• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.77.1-77.1
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• 2015

We present our recent work published in the MNRAS (Lee and Kim, 2014). Numerical studies of the imaging and caustic properties of the singular isothermal sphere (SIS) under a wide range of external shear (from 0.0 to 2.0) are presented. Using a direct inverse mapping formula for this lensing system, we investigate various lensing properties for both low-shear (i.e. ${\gamma}$<1.0) and high-shear (i.e. ${\gamma}$ >1.0) cases. We systematically analyse the effective lensing cross-sections of double-lensing and quadruple-lensing systems, based on the radio luminosity function obtained by the Jodrell-VLA Astrometric Survey (JVAS) and the Cosmic Lens All-Sky Survey (CLASS). We find that the limit of a survey selection bias (i.e. between brighter and fainter images) preferentially reduces the effective lensing cross-sections of two-image lensing systems. By considering the effects of survey selection bias, we demonstrate that the long-standing anomaly over the high quads-to-doubles ratios (i.e. 50~70 % for JVAS and CLASS) can be explained by the moderate effective shear of 0.16~0.18, which is half that of previous estimates. The derived inverse-mapping formula could make the SIS + shear lensing model useful for galaxy-lensing simulations.

• Current Optics and Photonics
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• v.2 no.6
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• pp.576-581
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• 2018

A new approach for identification of a microwave frequency using an integrated optical waveguide chip, combined with a phase modulator (PM) and two microring resonators (MRRs), is proposed, theoretically deduced, and verified. By wavelength tuning to set the PM under the condition of a double side band (DSB), the measurement range can be started from the dc component, and the measurement range and response slope can be adjusted by designing the radius and transmission coefficient of the MRR. Simulations reveal that the amplitude comparison function (ACF) has a monotonic relationship from dc to 32.5 GHz, with a response slope of 5.15 dB under conditions of DSB modulation, when the radius values, transmission coefficients, and the loss factors are designed respectively as $R_1=400{\mu}m$, $R_2=600{\mu}m$, $t_1=t_2=0.63$, and ${\gamma}_1={\gamma}_2=0.66$. Theoretical calculations and simulation results both indicate that this new approach has the potential to be used for measuring microwave frequencies, with the advantages of compact structure and superior reconfigurability.

• Corrosion Science and Technology
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• v.19 no.1
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• pp.37-42
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• 2020

Even though 304 low-carbon (304L) stainless steel was developed to enhance the resistance to intergranular corrosion and stress corrosion cracking, it is occasionally subject to degradation in harsh environments. The degree of sensitization (DOS) of 304L stainless steel was studied as a function of sensitization using a double-loop electrochemical potentiokinetic reactivation (DL-EPR) method. Sensitizing heat treatment was performed in an Ar atmosphere at 500℃, 600℃, and 700℃, with heat treatment times varying from 0 to 96 h. DOS was measured by the ratio of the peak current density value of the forward scan to that of the reverse scan. After the EPR experiment, the specimen surface was observed by scanning electron microscopy and energy dispersive spectroscopy. The DOS of the specimens heat-treated at 600℃ increased with heat treatment times up to 48 h and then decreased due to a self healing effect. The DOS was higher in specimens heat-treated at 600℃ than those at 500℃ or 700℃. Corrosion of the sensitized specimens occurred mainly at the δ-γ phase boundary. The corrosion morphology at the δ-γ phase boundary changed with sensitizing heat-treatment conditions due to differences in chromium activity in γ austenite and δ ferrite.

• The Korean Journal of Pharmacology
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• v.32 no.2
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• pp.177-188
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• 1996

The effects of cytokines on the growth and differentiation of glial cells in culture were evaluated to confirm that cytokines could modify the number and function of glial cells. Proliferation of glial cells was determined by the $^3H-thymidine$ uptake and the double immunostain with anti-cell specific marker and anti-bromodeoxyuridine(BrdU) antibody. To check the effect on the differentiation of glial cells, the amount of glial fibrillar acidic protein(GFAP) and the activity of glutamine synthetase(GS) were measured in astrocytes. And also the amounts of myelin basic protein(MBP) and the activity of 2',3'-cyclic nucleotide phosphohydrolase(CNPase) were measured in oligodendrocytes. Among the cytokines used, only interleukin-$1{\beta}(IL-1{\beta})$ stimulated the growth of type 1 and type 2 astrocyte as well as 0-2A precursor cell. When the functional changes in these glial cells by cytokines were tested, $IL-1{\beta}$ did not increase GFAP content in type 1 and type 2 astrocyte, but $IL-1{\beta}$ increased GS activity in type 1 astrocyte, and slightly decreased this enzyme activity in type 2 astrocyte. Also interleukin-2(IL-2) and $interferon-{\gamma}$ $(IFN-{\gamma})$ inhibited the activity of GS in type 1 and type 2 astrocyte. On the other hand, all cytokines used did not modify the growth and differentiation in oligodendrocytes. From these results we could suggest that $IL-1{\beta}$ increases the growth of type 1 and type 2 astrocyte and also promotes the development for 0-2A precursor cell to type 2 astrocyte.

• Journal of Radiation Protection and Research
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• v.33 no.2
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• pp.47-51
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• 2008

Objective: This study analyzed errors due to rotation or tilt of the magnetic resonance (MR) imaging indicator during image acquisition for a stereotactic radiosurgery. The error correction procedure of a commercially available stereotactic neurosurgery treatment planning program has been verified. Materials and Methods: Software virtual phantoms were built with stereotactic images generated by a commercial programming language, Interactive Data Language (version 5.5). The thickness of an image slice was 0.5 mm, pixel size was $0.5{\times}0.5mm$, field of view was 256 mm, and image resolution was $512{\times}512$. The images were generated under the DICOM 3.0 standard in order to be used with Leksell GammaPlan$^{(R)}$. For the verification of the rotation error correction function of Leksell GammaPlan$^{(R)}$, 45 measurement points were arranged in five axial planes. On each axial plane, there were nine measurement points along a square of length 100 mm. The center of the square was located on the z-axis and a measurement point was on the z-axis, too. Five axial planes were placed at z=-50.0, -30.0, 0.0, 30.0, 50.0 mm, respectively. The virtual phantom was rotated by $3^{\circ}$ around one of x, y, and z-axis. It was also rotated by $3^{\circ}$ around two axes of x, y, and z-axis, and rotated by $3^{\circ}$ along all three axes. The errors in the position of rotated measurement points were measured with Leksell GammaPlan$^{(R)}$ and the correction function was verified. Results: The image registration errors of the virtual phantom images was $0.1{\pm}0.1mm$ and it was within the requirement of stereotactic images. The maximum theoretical errors in position of measurement points were 2.6 mm for a rotation around one axis, 3.7 mm for a rotation around two axes, and 4.5 mm for a rotation around three axes. The measured errors in position was $0.1{\pm}0.1mm$ for a rotation around single axis, $0.2{\pm}0.2mm$ for double and triple axes. These small errors verified that the rotation error correction function of Leksell GammaPlan$^{(R)}$ is working fine. Conclusion: A virtual phantom was built to verify software functions of stereotactic neurosurgery treatment planning program. The error correction function of a commercial treatment planning program worked within nominal error range. The virtual phantom of this study can be applied in many other fields to verify various functions of treatment planning programs.

• The Journal of Korean Medicine
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• v.39 no.2
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• pp.36-55
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• 2018

Objectives: The purpose of this study was to investigate the effectiveness and safety of ginseng seed oil in healthy subjects who have mild liver dysfunction. Methods: A randomized, double blinded, placebo-controlled trial was conducted. A total of 167 subjects visited Semyung University Hospital from July 1st, 2016 to June 10th 2017. Except for the 103 excluded subjects, 64 subjects were randomized into one of the two groups: an treatment group(n=33) and control group(n=31). Subjects were randomly given either ginseng oil seed capsules or indistinguishable placebo capsules(2 capsules per dose, twice per day). Laboratory tests(aspartate aminotransferase, alanine aminotransferase, gamma glutamyl transpeptidase, triglyceride, total cholesterol, high density lipoprotein-cholesterol, low density lipoprotein-cholesterol) were performed to evaluate the effectiveness after 6, 12 weeks of treatment. Vital sign, laboratory test were performed to assess safety at every visit. Results: There were no significant differences in efficacy between treatment group and control group. There were some adverse events with no significant difference in symptoms and frequency between treatment group and control group. Conclusions: Although the efficacy of ginseng seed oil was not proved, ginseng seed oil did not worsen liver function and proved its safety. More study of ginseng seed oil and clinical trials are necessary to increase the usefulness of above-ground parts of ginseng.

• The Korea Journal of Herbology
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• v.35 no.1
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• pp.45-55
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• 2020

Objectives : The purpose of this study is to determine whether Rhus verniciflua Stokes with Latin name Lacca Sinica Exsiccata, and Eucommia ulmoides Oliver with Latin name Eucommiae Cortex Extract Combination (ILF-RE) improves laboratory test results in participants with liver function disorder. Methods : This study was conducted at Woosuk university Korean medicine hospital where participants with high serum alanine transaminase (ALT) levels from 45 to 135 U/L were enrolled. Subjects received ILF-RE 3.6 g (1.2 g/day as ILF-RE) or placebo 3.6 g for 12 weeks. It was confirmed that urushiol was not detected in ILF-RE. The primary outcomes were the decrement degree of serum ALT and gamma-glutamyl transferase (GGT) levels between two groups. The secondary outcomes were the decrement degree of serum aspartate transaminase (AST), alkaline phosphatase (ALP), lactate dehydrogenase (LD), total bilirubin, total cholesterol, triglyceride (TG) and fatty liver index (FLI) levels between two groups. Adverse events, skin prick tests, laboratory tests, and vital signs were observed and analyzed to confirm the safety of ILF-RE.1) Results : In the ILF-RE group, the liver function index ALT, GGT, lipid metabolism index TG, and fatty liver index FLI were significantly decreased compared to the placebo group. There was no significant difference in ILF-RE group in terms of adverse events, severe adverse events, skin prick test, laboratory test, and vital signs compared with placebo group. Conclusions : ILF-RE was found to be effective in improving liver function. In addition, no clinically significant adverse events or body changes were observed during this study.

• IMMUNE NETWORK
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• v.15 no.3
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• pp.150-160
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• 2015

We previously reported that 1-palmitoyl-2-linoleoyl-3-acetyl-rac-glycerol (PLAG) accelerates hematopoiesis and has an improving effect on animal disease models such as sepsis and asthma. The effects of PLAG supplementation on immune modulation were assessed in healthy men and women. The objective was to evaluate the effects of PLAG supplementation on immune regulatory functions such as activities of immune cells and cytokine production. A randomized double blind placebo-controlled trial was conducted. Seventy-five participants were assigned to one of two groups; all participants had an appropriate number of white blood cells on the testing day. The PLAG group (n=27) received oral PLAG supplements and the control group (n=22) received oral soybean oil supplements. IL-4 and IL-6 production by peripheral blood mononuclear cells (PBMC) were lower (p<0.001 and p<0.001, respectively) with PLAG than with soybean oil. However, the production of IL-2 and IFN-$\gamma$ by PBMC was unaltered with PLAG supplementation. The B cell proliferation decreased significantly in the PLAG group compared to the soybean oil control (p<0.05). The intake of PLAG in healthy adults for 4 weeks was deemed safe. These data suggest that PLAG has an immunomodulatory function that inhibits the excessive immune activity of immunological disorders such as atopic and autoimmune diseases. PLAG could improve the condition of these diseases safely as a health food supplement.

• Korean Journal of Acupuncture
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• v.30 no.2
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• pp.135-142
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• 2013

Objectives : This study aimed to investigate the general effects of low-frequency electrical stimulation of the ankle joint acupuncture points(BL62 and KI6) on the brain waves of elderly women as a pilot study to figure out the possibility of candidate non-invasive and non-chemical stimulation method for the enhancing the brain function. Methods : A randomized, controlled, double-blinded clinical trial was performed in 31 healthy women(mean age, 54.5 years) within a treatment duration of 12 sessions. In the experimental group, low-frequency electrical stimulation was applied using the maximum range of the individual insensible strength(mean current, $0.04{\mu}A$). The control group received sham stimulation. The background electroencephalographic activity was measured before and after the12 sessions. Results : After 12 sessions of stimulation, the relative power of the alpha wave increased(32 of 32 channels: significant difference in 11 channels, p<0.05); the theta(30 of 32 channels: significant difference in 10 channels, p<0.05), beta(31 of 32 channels), and gamma(30 of 32 channels: significant difference in 7 channels, p<0.05) powers were also decreased compared with the sham group. Conclusions : Electrical stimulation on the ankle joint acupuncture points(BL62 and KI6) seemed to stabilize the elderly women brain by inducing the alpha power and reducing beta, theta, and gamma powers. These results provide insight into the action mechanism of the stimulation and can assist the future developement of a non-invasive and non-chemical treatment technique for stressor related cognitive problems.

• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.52-52
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• 2001

Many nucleoside diphosphate (NDP) kinases are ubiquitous enzymes responsible for the exchange of ${\gamma}$-phosphates between tri- and diphosphonucleosides. The catalytic Many nucleoside diphosphate (NDP) kinases are ubiquitous enzymes responsible for the exchange of ${\gamma}$-phosphates between tri- and diphosphonucleosides. The catalytic reaction follows a ping-pong mechanism in which the enzyme is transiently phosphorylated on a histidine residue conserved in all nucleoside diphosphate kinases. Beside their role in nucleotide synthesis, these enzymes present additional functions, possibly independent of catalysis, in processes such as differentiation, cell growth, tumor progression, metastasis and development. To clone murine nm23-M5, several expressed sequence tags (ESTs) of the GenBank data base, selected according to their homology to nm23-H5 cDNA, reconstituted a complete open reading frame (GenBank AF222750). To test whether murine NDPKs (1, 2, 3, 4, 5, and 6) can inhibit Bax-mediated toxicity in yeast, co-transformation was performed respectively. The yeast S.cerevisiae was transformed with a copy expression plasmid containing the histidine selection marker and expressing murine Bax under the control of a galactose-inducible promoter. Several clones were selected and found to be growth inhibited when Bax expression was induced with galactose. A representative clone was transformed again with a copy expression plasmid containing the tryptophane selection marker and expressing either murine Bcl-xL or NDPK under the control of a galactose-inducible promoter. Several subclones of the double-transformants were selected and characterized. The ability of Bcl-xL and NDPKs to suppress Bax-mediated toxicity was determined by growing yeast cells overnight in galactose media and spot-testing on galactose plates starting with an equal number of yeast cells as determined by taking the OD$_{600}$. Ten-fold serial dilutions were used in the spot-test. Plates were grown at 3$0^{\circ}C$ for 2-3 days. All murine NDPKs suppressed Bax dependent apoptosis. Futher study will be peformed whether Bax-toxicity inhibition was caused by NDP kinase activity or additional function.n.