• Bulletin of the Korean Chemical Society
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• v.25 no.10
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• pp.1525-1530
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• 2004

Mutagen X (MX) exists in our drinking water as the bi-products of chlorine disinfection. Being one of the most potent mutagen, it attracted much attention from many researchers. MX and its analogs are synthesized and modeled by quantitative structure activity relationship (QSAR) methods. As a result, factors affecting this class of compounds have been found to be steric and electrostatic effects. We tried to collect all the data available from the literature. With both CoMFA and CoMSIA various combinations of physiochemical parameters were systematically studied to produce reasonable 3-dimensional models. The best model for CoMFA gave $q^2$ = 0.90 and $r^2$ = 0.97, while for CoMSIA $q^2$ = 0.85 and $r^2$ = 0.94. So the models seem to be reasonable. Unlike previous result of CoMFA, in our case steric parameter alone gave the best statistics. Although the steric contribution was found to be the most important in both CoMFA and CoMSIA, steric parameter along with electrostatic parameter produced slightly better model in CoMSIA. Overall, steric contribution is clearly the most important single factor. However, when we compare chlorine and bromine substitution, chlorine substitution can be more mutagenic. This indicates that other factors such as electrostatic effect also influence the mutagenicity. From the contour maps, steric contribution seems to be focused on rather small area near C6 substituent of the furanone ring, rather than C3 substituent. Therefore the locality of steric contribution can play a significant role in mutagenicity.

• Journal of the Korean Chemical Society
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• v.54 no.5
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• pp.621-632
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• 2010

In this study, we examined the characteristics of analogies generated by science-gifted students depending on the consideration of attributes and relationships in the processes of generating analogies and investigated the applicability of analogy-generating activities in science-gifted education programs. The analyses of the results revealed that the analogy-generating processes of science-gifted students were categorized into three kinds of patterns depending on the consideration of attributes and relationships of the target concept and the source analog. There are also some differences in the types of analogies generated and selected to be good, and in the proper mapping numbers by the patterns depending on the consideration of attributes and relationships. Most science-gifted students used the analogy-generating activities to other target concept, and recognized them to be useful. However, they had difficulties in selecting source analogs at the processes of generating analogy. These obtained in this study will help to explore a potential use of the analogy-generating activities in an effective education program for fostering the creativity of science-gifted students.

• Advances in environmental research
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• v.4 no.1
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• pp.39-48
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• 2015

Bisphenol A is widely used in plastic and other industrial consumer products. Release of bisphenol A and its analogues into the aquatic environment during manufacture, use and disposal has been a great scientific and public concern due to their toxicity and endocrine disrupting effects on aquatic wildlife and even human beings. More recent studies have shown that these alkylphenols may affect the molting processes and survival of crustacean species such as American lobster, crab and shrimp. In this study, we have developed gas chromatography with flame ionization detection (GC-FID) and gas chromatography-mass spectrometric (GC-MS) methods for the determination of bisphenol A and its analogues in shrimp Macrobrachium rosenbergii, blue crab Callinectes sapidus and American lobster Homarus americanus samples. Bisphenol A, 2,4-bis-(dimethylbenzyl)phenol and 4-cumylphenol were found in shrimp in the concentration ranges of 0.67-5.51, 0.36-1.61, and < LOD (the limit of detection)-1.96 ng/g (wet weight), and in crab of 0.10-0.44, 0.13-0.62, and 0.26-0.58 ng/g (wet weight), respectively. In lobster tissue samples, bisphenol A, 2-t-butyl-4-(dimethylbenzyl)phenol, 2,6-bis-(t-butyl)-4-(dimethylbenzyl)phenol, 2,4-bis-(dimethybenzyl)phenol, 2,4-bis-(dimethylbenzyl)-6-t-butylphenol and 4-cumylphenol were determined at the concentration ranges of 4.48-7.01, 1.23-2.63, 2.71-9.10, 0.35-0.91, 0.64-3.25, and 0.44-1.00 ng/g (wet weight), respectively. At these concentration levels, BPA and its analogs may interfere the reproduction and development of crustaceans, such as larval survival, molting, metamorphosis and shell hardening.

• Journal of the Korean Chemical Society
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• v.57 no.6
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• pp.744-754
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• 2013

Quantitative structure-activity relationship (QSAR) analysis for recently synthesized imidazole-(benz)azole and imidazole - piperazine derivatives was studied for their anticancer activities against breast (MCF-7) cell lines. The statistically significant 2D-QSAR models ($r^2=0.8901$; $q^2=0.8130$; F test = 36.4635; $r^2$ se = 0.1696; $q^2$ se = 0.12212; pred_$r^2=0.4229$; pred_$r^2$ se = 0.4606 and $r^2=0.8763$; $q^2=0.7617$; F test = 31.8737; $r^2$ se = 0.1951; $q^2$ se = 0.2708; pred_$r^2=0.4386$; pred_$r^2$ se = 0.3950) were developed using molecular design suite (VLifeMDS 4.2). The study was performed with 18 compounds (data set) using random selection and manual selection methods used for the division of the data set into training and test set. Multiple linear regression (MLR) methodology with stepwise (SW) forward-backward variable selection method was used for building the QSAR models. The results of the 2D-QSAR models were further compared with 3D-QSAR models generated by kNN-MFA, (k-Nearest Neighbor Molecular Field Analysis) investigating the substitutional requirements for the favorable anticancer activity. The results derived may be useful in further designing novel imidazole-(benz)azole and imidazole-piperazine derivatives against breast (MCF-7) cell lines prior to synthesis.

• Archives of Pharmacal Research
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• v.29 no.11
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• pp.969-976
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• 2006

Novel chalcones were found as potent inhibitors of interleukin-5 (II-5). 1-(6-Benzyloxy-2-hydroxyphenyl)-3-(4-hydroxyphenyl)propenone (2a, 78.8% inhibition at $50\;{\mu}M,\;IC_{50}=25.3\;{\mu}M$) was initially identified as a potent inhibitor of IL-5. This activity is comparable to that of budesonide or sophoricoside (1a). The benzyloxy group appears to be critical for the enhancement of the IL-5 inhibitory activity. To identify the role of this hydrophobic moiety, cyclohexyloxy (2d), cyclohexylmethoxy (2c), cyclohexylethoxy (2e), cyclohexylpropoxy (2f), 2-methylpropoxy (2g), 3-methylbutoxy (2h), 4-methylpentoxy (2i), and 2-ethylbutoxy (2j) analogs were prepared and tested for their effects on IL-5 bioactivity. Compounds 2c ($IC_{50}=12.6\;{\mu}M$), 2d ($IC_{50}=12.2\;{\mu}M$), and 2i ($IC_{50}=12.3\;{\mu}M$) exhibited the most potent activity. Considering the cLog P values of 2, the alkoxy group contributes to the cell permeability of 2 for the enhancement of activity, rather than playing a role in ligand motif binding to the receptor. The optimum alkoxy group in ring A of 2 should be one that provides the cLog P of 2 in the range of 4.22 to 4.67.

• The Journal of Korean Academy of Prosthodontics
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• v.44 no.1
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• pp.63-72
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• 2006

Purpose: The purpose of this study was to compare the accuracy of master cast fabricated by using different impression methods at the different impression levels. Material and Method: The master model used in this study was resin block having low implant analogs. Impression method studied were 1) direct method on future level (Group FIX-D), 2) Indirect method on fixture level(Group FIX-I), 3) Modified indirect method on fixture level(Group FD(-M), 4) Direct method on abutment level(Group AB-D) and 5) Indirect method on abutment level(Group AB-I). Each of the five groups took 10 impressions. Fifty impressions were made for master cast by using Impregum $F^(R)$ impression material loaded on individual tray. Three dimensional measuring microscope was used to measure the inter-implant distance. Error rate of each inter-implant distance were calculated and evaluated. Results: The results were as follows. 1. Group FIX exhibited higher accuracy than group AB. 2 In group FIX, modified indirect method showed the highest accuracy, while indirect method showed the lowest accuracy. In group Ab, indirect method showed the higher accuracy than direct method. 3. Group FIX showed larger horizontal error than group AB. But, group AB showed the larger vertical error than group FIX. 4. Group Fix-M showed smallest vertical and horizontal error.

• The Journal of Korean Academy of Prosthodontics
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• v.30 no.4
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• pp.611-621
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• 1992

The Present study was performed to evaluate the stress distribution patterns of bone tissues around two Branemark implant fixtures with varying lengths. Six models were used with the combination of 10mm, 7mm, 5mm Branemark implant fixture analogs. The load distribution characteristics of surrounding bone tissues were observed under 64kg vertical static loading on central part of fixed bridge using 2 dimensional photoelastic technique. Through observing the pattern of stress distribution around the implant fixtures, I got the results as follow : 1. Stress distribution pattern of model I(10mm, 10mm) was best among those of six models. 2. When two fixtures were in equal length, stress was increased in proportion to the reduction of implant surface area. 3. When two fixtures were in unequal length, stress was concentrated on the neck portion of the shorter one.

• The Korean Journal of Physiology and Pharmacology
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• v.2 no.3
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• pp.395-401
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• 1998

We have synthesized new platinum(II) analogs containing 1,2-diaminocyclohexane (dach) as a carrier ligand, 1,3-bis(diphenylphosphino) propane (DPPP) /1,2-bis(diphenylphosphino)ethane (DPPE) as a leaving group and nitrates to improve solubility. In the present study, the cytotoxicity of $[Pt(trans-l-dach)(DPPP)]\;2NO_3$ (KHPC-001) and $[Pt(trans-l-dach)(DPPE)]\;2NO_3$ (KHPC-002) was evaluated and compared on various P-388 cancer cell lines and porcine kidney cell line ($LLC-PK_1$). The new platinum complexes demonstrated high efficacy on P-388 mouse leukemia cell line as well as cisplatin-resistant (P-388/CDDP) and adriamycin-resistant (P-388/ADR) P-388 cell lines. The intracellular platinum content was measured by a flame atomic absorption spectrophotometer (FAAS), and it was comparable to the results of $IC_{50}$ of the three complexes on $LLC-PK_1$ and P-388/S cells, while only DPPE compound was accumulated in high volume in P-388/ADR and P-388/CDDP cells. While the DNA-interstrand cross-links of KHPC-001, KHPC-002 and cisplatin were similar on P-388/S leukemia cells, these new platinum complexes were much less DNA cross-linking to a kidney derived cell line, $LLC-PK_1$. These results indicate that KHPC-001 and KHPC-002 are a third-generation platinum complexes with potent antitumor activity and low nephrotoxicity.

• Journal of Veterinary Clinics
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• v.28 no.5
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• pp.526-529
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• 2011

The brachiocephalic trunk (Bct) branches from the aortic arch (Aa) and consists, in ruminants, of the common trunk of the left subclavian artery (LSb), the bicarotid artery (Bc) or left and right common carotid artery (LCc and RCc), and the right subclavian artery (RSb). This pattern differs from the primitive mammalian Aa pattern due to the fact that the analogs of the LCc and LSb migrate cranially and merge with the common trunk of the RCc and RSb in the embryonic stage. A Bct having a septal remnant that consisted of the tunica media was observed in a female Korean water deer (Hydropotes inermis argyropus), which was deemed to have resulted from an incomplete merging of the vessel walls between a carnivoran-type Bct and an incomplete LSb. This is the first report of an abnormal Bct in a Korean water deer.

• Journal of Ginseng Research
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• v.45 no.5
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• pp.539-545
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• 2021

Background: Red ginseng polysaccharides (RGPs) have been acknowledged for their outstanding immunomodulation and anti-tumor activities. However, their studies are still limited by the complexity of their structural features, the absence of purification and enrichment methods, and the rarity of the analytical instruments that apply to the analysis of such macromolecules. Thus, this study is an attempt to establish a new mass spectrometry (MS)-based analysis procedure for RGPs. Methods: Saponin pre-excluded powder of RG (RG-SPEP, 10 mg) was treated with 200 µL of distilled water and centrifuged for 5 h at 1000 rpm and 85 ℃. Ethanol-based precipitation and centrifugation were applied to obtain RGPs from the heated extracts. Further, endo-carbohydrase treatments were performed to produce specific saccharide fragments. Solid-phase extraction (SPE) processes were implemented to purify and enrich the enzyme-treated RGPs, while matrix-assisted laser desorption/ionization time-of-flight/time-of-flight (MALDI-TOF/TOF) MS was employed for the partial structural analysis of the obtained RGPs. Results: Utilizing cellulase, porous graphitized carbon (PGC), hydrophilic interaction chromatography (HILIC), and MALDI-TOF/TOF MS, the neutral and acidic RGPs were qualitatively analyzed. Hex_n and Hex_n-18 (cellulose analogs) were determined to be novel neutral RGPs. Additionally, the [Unknown + Hex_n] species were also determined as new acidic RGPs. Furthermore, HexA_n (H) was determined as another form of the acidic RGPs. Conclusion: Compared to the previous methods of analysis, these unprecedented applications of HILIC-SPE and MALDI-TOF/TOF MS to analyze RGPs proved to be fairly effective for fractionating and detecting neutral and acidic components. This new procedure exhibits great potential as a specific tool for searching and determining various polysaccharides in many herbal medicines.