• Composites Research
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• v.12 no.6
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• pp.74-82
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• 1999

The static and fatigue characteristics of polyurethane foam cored sandwich structures are investigated. Three types of the specimens with the glass fabric faces and the polyurethane foam core are used; non-stitched. stitched, and stiffened sandwich specimen. Especially additional structural reinforcements with the twisted polyester and glass fiber for thickness direction are made to stitched sandwich structure panel to minimize the delamination of structure which is stitched the upper and lower faces through the core and the resin is impregnated Into stitched fiber with the characteristics of low viscosity of resin at resin flow temperature and cured together with during the curing process. Bending strength of stitched specimen which is 50 mm $50{\times}50{\;}mm$ pitched is improved by 50 % as com-pared with non-stitched specimen and stiffened specimen is improved 10 times more than non-stitched structure. After fatigue testing of $10^6$cycles by 20% of ultimate load under monotonic load, the bending fatigue strength of non-stitched specimen is decreased by 27% of monotonic bending strength, 39% for stitched structure and 20% for stiffened specimen. To verify the aging effect of polyurethane form core, Ultrasonic C-scanning equipment is used to detect the damage of skin laminate alone after fatigue test. From results of UT C-scan images, there is no defect that can be damaged occurred during fatigue test. It is concluded that the decrease of bending strength for foam cored sandwich specimen is caused by the decrease of stiffness due to the aging of polyurethane foam core during fatigue cycles.

• Journal of the Korean Society of Visualization
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• v.12 no.1
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• pp.49-53
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• 2014

In this study, a novel FDR-SPC is first synthesized in this study. The drag reducing functional radical such as PEGMA (Poly(ethylene) glycol methacrylate) has been utilized to participate in the synthesis process of the SPC. The types of the baseline SPC monomers, the molecular weight and the mole fraction of PEGMA were varied in the synthesis process. The resulting SPCs were coated to the substrate plates for the subsequent hydrodynamic test for skin friction measurement. In a low-Reynolds number flow measurement using PIV (Particle Image Velocimeter), a significant reduction in Reynolds stress was observed in a range of specimen, with the maximum drag reduction being 15.9% relative to the smooth surface.

• Steel and Composite Structures
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• v.35 no.6
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• pp.779-788
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• 2020

Multi-Walled Carbon nanotubes (MWCNT) coupled with Silicone Rubber (SR) can represent applicable strain sensors with accessible materials, which result in good stretchability and great sensitivity. Employing these materials and given the fact that the combination of these two has been addressed in few studies, this study is trying to represent a low-cost, durable and stretchable strain sensor that can perform excellently in a high number of repeated cycles. Great stability was observed during the cyclic test after 2000 cycles. Ultrahigh sensitivity (GF>1227) along with good extensibility (ε>120%) was observed while testing the sensor at different strain rates and the various number of cycles. Further investigation is dedicated to sensor performance in the detection of human body movements. Not only the sensor performance in detecting the small strains like the vibrations on the throat was tested, but also the larger strains as observed in extension/bending of the muscle joints like knee were monitored and recorded. Bearing in mind the applicability and low-cost features, this sensor may become promising in skin-mountable devices to detect the human body motions.

• Journal of Oral Medicine and Pain
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• v.25 no.2
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• pp.167-172
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• 2000

Both immune reaction and hypersensitivity reaction are occurred by the same mechanism, the antigen and antibody reaction. The favorable result of this reaction towards a host is called clinically an immune reaction and the opposite results is called an hypersensitivity reaction. Type IV hypersensitivity reaction is a delayed type which is related to the cellular immune reaction and a contact hypersensitivity is included in this type. Various dental materials such as metal (mercury, nickel, chrome, cobalt), resin and eugenol are etiologic substances. Patch test kit is composed of test substance with a controlled concentration which respond only to a susceptible patient and an aluminum chamber, and etiologic substances for hypersensitivity can be easily and comfortably found just by applying the kit to the patient's skin. In this case report, the patch test was performed to a patients with oral lichen planus and the allergen, restorative material was found. After removal of the matching restoration from the patient's mouth, the symptom was improved.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.33 no.3
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• pp.189-196
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• 2007

In order to investigate the potential of very low molecular weight hyaluronic acid(oligo HA) as a cosmetic ingredient, we first measured its cytotoxicity in fibroblast, keratinocyte, and SIRC cell lines. For efficacy test, its moisturizing effect and penetration rate were evaluated in an artificial skin system and Caco-2 cells. Oligo HA did not show any cytotoxicity at a concentration of 300 ${\mu}g/mL$ in fibroblasts and 1,000 ${\mu}g/mL$ in keratinocytes but it showed weak proliferation. In vitro ocular test, oligo HA showed negligible cytotoxicity at the maximum concentrations used(2,000 ${\mu}g/mL$) in SIRC cells. In the test of the single and repeated cutaneous applications, oligo HA under occlusive patch did not provoke any cumulative irritation and sensitization. Oligo HA at a concentration of 0.01 % exhibited a more potent moisturizing effect than hyaluronic acid at a concentration of 0.01 %. In the permeability test using artificial skin and Caco-2 cell lines, hyaluronic acid(M.W. $1.1{\times}10^6$) was hardly observed in the down medium of the inserts. On the other hand, oligo HA(M.W. 5,000) was detected in the down medium up to 16.0 % at 6 h in Caco-2 cell culture and up to 90 % at 6 h in an artificial skin system. These results suggest that oligo HA could be useful as an active ingredient for cosmetics.

• Journal of Korean Medical Ki-Gong Academy
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• v.11 no.1
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• pp.80-116
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• 2009

It studies into viewpoints of 7 doctors of Wenbing studies on macula. The results concerning characteristics, remedy and prevention of macula are as follows; Macule does not protrude on the surface of skin and does not have any color change for external stimulus, but rash out on the surface and becomes white when pushed. It becomes macule when the blood leaks beneath skin as stomach-heat of yangming enters into blood system and damages it. On the other hand, when heat enters lung meridian, penetrates beneath the skin and congeals inside the vessel, it becomes rash. When you combine symptoms of body and pulse with numbers, color, shape and distribution status of macula, you can diagnose the depth of rash, seriousness, the possibility of treatment and prognosis of macula. The remedy for macule consists of cooling heat of yaming, removing heat from the blood and relieving feverish rash, and the one for rash consists of facilitating meridian with aroma, expelling pathogenic factors from muscles with drugs of pungent flavor and cool nature and clearing away heat from the blood systems. It relieves the inhibited functional activities of lung-Ki, and helps extermination of rash as well as clearing heat of the vessel. Also, it is the most important to preserve resin of stomach for every treatment. It is good to avoid expelling pathogenic factors with drugs of pungent flavor and warm nature, raising drugs and invigorating drugs during treating macula. Moreover, the patients should not over dose cold-natured drugs and purgative therapy. There are common clinical symptoms of macula in advance, so right recognition of symptoms can contribute to prevention of macula.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.25 no.3
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• pp.13-33
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• 2012

Objective : The aim of this study is to find the therapeutic meaning of Pericarpium Granati and Cortex Betulae Platyphyllae in herbal medication. Methods : About the origin, the component, the processing the drug, the properties and tastes of drugs, the meridian tropism, the effects, the treating disease, the contraindication and the method of adminictration, I have researched 23 literatures and 10 disquisitions to mention the Pericarpium Granati and Cortex Betulae Platyphyllae. Result : 1. Pericarpium Granati is pericarp of mature fruit of The Pomegranate belongs to Punicaceae and Cortex Betulae Platyphyllae is bark of Betula platyphylla var. japonica (Miquel) Hara belongs to Betulaceae. 2. Pericarpium Granati consists of tannin 10.4~21.3%, lead 0.8%, resin 4.5%, mannitol 1.8%, sugar 2.7%, gum 3.2%, inulin 1.0%, musilage 0.6%, gallic acid 4.0%. Cortex Betulae Platyphyllae consists of betulin about 35%, various higher fatty acid about 35%, tannin about 7%. 3. The properties and taste of Pericarpium Granati is acid, astringency, warm, nontoxic and the meridian tropism is mainly stomach and large intestine meridian. The properties and taste of Cortex Betulae Platyphyllae is bitter, cold, nontoxic and the meridian tropism is mainly stomach meridian. 4. Pericarpium Granati has come into general use to treat roundworm, tapeworm, old diarrhea, anal prolapse, melena, metrorrhagia, leukorrhea, stomachache from worms, scabies etc. because it is effective on insecticiding, stopping diarrhea, controling hemorrhage and leukorrhea. Cortex Betulae Platyphyllae has come into general use to treat shigellosis, diarrhea, jaundice, cough, sputum, tonsillitis, pneumonia, nephritis, furuncle, prurigo, acne etc. because it is effective on cooling down heat, circulating humidity, removing phlegm, stopping cough, neutralizing poison. 5. Pericarpium Granati and Cortex Betulae Platyphyllae is useful method to external care. To use the herba, pulverize amount of property and then apply to the affected part. Conclusion : This study showed that Pericarpium Granati and Cortex Betulae Platyphyllae is useful herb to treat of skin disease and useful method to external care.

• The Korean Journal of Nuclear Medicine
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• v.7 no.1
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• pp.15-29
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• 1973

To attain a simple and reliable method of evaluating the thyroid function the reliability of the clinical manifestation and the conventional thyroid function tests in diagnosing the hyperthyroidism was studied. The subjects included 184 patients with hyperthyroidism and 66 cases with euthyroidism, who were treated at the Thyroid Clinic, Seoul National University Hospital, from July 1971 through August 1972. The observed results were as follows: 1. In the cases of hyperthyroidism, 19% of the patients were male and 81% female; in the cases of euthyroidism, 7.6% of the patients were male and 92.4% female. The majority of the patients were in 2nd to 4th decades of their lives. 2. There were objective signs clearly manifested in hyperthyroidism which were rare or absent in the euthyroid state. These clinical signs included wide pulse pressure, tachycardia, systolic murmur, exophthalmos, tremor, and warm skin. In the hyperthyroid state 91.3% of the cases manifested two or more of the above signs, whereas in the euthyroid state no patients manifested any two of the above signs. 3. The most frequent complaints of the patients with thyroid disease were palpitation, weight loss, increased appetite, heat intolerance, perspiration, hunger feeling; nervousness, exertional dyspnea, etc. There was no clear difference in the incidence of the symptoms between hyperthyroidism and euthyroidism. 4. In the diagnosis of hyperthyroidism, the reliability of thyroid ?unction tests was as follows; $T_7$ was 92.4% reliable, $^{125}IT_3$ resin uptake rate 91.6% reliable, $^{131}I$ thyroid uptake rate in 24 hrs. 89.4% reliable, serum $T_4$ level 85.9% reliable and BMR 75.5% reliable. Therefore the careful observation of the clinical manifestation of the disease is a simple and reliable way of making a correct diagnosis of either hyperthyroidism or euthyroidism. 5. In hyperthyroidism there shows no correlationship between the results of the thyroid function test and clinical signs but a high BMR was associated with both tachycardia and systolic murmur.

• Bulletin of the Korean Chemical Society
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• v.34 no.10
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• pp.3017-3021
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• 2013

Coumaroyl dipeptide amide, Coumaric acid-LG-$NH_2$, was prepared successfully using the solid-phase method, and its efficacy as a skin whitening agent was studied. Coumaric acid-LG-$NH_2$ was prepared with Rink-amide resin, and 96.354% of purity was obtained. Using MTT assay and LDH release assay, we found that it exhibited very low cytotoxicity. And, we found that Coumaric acid-LG-$NH_2$ inhibited tyrosinase activity dose-dependently and showed superior tyrosinase inhibitory activity to well-known whitening agent, arbutin. $IC_{50}$ value of Coumaric acid-LG-$NH_2$ was 182.4 ${\mu}M$, and $IC_{50}$ value of arbutin was 384.6 ${\mu}M$. Also, in measurement of melanin contents using B16F1 melanoma cell lines, Coumaric acid-LG-$NH_2$ reduced melanin production induced by ${\alpha}$-MSH statistically significant, and showed superior melanin inhibitory activity to p-coumaric acid or arbutin. In addition, Coumaric acid-LG-$NH_2$ reduced MC1R mRNA expression level. Thus, we concluded that MC1R pathway is the significant pathway of Coumaric acid-LG-$NH_2$, and Coumaric acid-LG-$NH_2$ has great potential to be used as novel whitening agents.

• Journal of Korean Society on Water Environment
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• v.22 no.1
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• pp.37-44
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• 2006

Ecotoxicity assessments of 90 selected effluents of 22 industry types from 2002 to 2004 in Korea were evaluated by a toxic battery of bioassay test using fish Oryzias latipes, invertebrate Daphnia magna, algae Selenastrum capricornutum and bacteria Vibrio fischeri with the physicochemical measurement items and permit concentrations on the present Water Quality Conservation Act in Korea. Total toxic unit (${\Sigma}TU$) of 8 industry types of 22 industry types by the toxic battery appeared in order of the value site as follows; Pigment Dye Manufacturing (${\Sigma}TU$ 217.1) > Textile and Dye (${\Sigma}TU$ 39.3) > Semiconductor Electronic Manufacturing (Small) (${\Sigma}TU$ 25.6) > Wastewater and Sewage Treatment Plants (${\Sigma}TU$ 25.4) > Coating (${\Sigma}TU$ 23.8) > Leather Skin Manufacturing (${\Sigma}TU$ 18.0) > Synthetic Resin Manufacturing (${\Sigma}TU$ 15.6) > Assemble Metal Manufacturing (${\Sigma}TU$ 10.7). Our results demonstrate that ecotoxicity assessment, by bioassay test, is effective and practical for industrial wastewater management for 90 selected effluents with the limitation of the physicochemical permit. Among 90 effluents, 9 samples failed physicochemical permit limitation and 81 passed it. In result of ecotoxicity assessment of 90 effluents by the toxic battery, 76 effluents exhibited ecotoxicity and the others did not. The physicochemical measurement items and permit concentrations on the present Water Quality Conservation Act in Korea were low related to the ecotoxicity value by the toxic battery and appeared limited for water quality management to water-ecosystem and environment-friendly management of water.