• Annals of Clinical Neurophysiology
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• 제2권2호
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• pp.119-124
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• 2000

Background : We studied EEG changes during pilocarpine-induced status epilepticus(SE), a widely used model whose EEG characteristics have not been fully described previously. Methods : Male Sprague-Dawley rats weighing 250-350 grams were used as subjects. SE was induced 5-7 days after placement of chronic epidural electrodes, using 360-380 mg/Kg pilocarpine IP. Rats were observed with continuous EEG recording following pilocarpine injection until end of the SE episode. Results : SE occurred in 10/12 rats studied. SE began with a series of discrete seizures $11.1{\pm}3.93$ minutes after pilocarpine injection. $5.2{\pm}2.71$ seizures occurred over $10.9{\pm}4.62$ minutes, until the EEG converted to a waxing and waning pattern, during which the amplitude and frequency of epileptiform activity increased. After $1.4{\pm}1.82$ minutes, a pattern of continuous high amplitude rapid spiking was established. Continuous spiking continued for $3.4{\pm}0.48$ hours with a very gradual decline in amplitude and frequency, until periodic epileptiform discharges(PEDs) began to occur. The EEG consisted primarily of PEDs for another $7.4{\pm}3.09$ hours, until electrographic generalized seizures began to occur. These continued for $5.8{\pm}4.82$ hours until death. Duration of SE was $17.0{\pm}5.88$ hours. Flat periods were a prominent feature during all EEG patterns in this model. Conclusion : EEG features distinctive in pilocarpine SE(but not unique to it) include flat periods during all patterns and resumption of continuous spiking episodes after the onset of PEDs. The sequence of discrete seizures to waxing and waning to continuous spiking to PEDs was identical to that which has been described in humans and other animal models.

• 한국환경과학회지
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• 제24권11호
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• pp.1525-1540
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• 2015

In order to clarify the contribution rate of PM concentration due to regional emission distribution, Brute force analysis were carried out using numerical estimated PM data from WRF-CMAQ. The emission from Kyeongki region including Seoul metropolitan is the largest contribution of PM concentration than that from other regions except for emission of trans-country and source itself. Contribution rate of self emission is also the largest at Kyeongki region and its rate reach on over 95 %. And the rate at Gangwon region also higher than any region due to synoptic wind pattern. Due to synoptic wind direction at high PM episode, pollutants at downwind area along from west to east and from north to south tends to mix intensively and its composition is also complicated. Although the uncertainty of initial concentration of PM, the contribution of regional PM concentration tend to depend on the meteorological condition including intensity of synoptic and mesoscale wind and PM emission pattern over upwind region.

• 한국대기환경학회지
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• 제19권4호
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• pp.347-361
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• 2003

Sulfur dioxide (SO$_2$), ozone, total suspended particulates (TSP) and PM$_{2.5}$ were measured at Deokjeok Island in the Yellow Sea during April 1999 to June 2000. Although the emission amount of air pollutants is quite low in this small island of 36 km$^2$ with 1.4 thousand inhabitants, there are pollutant sources such as an oil -firing power plant and a wharf for ferryboat. The island is also influenced from the emissions from the greater Seoul area in the east and from China in the west. In order to characterize the pollutant variations due to interactions between transport and local emissions. the correlation between variations of SO$_2$ and ozone was investigated. Mass and ion concentrations of TSP and PM$_{2.5}$ were examined on selected episode days of positive and negative correlations between the two gaseous species in spring and winter. The effects of transport were pronounced on the days of positive correlation in spring with higher concentrations of ozone and PM$_{2.5}$. TSP concentrations were also high on these days because of high wind speeds. On the days of negative correlation in spring, frequent fog associated with low wind speeds facilitated SO$_2$ oxidation and increased sulfate accompanied with decrease in nitrate in PM$_{2.5}$ and chloride in TSP. This latter phenomena was noticeable since it showed that chemical composition of fine particles could be significantly altered not only during the transport but also by local environment.ronment.

• Asian Pacific Journal of Cancer Prevention
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• 제14권6호
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• pp.3653-3661
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• 2013

Along with rapid economic growth and enhanced agricultural productivity, particulate matter emissions in the northern cities of Thailand have been increasing for the past two decades. This trend is expected to continue in the coming decade. Emissions of particulate matter have brought about a series of public health concerns, particularly chronic respiratory diseases. It is well known that lung cancer incidence among northern Thai women is one of the highest in Asia (an annual age-adjusted incidence rate of 37.4 per 100,000). This fact has aroused serious concern among the public and the government and has drawn much attention and interest from the scientific community. To investigate the potential causes of this relatively high lung cancer incidence, this study employed Fourier transform infrared spectroscopy (FTIR) transmission spectroscopy to identify the chemical composition of the $PM_{2.5}$ collected using Quartz Fibre Filters (QFFs) coupled with MiniVol$^{TM}$ portable air samplers (Airmetrics). $PM_{2.5}$ samples collected in nine administrative provinces in northern Thailand before and after the "Haze Episode" in 2013 were categorised based on three-dimensional plots of a principal component analysis (PCA) with Varimax rotation. In addition, the incremental lifetime exposure to $PM_{2.5}$ of both genders was calculated, and the first derivative of the FTIR spectrum of individual samples is here discussed.

• 한국대기환경학회지
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• 제21권4호
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• pp.439-458
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• 2005

An automated analysis system for water soluble constituents in $PM_{2.5}$ has been developed. The system consists of a high capacity multi tube diffusion scrubber (MTDS), a low temperature particle impactor (LTPI), and two ion (anion and cation) chromatography (IC) systems. Atmospheric particles have been collected by passing sample air through a thermostated MTDS followed by a LTPI. This system allows simultaneous measurements of soluble ions in $PM_{2.5}$ at 30 minutes interval. At the air sampling flow rate of 1.0L/min, the detection limits of the overall system are in the order of tens of $ng/m^3$. This system has been successfully used for the measurement of particulate components of Seoul air from April 2003 to January 2004. $SO_4^{2-},\;NO_3^-,\;NH_4^+,\;NO_2^-,\;Cl^-,\;Na^+,\;K^+,\;Ca^{2+},\;and\;Mg^{2+}$ are the major ionic species for $PM_{2.5}$ at Seoul. Among them, $SO_4^{2-},\;NO_3^-\;and\;NH_4^+$ are the most abundant ions, contributed up to $86\%$ of the total and the concentrations were higher than those in any other urban sites in the world except for Chinese cities. There are high pollutant episodes which contribute about $15\~20\%$ of annual average values of the major ions. During the episode, the all parcels were transported from the asian continent and $PM_{2.5}$ were significantly neutralized. This suggests that aged and long range transported pollutants caused the high pollutant episodes. They showed a distinct daily and seasonal variations:they showed a peak in the early morning caused by the night-time accumulation of particulate matters. Atmospheric reactions including gas-to-particle reactions and inter-particle reactions and meteorological parameters including relative humidity and ambient temperature were described with related to the $PM_{2.5}$ 5 concentrations. All of the ionic species showed higher concentrations during the spring than those for summer and winter.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.491-492
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• 2003

The large amount of smoke produced near Lake Baikal was transported to Northeast Asia with high AOT (Aerosol Optical Thickness) as seen in satellite images. Aerosol retrieval using a separation technique was applied to MODIS (Moderate Imaging Spectroradiometer) and SeaWiFS (Sea-viewing Wide Field-of-view Sensor) data observed during 14-22 May 2003. Large AOT, 2.0~5.0 was observed on 20 May 2003 over Korea due to the influence of the long range transport of smoke aerosol plume from the Russian fires, resulting in high PM10 concentration was observed at the surface.

• 한국지구과학회지
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• 제30권2호
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• pp.196-209
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• 2009

2005년 1월부터 12월까지 지속적으로 몽골과 중국 북부의 사막과 건조지대에서 모래폭풍의 발생, 이동 그리고 한국에서 먼지침전(황사)을 모니터링하였다. NOAA 위성의 AVHRR(Advanced Very High Resolution Radiometer) 관측 자료를 직접 수신하여 false colour 합성영상을 만들어 모래폭풍의 발생과 이동 사례를 중점 분석하였다. 또한 모래폭풍 발원지의 풍하측에 위치한 한국 중부의 청원에서 PM10 농도가 $190{\mu}g\;m^{-3}$ 이상인 황사 사례에 대한 PM10, PM2.5농도와 시정 그리고 $O_3,\;NO_2,\;CO,\;SO_2$ 농도의 변동을 분석하였다. 2005년에는 발원지에 적설과 강력한 고기압, 저기압의 이동이 미흡하여 강한 모래폭풍의 발생이 적었고 한국에서도 황사의 발생 빈도가 1997-2005년의 평균과 비교하여 적었다. 한국에는 2005년 총 7회, 11일간의 황사 사례가 발생하였다. 여름에는 발원지가 습하고 바람이 약해 모래폭풍의 발생이 적었으며, 한국에서도 황사의 발생이 없었다. 발원지에서 발생한 모래폭풍이 중국의 대도시와 산업지대를 거치지 않고 한국으로 직접 이동할 경우, 먼지침전에 따른 PM2.5 농도는 PM10 농도의 20% 이하였다. 그러나 모래폭풍이 중국 동부의 산업지역을 거쳐 한국으로 이동할 경우 인위적 대기오염 물질이 함께 유입되어 PM2.5 농도가 증가하여 PM10농도의 25%이상을 나타내었다. 또한 2005년에는 사막에서 날아온 모래 먼지의 PM10농도가 $190{\mu}g\;m^{-3}$ 이하여서 황사로는 미흡한 5개 이상 사례를 관측 및 분석하였다.

• 한국지구과학회지
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• 제31권6호
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• pp.600-607
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• 2010

2008년 동아시아 대륙에서 발생기원이 다른 먼지(황사)와 인위적 오염입자의 광역적 이동 사례를 NOAA위성 RGB 합성영상과 지상 입경별 분진(TSP, $PM_{10}$, $PM_{2.5}$)의 질량농도 관측으로 분석하였다. 또한 Terra/Aqua 위성 MODIS(Moderate resolution Imaging Spectroradiometer) 센서의 AOD(Aerosol Optical Depth)와 FW(Fine aerosol Weighting)를 통해 동아시아 지역에서 발생기원이 다른 대기 에어로졸의 분포와 입자 크기 특성을 분석하였다. 중국 북부와 몽골, 그리고 중국 황토고원에서 모래폭풍이 발생하여 광역적으로 이동하여 청원에 먼지입자(황사)로 영향을 주는 6 개의 사례분석을 실시하였다. 질량농도 TSP중 $PM_{10}$은 70%, $PM_{2.5}$는 16%로 조대입자(> $2.5\;{\mu}m$)의 비율이 큰 것은 사막과 반사막의 자연적 발생원에서 생성되었기 때문이다. 그러나, 모래 폭풍이 이동 과정에서 중국 동부의 산업 지역을 거쳐 유입하는 사례에서는 TSP 중 $PM_{2.5}$가 23%까지 증가하기도 했다. 중국 동부로부터 황해를 거쳐 한반도로 유입한 5개 다른 사례의 경우, TSP 중 $PM_{10}$, $PM_{2.5}$가 각각 82, 65%로 나타났다. 이와 같이 $PM_{2.5}$의 상대적 비율이 증가한 것은 인위적 오염입자의 영향 때문이다. 동아시아 지역에서 인위적 오염입자의 광역적 이동 사례에 대한 평균 AOD는 $0.42{\pm}0.17$로 황사에 의한 AOD($0.36{\pm}0.13$)와 비교하여 대기 에어로졸에 대한 비율이 높게 나타났다. 특히, 중국 동부에서 황해, 한반도, 동해에 이르는 광역적 지역에 AOD값이 높게 분포했다. 인위적 오염입자의 사례는 FW가 평균 $0.63{\pm}0.16$로 모래폭풍의 이동 사례의 $0.52{\pm}0.13$ 보다 높은 값을 보였다. 이는 대기 에어로졸에 대한 인위적 미세 오염 입자의 기여도가 클 수 있음을 제시하고 있다.

• 한국대기환경학회지
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• 제31권3호
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• pp.223-238
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• 2015

The $PM_{2.1}$ was collected by LVCI (low volume cascade impactor) during Group-A Period (September 1990 to December 2012) and the $PM_{2.5}$ was collected by HVAS (high volume air sampler) during Group-B Period (September 2009 to April 2012) at Kyung Hee University, Global Campus located on the boarder of Yongin and Suwon. The 8 water-soluble ions ($Na^+$, $NH_4{^+}$, $K^+$, $Mg^{2+}$, $Ca^{2+}$, $Cl^-$, $ NO_3{^-}$, and $SO_4{^{2-}}$) were analyzed by IC, and the 14 inorganic elements (Al, Mn, Si, Fe, Cu, Pb, Cr, Ni, V, Cd, Ba, Zn, Ti, Ag) were analyzed by XRF and ICP-AES after performing proper pre-treatments of each sample filter. The average total mass fractions of $SO_4{^{2-}}$, $NO_3{^-}$, and $NH_4{^+}$+ to $PM_{2.5}$ samples during Group-B Period were 0.39 in normal days, 0.44 in haze days, and 0.27 in Asian dust days, respectively; however, the average total mass fractions of Al, Fe, and Si to $PM_{2.5}$ mass were 0.043 in normal days, 0.021 in haze days, and 0.036 in Asian dust days, respectively. Especially the concentration of Pb was significantly decreased during Group-B Period rather than during Group-A Period, while Cr and Ni was increased during Group-B Period. In this study, we intensively compared the annual and seasonal patterns of major chemical species among normal days, haze days, and Asian dust days. Further we developed mass fraction profiles by collecting episode cases of haze days and Asian dust days, which were consisting of 22 chemical species. Those profiles are considered to be useful when applying various receptor models and establishing air quality management plans near future.

• 한국임상수의학회지
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• 제22권2호
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• pp.94-99
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• 2005

Xylazine hydrochloride로 진정한 개에서 발생하는 구토에 대한 dexamethasone의 항구토 효과를 평가하고자 본 실험을 수행하였다. $4.64\pm1.25kg$의_임상적으로 건강한 28마리 잡종견을 사용하였으며, 사료공급과 음수급여는 실험 3시간 전 실시하였다. 실험 전과 추 정맥에서 채혈하여 혈액검사와 혈청화학검사를 실시하였다. Dexamethasone 1 mg/kg (D1군), 2mg/kg (D2군), 4mg/kg (D4군) 또는 생리 식염수 0.2ml/kg (Control군)를 정맥내 주사하고 5분 후에 xylazine hydrochloride를 근육내 주사하여 진정시켰다. 각각 구토 발생시간과 구토 유무를 측정하였고, xylazine hydrochloride 진정 후 5, 15, 30, 60분에 Visual Sedation Score를 사용하여 진정정도를 평가하였다. 구토 발생시간은 대조군에서 $203.25\pm11.35$초였고, D1군과 D2군에서 각각 $187.33\pm48.01$초와 $218.33\pm13.58$초로 차이가 없었다. 구토율은 D4군 전체 실험견이 구토를 보이지 않는 반면, Control군 실험견 중 $57\%$가 구토를 하였고, D1군과 D2군 실험견들은 각각 $43\%$구토율을 나타냈다. 진정 정도는 실험군에 관계없이 dexamethasone을 투여한지 15분 후에 높은 수치를 나타냈다. 혈액검사, 혈청화학검사결과는 정상수치를 보였다. 이상 결과로, 개에서 전처치로 사용한 4mg/kg용량 dexamethasone은 진정작용에 관계없이 xylazine hydrochloride가 유발시키는 구토를 예방한다는 것을 알 수 있다.