• Bulletin of the Korean Chemical Society
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• 제20권1호
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• pp.42-48
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• 1999

We have performed a quantum-chemical investigation on the conformations and electronic properties of a variety of methoxy-substituted poly(p-phenylenevinylenes) (PPVs) to elucidate the effects of alkoxy substitution. Geometrical parameters for the polymers were fully optimized through Austin Model I (AM I) semi-empirical Hartree-Fock (HF) band calculations. Electronic properties of the polymers were obtained by applying the AM I optimized structures to the modified extended Huckel method. To confirm validity of the AM I conformational results, we also carried out ab initio HF calculations with the 6-31G (d) basis set for a variety of methoxy-substituted divinylbenzenes. It is found that the potential energy surfaces of alkoxy-substituted PPVs are quite shallow around the planar conformations, suggesting that the prepared films possess a variety of conformations with different torsion angle in the solid state, depending on the synthetic conditions. When two alkoxy groups are concurrently substituted at the adjacent sites in the phenylene ring, these groups are subject to rotating around the C(sp2)-O bonds by 70-80° to avoid the strong steric repulsion between them. Consequently, the overlap between the π-type p orbital of oxygen and the π molecular orbitals of the polymer decreases. This leads to a wide gap and a high oxidation potential for tetramethoxy-substituted PPV, compared to those of dialkoxy-substituted PPV.

• Journal of Korean Neurosurgical Society
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• 제63권3호
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• pp.386-396
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• 2020

Objective : To generate synthetic spine magnetic resonance (MR) images from spine computed tomography (CT) using generative adversarial networks (GANs), as well as to determine the similarities between synthesized and real MR images. Methods : GANs were trained to transform spine CT image slices into spine magnetic resonance T2 weighted (MRT2) axial image slices by combining adversarial loss and voxel-wise loss. Experiments were performed using 280 pairs of lumbar spine CT scans and MRT2 images. The MRT2 images were then synthesized from 15 other spine CT scans. To evaluate whether the synthetic MR images were realistic, two radiologists, two spine surgeons, and two residents blindly classified the real and synthetic MRT2 images. Two experienced radiologists then evaluated the similarities between subdivisions of the real and synthetic MRT2 images. Quantitative analysis of the synthetic MRT2 images was performed using the mean absolute error (MAE) and peak signal-to-noise ratio (PSNR). Results : The mean overall similarity of the synthetic MRT2 images evaluated by radiologists was 80.2%. In the blind classification of the real MRT2 images, the failure rate ranged from 0% to 40%. The MAE value of each image ranged from 13.75 to 34.24 pixels (mean, 21.19 pixels), and the PSNR of each image ranged from 61.96 to 68.16 dB (mean, 64.92 dB). Conclusion : This was the first study to apply GANs to synthesize spine MR images from CT images. Despite the small dataset of 280 pairs, the synthetic MR images were relatively well implemented. Synthesis of medical images using GANs is a new paradigm of artificial intelligence application in medical imaging. We expect that synthesis of MR images from spine CT images using GANs will improve the diagnostic usefulness of CT. To better inform the clinical applications of this technique, further studies are needed involving a large dataset, a variety of pathologies, and other MR sequence of the lumbar spine.

• 한국미생물학회:학술대회논문집
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• 한국미생물학회 2003년도 International Meeting of the Microbiological Society of Korea
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• pp.83-86
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• 2003

Major advances in positive-sense RNA virus research have been facilitated by the development of reverse genetics systems. These systems consist of an infectious cDNA clone that encompasses the genome of the virus in question. This clone is then used as a template for the subsequent synthesis of infectious RNA for the generation of synthetic viruses. However, the construction of infectious cDNA for the Japanese encephalitis virus (JEV) has been repeatedly thwarted by the instability of its cDNA. As JEV is an important human pathogen that causes permanent neuropsychiatric sequelae and even fatal disease, a reliable reverse genetics system for this virus is highly desirable. The availability of this tool would greatly and the development of effective vaccines as well as facilitate studies into the basic biology of the virus, including the molecular mechanisms of viral replication, neurovirulence, and pathogenesis. We have successfully constructed a genetically stable infectious JEV cDNA containing full-length viral RNA genome. Synthetic RNA transcripts generated in vitro from the cDNA were highly infectious upon transfection into susceptible cells, and the cDNA remained stable after it had been propagated in E. coli for 180 generations. Using this infectious JEV cDNA, we have successfully expressed a variety of reporter genes from the full-length genomic and various subgenomic RNAs in vitro transcribed from functional JEV cDNAS. In summary, we have developed a reverse genetics system for JEV that will greatly facilitate the research on this virus in a variety of different fields. It will also be useful as a heterologous gene expression vector and aid the development of a vaccine against JEV.

• 한국수자원학회논문집
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• 제49권4호
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• pp.335-346
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• 2016

본 연구에서는 포아송 클러스터 강우생성모형의 하나인 MBLRP 모형의 매개변수지도를 우리나라에 대하여 제작하고 이에 기반을 둔 가상강우생성 웹 어플리케이션을 개발 및 검증하였다. 이를 위하여 우리나라의 62개 ASOS 지상 강우 관측소에서 관측된 강우자료를 기반으로 서로 다른 수문모의의 목적(홍수량 모의, 장기 유출량 모의, 일반 모의)에 따른 MBLRP 모형의 매개변수지도를 산정한 후, 이를 Ordinary Kriging 기법을 통해 공간 보간하여 우리나라에 대한 매개변수지도를 제작하였으며, 이에 기반을 두고 가상강우 시계열을 생성하는 웹 어플리케이션을 개발하였다. 검증을 위하여 웹어플리케이션을 사용하여 가상강우를 생성한 후 평균, 분산, 자기상관계수, 무강우 확률, 극한강우량 및 다양한 유역에 대한 극한홍수량과 유출량을 계산하고 이를 관측 강우에 근거하여 산출된 값과 비교하였다. 비교 결과 가상 강우의 각종 통계값은 관측강우에 근거한 값과 매우 유사하게 나타났으나, 극한강우와 극한홍수는 관측치에 근거한 값과 비교하여 16%-40% 정도 과소산정되는 경향을 보였다. 이러한 결과는 교정계수로 활용할 수 있도록 등고선도의 형태로 제공되었다. 본 연구에서 개발한 웹 어플리케이션은 모형의 매개변수 산정부터 가상 강우 시계열 생성까지 일련의 과정을 포함하고 있어 강우자료를 필요로 하는 다양한 수문 분석에 활발히 활용될 것으로 기대된다.

• Journal of Periodontal and Implant Science
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• 제26권2호
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• pp.396-413
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• 1996

Current acceptable methods for promoting periodontal regeneration are based on removal of diseased soft tissue. root treatment, guided tissue regeneration, introduction of new graft materials and biological mediators. Insulin-like growth factor-I(IGF-I) and Platelet-derived growth factor-BB(PDGF-BB), the members of the polypeptuyde growth factor family have been reported as the biological mediators which regulate a variety cellular matrix biologic activities of wound healing process including the cell proliferation, migration and extracellular matrix synthesis.The purposes of this study is to evaluate the combination effects of IGF-I and PDGF-BB on the cellular activity of the periodontal ligament cells to act as a regeneration promoting agent of periodontal tissue. Human periodontal ligament cells were prepared from the first premolar tooth extracted for the orthodontic treatment and were cultured in DMEM containing 10% FBS at the $37^{\circ}C$, 5% CO2 incubator. Author measured the DNA synthetic activity, and total protein, collagen and noncollagenous protein synthetic activities according to the concentration of 10,100ng/ml IGF-I and1,10 ng/ml PDGF-BB in combination. The results were as follows: Significantly increased in the 1 ng/ml PDGF-BB alone compared to the 10 ng/ml PDGF-BB alone(P<0.01) and in the 1 ng/ml PDGF-BB and 10, 100ng/ml IGF-I in combination compared to the 1 ng/ml PDGF-BB alone(P<0.05, P<0.0l). The synthetic activity of the total protein and collagen is significantly increased like to the synthetic activity of the DNA(P<0.05). The synthetic activity of the noncollagenous protein is increased according to the concentration of IGF_I, but not statistically statistically significant(P>0.05). The percent of the collagen is significantly in the 1ng/ml PDGF-BB and 10ng/ml IGF-I in combination compared to the 1ng/ml PDGF-BB alone(P<0.05) and in the 10ng/ml IGF-I in combination compared to the 10ng/ml PDGF-BB alone(P<0.05). The synthetic activity of the DNA is In conclusions, the percent study shows that PDGF-BB and IGF-I in combination have a potentiality to enhance the DNA synthesis and the total protein and collagen synthesis of The periodontal ligament cells, especially it is more significant in the low concentration of PDGF-BB compared to the high one. Thus, the PDGF-BB and IGF-I in combination may have important roles in promotion of periodontal litgment healing, and consequently, may useful for clinical application in periodontal regenerative procedures.

• 한국환경과학회지
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• 제23권7호
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• pp.1269-1275
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• 2014

Ecotoxicity assessments with the physiochemical water quality items and the bioassay test using Daphnia magna were conducted for 18 selected effluents of 6 industrial types (metal processing, petroleum refining, synthetic textile manufacturing, plating, alcohol beverage manufacturing, inorganic compound manufacturing) being detected toxicity from industrial effluent in Ulsan city, and the interrelationship between total toxic unit (${\Sigma}TU$) and concentrations of Water Quality Conservation Act in Korea were investigated. The average toxic unit(TU) of effluents for 6 industrial types displayed the following ascending order: petroleum refining (0.2) < synthetic textile manufacturing (0.6) < alcohol beverage manufacturing (0.9) < metal processing (1.3) ${\leq}$ inorganic compound manufacturing (1.3) < plating (3.0). These values were less than effluent permission standard. Based on the result of substances causing ecotoxicity, the correlation analysis was not easy because most of heavy metals were not detected or were less than effluent permission standard. Toxicological assessment of industrial effluent was suitable for the evaluation of the mixture toxicity for pollutant. The whole effluent toxicity test using a variety of species was needed for the evaluation of industrial wastewater.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 1999년도 The 6th International Symposium on the Development of Anti-Cancer Resource from Plants
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• pp.90-109
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• 1999

Many plant species are used in Malaysia in folk medicine for the treatment of cancer. This paper presents some of these species with details on other ethnopharmacological uses, the known bioactivities and some chemical constituents of each of the species given. It is normal practice in traditional medicine that one species of plant is used to treat various ailments. Thus the plant species listed are all used to treat cancer but have various other ethnophrmacological uses as well, some with few other uses and rest with many other uses. Information on bioactivities of each species resulting from tests on human and experimental animals are also given. Proven bioactivities give strength to ethnopharmacological claims on the efficacies of plant resources in the treatment of cancer and various other ailments but will but will not necessarily lead to the production of new pharmaceutical drugs. Many of the known chemical constituents of each species are given. This shows the richness and variety of chemicals containes in each of the species listed, The chemicals listed may or may not prove to be important in the pharmaceutical sciences but is an indication of what each species contatin in thrms of plant chemicals, It is a well known fact that many of the pharmaceutical prescriptions in present day use are of plant origin and semi-synthetic or fully synthetic chemicals produced using knowledge gained from studies of phytochemicals. Thus the paper presented will give useful information and also shows the richness of plant species that have high potentials for the development of anti-cancer resources from plants in Malaysia.

• Archives of Pharmacal Research
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• 제28권2호
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• pp.216-219
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• 2005

Wogonin (5,7-dihydroxy-8-methoxyflavone) has been reported to exhibit a variety of biological properties including anti-inflammatory and neuroprotective functions. In this study, biological activities of diverse synthetic wogonin derivatives have been evaluated in two experimental cell culture models. Inhibitory activities of wogonin derivatives on lipopolysaccharide (LPS)-induced nitric oxide (NO) production in BV2 microglial cells and on hydrogen peroxide ($H_{2}O_2$)-induced neuronal cell death in SH-SY5Y human neuroblastoma were examined. Wogonin derivatives such as WS2 and WS3 showed more potent suppressive activities on LPS-induced NO production and $H_{2}O_2$-induced cytotoxicity than wogonin itself. In addition, thiol substitution played a minor role in enhancing the activities of the derivatives. These findings may contribute to the development of novel anti-inflammatory and neuroprotective agents derived from wogonin.

• Bulletin of the Korean Chemical Society
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• 제32권3호
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• pp.768-778
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• 2011

Calixpyrroles and related macrocycles are non-planer synthetic anion receptors that have attracted considerable attentions in recent years. Although the synthesis of calix[4]pyrrole (known as meso-octamethylporphyrinogen) was reported more than 100 years ago, the anion binding properties were first discovered in 1996. The simple calix[4]pyrroles can be synthesized in single step in high yield by condensation of pyrrole with acetone. The compounds showed preferential binding for halide anions including fluoride, phosphate, carboxylate, and chloride in organic media. Efforts to improve the anion affinity of calix[4]pyrrole and to enhance its selectivity have led to the synthesis of a variety of new calixpyrrole derivatives. Among the various modifications, introduction of straps on one side of the calix[4]pyrroles are the most effective. Incorporation of aromatic rings other than pyrroles also exhibited interesting binding behaviour. Introduction of signalling units as part of the strapping element enable to detect the anions on chromogenic or fluorogenic fashion. Finding of the anion transport properties across the membrane and cytotoxic effects of the calix[4]pyrroles open new window for calixpyrrole-related research. The polymer-incorporated systems have also been employed as anion complexants in solvent-solvent extraction. These old, yet easy-to-make macrocycles have well advanced more recently with the discovery of the ion-pair complexation properties. In this review, the synthetic developments and anion binding properties of calixpyrroles for the last decades will be discussed and will cover the advances in calixpyrrole chemistry.

• 한국수소및신에너지학회논문집
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• 제20권6호
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• pp.519-525
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• 2009

The catalytic steam reforming of woody biomass tar and soot to convert a synthetic gas containing hydrogen was investigated by using a bench-scale biomass gasification system. One commercial nickel-based catalyst, Katalco 46-6Q, and two different kinds of natural minerals, dolomite and olivine, were tested as a reforming catalyst at various reforming temperatures. The reaction characteristics of woody biomass tar were also investigated by TGA at a variety of heating rates. With all three catalysts conversion efficiency of tar and soot increased at increasing temperature. The reforming of tar and soot in the synthetic gas induce the increase of combustible gases such as $H_2$, CO and $CH_4$ in the product gas. The nickel-based catalyst showed a higher tar and soot conversion efficiency than mineral catalysts under the same temperature conditions.