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검색결과 731건 처리시간 0.033초

Hazards Caused by UV Rays of Xenon Light Based High Performance Solar Simulators

  • Dibowski, Gerd;Esser, Kai
    • Safety and Health at Work
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    • 제8권3호
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    • pp.237-245
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    • 2017
  • Background: Solar furnaces are used worldwide to conduct experiments to demonstrate the feasibility of solar-chemical processes with the aid of concentrated sunlight, or to qualify high temperature-resistant components. In recent years, high-flux solar simulators (HFSSs) based on short-arc xenon lamps are more frequently used. The emitted spectrum is very similar to natural sunlight but with dangerous portions of ultraviolet light as well. Due to special benefits of solar simulators the increase of construction activity for HFSS can be observed worldwide. Hence, it is quite important to protect employees against serious injuries caused by ultraviolet radiation (UVR) in a range of 100 nm to 400 nm. Methods: The UV measurements were made at the German Aerospace Center (DLR), Cologne and Paul-Scherrer-Institute (PSI), Switzerland, during normal operations of the HFSS, with a high-precision UV-A/B radiometer using different experiment setups at different power levels. Thus, the measurement results represent UV emissions which are typical when operating a HFSS. Therefore, the biological effects on people exposed to UVR was investigated systematically to identify the existing hazard potential. Results: It should be noted that the permissible workplace exposure limits for UV emissions significantly exceeded after a few seconds. One critical value was strongly exceeded by a factor of 770. Conclusion: The prevention of emissions must first and foremost be carried out by structural measures. Furthermore, unambiguous protocols have to be defined and compliance must be monitored. For short-term activities in the hazard area, measures for the protection of eyes and skin must be taken.

빛 보상과 외형 기반의 특징을 이용한 얼굴 특징 검출 (A Facial Feature Detection using Light Compensation and Appearance-based Features)

  • 김진옥
    • 인터넷정보학회논문지
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    • 제7권3호
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    • pp.143-153
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    • 2006
  • 얼굴 특징 검출은 HCI, 얼굴 인식, 얼굴 추적, 표정 인식 및 이미지 데이터 검색등과 같은 응용분야의 근간 기술이다. 실시간 환경에서 얼굴 특징 검출을 처리하기 위해서는 검출 알고리즘의 속도가 중요한 관건으로 작용하고 있다. 또한 빛의 변화, 대상의 위치, 각도, 복잡한 배경등과 같은 요인들은 얼굴 특징 검출 알고리즘의 검출율을 낮추는데 영향을 미치므로 이를 개선한 방법이 필요하다. 본 연구에서는 검출율과 검출 속도를 동시에 개선한 알고리즘을 제안한다. 제안 알고리즘은 얼굴 이미지에 빛 보상 알고리즘인 CLAHE를 이용하여 빛의 변화에 강건하도록 이미지를 개선한 다음 얼굴 피부 영역을 검출한다. 검출한 피부 영역에서 얼굴 특징 포인트를 추출하기 위해 얼굴 특징의 외형기반 기하학적 성질을 이용한다. 제안 알고리즘은 얼굴 특징 검출의 정확도를 높일 뿐 아니라 빠른 검출 속도를 보임으로써 얼굴 추적, 인식 등과 같은 실시간 응용분야에 적용할 수 있다.

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소형동물 전임상실험을 위한 하이퍼스펙트럼 영상장비 연구 (Research about Hyperspectral Imaging System for Pre-Clinical testing of Small Animal)

  • 이경희;최영욱
    • 전기학회논문지
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    • 제56권12호
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    • pp.2208-2213
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    • 2007
  • In this study we have developed a hyperspectrum imaging system for highly sensitive and effective imaging analysis. An optical setup was designed using acoustic optical tunable filter (AOTF) for high sensitive hyperspectrum imaging. Light emitted by mercury lamp gets split in to diffracted and undiffracted beams while passing though AOTF. GFP transfected HEK-293 cell line was used as a model for in vitro imaging analysis. Cells were first, analyzed by fluorescence microscope followed by flow cytometric analysis. Flow cytometric analysis showed 66.31% transfection yield in GFP transfected HEK-293 cells. Various images of GFP transfected HEK-293 cell were grabbed by collecting the diffracted light using a CCD over a dynamic range of frequency of 129-171 MHz with an interval of 3 MHz. Subsequently, for in vivo image analysis of GFP transfected cells in mouse, a whole-body-imaging system was constructed. The blue light of 488 nm wavelength was obtained from a Xenon arc lamp using an appropriate filter and transmitted through an optical cable to a ring illuminator. To check the efficacy of the newly developed whole-body-imaging system, a comparative imaging analysis was performed on a normal mouse in presence and absence of Xenon arc irradiation. The developed hyperspectrum imaging analysis with AOTF showed the highest intensity of green fluorescent protein at 153 MHz of frequency and 494 nm of wavelength. However, the fluorescence intensity remained same as that of the background below 138 MHz (475 nm) and above 162 MHz (532 nm). The mouse images captured using the constructed whole-body-imaging system appeared monochromatic in absence of Xenon arc irradiation and blue when irradiated with Xenon arc lamp. Nevertheless, in either case mouse images appeared clearly.

Real-Time PCR Detection of 16S rRNA Novel Mutations Associated with Helicobacter pylori Tetracycline Resistance in Iran

  • Dadashzadeh, Kianoosh;Milani, Morteza;Rahmati, Mohammad;Akbarzadeh, Abolfazl
    • Asian Pacific Journal of Cancer Prevention
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    • 제15권20호
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    • pp.8883-8886
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    • 2014
  • Background: Tetracycline is an antibiotic widely used for the treatment of Helicobacter pylori infection, but its effectiveness is decreasing due to increasing bacterial resistance. The aim of this study was to investigate the occurrence of 16S rRNA mutations associated with resistance or reduced susceptibility to tetracycline ofHelicobacter pylori by real-time PCR (RT-PCR) assays from culture. Materials and Methods: Tetracycline susceptibility and minimal inhibition concentration (MIC) was determined by the Epsilometer test (Etest) method. A LightCycler assay developed to detect these mutations was applied to DNA extracted from culture. The 16S rRNA of these isolates was sequenced and resistance-associated mutations were identified. From 104 isolates of H. pylori examined, 11 showed resistance to tetracycline. Results: LightCycler assay was applied to DNA extracted from 11 tetracycline-susceptible and 11 tetracycline resistance H. pylori isolates. In our study the sequencing of the H. pylori wild types in 16 s rRNA gene were AGA 926-928 with MIC (0.016 to $0.5{\mu}g/ml$), while the sequencing and MIC for resistant were GGA and AGC, (0.75 to $1.5{\mu}g/ml$), respectively. Also we found a novel mutation in 2 strains with $84^{\circ}C$ as their melting temperatures and exhibition of an A939C mutation. Conclusions: We conclude that real-time PCR is an excellent method for determination of H. pylori tetracycline resistance related mutations that could be used directly on biopsy specimens.

Improved Detection of Helicobacter pylori Infection and Premalignant Gastric Mucosa Using Conventional White Light Source Gastroscopy

  • Matrakool, Likit;Tongtawee, Taweesak;Bartpho, Theeraya;Dechsukhum, Chavaboon;Loyd, Ryan A;Kaewpitoon, Soraya J;Kaewpitoon, Natthawut
    • Asian Pacific Journal of Cancer Prevention
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    • 제17권4호
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    • pp.2099-2103
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    • 2016
  • Background: The gold standard diagnosis of H. pylori related gastritis is evidence of bacteria on histopathological examination of gastric mucosa. Our aim was to study the correlation between gastric mucosal morphology and histopathological severity of H. pylori related gastritis. Materials and Methods: Division was made on morphological features into:Type 1, showing regular arrangement of red dots; Type 2, showing cleft-like appearance; Type 3, with a mosaic appearance; and Type 4, having a mosaic appearance with focal or diffuse hyperemia. Results: Types 1 and 2 gastric mucosal morphologies were statistically significant in predicting an H. pylori negative status (137/145, p<0.01), while Types 3 and 4 were significant a positive status (139/155, p<0.01). The sensitivity, specificity, positive and negative predictive values of Type 3 and 4 morphologies for predicting H. pylori positive were 94.6%, 89.5%, 89.7% and 94.5%, respectively, with a good correlation with inflammation grading (p<0.01). Conclusions: Our study suggests that gastric mucosal morphology can be reliably identified using conventional white light source gastroscopy with good correlation between findings and inflammation grading.

저온처리가 케일(Brassica oleracea)잎 내 Carotenoid에 미치는 영향 (Effect of Cold Stress on Carotenoids in Kale Leaves (Brassica oleracea))

  • 황소정;천진혁;김선주
    • 한국환경농학회지
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    • 제36권2호
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    • pp.106-112
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    • 2017
  • BACKGROUND: Kale (Brassica oleracea) biosynthesizes various phytochemicals including glucosinolates, flavonoids, and carotenoids. Phytochemicals of plants are influenced by light, temperature, carbon dioxide, and growing conditions. Specifically, carotenoids are affected by temperature, light, and oxygen. The aim of this study was to investigate the effect of cold stress (day/night: $25^{\circ}C/20^{\circ}C$, $20^{\circ}C/15^{\circ}C$, $15^{\circ}C/10^{\circ}C$) on carotenoids in kale leaves. METHODS AND RESULTS: Kale was grown in pots for up to 50 days after sowing (DAS) in a greenhouse. For cold acclimation experiments, kale grown in growth chambers for 3 days and was subjected to low temperature for 4 days. The conditions maintained in the growth chambers were as follows: photoperiod, 12/12 h (day/night); light, fluorescent; and relative humidity, 60%. Carotenoid (lutein, ${\alpha}-carotene$, zeaxanthin, ${\beta}-carotene$) contents were analyzed by high-performance liquid chromatography (HPLC). The total carotenoid content gradually increased during cold acclimation for 3 days. When kale was subjected to cold stress, the total carotenoid content was high at $25^{\circ}C/20^{\circ}C$ treatment, but low at $15^{\circ}C/10^{\circ}C$ treatment. The total carotenoid content of kale leaves continuously grown in greenhouse decreased from 50 to 57 DAS (1,418 and 1,160 mgkg-1 dry wt., respectively). The lutein, ${\alpha}-carotene$, and ${\beta}-carotene$ contents were very low and the zeaxanthin contents were very high at $15^{\circ}C/10^{\circ}C$ treatment. When kale was subjected to cold stress, the ratio of individual to the total carotenoid contents of kale leaves was 4553% for -carotene and 210% for zeaxanthin. CONCLUSION: The ${\beta}-carotene$ and zeaxanthin contents in kale leaves indicate their sensitiveness toward cold stress.

경주 황성동 목곽묘에서 출토된 단조 철부의 금속학적 특성 분석 (Metallurgical Analysis of Forged Iron Axe Excavated from the Wood-framed Tomb at the Hwangseongdong, Gyeongju, Korea)

  • 이찬희;이명성;김정훈;이기욱
    • 한국문화재보존과학회:학술대회논문집
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    • 한국문화재보존과학회 2004년도 제20회 발표논문집
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    • pp.33-42
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    • 2004
  • The forged iron axe found in the No. 2 wood-framed tomb (the middle 3rd century) of Hwangseongdong, Gyeongju is rectangular on the plane level. It shows an obtuse angle in the edge part, while the joint part has the both sides folded up and shows the traces of wood. Under the reflected light, the Iron axe shines in metal luster, which is bright light gray or light creamy colors. The result of x-ray diffraction analysis shows that the axe consists of magnetite and geothite, which can explain why the composition and structure of the original ore has been kept intact. The microtexture of the axe has the irregular network of ferrite and pearlite, and tile cementite of tiny amount in the ferrite background. The overall treatment of the texture seems to be thermal with a high ratio of carbon. There are fine-grained magnetite, wolframite, quartz, calcite, mica, hornblende and pyroxene inside the axe. Those must be the impurities that they failed to remove in the refining process. The normal ferrite is composed of pure iron whose $Fe_2O_3$ proportion is from 99.16 to $99.84\;wt.\%$. Other than them, the ferrite parts usually contain $Al_2O_3\;and\;SiO_2$. The irregular network of pearlite also contains Impurities including $Al_2O_3\;and\;SiO_2$ and shows highly diverse patterns of carbon content. It's because the axe was carburized after the material was made to resemble pure iron. The decarbonization work didn't go well along the process marks. It's estimated that the original ore was bloom produced in low-temperature reduction and formed around in $727^{\circ}C$, which is eutetic temperature.

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디지털영상처리 기술을 이용한 교통신호등 자동 판별 시스템 개발 (Development of Traffic Light Automatic Discrimination System Using Digital Image Processing Technology)

  • 김선동;백영현;문성룡
    • 전자공학회논문지CI
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    • 제46권2호
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    • pp.92-99
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    • 2009
  • 본 논문에서는 교통 신호등 영역 검출을 포함한 교통 신호등 외곽 부분과 신호등 색을 자동으로 판별하여 사용자에게 알려주는 교통 신호등 자동 판별 시스템 구현을 제안하였다. 본 논문은 교통 신호등색을 정확하게 검출하기 위하여 교통 신호등색에 해당하는 파장 범위를 설정하고, 색상 성분을 분할하였다. 색상 성분을 통해 교통 신호등색(빨강 주황 녹색)을 검출하며 배경부분은 그레이 영상으로 변환한다. 다음으로 웨이브렛 변환 알고리즘을 사용하여 다양한 환경에서 신호등 영역을 검출할 수 있는 알고리즘을 제안하였다. 또한, 교통 신호등 인식 부분은 CBIR(Content-Based Image Retrieval)기반에서 캐니 에지 연산자와 허도로프 매칭 알고리즘의 특성을 적용한 인식 알고리즘을 제안하였다. 제안된 알고리즘은 교통 신호등이 첨가되어 있는 조명, 배경 등이 다양한 영상을 대상으로 실험하며, 기존 알고리즘과 비교하여 제안 알고리즘의 성능이 향상되었음을 확인하였다.

Development of an Accident Consequence Assessment Code for Evaluating Site Suitability of Light- and Heavy-water Reactors Based on the Korean Technical Standards

  • Hwang, Won Tae;Jeong, Hae Sun;Jeong, Hyo Joon;Kil, A Reum;Kim, Eun Han;Han, Moon Hee
    • Journal of Radiation Protection and Research
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    • 제41권4호
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    • pp.368-372
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    • 2016
  • Background: Methodologies for a series of radiological consequence assessments show a distinctive difference according to the design principles of the original nuclear suppliers and their technical standards to be imposed. This is due to the uncertainties of the accidental source term, radionuclide behavior in the environment, and subsequent radiological dose. Both types of PWR and PHWR are operated in Korea. However, technical standards for evaluating atmospheric dispersion have been enacted based on the U.S. NRC's positions regardless of the reactor types. For this reason, it might cause a controversy between the licensor and licensee of a nuclear power plant. Materials and Methods: It was modelled under the framework of the NRC Regulatory Guide 1.145 for light-water reactors, reflecting the features of heavy-water reactors as specified in the Canadian National Standard and the modelling features in MACCS2, such as atmospheric diffusion coefficient, ground deposition, surface roughness, radioactive plume depletion, and exposure from ground deposition. Results and Discussion: An integrated accident consequence assessment code, ACCESS (Accident Consequence Assessment Code for Evaluating Site Suitability), was developed by taking into account the unique regulatory positions for reactor types under the framework of the current Korean technical standards. Field tracer experiments and hand calculations have been carried out for validation and verification of the models. Conclusion: The modelling approaches of ACCESS and its features are introduced, and its applicative results for a hypothetical accidental scenario are comprehensively discussed. In an applicative study, the predicted results by the light-water reactor assessment model were higher than those by other models in terms of total doses.

Transcriptome analysis of Panax ginseng response to high light stress

  • Jung, Je Hyeong;Kim, Ho-Youn;Kim, Hyoung Seok;Jung, Sang Hoon
    • Journal of Ginseng Research
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    • 제44권2호
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    • pp.312-320
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    • 2020
  • Background: Ginseng (Panax ginseng Meyer) is an essential source of pharmaceuticals and functional foods. Ginseng productivity has been compromised by high light (HL) stress, which is one of the major abiotic stresses during the ginseng cultivation period. The genetic improvement for HL tolerance in ginseng could be facilitated by analyzing its genetic and molecular characteristics associated with HL stress. Methods: Genome-wide analysis of gene expression was performed under HL and recovery conditions in 1-year-old Korean ginseng (P. ginseng cv. Chunpoong) using the Illumina HiSeq platform. After de novo assembly of transcripts, we performed expression profiling and identified differentially expressed genes (DEGs). Furthermore, putative functions of identified DEGs were explored using Gene Ontology terms and Kyoto Encyclopedia of Genes and Genome pathway enrichment analysis. Results: A total of 438 highly expressed DEGs in response to HL stress were identified and selected from 29,184 representative transcripts. Among the DEGs, 326 and 114 transcripts were upregulated and downregulated, respectively. Based on the functional analysis, most upregulated and a significant number of downregulated transcripts were related to stress responses and cellular metabolic processes, respectively. Conclusion: Transcriptome profiling could be a strategy to comprehensively elucidate the genetic and molecular mechanisms of HL tolerance and susceptibility. This study would provide a foundation for developing breeding and metabolic engineering strategies to improve the environmental stress tolerance of ginseng.