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        검색결과 14

        1.
        2015.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The analytical method for the determination of phosphorus in foods was validated by inductively coupled plasma optical emission spectrometry (ICP-OES) in terms of precision, accuracy, recovery efficiency and linearity. Regression analysis revealed good correlation coefficient, higher than 0.999. Recovery efficiencies of the minerals ranged from 90.36% to 110.63%, and the limit of detection (LOD) and the limit of quantification (LOQ) were 0.0745 mg/ kg and 0.2482 mg/kg, respectively. The value of inter-day and intra-day ranged from 1.43 to 3.23% and from 0.40 to 1.77%. The recovery efficiencies ranged from 97.8 to 110.6%. The method was also compared with Molybdenum blue colorimetric method using certified and statistically significant difference was also not observed in the between two different analytical methods. The ICP-OES method was applied to phosphorus determination in commonly consumed foods. The obtained results suggest that the method verified in the present study may be used as an official analytical method for clear understanding of phosphorus database for national health promotion.
        4,000원
        2.
        2018.11 KCI 등재 서비스 종료(열람 제한)
        인공지능에 대한 관심이 높아짐에 따라 의료분야에서도 활발하게 인공지능이 연구되고 있다. 현재 국내에서는 엑스선 촬영, 컴퓨터단층촬영(Computer Tomography), 자기공명영상(Magnetic Resonance Imaging) 등의 의료영상장치에 인공지능이 접목되고 있으며 향후 방사선사 없이 환자의 방사선 영상을 획득 할 수 있는 인공지능을 탑재한 의료기기가 발명 될 것으로 예상된다. 본 연구는 엑스선 촬영에 있어서 환자 위치잡이에 대한 자동화에 대해서 초기 연구를 했다. 위치잡이에 대한 평가를 위해 엑스선 장비와 인체 팬텀을 사용했다. 프로그램은 Visual Studio 2010 MFC로 구현했으며 영상은 1,450 × 1,814 크기로 했다. 픽셀 값을 눈으로 식별 가능한 0 ~ 255 값을 갖는 명암으로 변환하여 모니터에 출력했다. 출력한 영상에 세 픽셀 좌표 값을 통해 각도를 예측하고 각도에 따른 음성안내에 따라 환자가 바른 위치잡이를 하도록 유도하는 절차 알고리즘 프로그램을 개발 했다. 다음 연구에서는 사용자가 좌표의 기준을 인공지능에게 전달하는 것이 아닌 인공지능 스스로 구조물을 파악하여 각도를 계산하는 연구를 진행할 것이다. 향후 위치잡이의 자동화를 통해 촬영부터 위치잡이까지 인공지능이 실시하도록 하는 연구에 도움이 될 것으로 예상된다
        3.
        2018.06 KCI 등재 서비스 종료(열람 제한)
        현재 우리나라의 암 사망률 중 가장 높은 암은 폐암이며 조기발견이 어려운 대표적인 암이다. 조기 발견을 위하여 저선량 흉부 CT를 활용하고 있으며 이는 일반 흉부 X선 사진에 비해 약 3배 정도 폐암 진단율이 높다. 그러나 저선량 흉부 CT는 영상 해상도가 크게 저하될 뿐 아니라 신호가 약해 잡음에 민감한 단점이 있다. 또한 공기로 채워져 있는 폐는 밀도가 낮은 장기로 잡음의 유무가 암의 조기 진단에 영향을 크게 줄 수 있다. 본 연구는 Visual C++을 이용하여 2.0밀도를 가진 큰 원 내부에 물의 밀도인 1.0을 값을 갖는 원을 설정하고 그 안에 각각 밀도가 다른 작은 5개의 원을 수학적 팬텀화하고 가우시안 노이즈를 1%, 2%, 3%, 4% 각각 발생시켜 밀도차에 의한 노이즈의 영향을 평균 값과 표준편차 값, 신호대잡음비(SNR)로 확인하였다. 1% 노이즈 발생 시 큰 원과 작은 원의 밀도차가 가장 큰 영역의 SNR은 4.669로 노이즈의 영향이 작게 나타났으며 밀도차가 가장 낮은 영역의 SNR은 1.183으로 노이즈의 영향이 크게 나타났다. 또한 음의 밀도차에서도 같은 결과 값을 얻었으며 양의 밀도와 음의 밀도 모두 큰 원과 작은 원의 밀도차이가 높은 경우에 SNR 값이 높은 것을 확인 할 수 있다. 화질 또한 밀도차가 크게 나타났을 때 확연하게 육안으로 확인할 수 있었으며 노이즈레벨이 증가하는 경우에는 SNR이 감소하여 잡음의 영향이 크게 나타났다. 이는 밀도차가 적은 장기 또는 암과의 밀도가 비슷한 영역의 장기는 노이즈 영향이 크게 나타날 것이며 노이즈의 발생 확률에 따른 밀도차이의 영향이 진단에 영향을 끼칠 것으로 사료된다.
        4.
        2015.07 서비스 종료(열람 제한)
        Panax ginseng C.A. meyer (family: Araliaceae) is a perennial crop that has been widely used as a traditional medicine in Korea. Various P. ginseng cultivars exhibit a range of morphological and physiological traits as well as genetic diversity. To elucidate the differences of primary metabolism underlying such genetic diverstiy, we performed primary metabolite profiles in adventitious roots from five Panax ginseng cultivars using gas chromatography-mass spectrometry (GC-MS). The GC-MS analysis revealed eight primary metabolites as biomarkers and allowed us to classify the five cultivars into three groups. We selected three cultivars to represent each group and analyzed their transcriptomes by Illumina sequencing. We inspected 100 unigenes involved in seven primary metabolite biosynthesis pathways and found that 21 unigenes encoding 15 enzymes were differentially expressed among the three cultivars. Integrated analysis of transcriptomes and metabolomes revealed that the ginseng cultivars differ in primary metabolites as well as in the putative genes involved in the complex process of primary metabolic pathways. Our data derived from this integrated analysis provide insights into the underlying complexity of genes and metabolites that co-regulate flux through these pathways in ginseng.
        5.
        2015.07 서비스 종료(열람 제한)
        Panax Ginseng is a perennial medicinal plant originated from North-east asia. Because of its well-known tonic effects mainly from ginsenosides, various types of processed ginseng products have been distributed around the world. Here, we analyzed secondary metabolite profiling of adventitious roots of 5 korean ginseng cultivars, Chunpoong (CP), Sunhyang (SH), Gopoong (GO), Sunun (SU), and Cheongsun (CS). At the same time, the profiles of relative gene expressions related to ginsenoside biosynthesis pathway were compared among ginseng cultivars. Secondary metabolite profiles were revealed by UPLC/Q-TOF-MS from extracts of bioreactor derived adventitious roots of five ginseng cultivars. Using principal component analysis, secondary metabolite profiles of ginseng cultivars were categorized into three groups. Metabolites with high VIP values were annotated using known database and standards compounds. Relative gene expression of ginsenoside related gene were analyzed using realtime PCR. The three groups had distinct metabolite contents. Furthermore, gene expression profiles related to ginsenoside were also different, which might contribute diverse secondary metabolite composition of ginseng cultivars. Further integrated analysis would provide a relationship between genetic background of ginseng cultivars and secondary metabolite profiles.
        7.
        2011.05 KCI 등재 서비스 종료(열람 제한)
        This study analyzed the concentration of the heavy metals(Cd, Hg, iAs) of urine(n=576) from May, 2007 to Oct 2007. The subject was residents in G, Y, H industrial area, Jeollanam-do, in which exposure due to the adjacency of the industrial complex. As to the heavy metal concentration in the urine of the residents in the whole exposed region and the comparing region, the content of cadmium, mercury, and inorganic arsenic in the exposed region group were 1.23, 1.85, and 8.80 μg/g_ct respectively, and those of the comparing region group were 1.87, 2.00, and 8.93 μg/g_ct respectively, which indicates that the concentration of the comparing group was higher than that of the exposed group. The heavy metal concentration for each age group increased in proportion to age except those under 10 for some substances(p<0.01). As to geometric mean concentration cadmium and inorganic arsenic in urine according to the smoking history of the subject, the concentration of the smoking group and the non-smoking group were 1.65 μg/g_ct and 9.13 μg/g_ct respectively, while those of the non-smoking group were 1.47 μg/g_ct and 8.91 μg/g_ct respectively, which indicates that the former is higher than the latter. As to the inorganic arsenic concentration in urine according to the food preference, in order of vegetable, fish, and meat showed high concentration (p<0.01). To clarify the factors affecting the heavy metal concentration in urine among the subjects, the multiple regression analysis was conducted. As a result, it turned out that as to cadmium content in urine, gender, age, drinking, and smoking have influence on the subjects, with explanatory adequacy of 37.5 %.
        8.
        2007.09 KCI 등재 서비스 종료(열람 제한)
        This study was performed in 30 selected apartments in Seoul, Asan and Daegu area which were constructed within 4 years and over 4 years, to measure the concentration of VOCs(benzene, toluene, xylene) from July, 2004 to September. Mean ratios of indoor to outdoor VOCs concentrations in the construction under 4 years were higher in 1 than average, I/O ratio of over 4 years were lower in 1. This was considered that the VOCs density influences indoor pollutant. For the indoor air quality estimation, the deposition constant and the source strength factor of toluene were 1.49±2.05 hr-1 and 36.95±52.26 ppb/h, respectively.
        9.
        2006.10 KCI 등재 서비스 종료(열람 제한)
        Indoor air quality is the dominant contributor to total personal exposure because most people spend a majority of their time indoors. Especially when indoor environments have sources of contaminants, exposure to indoor air can potentially pose a greater threat than exposure to ambient air. In this study, estimations of volatile organic compounds and formaldehyde emission rate in indoor environments of new apartments were carried out using mass balance model in indoor environment, because indoor air quality can be affected by source generation, outdoor air level, ventilation, decay by reaction, temperature, humidity, mixing condition and so on. Considering the estimated emission rate of volatile organic compounds and formaldehyde, it is suggested that new apartment should be designed and constructed in the aspect of using construction materials to emit low hazardous air pollutants.
        10.
        2006.10 KCI 등재 서비스 종료(열람 제한)
        Despite the wide distribution of air pollutants, the concentrations of indoor air pollutants may be the dominant risk factor in personal exposure due to the fact that most people spend an average of 80% of their time in enclosed buildings. Researches for improvement of indoor air quality have been developed such as installation of air cleaning device, ventilation system, titanium dioxide(TiO2) coating and so on. However, it is difficult to evaluate the magnitude of improvement of indoor air quality in field study because indoor air quality can be affected by source generation, outdoor air level, ventilation, decay by reaction, temperature, humidity, mixing condition and so on. In this study, evaluation of reduction of formaldehyde and nitrogen dioxide emission rate in indoor environments by TiO2 coating material was carried out using mass balance model in indoor environment. we proposed the evaluation method of magnitude of improvement in indoor air quality, considering outdoor level and ventilation. Since simple indoor concentration measurements could not properly evaluate the indoor air quality, outdoor level and ventilation should be considered when evaluate the indoor air quality.
        11.
        2006.03 KCI 등재 서비스 종료(열람 제한)
        Oxidative TCE decomposition over TiO2-supported single and complex metal oxide catalysts has been conducted using a continuous flow type fixed-bed reactor system. Different types of commercial TiO2 were used for obtaining the supported catalysts via an incipient wetness technique. Among a variety of titanias and metal oxides used, a DT51D TiO2 and CrOx would be the respective promising support and active ingredient for the oxidative TCE decomposition. The TiO2-based CrOx catalyst gave a significant dependence of the catalytic activity in TCE oxidation reaction on the metal loadings. The use of high CrOx contents for preparing CrOx/TiO2 catalysts might produce Cr2O3 crystallites on the surface of TiO2, thereby decreasing catalytic performance in the oxidative decomposition at low reaction temperatures. Supported CrOx-based bimetallic oxide systems offered a very useful approach to lower the CrOx amounts without any loss in their catalytic activity for the catalytic TCE oxidation and to minimize the formation of Cl-containing organic products in the course of the catalytic reaction.
        12.
        2006.02 KCI 등재 서비스 종료(열람 제한)
        The work of hairdressers includes washing, coloring, bleaching, permanent waving, conditioning, and cutting hair. Hairdressers are subjected to a number of physical and toxicological hazards. The toxicological hazards are those resulting from exposure to a wide range of chemicals that are usually classified active processes. In this study, twenty beauty shops were selected to assess the exposure to indoor air pollutants such as VOCs and particulate matter (PM10) during one month from September 1 to September 30, 2003. Indoor air quality of beauty shops might be worse by vehicle emissions because the beauty shops were generally located near roadways. Personal exposures to VOCs and PM10 were related to indoor concentrations of beauty shops. According to the questionnaire, hairdressers complained of sore throat, eye irritation, and nervousness as physical symptoms. The measured mean concentrations of respiratory particulates were 30.5ng/㎥ in indoor, 30.5ng/㎥in outdoor and 44.0ng/㎥ on personal levels. The personal concentration was found higher than indoor and outdoor concentrations. The heavy metals mean concentrations were shown as indoor (Na>Zn>Cr), outdoor (Cr>Zn>Pb), and personal (Na>Cr>Zn) levels. Conclusively, customers as well as workers in the beauty shops might be highly exposed to air pollutants from indoor and outdoor sources. Therefore, proper management should be taken to improve the indoor air quality in beauty shops.
        13.
        2005.01 KCI 등재 서비스 종료(열람 제한)
        Several samplers using gravimetric methods such as high-volume air sampler, MiniVol portable sampler, personal environmental monitor(PEM) and cyclone were applied to determine the concentrations of fine particles in atmospheric condition. Comparative evaluation between high-volume air sampler and MiniVol portable sampler for PM10, and between MiniVol portable sampler and PEM was undertaken from June, 2003 to January 2004. Simultaneously, meteorological conditions such as wind speed, wind direction, relative humidity and temperature was measured to check the factors affecting the concentrations of fine particles. In addition, particle concentrations by cyclone with an aerodynamic diameter of 4 ㎛ were measured. Correlation coefficient between high- volume air sampler and portable air sampler for PM10 was 0.79 (p<0.001). However, the mean concentration for PM10 by high-volume air sampler was significantly higher than that by MiniVol portable sampler (p=0.018). Correlation coefficient between Minivol portable sampler and PEM for PM2.5 was 0.74 (p<0.001), and the measured mean concentrations for PM2.5 did not show significant difference. Difference of the measured concentrations of fine particle might be explained by wind speed and humidity among meteorological conditions. Particle concentration differences by measurement samplers were proportional to the wind speed, but inversely proportional to the relative humidity, though it was not a significant correlation.
        14.
        2001.06 KCI 등재 서비스 종료(열람 제한)
        The personal exposures of nitrogen dioxide(NO2), microenvironmental levels and daily time activity patterns on Seoul subway station workers were measured from February 10 to March 12, 1999. Personal NO2 exposure for 24 hours were 29.40±9.75 ppb. NO2 level of occupational environment were 27.87±7.15 ppb in office, 33.60±8.64 ppb in platform and 50.13±13.04 ppb in outdoor. Personal exposure time of subway station workers was constituted as survey results with 7.94±3.00 hours in office, 2.82±1.63 hours in platform and 1 hours in outdoor. With above results, personal NO2 exposure distributions on subway station workers in Seoul were estimated with Monte Carlo simulation which uses statistical probabilistic theory on various exposure scenario testing. Some of distributions which did not have any formal patterns were assumed as custom distribution type. Estimated personal occupational NO2 exposure using time weighted average (TWA) model was 31.29±5.57 ppb, which were under Annual Ambient Standard (50 ppb) of Korea. Though arithmetic means of measured personal NO2 exposure was lower than that of occupational NO2 exposure estimated by TWA model, considering probability distribution type simulated, probability distribution of measured personal NO2 exposures for 24 hours was over ambient standard with 3.23%, which was higher than those of occupational exposure (0.02%). Further research is needed for reducing these 24 hour NO2 personal excess exposures besides occupational exposure on subway station workers in Seoul.