• 대한전기학회논문지
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• 제44권12호
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• pp.1610-1616
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• 1995

The (Sr$_{1-x}$ .Ca$_{x}$)TiO$_{3}$(0.05.leq.x.leq.0.2) ceramics were fabricated to form semiconducting ceramics by sintering at about 1350[.deg. C] in a reducing atmosphere (N$_{2}$ gas). After being fired in a reducing atmosphere, metal oxides, CuO, was painted on the both surface of the specimens to diffuse to the grain boundary. They were annealed at 1100[.deg. C] for 2 hours. The 2nd phase formed by thermal diffusing from the surface lead to a very high apparent dielectric constant. The results of the capacitance-valtage measurements indicated that the grain boundary was composed of the continuous insulating layers. The capacitance is almost unchanged below about 20[V], but decreased slowly over 20[V]. The conduction mechanism of the specimens observed in the temperature range of 25~125[.deg. C], and is divided into three regions having different mechanism as the current increased: the region I below 200[V/cm] shows the ohmic conduction. The region II between 200[V/cm] and 2000[V/cm] can be explained by the Poole-Frenkel emission theory, and the region III above 2000[V/cm] is dominated by the tunneling effect.ct.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 2007년도 Proceedings of The Convention
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• pp.129-139
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• 2007

Many modalities of treatment for acquired skin hyperpigmentation are available including chemical agents or physical therapies, but none are completely satisfactory. The ideal depigmenting compound should have a potent. rapid and selective bleaching effect on hyperactivated melanocytes, carry no short- or long-term side-effects and lead to a permanent removal of undesired pigment. acting at one or more steps of the pigmentation process. Depigmentation can be achieved by regulating (i) the transcription and activity of tyrosinase, tyrosinase related protein-1 (TRP-1), tyrosinase related protein-2 (TRP-2), and/or peroxidase; (ii) the uptake and distribution of melanosomes in recipient keratinocytes and (iii) melanin and melanosome degradation and turnover of pigmented keratinocytes. One of the interesting point for development of skin whitening agent is Mitf(Microphthalmia-associated transcription factor). Mitf belongs to the basic helix-loop-helix-zip family of trabscription factors and it is crucial as it regulates both melanocyte proliferation as well as melanogenesis and is the major regulator of tyrosinase and the related enzymes (TRPs), as well as many melanosome structural proteins such as pMel17. Recently, we developed MITF-down-regulating agents from natural and synthetic sources, which have anti-melanogenic effect on in vitro and in vivo. We suggested that potent MITF-down regulating agents might be used for skin whitening cosmeceuticals.

• Bulletin of the Korean Chemical Society
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• 제19권10호
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• pp.1036-1042
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• 1998

The preconcentration and determination of trace elements in water samples were studied by a solvent sublation utilizing dithizonate complexation. After metal dithizonates were formed, trace amounts of cadmium, cobalt, copper and lead were floated and extracted into small volume of a water-immiscible organic solvent on the surface of sample solution and determined in the solvent directly by GF-AAS. Several experimental conditions as formation condition of metal-dithizonate complexes, pH of solution, amount of dithizone, stirring time, the type and amount of surfactants, N2 bubbling rate and so on were optimized for the complete formation and effective flotation of the complexes. And also four kinds of light solvents were compared each other to extract the floated complexes, effectively. After the pH was adjusted to 4.0 with 5 M HNO3, 8.0 mL of 0.05% acetone solution of dithizone was added to 1.00 L water sample. The dithizonate complexes were flotated and extracted into the upper methyl isobutylketone (MIBK) layer by the addition of 2.0 mL 0.2% ethanolic sodium lauryl sulfate solution and with the aid of small nitrogen gas bubbles. And this solvent sublation method was applied to the analysis of real water samples and good results of more than 85% recoveries were obtained in spiked samples.

• Bulletin of the Korean Chemical Society
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• 제19권5호
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• pp.569-575
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• 1998

Investigation of the structure of the gangliosides has proven to be very important in the understanding of their biological roles. We have determined the tertiary structure of asialoganglioside GM1 $(GA_1)$ using NMR spectroscopy and distance geometry calculations. All of the structures are very similar except the glycosidic torsion angles in the ring IV and ring III linkages. There are two low-energy structures for GA1, G1 and G2. G1 differs from G2 only in the IV-III glycosidic linkages and the orientation of acetamido group in ring III. There is a stable intramolecular hydrogen bond between the third hydroxyl group in ring I and the ring oxygen atom in ring II. Also, there may be a weak hydrogen bond between the second hydroxyl group in ring IV and the acetamido group in ring III. Small coupling constants of $^3J_{IH3,IOH3}\; and\; ^3J_{IVH2,IVOH2}$ support this result. Overall structural features of $(GA_1)$ are very similar to those of $(GM_1)$. It implicates that specificities of the sugar moieties in GM1 are caused not by their tertiary foldings, but mainly by the electrostatic interactions between the polar sialic acid and its receptors. Since it is evident that $(GA_1)$ is more hydrophobic than $(GA_1)$, a receptor with a hydrophobic binding site can recognize the $(GA_1)$ better than $(GA_1)$. Studies on the conformational properties of $(GA_1)$ may lead to a better understanding of the molecular basis of its functions.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2016년도 학술발표회
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• pp.329-329
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• 2016

Rapid urbanization has taken environmental toll on the surrounding which can be witnessed by the advent of global warming and climate change. Driven by environmental needs, Green Building Index (GBI) was established in Malaysia to drive initiative to lead the property industry towards becoming more environmental friendly. Green roofs (roof with vegetated cover) as one of the assessment criteria of GBI, are gaining attention in the Malaysian society as a versatile new environmental friendly mitigation technology. This paper evaluates the qualitative and quantitative performances of an extensive green roof at Humid Tropics Centre under local tropical climate. Simulations showed that the extensive green roof system could reduce the peak discharge up to 26% in relation to impervious brown roof. Its reduction ability decreased for storms with intense rainfall. Increment of pH was observed for the green roof runoff and the runoff water quality ranged between class I and II under Water Quality Index (WQI). High concentrations of phosphate were noticed in the runoff samples and substrates (fertilized planting soil) might be the potential contributor. Findings indicate that there was a reduction of around $1.5^{\circ}C$ for indoor temperature of the building after installation of the extensive green roof.

• 한국보건간호학회지
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• 제33권1호
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• pp.59-72
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• 2019

Purpose: Nursing homes are a type of residential care that provide diverse services such as planned activities, convalescent care, skilled nursing and memory care. Nursing homes are good facilities for old people with dementia to improve their quality of life. On the other hand, the subjectivity toward nursing homes can vary to greater or lesser degrees. The purpose of this study was to identify the subjective attitudes and viewpoints toward nursing homes in undergraduate nursing students. Methods: The Q methodology, which is a research method to study the people's subjectivity, was used. The 40 Q-statements selected from each of 43 participants were classified into the shape of a normal distribution. The data collected were analyzed using the QUANL program. Results: Three types of subjectivity toward nursing homes emerged: 'Type I, in terms of usage of nursing homes-hesitative perspectives;', 'Type II, in terms of running of nursing homes-progressive perspectives;', and 'Type III, in terms of admission to nursing homes-constructive perspectives'. Conclusion: The findings of this study suggest that nursing intervention programs should be developed for the three types. The study results will lead to further research.

• Child Health Nursing Research
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• 제27권1호
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• pp.65-74
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• 2021

Purpose: The purpose of this study was to gain insights into empathy, cyberbullying, and cybervictimization among Filipino adolescents. Methods: The participants were 168 junior high school students in the 7th to 10th grades at a public high school in Cavite Province, Philippines. Data were collected on demographic characteristics, the Basic Empathy Scale, and Revised Cyber Bullying Inventory-II scores. The data were analyzed in SPSS using descriptive statistics (frequency and mean), the independent t-test, bivariate correlation, and one-way analysis of variance. Results: The degree of empathy did not show a statistically significant relationship with cyberbullying (r=-.07, p=.359) but did show a significant relationship with cybervictimization (r=.18, p=.025). Furthermore, cyberbullying had a statistically significant association with cybervictimization (r=.60, p<.001). Conclusion: Although empathy does not necessarily affect cyberbullying, higher levels of empathy were found among cyberbullying victims. However, an alarming result of this study is the possibility that victims may become cyberbullies. Therefore, we should highlight empathy as part of efforts to prevent cyberbullying and to solve various cyber-related problems. Since cyberbullying and cybervictimization are closely related, it is important to focus on this relationship and to make multilateral efforts to ensure that cyberbullying does not lead to other negative issues.

• Journal of Dental Anesthesia and Pain Medicine
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• 제21권3호
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• pp.261-268
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• 2021

Hemophilia A is a hemorrhagic disease caused by coagulation factor VIII deficiency. In head and neck cancer surgery, especially during a reconstructive one, complications can occur. These include hematomas due to bleeding which can then lead to flap ischemia, necrosis, and impaired wound healing. There are fewer cases of reconstructive surgery in patients with hemophilia A. Here in we report, a reconstructive surgery that involved mass resection, partial glossectomy (right), selective neck dissection (right, Levels I, II, III, IV), and reconstruction at the lateral arm free flap (left) in a 25-year-old man with hemophilia A. The surgery was successfully performed without any complications after pretreatment with Factor VIII concentrate, which has not been reported earlier.

• 방사성폐기물학회지
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• 제20권1호
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• pp.65-98
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• 2022

The nuclear legacy that remains in the United Kingdom (UK) is complex and diverse. Consisting of legacy ponds and silos, redundant reprocessing plants, research facilities, and non-standard or one-off reactor designs, the clean-up of this legacy is under the stewardship of the Nuclear Decommissioning Authority (NDA). Through a mix of prompt and delayed decommissioning strategies, the NDA has made great strides in dealing with the UK's nuclear legacy. Fuel debris and sludge removal from the legacy ponds and silos situated at Sellafield, as part of a prompt decommissioning strategy for the site, has enabled intolerable risks to be brought under control. Reactor defueling and waste retrievals across the Magnox fleet is enabling their transition to a period of care and maintenance; accelerated through the adopted 'Lead and Learn' approach. Bespoke decommissioning methods implemented by the NDA have also enabled the relevant site licence companies to tackle non-standard reactor designs and one-off wastes. Such approaches have potential to influence and shape nuclear decommissioning decision making activities globally, including in Korea.

• Current Photovoltaic Research
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• 제10권2호
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• pp.49-55
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• 2022

With rapid growth in light-harvesting efficiency from 3.8 to 25.8%, organic-inorganic hybrid perovskite solar cells (PSCs) have attracted great attention as promising photovoltaic devices. However, despite of their outstanding performance, the commercialization of PSCs has been suffered from severe stability issues, especially for UV and humidity: (i) UV irradiation towards PSCs is able to lead UV-induced decomposition of perovskite films or catalytic reactions of charge-transporting layers, and (ii) exposure to surrounding humidity causes irreversible hydration of perovskite layers by the penetration of water molecules, resulting considerable decrease in their power-conversion efficiency (PCE). This review investigates current status of strategies to enhance UV and humidity stability of PSCs in terms of UV-management and moisture protection, respectively. Furthermore, the multifunctional approach to increase long-term stability as well as performance is discussed as advanced research directions for the commercialization of PSCs.