are composed of quartz, feldspar and rock fragments of volcanic origin. The overall geochemical characteristics of the rocks indicate that the rocks have mainly rhyolitic composition with 64.5-72 wt% SiO$_2$ and are similar to the trend of Cretaceous and Tertiary volcanic rocks around this area. On the contrary, the geochemical characteristics of rocks are distinguished from those of Lower Cretaceous Sindong and Mayans mudrocks in the Gyeongsang Basin. We re-name the rocks as rhyolitic tuffite.

• Journal of Korean Society of Forest Science
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• v.13 no.1
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• pp.1-24
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• 1971

In order to elucidate the feasibility to identify the plant species through the photographic tone this study was made. In this study the author made photographs of Juniperus chinensis L., and Populus glandulosa Uyeki, with the panchromatic film using either yellow filter or red filter in different seasons respectively. The author analyzed the value of tone variation at the level of stereoscopic view of the same photographs by using tone scale and Automatic Micro-Photo-Densitometer. The results obtained are summarized as follows: A. Tone scale reading 1. The tone of Populus glandulosa Uyeki was darker than that of Juniperus chinensis L. in a photograph. 2. Regardless of the tree species, tone of photographs obtained with yellow filter was darker than that with red filter. 3. Along the progresses of seasons, the photographic tone was changed. That is, from the spring to the summer it showed darker and than, from the summer to winter it changed lighter. 4. During winter and spring the discrimination between the both species of trees can be easily made by stereoscopic view whether there are leaves on the tree or not rather than by tone observation. 5. Regardless of tree species, variation of tone due to the age was noticed. The older trees have darker tone than the younger one. 6. It is recognized that the yearly difference depends on insolation quantities. 7. The highest reflex light-waves were in between $600m{\mu}$ and $660m{\mu}$ for both species of trees. B. Density reading 1. For the density reading, there was the same tendency as in tone scale reading. 2. The changes of peaks of the scanning curves with Populus glandulosa Uyeki is smoother and takes place in lower position than with Juniperus chinensis L. 3. The scanning curves on the 20th May was smoothest, and change of peaks increased gradually according to the season progresses. 4. In relation to the types of filter the photographs with yellow filter showed less changes of peaks then that with red filter.

• Tuberculosis and Respiratory Diseases
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• v.58 no.4
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• pp.385-391
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• 2005

Background : The incidence of nontuberculous mycobacterium (NTM) infections in Korea is increasing. This retrospective study was performed to examine the recovery rate of NTM from respiratory specimens as well as the isolated NTM colony characteristics, and to assess the clinical significance of a NTM isolation. Methods : The results of the respiratory specimens requested for an acid-fast bacilli (AFB) examination during 2002 at Asan Medical Center, along with the patients clinical characteristics were analyzed. Results : A total 26,820 respiratory specimens were requested for the acid-fast bacilli (AFB) smear and culture during the study period. The proportion of M. tuberculosis and NTM isolation was 5.7% and 2.2%, respectively. Among the AFB smear and culture positive specimens, 12.2% were found to be NTM. The scotochromogen showing a low colony count < 20, which appeared to be contaminants, were isolated in 31.8% of the 584 NTM isolates. Excluding the low-colony scotochromogens, the M. avium-intracellulare complex was the most common NTM isolates (42.1%), and was also the most common causative organism for NTM pulmonary diseases. 8.4% (23/275) and 17.8% (49/275) of patients with NTM isolates met the American and British Thoracic Society diagnostic criteria for NTM pulmonary disease, respectively. Conclusion : In case of a positive AFB-smear or culture result, the possibility of NTM being a causative organism should always be considered, even in Korea, which has an intermediate incidence of tuberculosis.

• Economic and Environmental Geology
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• v.23 no.2
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• pp.201-213
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• 1990

Mineralogy, chemistry, physical property, and fossil abundance have been studied for the samples collected from three weathering profiles, two from the Duho Formation and one from the Hagjeon Formation in the Tertiary sediments in the Pohang area. The mineralogy of the samples from the Duho Formation shows somewhat different from that of the Hagjeon Formation. Kaolinite is more abundant and shows higher crystallinity in samples from the Duho Formation than those in the Hagjeon Formation, but clay mineral assemblage in each weathering profile remain fairly constant with depth. This difference in mineral distribution seems to be inherited from original source materials. It indicates that little or not severe leaching has been taking place in these three weathering profiles. Weathering indicies indicate different degrees of susceptibility to chemical weathering in these two formations. The Duho Formation has a higher degree of susceptibility to weathering than that of the Hagjeon Formation which is mainly due to differences in clay mineral assemblages in both formations. A noticeble colour difference between oxidized and unoxidized zones in each profile can be easily recognized which is definetely due to different decomposition rate organic carbon by various oxidation state from surface to bottom of the profile. Weathering process have also intensively influenced microfossil preservation about up to 7-10 m in depth in the Duho Formation. Consequently, characteristics observed at weathering surface should be used as a subsidiary tool in setting geologic boundary or establishing formation. Great care must be taken to choose sampling site for microfossil study.

• Economic and Environmental Geology
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• v.38 no.6 s.175
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• pp.707-716
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• 2005

Organic geochemical analyses including Rock-Eval pyrolysis, elemental analysis and stable carbon isotope analysis were performed to evaluate the characteristics of organic matter in the ODP Leg 127 Site 794A sediments and to understand paleoceanographic changes. Based on the TOC contents, C/N ratio, HI vs. OI, $\delta^{13}C_{org}$ and C/S ratio, results imply that dark layers containing a large amount of terrigenous organic matter were deposited under the suboxic/anoxic conditions, whereas the light layers containing largely marine organic matter were deposited under the oxic conditions. These results indicate that increasing surface-productivity by the input of a large amount of terrigenous organic matter from adjacent continent led to the deposition of dark layers during the interglacial highstands, whereas marine primary production and dilution caused by Kosa from the China desert area led to the deposition of light layers with the decreased to terrigenous organic matter during the glacial lowstands.

• Korean journal of applied entomology
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• v.4
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• pp.19-24
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• 1965

In an attempt to find a satisfactory environmental factors which facilitate abundant conidial production of Piriculariaoryzae Cav. on tomato juice media, various environmental factors were studied for their effect on sporulation and mycelial growth of the fungus. Those factors were conditions of irradiation, color of light, age of culture and pH of the media. l) Continuous exposure to fluorescent light (Mitsubish FL-20-35 W) produced more conidia and much mycelial growth than did intermittent photoperiods and darkness. 2) Of 3 cellophane filters and direct exposure to fluorescent light used, conidia were produced best under the direct exposure to the light. Conidial production in color filter conditions sequently decreased with red, yellow and blue. Growth of mycelium was not significantly different within colors. 3) Periodic irradiation of 12-hour unit brought about zones on mycelial growth no matter what the color filter was used. 4) Older cultures responding to the light were more stimulated by light than were the younger one in the conidia production, but maximum production of conidia was 48 hours of age in this case. 5) Color of the mycelial mat and the aerial mycelium seemed to have a close relation to the production of conidia. The more darkness of the mycelial mat was produced the more conidia and the much aerial mycelium was produced the least conidia. The color of mycelium was more dark under the continuous irradiation than continuous darkness, while the periodic irradiation showed intermediate effect. 6) The concentration of hydrogen ion for growth and sporulation of the fungus was investigated the ranges between 5 and 9. The best pH for the fungus was also noted at 7. whereas the below of pH 4 was not occurred any mycelial growth and sporulation.