http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Epigenetic regulation of the potential tumor suppressor gene, hLHX6.1, in human cervical cancer
JUNG, SAMIL;JEONG, DONGJUN;KIM, JINSUN;YI, LISHA;KOO, KEUNHOE;LEE, JAEHYOUK;KIM, CHANG-JIN;KIM, CHANG-HWAN;AN, SUNGWHAN;YANG, YOUNG;LIM, JONG-SEOK;KIM, KEUN IL;LEE, MYEONG-SOK Sookmyung Women's University Research Institute of 2011 여성과 건강 Vol.6 No.2
It is well known that the Homo sapiens LIM homeobox domain 6 gene (hLHX6), a putative transcription regulator, controls the differentiation and development of neural and lymphoid cells, particularly in the central nervous system. In this study, we investigated hLHX6.1 (an isoform of hLHX6), which functions as a tumor suppressor gene in the cervix. Firstly, the methylation levels of the h내X6 and hLHX6.1 promoters were investigated in 8 cervical cancer cell lines and human tissue samples with a distinctive degree of malignant transformation. In spite of the presence of multiple cytosine guanine dinucleotides (CpG islands) in 2 proximal promoters of the hLHX6 and hLHX6.1 genes, only the HLHX6.1 promoters were found to be mostly hyper¬methylated and associated with transcriptional silencing by promoter methylation, whereas the hLHX6 promoters were not. Methylation levels in the hLX6.1 promoter were also found to be strongly related to cervical cancer development. The level of hLHX6.1 gene expression was found to be relatively high in normal cells, in which the hLHX6.1 promoter was mostly unmethylated. However, the hLHX6.1 gene expression was down-regulated or undetectable in cervical cancer cell lines and cancer tissues, in which the hLHX6.1 promoter was hypermethylated. This epigenetic alteration in the hLHX6.1 promoter begins at a relatively early stage, suggesting its potential as a biomarker for the early diagnosis and prevention of cervical cancer. Moreover, the overexpression of the hLHX6.1 gene in cervical cancer cells suppressed the tumorigenic phenotype, as shown by soft agar colony formation and migration assays, suggesting that hLHX6.1 could be a new tumor suppressor gene in the cervix.
USEFULNESS OF A NEW POTENTIAL FOR A THIN MEMBRANE-LIKE ANOMALY DETECTION IN EIT
Sungwhan KIM 한국산업응용수학회 2011 한국산업응용수학회 학술대회 논문집 Vol.6 No.1
In this work, we introduce a new elliptic PDE: where γ<SUP>ω</SUP> = σ + iωε is the admittivity distribution of the conducting material Ω. In comparison with the standard elliptic PDE with conductivity coefficient, the usefulness of the introduced elliptic PDE is numerically explained in detecting a thin membrane-like anomaly located in the conducting object Ω.
Kim, Sungwhan,Lee, Eun Jung,Woo, Eung Je,Seo, Jin Keun Institute of Physics 2012 Inverse problems Vol.28 No.7
<P>There have been numerous studies using multi-frequency electrical impedance tomography to image frequency-dependent admittivity spectra of biological tissues. Considering the fundamental drawback of the static EIT in recovering the absolute admittivity image at a certain frequency, we will focus on a difference imaging method using a currently available EIT system. We are particularly interested in the frequency-difference EIT (fdEIT) in this paper since it may provide spectroscopic admittivity images without requiring a time-reference data. Noting that non-negligible susceptivity values of biological tissues are attributed to thin cell membranes, we analyze the role of the membrane in terms of the sensitivity of the complex voltage data in fdEIT. Such an analysis requires one to study the frequency-dependent behavior of a complex potential in the framework of the elliptic partial differential equation (PDE) with a frequency-dependent complex coefficient representing the admittivity. Due to complicated coupling between the real and imaginary parts of the complex potential, there is little study on the complex elliptic PDE. Although there exist several previous studies using spherical models which allow the potential to be represented as trigonometric series, these approaches are not apt for biological tissues. In this paper, we decouple the real and imaginary parts via a key asymptotic analysis and approximate the real part as a solution of a well-established elliptic PDE with a real coefficient whose value changes with frequency. This more general approach provides a quantitative analysis of the role of the thin membrane in forming a fdEIT image. We perform numerical simulations and phantom experiments on a two-dimensional imaging object containing an anomaly with a thin insulating membrane. The results provide better understanding of the role of the thin membrane in the sensitivity of a multi-frequency current–voltage data.</P>
A NEW ALTERNATIVE ELLIPTIC PDE IN EIT IMAGING
Kim, Sungwhan Korean Mathematical Society 2012 대한수학회보 Vol.49 No.6
In this paper, we introduce a new elliptic PDE: $$\{{\nabla}{\cdot}\(\frac{|{\gamma}^{\omega}(r)|^2}{\sigma}{\nabla}v_{\omega}(r)\)=0,\;r{\in}{\Omega},\\v_{\omega}(r)=f(r),\;r{\in}{\partial}{\Omega},$$ where ${\gamma}^{\omega}={\sigma}+i{\omega}{\epsilon}$ is the admittivity distribution of the conducting material ${\Omega}$ and it is shown that the introduced elliptic PDE can replace the standard elliptic PDE with conductivity coefficient in EIT imaging. Indeed, letting $v_0$ be the solution to the standard elliptic PDE with conductivity coefficient, the solution $v_{\omega}$ is quite close to the solution $v_0$ and can show spectroscopic properties of the conducting object ${\Omega}$ unlike $v_0$. In particular, the potential $v_{\omega}$ can be used in detecting a thin low-conducting anomaly located in ${\Omega}$ since the spectroscopic change of the Neumann data of $v_{\omega}$ is inversely proportional to thickness of the thin anomaly.