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Cho, Sunghee,Seo, Chulhun Wiley Subscription Services, Inc., A Wiley Company 2007 MICROWAVE AND OPTICAL TECHNOLOGY LETTERS - Vol.49 No.2
<P>In this article, adaptive bias circuit and PBG structure have been employed to achieve high power added efficiency (PAE) and high third-order intermodulation (IM3) suppression in power amplifier simultaneously. The dc bias voltage of the gate in FET has been controlled by envelope of the input signal. The PBG structure has been employed to suppress IM3 on the output port of the power amplifier. The PBG structure was optimized to suppress the second harmonics of the amplifier. IM3 and PAE of the proposed power amplifier using adaptive bias circuit and PBG structure has been improved by 2.73 dBc, and by 35.54%, respectively. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 443–446, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22158</P>
Splicing inhibition of U2AF<sup>65</sup> leads to alternative exon skipping
Cho, Sunghee,Moon, Heegyum,Loh, Tiing Jen,Jang, Ha Na,Liu, Yongchao,Zhou, Jianhua,Ohn, Takbum,Zheng, Xuexiu,Shen, Haihong National Academy of Sciences 2015 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.112 No.32
<P><B>Significance</B></P><P>Transcription is a biological procedure in which DNA is transcribed to an RNA molecule. However, only fragments of this RNA are needed for protein synthesis. These fragments are exons that are interrupted by introns. Introns are removed by so-called RNA splicing process. Some exons could be alternatively included or excluded from the final RNA molecule. In this study, we have found that U2 snRNP auxiliary factor 65 kDa (U2AF<SUP>65</SUP>), a general splicing regulator, can significantly promote the exclusion of alternative exons. Strikingly, U2AF<SUP>65</SUP> suppresses flanking intron splicing of alternative exons, and even constitutive intron splicing. We deduce that the stimulatory effects of U2AF<SUP>65</SUP> on alternative exon exclusion are induced by the splicing inhibitory effects of U2AF<SUP>65</SUP>.</P><P>U2 snRNP auxiliary factor 65 kDa (U2AF<SUP>65</SUP>) is a general splicing factor that contacts polypyrimidine (Py) tract and promotes prespliceosome assembly. In this report, we show that U2AF<SUP>65</SUP> stimulates alternative exon skipping in spinal muscular atrophy (SMA)-related survival motor neuron (<I>SMN</I>) pre-mRNA. A stronger 5′ splice-site mutation of alternative exon abolishes the stimulatory effects of U2AF<SUP>65</SUP>. U2AF<SUP>65</SUP> overexpression promotes its own binding only on the weaker, not the stronger, Py tract. We further demonstrate that U2AF<SUP>65</SUP> inhibits splicing of flanking introns of alternative exon in both three-exon and two-exon contexts. Similar U2AF<SUP>65</SUP> effects were observed in Fas (Apo-1/CD95) pre-mRNA. Strikingly, we demonstrate that U2AF<SUP>65</SUP> even inhibits general splicing of adenovirus major late (Ad ML) or β-globin pre-mRNA. Thus, we conclude that U2AF<SUP>65</SUP> possesses a splicing Inhibitory function that leads to alternative exon skipping.</P>
Cho, Sunghee,Moon, Heegyum,Loh, Tiing Jen,Oh, Hyun Kyung,Kim, Hey-Ran,Shin, Myung-Geun,Liao, D. Joshua,Zhou, Jianhua,Zheng, Xuexiu,Shen, Haihong Hindawi Publishing Corporation 2014 The Scientific World Journal Vol.2014 No.-
<P>Spinal muscular atrophy (SMA) is a human genetic disease which occurs because of the deletion or mutation of SMN1 gene. SMN1 gene encodes the SMN protein which plays a key role in spliceosome assembly. Although human patients contain SMN2, a duplicate of SMN1, splicing of SMN2 produces predominantly exon 7 skipped isoform. In order to understand the functions of splice site sequences on exon 7 and 8, we analyzed the effects of conserved splice site sequences on exon 7 skipping of SMN2 and SMN1 pre-mRNA. We show here that conserved 5′ splice site sequence of exon 7 promoted splicing of nearby exons and subsequently reduced splicing of distant exons. However, to our surprise, conserved 3′ splice site sequence of exon 7 and 8 did not promote splicing of nearby exons. By contrast, the mutation inhibited splicing of nearby exons and subsequently promoted splicing of distant exons. Our study shows that 3′ splice sites of exon 7 and 8 contain enhancer for their splice site selection, in addition to providing cleavage sites.</P>
모사챔버 실험을 통한 실내공간의 재실자 활동에 따른 미세먼지 비산 특성 연구
조성희(Sunghee Cho),조영민(Yeongmin Cho),박덕신(Duckshin Park),김민정(Minjeong Kim) 한국산학기술학회 2021 한국산학기술학회논문지 Vol.22 No.11
본 연구는 실내공간 중 학교 교실의 특성을 반영한 모사챔버를 활용하여 주요 영향인자를 제어한 조건에서 재실자 활동에 따른 미세먼지 비산을 측정하였다. 이를 위해 67㎥ 크기의 모사챔버를 제작하였으며, 실험자가 모사챔버 내부를 걷기(1 m/s), 빠르게 걷기(2 m/s), 뛰기(3 m/s)로 편도 이동 시 비산되는 미세먼지 농도를 측정하였다. 이때 모사챔버의 바닥 미세먼지 침적량은 0.3 g/㎡, 온도는 20~25 ℃, 습도는 45~50 %를 유지하였다. 또한 바닥에 침적된 미세먼지 질량 대비 공기 중으로 부유하는 미세먼지 질량 비율인 비산계수[㎍/㎍]를 각 활동의 이동 속도별로 산출하였다. 모사챔버 내 PM10 비산농도는 걷기 시 7.3 ㎍/㎥, 빠르게 걷기 시 17.6 ㎍/㎥, 뛰기 시 26.7 ㎍/㎥이며 PM2.5 비산농도는 걷기 시 3.0 ㎍/㎥, 빠르게 걷기 시 4.7 ㎍/㎥, 뛰기 시 5.2 ㎍/㎥로 실험자의 이동속도가 증가함에 따라 선형적으로 증가하였다. 이는 이동속도가 증가함에 따라 실험자 주변 공기의 유동 및 유속이 증가하며, 이에 따라 입자의 비산 속도가 증가하기 때문으로 사료된다. 비산계수의 경우 PM10은 걷기에서 0.0097, 빠르게 걷기에서 0.0254, 뛰기에서 0.0454를 보였으며, PM2.5는 걷기에서 0.0040, 빠르게 걷기에서 0.0062, 뛰기에서 0.0095로 이동속도에 대해 선형적인 증가 경향을 보였다. 또한 이동속도와 비산 농도, 비산계수 간의 선형 회귀식을 도출하여 PM10은 99%, PM2.5는 97~99%의 정확도를 확인하였다. 모사챔버 실험을 통해 도출된 재실자 이동속도와 비산 농도, 비산계수 간의 회귀식을 활용하여 재실자의 여러 이동속도 조건에서의 미세먼지 비산 양 추정이 가능할 것으로 사료된다. This research investigates the properties of a particulate matter (PM) suspension in accordance with occupants" activity through a simulation chamber experiment that reflects the indoor characteristics. Experimenters move across the simulation chamber at a pace of 1 m/s (walking case), 2 m/s (jogging case), and 3 m/s (running case). Then, the PM10 and PM2.5 concentration that increases due to the suspension resulting because of the experimenters" activity is measured. During the experiments, the simulation chamber condition is set at as follows: dust surface mass is 0.3 g/㎡, temperature is 20~25℃, and humidity is 45~50%. Then, the PM suspension factor, the ratio of airborne PM mass above the suspension site to its surface mass, is analyzed at the respective activity conditions. Both the PM suspension concentration and factor tend to show a linear increase as the moving speed of experimenters" increases. At the respective walking, jogging, and running conditions, the PM10 suspension concentration is 7.3 ㎍/㎥, 17.6 ㎍/㎥, and 26.7 ㎍/㎥; the PM2.5 suspension concentration is 3.0 ㎍/㎥, 4.7 ㎍/㎥, and 5.2 ㎍/㎥. Furthermore, the regression equations between (1) experimenters" moving speed and suspension concentration and (2) experimenters" moving speed and suspension factor are suggested. The accuracy of regression equations is 99% for PM10 and 97~99% for PM2.5.