• Journal of Soil and Groundwater Environment
• /
• v.16 no.4
• /
• pp.10-22
• /
• 2011

Human health risk assessment for petroleum, oil and lubricant (POL) contaminated sites is challenging as total petroleum hydrocarbon (TPH) is not a single compound but rather a mixture of numerous substances. To address this concern, several TPH fractionation approaches have been proposed and used as an effective management tool for the POL-contaminated sites in many countries. In Korea, there are also recognized needs to establish a reliable and cost-effective human health risk assessment strategy based on the TPH fractionation method. In order to satisfy the social and institutional demand, this study suggested that the comprehensive risk assessment strategy based on a newly modified TPH fractionation method with 10 fractions, the Korean Standard Test Method (KSTM)-based analytical protocol and a stepwise risk assessment framework should be introduced into the domestic contaminated land management system. Under the proposed strategy, POL-contaminated sites can be effectively managed in terms of human health protection, and remedial cost and time can be determined reasonably. In addition, more researches required to increase our understanding of environmental risks and improve the domestic management system were proposed.

• Asian Pacific Journal of Cancer Prevention
• /
• v.13 no.4
• /
• pp.1321-1324
• /
• 2012

Background: DNA polymerase beta ($pol{\beta}$) is a key enzyme in the base excision repair pathway. It is 39kDa protein, with two subunits, one large subunit of 31 kDa having catalytic activity between exon V to exon XIV, and an 8 kDa smaller subunit having single strand DNA binding activity. Exons V to VII have double strand DNA binding activity, whereas exons VIII to XI account for the nucleotidyl transferase activity and exons XII to XIV the dNTP selection activity. Aim: To examine the association between $pol{\beta}$ polymorphisms and the risk of ovarian cancer, the present case control study was performed using 152 cancer samples and non-metastatic normal samples from the same patients. In this study, mutational analysis of $pol{\beta}$ genomic DNA was undertaken using primers from exons IX to XIV - the portion having catalytic activity. Results: We detected alteration in DNA polymerase beta by SSCP. Two specific heterozygous point mutations of $pol{\beta}$ were identified in Exon 9:486, A->C (polymorphism 1; 11.18%) and in Exon 11:676, A->C (polymorphism 2; 9.86%). The correlation study involving polymorphism 1 and 4 types of tissue showed a significant correlation between mucinous type with a Pearson correlation value of 4.03 (p=0.04). The association among polymorphism 2 with serous type and stage IV together have shown Pearson ${\chi}^2$ value of 3.28 with likelihood ratio of 4.4 (p=0.07) with OR =2.08 (0.3-14.55). This indicates that there is a tendency of correlation among polymorphism 2, serous type and stage IV, indicating a risk factor for ovarian cancer. Conclusion: Hence, the results indicate that there is a tendency for $pol{\beta}$ polymorphisms being a risk factor for ovarian carcinogenesis in India.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2003.09a
• /
• pp.3-10
• /
• 2003

Soil and groundwater contamination by petroleum hydrocarbon products is only one of many environmental problems in Korea. However, many environmental consulting companies have been targeted their business on this subject because the petroleum-oil-lubricant (POL) products have been widely used product and accidental releases of the products from storages resulted numerous small and large contaminated sites throughout Korea. Therefore, many small and large companies are actively participating in environmental assessment and remediation projects for the POL contaminated sites. Remedial technologies for the POL contaminated sites have been developed for many years by government and private institutions throughout the world. Development of a new decontamination technology for the POL contaminated sites is no longer attractive issue in research community because scientific bases of most cost-effective remedial technologies are well understood and have been used in the field by commercial sector. Numerous sites contaminated by underground tanks at gas stations have been remediated by relatively small companies in this country. We should appreciate their noticeable contributions as a frontier under very difficult market environment in Korea. We heard many successful stories as well as a few failure stories. Soil-groundwater remediation of POL contaminated site is not a simple task as shown in the text books or protocols. Therefore, failure risk is always with us, which requires continuous efforts for improvement of the technologies by the users and developers. In this presentation, author will discuss technical problems encountered and improvement made during implementation of several remedial technologies applied by Samsung Environmental Team. This is not a presentation about research or case study. We want to share our thought and experience with environmental engineers actively engaged in soil and groundwater remediation projects in Korea.

• Journal of The Korean Astronomical Society
• /
• v.56 no.2
• /
• pp.293-299
• /
• 2023

The Wide-Angle Polarimetric Camera (PolCam) is installed on the Korea's lunar orbiter, Danuri, which launched on August 5, 2022. The mission objectives of PolCam are to construct photometric maps at a wavelength of 336 nm and polarization maps at 461 and 748 nm, with a phase angle range of 0°-135° and a spatial resolution of less than 100 m. PolCam is an imager using the push-broom method and has two cameras, Cam 1 and Cam 2, with a viewing angle of 45° to the right and left of the spacecraft's direction of orbit. We conducted performance tests in a laboratory setting before installing PolCam's flight model on the spacecraft. We analyzed the CCD's dark current, flat-field frame, spot size, and light flux. The dark current was obtained during thermal / vacuum test with various temperatures and the flat-field frame data was also obtained with an integrating sphere and tungsten light bulb. We describe the calibration method and results in this study.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.1 no.1
• /
• pp.49-55
• /
• 2006

Applied by periodic Stimulating Currents in Bonhoeffer -Van der Pol(BVP) model, chaotic and periodic phenomena occured at specific conditions. The conditions of the chaotic motion in BVP comprised 0.7182< $A_1$ <0.792 and 1.09< $A_1$ <1.302 proved by the analysis of phase plane, bifurcation diagram, and lyapunov exponent. To control the chaotic motion, two methods were suggested by the first used the amplitude parameter A1, $A1={\varepsilon}((x-x_s)-(y-y_s))$ and the second used the temperature parameterc, $c=c(1+{\eta}cos{\Omega}t)$ which the values of ${\eta},{\Omega}$ varied respectlvly, and $x_s$, $y_s$ are the periodic signal. As a result of simulating these methods, the chaotic phenomena was controlled with the periodic motion of periodisity. The feasibilities of the chaotic and the periodic phenomena were analysed by phase plane Poincare map and lyapunov exponent.

• Journal of Microbiology
• /
• v.33 no.3
• /
• pp.252-259
• /
• 1995

The PCR was employed to detect and characterize the bovine immunodeficiency-like virus (BIV), which is a newly recognized member of the I entivirinae of the retroviruses. Degenerate primers representing the conserved regions in the pol genes of the Lentivirinae, were used to detect proviral DNA obtained from the bovine embryonic spleen cell cultures infected with BIV. The PCR amplified DNA fragment was molecularly cloned and sequenced. The BIV DNA fragment contained a sequence identical to that reported by Garvey et al. (Garvey et al., 1990. Virology, 175, 391-409). With the degenerate primers, peripheral blood mononuclear cells (PBMCs) of sick cattle and cells cultured with BIV were tested to determine genetic variation of BIV pol conserved sequence. We found the sequence heterogeneity within cultures and most variations occurred at the third base of codons that would not lead to amino acid substitutions. Another change was GAG (Glu) to AAG (Lys) within the BIV isolates. Interestingly, the altered sequence is also found in other lentiviruses such as HIV-2, SIV mac, CAEV and EIAV.

• Genomics & Informatics
• /
• v.3 no.4
• /
• pp.133-141
• /
• 2005

Most of the endogenous retroviral genes integrated into the primate genome after the split of New World monkeys in the Oligocene era, approximately 33 million years ago. Because they can change the structure of adjacent genes and move between and within chromosomes they may play important roles in evolutionas well as in many kinds of disease and the creation of genetic polymorphism. Comparative analysis of HERVs (human endogenous retroviruses) and their LTR (long terminal repeat) elements in the primate genomes will help us to understand the possible impact of HERV elements in the evolution and phylogeny of primates. For example, HERV-K LTR and SINE-R elements have been identified that have been subject to recent change in the course of primate evolution. They are specific elements to the human genome and could be related to biological function. The HERV-M element is related to the superfamily of HERV-K and is integrated into the periphilin gene as the truncated form, 5'LTR-gag-pol-3'LTR. PCR and RT-PCR approaches indicated that the insertion of various retrotransposable elements in a common ancestor genome may make different transcript variants in different primate species. Examination of the HERV-W elementrevealed that env fragments were detected on human chromosomes 1, 3-7, 12, 14, 17, 20, and X, whilst the pol fragments were detected on human chromosomes 2-8, 10-15, 20, 21, X, and Y. Bioinformatic blast search showed that almost full-length of the HERV-W family was identified on human chromosomes 1-8, 11-15, 17, 18, 21, and X. Expression analysis of HERV-W genes (gag, pol, and env) in human tissues by RT-PCR indicated that gag and pol were expressed in specific tissues, whilst env was constituitively expressed in all tissues examined. DNA sequence based phylogenetic analysis indicated that the gag, pol and env genes have evolved independently during primate evolution. It will thus be of considerable interest to expand the current HERV gene information of various primates and disease tissues.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• v.9 no.1
• /
• pp.937-941
• /
• 2005

In this paper, we propose a chaotic underwater robots that have unstable limit cycles in a chaos trajectory surface with Arnold equation, Chua's equation. We assume all obstacles in the chaos trajectory surface have a Van der Pol equation with an unstable limit cycle. We also show computer simulation results of Arnold equation and Chua's equation chaos trajectories with one or more Van der Pol obstacles

• Journal of the Korean Mathematical Society
• /
• v.44 no.3
• /
• pp.511-523
• /
• 2007

We consider a two parametric family of the planar systems with the form $\dot{x}=P(x,\;y)+{\in}_1p_1(x,\;y)+{\in}_2p_2(x,\;y)$, $\dot{y}=Q(x,\;y)+{\in}_1p_1(x,\;y)+{\in}_2p_2(x,\;y)$, where the unperturbed equation(${\in}_1={\in}_2=0$) is assumed to have at least one periodic solution or limit cycle. Our aim here is to study the behavior of the system under two parametric perturbations; in fact, using the Poincare-Andronov technique, we impose conditions on the system which guarantee persistence of the periodic trajectories. At the end, we apply the result on the Van der Pol equation ; where, we consider the effect of nonlinear damping on the equation. Also the Hopf bifurcation for the Van der Pol equation will be investigated.

• The Bulletin of The Korean Astronomical Society
• /
• v.44 no.1
• /
• pp.55.2-55.2
• /
• 2019

한국형 시험용 달 궤도선(KPLO)에 실릴 과학 탑재체 가운데 하나인 광시야 편광 카메라(PolCam)는 최초로 달 표면전체의 편광 특성을 관측한다. 편광 특성은 태양-달-관측기기 사이의 각도인 위상각에 따라 달라지므로, 다양한 위상각에서의 반복 관측을 통해 달 전 지역에 대한 각각의 편광곡선을 얻을 예정이다. 편광곡선으로부터 달 표면의 입자 크기와 성분 등의 분포를 알 수 있다. 이는 과학적으로도 흥미로울 뿐 아니라, 미래의 달 탐사 임무를 위한 착륙지 선정 시에도 중요한 참고자료가 된다. 여기에서는, PolCam이 1년간의 KPLO 임무 동안 관측할 수 있는 지역 및 위상각의 분포를 소개한다. 또한, 임무 도중 관측이 일시중지되거나 임무 자체가 비정상종료되는 경우 불완전한 관측 자료로부터 편광곡선을 구하는 방법에 대해 알아본다.