• Journal of Microbiology and Biotechnology
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• v.33 no.9
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• pp.1250-1256
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• 2023

Herein, different extracts of Scenedesmus deserticola JD052, a green microalga, were evaluated in vitro as a potential anti-aging bioagent. Although post-treatment of microalgal culture with either UV irradiation or high light illumination did not lead to a substantial difference in the effectiveness of microalgal extracts as a potential anti-UV agent, the results indicated the presence of a highly potent compound in ethyl acetate extract with more than 20% increase in the cellular viability of normal human dermal fibroblasts (nHDFs) compared with the negative control amended with DMSO. The subsequent fractionation of the ethyl acetate extract led to two bioactive fractions with high anti-UV property; one of the fractions was further separated down to a single compound. While electrospray ionization mass spectrometry (ESI-MS) and nuclear magnetic resonance (NMR) spectroscopy analysis identified this single compound as loliolide, its identification has been rarely reported in microalgae previously, prompting thorough systematic investigations into this novel compound for the nascent microalgal industry.

• Molecules and Cells
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• v.46 no.10
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• pp.611-626
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• 2023

Acute myeloid leukemia (AML) is a heterogeneous disease caused by distinctive mutations in individual patients; therefore, each patient may display different cell-type compositions. Although most patients with AML achieve complete remission (CR) through intensive chemotherapy, the likelihood of relapse remains high. Several studies have attempted to characterize the genetic and cellular heterogeneity of AML; however, our understanding of the cellular heterogeneity of AML remains limited. In this study, we performed single-cell RNA sequencing (scRNAseq) of bone marrow-derived mononuclear cells obtained from same patients at different AML stages (diagnosis, CR, and relapse). We found that hematopoietic stem cells (HSCs) at diagnosis were abnormal compared to normal HSCs. By improving the detection of the DNMT3A R882 mutation with targeted scRNAseq, we identified that DNMT3A-mutant cells that mainly remained were granulocyte-monocyte progenitors (GMPs) or lymphoid-primed multipotential progenitors (LMPPs) from CR to relapse and that DNMT3A-mutant cells have gene signatures related to AML and leukemic cells. Copy number variation analysis at the single-cell level indicated that the cell type that possesses DNMT3A mutations is an important factor in AML relapse and that GMP and LMPP cells can affect relapse in patients with AML. This study advances our understanding of the role of DNMT3A in AML relapse and our approach can be applied to predict treatment outcomes.

• Journal of the Korean Electrochemical Society
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• v.4 no.3
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• pp.125-131
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• 2001

A long-term variation of electrode polarization in the MCFC has been analyzed successfully using a single cell with a Au, $CO_2/O_2$ reference electrode Four different cells with different components were operated and their electrode polarizations were analyzed. As published in the literatures, the cathode polarization was larger than that of the anode. The more stable operation of a single cell with the Al-coated cell frame up to 6,000hrs indicates that the corrosion at the cell frame, particularly wet seal area, plays an important role to determine the lifetime of a MCFC. At the initial stage of the cell operation, the voltage of the cell using a cathode stabilized by the $LiCoO_2$ coating was relatively low due to the high cathode polarization. As the cell was operated and the stabilized cathode was lithiated sufficiently, the cathode polarization decreased and the cell voltage was recovered. It was observed that the voltage of the cell using the $Li_2CO_3/Na_2CO_3$ electrolyte fluctuated with operation time and the cathode polarization fluctuated along with the cell voltage quite similarly. Although the mechanisms of the voltage fluctuation were not clear yet, the results imply that the voltage fluctuation was related with a reaction in the cathode side. After testing every single cell, the cathode polarization increased with the steep decrease in the cell voltage. Thus, the cathode should be improved in order to develop more durable MCFC.

• Genomics & Informatics
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• v.8 no.4
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• pp.201-205
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• 2010

The H1 histone family, member N, testis-specific (H1FNT) is exclusively expressed in the testis, and had its possible role for sperm chromatin formation. The purpose of this study is to investigate any genetic association of H1FNT gene with male infertility, especially at the promoter region. We examined the promoter single nucleotide polymorphisms (SNP) of H1FNT gene which is located within transcription factor binding site for its association with male infertility. The statistical analysis showed that the -1129A>T polymorphism was present at a statistically significance in male infertility (p=0.0059 and 0.0349 for hetero and risk type, respectively). The dual-luciferase promoter assay was performed to examine the polymorphic effect of this promoter SNP by the cloning of promoter region (1700bp fragment) into pGL3-basic vector. In our plasmid based reporter system, there is no big difference between wild and risk type. In conclusion, H1FNT -1129A>T promoter SNP is statistically significant with male infertility, especially with subfertile (non-azoospermia) group. Further analysis of its functional polymorphic effect in vivo may provide the biological significance of testis-specific histone with spermatogenesis.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.9A
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• pp.1348-1358
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• 2000

The paper contributes to a traffic analysis for the CDMA cellular base station with repeater which are operated in a cell site. Usually the repeaters' traffic of the CDMA cellular system hardly could be separated from that of the base station because the links of the repeaters are divided from RF circuits of the base station. The paper introduces a traffic measuring method that separates the traffic of repeaters from that of the base station using time delay device. To get general results we use a single BTS(Base station Transceiver Subsystem) with three repeater as well as a single BTS with a single repeater. Then we proved that the traffic of the repeaters could separate from that of the base station clearly.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2003.10a
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• pp.92-92
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• 2003

Accurate analysis of nuclear status is needed when biopsied-blastomeres are used for embryo sexing. In this study, the nuclear status of blastomeres derived from 8- to 16-cell stage IVF bovine embryos was analyzed to evaluate the representative of single blastomere for embryo sexing. When 55 embryos were analyzed by PCR following biopsy, the coincident rate of sex determination between biopsied-single blastomere and matched blastocyst by PCR was 80 %. Karyotyping of biastomeres in 8- 16-cell stage bovine embryos was conducted to assess chromosome status of IVF embryos. To establish karyotyping of blastomeres, concentrations of vinblastine sulfate and duration of exposure time for metaphase plate induction with 8- to 16-cell stage bovine embryos were tested. The most effective condition for induction of metaphase plate (>45%) was 1.0 ug/ml vinblastine sulfate treatment for 15 h. In 22 embryos under the condition, only 8 embryos out of ten that had a normal diploid chromosome complement showed a sex-chromosomal composition of XX or XY (36.4%) and 2 diploid embryos showed mosaicism of the opposite sex of XX and XY in blastomeres of embryo (9.1%). One haploid embryo contained only one X-chromosome (4.5%). Four out of the other 11 embryos having a mixoploid chromosomal complement contained haploid blastomere with wrong sex chromosome (18.2%). These results suggested that morphologically normal bovine embryos derived from IVF had considerable proportion of mixoploid and sex-chromosomal mosaicism which could be the cause of discrepancies of the sex between biopsied-single blastomere and matched blastocyst by PCR analysis.

• Environmental Analysis Health and Toxicology
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• v.21 no.2 s.53
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• pp.127-138
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• 2006

In urban areas, diesel exhaust particles (DEP) are probably a major component of particulate matters, especially in Korea where drive many diesel vehicles. The aim of this study was to investigate genotoxic effects of DEP using single ceil gel electrophoresis. In order to evaluate the mechanisms of DEP genotoxicity, the rat microsome mediated and DNA repair enzyme treated comet assays together with conventional comet assay were performed. Total diesel particles (DEPT) was collected without site fractionation from diesel engine bus and dichloromethane extract was obtained. The organic extract of DEPT revealed DNA damage itself in NIH/3T3 cells. The level of DNA breaks plus oxidative DNA lesions and microsome mediated DNA damage was assessed by modified single cell gel eletrophoresis. DEPT was able to induce oxidative DNA damage as well as microsome mediated DNA damage. Vitamin C as an model antioxidant reduced DNA damage in endonuclase III treated comet assay. One of flavonoid, galangin as a CYP1A1 inhibitor. reduced DNA damage in the presence of S-9 mixture. $DEP_T$ is the sources of oxidative stress, but antioxidants can significantly reduce oxidative DNA dmage. And $DEP_T$ may contain indirect mutagens which can be inhibited by CYP1A1 inhibitors. The ethanol extracts of the mixed vegetables (BV) or the mixed fruits (BF) were evaluated for their in vitro antigenotoxic effects. BV and BF showed potent Inhibitory effects against DEPT induced DNA damage with oxidative DNA lesions and in the prescence of S-9 mixture. These results indicate that BV and BF could prevent cellular DNA damage by inhibiting oxidative stress and suppressing cytochrome P4501A1 in cell culture.

• Journal of Information Processing Systems
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• v.15 no.1
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• pp.47-54
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• 2019

This study is concerned with the mechanism and structure of an optical microscope and an automatic multi-focus algorithm for automatically selecting sharp images from multiple foci of a cell. To obtain precise cell images quickly, a z-axis actuator with a resolution of $0.1{\mu}m$ was designed to control an optical microscope Moreover, a lighting control system was constructed to select the color and brightness of light that best suit the object being viewed. Cell images are captured by the instrument and the sharpness of each image is determined using Gaussian and Laplacian filters. Next, cubic spline interpolation and peak detection algorithms are applied to automatically find the most vivid points among multiple images of a single object. A cancer cell imaging experiment using propidium iodide staining confirmed that a sharp multipoint image can be obtained using this microscope. The proposed system is expected to save time and effort required to extract suitable cell images and increase the convenience of cell analysis.

• Advances in Energy Research
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• v.8 no.4
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• pp.253-264
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• 2022

This paper deals with the effects of design (active area, current density, membrane conductivity) and operating parameters (temperature, relative humidity) on the performance of hydrogen-fuelled proton exchange membrane (PEM) fuel cell. The design parameter of a PEM fuel cell with the active area of the single cell considered in this study is 25 cm² (5 × 5). The operating voltage and current density of the fuel cell were 0.7 V and 0.5 A/cm² respectively. The variations of activation voltage, ohmic voltage, and concentration voltage with respect to current density are analyzed in detail. The membrane conductivity with variable relative humidity is also analyzed. The results show that the maximum activation overpotential of the fuel cell was 0.4358 V at 0.21 A/cm² due to slow reaction kinetics. The calculated ohmic and concentrated overpotential in the fuel cell was 0.01395 V at 0.76 A/cm² and 0.027 V at 1.46 A/cm² respectively.

• Architectural research
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• v.12 no.2
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• pp.93-98
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• 2010

This paper describes a numerical method for estimating the elastic moduli of cement paste. The cement paste is modeled as a unit cell which consists of three components: the unhydrated cement grain, the gel, and the capillary pore. In the unit cell, the volume fractions of the constituents are quantified using a single kinetic function calculating the degree of hydration. The elastic moduli of cement paste are calculated from the total displacements of constituents when a uniform pressure is applied to the gel contact area. The cement paste is assumed to be a homogenous isotropic matrix. Numerical simulations were conducted through the finite element analysis of the three-dimensional periodic unit cell. The model predictions are compared with experimental results. The predicted trends are in good agreement with experimental observations. This approach and some of the results might also be relevant for other technical applications.