• Parasites, Hosts and Diseases
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• 제57권3호
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• pp.291-294
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• 2019

Primary amebic encephalitis (PAM) is a devastating central nervous system infection caused by Naegleria fowleri, a free-living amoeba, which can survive in soil and warm fresh water. Here, a 43-year-old healthy male was exposed to warm freshwater 5 days before the symptom onset. He rapidly developed severe cerebral edema before the diagnosis of PAM and was treated with intravenous conventional amphotericin B while died of terminal cerebral hernia finally. Comparing the patients with PAM who has similar clinical symptoms to those with other common types of meningoencephalitis, this infection is probably curable if treated early and aggressively. PAM should be considered in the differential diagnosis of purulent meningoencephalitis, especially in patients with recent freshwater-related activities during the hot season.

• 한국농공학회논문집
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• 제55권4호
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• pp.21-28
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• 2013

The objective of the study was to investigate the effect of rice straw mat, rice straw mat with PAM (Polyacrylamide) and gypsum addition on surface runoff and sediment discharge in field. Six experimental plots of $5{\times}22m$ in size and 3 % in slope prepared on gravelly sandy loam soil were treated with control, rice straw mat cover with gypsum and rice straw mat cover with gypsum and PAM. Radish in Spring and Chinese cabbage in autumn growing seasons were cultivated. Non point source (NPS) pollution discharge was monitored and compared among the treatments. Rainfall of the 10 monitored events ranged from 17.0 mm to 93.5 mm. Runoff coefficient of the events was 0.005~0.239 in control plot, 0~0.176 in rice straw plot with gypsum and 0~0.046 in rice straw mat plot with gypsum and PAM. When compared to the control plot, the runoff amount was reduced by 10.4~100 % (Ave. 60.8) in rice straw plot with gypsum and 80.7~100 % (Ave. 96.7 %) in rice straw mat plot with gypsum and PAM. The reduction of NPS pollution load was 54.6 % for BOD5, 71.5 % for SS, 41.6 % for TN and 61.4 % for T-P in rice straw with gypsum plot and 91.9 % for BOD5, 92.0 % for SS, 88.0 % for TN and 88.5 % for T-P in rice straw mat with gypsum and PAM plot. This research revealed that rice straw mat cover with soil amendments on the soil surface could not only increase the crop yield but also reduce the NPS pollution loads substantially.

• Journal of Power Electronics
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• 제10권4호
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• pp.374-381
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• 2010

Typical power electronic converters employ only pulse width modulation (PWM) to generate specific switching patterns. In this paper, a novel control strategy combining both pulse-width and amplitude modulation strategies (PWAM) has been proposed for power converters. The Pulse Amplitude Modulation (PAM), used in communication systems, has been applied to power electronic converters. This increases the degrees of freedom in eliminating or mitigating harmonics when compared to the conventional PWM strategies. The role of PAM in the novel PWAM strategy is based on the control of the converter's dc sources values. Software implementation of the conventional PWM and the PWAM control strategies has been applied to a five-level inverter for mitigating selective harmonics. Results show the superiority of the proposed strategy from the THD point of view along with a reduction in the inverter power dissipation.

• 방송공학회논문지
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• 제11권2호
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• pp.191-199
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• 2006

본 논문은 심리음향 모델 II(PAM II)를 기반으로 한 MPEG 오디오 코더에 대해서 효율적으로 프리 에코(pre echo)를 제어하는 알고리듬을 제안한다. 프리 에코 제어는 PAM II에서 마스킹 임계값 계산의 마지막 단계로써, 현재 프레임에 대해서 발생하는 양자화 오차를 최소화시키는 역할을 한다. 기존에 부호화기에서 프리 에코는 추정되는 마스킹 임계치가 이전 프레임에서 얻어진 값을 넘지 않도록 제한함으로써 결정된다. 기존의 방법에서 사용되는 프리 에코 제어는 단구간 블록(short block)은 물론 장구간 블록(long block)에 대해서도 사용되는데, 이는 마스킹 임계값을 불필요하게 떨어뜨려 전체적인 양자화 잡음 레벨을 높이는 문제를 발생시킨다. 본 논문에서는 이러한 문제를 해결할 수 있는 효율적인 프리 에코 제어 과정을 제안하였다. 음질 테스트 결과에서 변화가 심한 오디오 신호에 대해서 ITU R 테스트를 시행한 결과 제안된 방법이 평균적으로 0.4점 이상 개선된 결과를 보였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1996년도 창립기념 전력전자학술발표회 논문집
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• pp.67-70
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• 1996

This paper presents SVC which use PAM method and eliminate harmonics. Inverter is connected directly so that SVC improve output voltage waveform into 24 steps. Inverter output waveform THD is reduced to 6.89%. Leading control of reactive power generated in power system is possible. Snubber is added to reduce switching loss.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.1103-1106
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• 2002

This paper presents SVC which use PAM method and eliminate harmonics. Inverter is connected directly so that SVC improve output voltage waveform into 24 steps. Inverter output waveform THD is reduced to 6.89%. Leading control of reactive power generated in power system is possible. Snubber is added to reduce switching loss.

• Journal of Microbiology and Biotechnology
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• 제30권12호
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• pp.1919-1926
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• 2020

CRISPR interference (CRISPRi) has been developed as a transcriptional control tool by inactivating the DNA cleavage ability of Cas9 nucleases to produce dCas9 (deactivated Cas9), and leaving dCas9 the ability to specifically bind to the target DNA sequence. CRISPR/Cas9 technology has limitations in designing target-specific single-guide RNA (sgRNA) due to the dependence of protospacer adjacent motif (PAM) (5'-NGG) for binding target DNAs. Reportedly, Cas9-NG recognizing 5'-NG as the PAM sequence has been constructed by removing the dependence on the last base G of PAM through protein engineering of Cas9. In this study, a dCas9-NG protein was engineered by introducing two active site mutations in Cas9-NG, and its ability to regulate transcription was evaluated in the gal promoter in E. coli. Analysis of cell growth rate, D-galactose consumption rate, and gal transcripts confirmed that dCas9-NG can completely repress the promoter by recognizing DNA targets with PAM of 5'-NGG, NGA, NGC, NGT, and NAG. Our study showed possible PAM sequences for dCas9-NG and provided information on target-specific sgRNA design for regulation of both gene expression and cellular metabolism.

• 한국농공학회논문집
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• 제54권2호
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• pp.95-102
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• 2012

The objective of this research was to experimentally test the effect of rice straw mats on the reduction of runoff, sediment discharge and turbidity under a laboratory scale. We used the small runoff plots of 1 m ${\times}$ 1 m ${\times}$ 0.65 m ($L{\times}W{\times}H$) in size filled with loamy sand. Experimental treatments were bare (control), rice straw mat cover of straw mats + PAM + Gypsum (SPG), rice straw mats + Chaff + PAM + Gypsum (SCPG) and rice straw mats + Sawdust + PAM + Gypsum (SSPG); slope of 10 % or 20 %; and rainfall intensity of 30 mm/hr. Runoff volume and rate of covered plots were significantly lower than those of control plot. Average runoff rate of covered plots, slope of 10 % and 20 %, decreased 85.6 % and 72 % in respectively. Sediment reduction ratio was more than 99 % regardless of slope. The differences runoff and sediment discharge among different cover materials were not significant. It was also shown that even if runoff reduction by surface cover were low, sediment discharge reduction could be very significant and contribute to improve the water quality of streams in sloping agricultural regions. It was concluded that the use of straw mat and soil amendments (PAM and Gypsum) on sloping agricultural fields could reduce soil erosion and muddy runoff significantly and help improve the water quality and aquatic ecosystem in receiving waters. But mixing effect of PAM and Gypsum was minimal.

• 한국농공학회논문집
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• 제53권6호
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• pp.129-136
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• 2011

To measure effects of surface cover on runoff and sediment discharge reduction using rainfall simulator, four(5 m${\times}$30 m scale) plot experiments were conducted in this study. Surface covers made with straw mat, Polyacrylamide (PAM), chaff, and sawdust were simulated 4 times under 31.1~44.4 mm/hr rainfall intensities. Compared with results from control plot, the time of runoff generation is delayed and outflow volume decreased with surface cover. Effects on runoff reduction of straw mat, PAM, sawdust and chaff ranged 4.7~81.5 % and runoff rate reduced by 6.5~76.1 % respectively, when compared with those from control plot. The percentage of decrease in sediment discharge were 99.7~99.8 % from straw mat+sawdust+PAM plots, 85.9~95.6 % from straw mat+PAM plots, and 98.5~99.4 % from straw mat+chaff+PAM plots. The runoff, sediment discharge, and SS concentration reduction efficiencies of the cover materials were outstanding when compared to control plot. It was analyzed that reduction of runoff and sediment discharge were mainly contributed by decrease in rainfall energy impact and flow velocity and increase of infiltration due to the surface cover materials. The results could be used as a base for the development of best management practices (BMPs) to reduce runoff, sediment discharge from sloping field.

• Tuberculosis and Respiratory Diseases
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• 제45권1호
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• pp.36-44
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• 1998

연구배경: IFN-$\gamma$는 단핵식세포를 활성화시키며 여러 종류의 세포내 세균에 대한 숙주의 방어기전에 중요한 역할을 하는 것으로 알려져있다. 그러나 사람에 있어서 IFN-$\gamma$의 항 결핵 효과와 작용기전에 대해서는 거의 알려진 바가 없다. 본 연구에서는 결핵의 발병기전에서 IFN-$\gamma$의 역할을 알아보기 위해 폐포대식세포의 결핵균 탐식과 TNF-$\alpha$ 생산에 IFN-$\gamma$가 미치는 영향을 알아보았다. 방 법: 활동성 폐질환이 없는 8명의 사람에게서 얻은 기관지 폐포세척액에서 폐포대식세포를 표면흡착법으로 분리하여 결핵균과 같이 배양하면서 ($1{\times}10^6$ cells/ml, $3{\times}10^7$ bacteria/ml) 배양액에 IFN-$\gamma$(300U/ml), LPS(0.5ug/ml), 자가혈청(10%)을 첨가하여 2시간 배양 후 항산성 염색(modified Kynion method)을 하여 결핵균을 탐식한 폐포대식세포를 관찰하였다. 그리고 폐포대식세포배양액에 IFN-$\gamma$(300U/ml), MTB($1{\times}106bacteria/ml$) and LPS(0.5ug/ml)를 각각 첨가하여 24시간 배양 후 상층액에서 TNF-$\alpha$의 농도를 ELISA method로 측정하였다. 그리고 IFN-$\gamma$(300U/ml), LPS(0.5ug/ml)로 24시간 자극한 폐포대식세포의 결핵균 탐식율도 관찰하였다. 결 과: IFN-$\gamma$는 폐포대식세포의 결핵균 탐식율을 증가시키지 않았으며(percentage of PAM-phagocytosed MTB: control: $22.1{\pm}4.9$, IFN-$\gamma$: $20.3{\pm}5.3$), 폐포대식세포를 24시간 자극하였을 때 폐포대식세포의 TNF-$\alpha$의 생산을 증가시키지 않았다 (control: $21{\pm}38pg/ml$, IFN-$\gamma$: $87{\pm}106pg/ml$). 그리고 IFN-$\gamma$로 24 시간 전처치한 폐포대식세포의 결핵균 탐식율 또한 증가하지 않았다(control: $24.5{\pm}9.5$, IFN-$\gamma$: $23.4{\pm}10.1$). 결 론: IFN-$\gamma$는 폐포대식세포의 결핵균 탐식과 TNF-$\alpha$ 생산에 영향을 미치지 않는다.