• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.16 no.3
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• pp.222-232
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• 2006

Objectives: The objective of this study was to propose the total isocyanate analytical method which involves derivation of 2,4-toluene diisocyanate(2,4-TDI), 2,6-toluene diisocyanate(2,6-TDI), 4,4'-methylenediphenyl diisocyanate(4,4'-MDI) and 1,6-hexamethylene diisocyanate(1,6-HDI) using 2-chlorobenzyl alcohol(2-CBA) or 2,4-dichlorobenzyl alcohol(2,4-DCBA), and analyzing of hydrolysate of the synthesized urethane with the gas chromatography(GC)/flame ionization detector(FID), GC/pulsed discharge ionization detector-electron capture detector(PD-ECD) and GC/mass selective detector(MSD). Methods: Urethanes were synthesized by reacting 2,4-TDI, 2,6-TDI, 4,4'-MDI and 1,6-HDI to 2-CBA or 2,4-DCBA. Urethanes was verified by TLC, HPLC/UVD and GC/MSD. For field application, the most suitable condition that 2-CBA coated in glass fiber filter removed completely and urethanes were not removed was searched. 2-CBA generated from hydrolysis of urethanes according to hydrolysis conditions. Diisocyanates were collected on field air and analyzed. Results: Urethanes which were white and solid phase synthesized by reacting 2,4-TDI, 2,6-TDI, 4,4'-MDI, 1,6-HDI and 2-CBA or 2,4-DCBA. And urethanes were verified by TLC, HPLC/UVD and GC/MSD. The most suitable conditions to remove 2-CBA coated in glass fiber filter were $87^{\circ}C$ and 20 mmHg and urethanes were not removed under same condition. Hydrolysis yields of urethanes were 99 % to 111 %. 2-CBA, the hydrolysate of urethanes was analyzed by GC/FID, GC/PD-ECD and GC/MSD. Conclusions: Simultaneous analysis of 2,4-TDI, 2,6-TDI, 4,4'-MDI and 1,6-HDI deriving with 2-CBA and 2,4-DCBA, along with a total isocyanate analysis, was feasible with GC/FID, GC/PD-ECD and GC/MSD. This result will be a guide of further study on total isocyanate analysis.

• Applied Biological Chemistry
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• v.38 no.2
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• pp.179-183
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• 1995

The brassinosteroid-like active principles from immature seeds of Zea mays were purified and identified as castasterone, teasterone, 28-norcastasterone and 6-deoxocastasterone by GC-MS analysis. Our work is probably the first report that showed the presence of brassinosteroids in Zea mays seeds.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.4
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• pp.1361-1365
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• 2015

Background: We aimed to discover potential gene biomarkers for gastric cancer (GC) diagnosis. Materials and Methods: Genechips of 10 GC tissues and 10 gastric mucosa (GM, para-carcinoma tissue, normal control) tissues were generated using an exon array of Affymetrix containing 30,000 genes. The differentially expressed genes (DEGs) between GC tissues and normal control were identified by the Limma package and analyzed by hierarchical clustering analysis. Gene ontology (GO) and pathway enrichment analyses were performed for investigating the functions of DEGs. Receiver operating characteristics (ROC) analysis was performed to measure the effects of biomarker candidates for diagnosis of GC. Results: Totals of 896 up-regulated and 60 down-regulated DEGs were identified to be differentially expressed between GC samples and normal control. Hierarchical clustering analysis showed that DEGs were highly differentially expressed and most DEGs were up-regulated. The most significantly enriched GO-BP term was revealed to be mitotic cell cycle and the most significantly enriched pathway was cell cycle. The intersection analysis showed that most significant DEGs were cyclin B1 (CCNB1) and cyclin B2 (CCNB2). The sensitivities and specificities of CCNB1 and CCNB2 were both high (p<0.0001). Areas under the ROC curve for CCNB1 and CCNB2 were both greater than 0.9 (p<0.0001). Conclusions: CCNB1 and CCNB2, which were involved in cell cycle, played significant roles in the progression and development of GC and these genes may be potential biomarkers for diagnosis and prognosis of GC.

• Genomics & Informatics
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• v.21 no.1
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• pp.8.1-8.19
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• 2023

Cancer of the stomach is the second most frequent cancer-related death worldwide. The survival rate of patients with gastric cancer (GC) remains fragile. There is a requirement to discover biomarkers for prognosis approaches. Helicobacter pylori in the stomach is closely associated with the progression of GC. We identified the genes associated with poor/favorable prognosis in H. pylori-induced GC. Multivariate statistical analysis was applied on the Gene Expression Omnibus (GEO) dataset GSE54397 to identify differentially expressed miRNAs (DEMs) in gastric tissues with H. pylori-induced cancer compared with the H. pylori-positive with non-cancerous tissue. A protein interaction map (PIM) was built and subjected to DEMs targets. The enriched pathways and biological processes within the PIM were identified based on substantial clusters. Thereafter, the most critical genes in the PIM were illustrated, and their prognostic impact in GC was investigated. Considering p-value less than 0.01 and |Log2 fold change| as >1, five microRNAs demonstrated significant changes among the two groups. Gene functional analysis revealed that the ubiquitination system, neddylation pathway, and ciliary process are primarily involved in H. pylori-induced GC. Survival analysis illustrated that the overexpression of DOCK4, GNAS, CTGF, TGF-b1, ESR1, SELE, TIMP3, SMARCE1, and TXNIP was associated with poor prognosis, while increased MRPS5 expression was related to a favorable prognosis in GC patients. DOCK4, GNAS, CTGF, TGF-b1, ESR1, SELE, TIMP3, SMARCE1, TXNIP, and MRPS5 may be considered prognostic biomarkers for H. pylori-induced GC. However, experimental validation is necessary in the future.

• Journal of Environmental Science International
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• v.6 no.4
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• pp.385-389
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• 1997

Pesticide residues were extracted with 70% acetone and transferred to dichloromethane. Extracts were applied to open-column chromatography with florisil and alumina-N. The final extract was analyzed by gas chromatography with electron-capture detector(GC /ECD) and nitrogen-phosphorus detector(GC/NPD). Recoveries of the 17 organochlorine pegticides were ranged from 60.8 to 84.9% and those of 15 organophosphate pesticides, from 70.5% to 100.0%(except phosmet and azlnphos-methyls. The minimum detectable levels of this analytical method were low(0.021-0.058mg/kg).

• Bulletin of the Korean Chemical Society
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• v.30 no.10
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• pp.2287-2293
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• 2009

Gas Chromatography-Mass Spectrometry (GC-MS) fingerprint analysis, Principle Components Analysis (PCA), and Hierarchical Cluster Analysis (HCA) were introduced for quality assessment of Curcuma longa L. (C. longa). The GC-MS fingerprint method was developed and validated by analyzing 33 batches of samples of C. longa from different geographic locations. 18 chromatographic peaks were selected as characteristic peaks and their relative peak areas (RPA) were calculated for quantitative expression. Two principal components (PCs) were extracted by PCA. C. longa collected from Guizhou and Fujian were separated from other samples by PC1, capturing 71.83% of variance. While, PC2 contributed for their further separation, capturing 11.13% of variance. HCA confirmed the result of PCA analysis. Therefore, GC-MS fingerprint study with chemometric techniques provides a very flexible and reliable method for quality assessment of C. longa.

• YAKHAK HOEJI
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• v.51 no.3
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• pp.206-213
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• 2007

Recently estimating the uncertainty of an analytical result has become an essential part of quantitative analysis. This study describes the uncertainty of the measurement for the determination of methamphetamine and its major metabolite amphetamine in human hair, The method consists of washing, drying, weighing, incubation and extraction with methanolic HCI solution, clean-up, trifluoroacetyl derivatization, and qualification/quantification of residues by gas chromatography/mass spectrometry (GC/MS). Traceability of measurement was established through traceable standards and calibrated volumetric equipment and measuring instruments. Measurement uncertainty associated with each analyte in real samples was estimated using quality control (QC) data. The main source of combined standard uncertainty comprised two components, which are uncertainties associated with calibration linearity and variations in QC, while those associated with preparation of analytical standards and sample weighing were not so important considering the degree of contribution. Relative combined standard uncertainties associated with the described method ranged for individual analytes from 4.99 to5.03%.

• Natural Product Sciences
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• v.21 no.2
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• pp.87-92
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• 2015

The stem barks, heartwoods, and leaves of Acer tegmentosum (Aceraceae) are widely used in Korea to treat hepatic or cerebral disorders mainly due to alcohol poisoning. This study was aimed to analyze phenolic substances in A. tegmentosum. Quantitative analysis of the three phenolic substances (salidroside, (+)-catechin and scopoletin) was performed by HPLC and the identification of volatile phenolic substances were done by GC-MS. The contents of the three compounds in the three MeOH extracts were higher in the stem bark (salidroside: 80.22 mg/g, (+)-catechin: 23.31 mg/g, and scopoletin: 9.45 mg/g) compared to the heartwoods and leaves. And GC-MS analysis of the stem bark extract demonstrated that p-tyrosol is a main substance of twenty-one compounds identified.

• Elastomers and Composites
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• v.52 no.1
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• pp.59-68
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• 2017

The effect on the hydrolysis resistance properties by the addition of maleic anhydride grafted EMDM (MA-g-EPDM) and PP (MA-g-PP) to a PA66/GF composite was investigated with respect to the mechanical properties, thermal properties, and morphology. The degree of hydrolysis of the PA66/GF composite was measured using py-GC/MS analysis. When compared to the PA66/GFcomposite in MEG/water solution, the composites where MA-g-EPDM and MA-g-PP were added to PA66/GF showed a higher degree of hydrolysis resistance, impact strength, and thermal properties, whereas their tensile strength, tensile modulus, flexural strength and flexural modulus decreased. As immersion time in the solution increases, the rate of tensile strength drop of the MA-g-PP added composite appeared lower than that of the PA66/MA-g-EPDM/GF and PA66/GF composites. The py-GC/MS analysis confirmed the formation of PA66 hydrolysis reaction by products such as carboxylic acid and alkylamine with increasing immersion time.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.3
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• pp.459-465
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• 1995

The ether extract of Salviae miltiorrhizae Radix(SMR) was fractioned to give five subfractions, so that two subfractions of them were recrystallized to yield each pure diterpene quinone pigment. On the basis of spectral evidence, these two compounds were identified as tanshinone II and crytotanshinone. Cryptotanshinone exhibited both of a potent platelet anti-aggregating activity in vitro and a potent antimicrobial activity. GC-MS analysis of the other extract showed that tanshinone II was contained in the largest proportion of all the diterpene quinones. In addition, GC-MS analysis gave other valuable analytical informations.