• The Korean Journal of Food And Nutrition
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• v.10 no.1
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• pp.25-30
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• 1997

Volatile components of green tea were isolated by purge and trap headspace method and were analyzed by GC and GC/MSD. And ten headspace volatiles were compared with volatiles isolated by simultaneous distillation-extraction(SDE) method. A total of 99 components were identified in the green tea volatile components, from which 88 components were identified in the headspace volatiles, contained 20 alcohols, 30 hydrocarbons, 21 aldehydes, 10 ketones, 2 acids and 5 miscellaneous components. The major components were low boiling components, such as methyl butanal(3.1%), 1-penten-3-ol(5.48%), 2-penten-1-ol(2.89%), hexanal(5.77%), heptanal(1.90%), and ere 2,4-eptadienal(4.28%), linalool(2.27%), 2,6-dimethyl cyclohexanol(2.57%), $\alpha$-pinene(1.52%), caryophyllene(1.70%), and carbonyl compounds, such as $\alpha$-ionone(2.62%), $\beta$-ionone(2.98%), $\beta$-cyclocitral(2.0%). On the other hand SDE volatiles, from which 64 components were identified, contained 16 alcohols, 16 ydrocarbons, 15 aldehydes, 10 ketones, 3 acids and 4 miscellaneous components. The major components were alcohols, such as, benzyl alcohol(3.79%), linalool(9.52%), terpineol(2.16%), geraniol(2.75%), nerolidol(6.50%), ketones, such as $\alpha$-ionone(1.77%), $\beta$-ionone(4.80%), geranyl acetone(1.82%) and acids, such as hexanoic acid(1.45%), nonanoic acid(1.11%).

• Journal of Environmental Science International
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• v.11 no.10
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• pp.1109-1116
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• 2002

This study analyzed concentrations of volatile organic compounds (VOCs) produced from incineration of papers at $600^{\circ}C$. The papers used in this study included A4 papers (new, printed with ink-jet, printed with carbon), newspapers (printed with bean oil, printed with a general newspaper ink), packaging box, document envelope, single-use paper cup, and cosmetic tissue. Papers were heated from room temperature upto $600^{\circ}C$ providing air inside of the electric furnace and then they were oxidized for 80 minutes at $600^{\circ}C$ maintaining the same air supply. VOCs emitted from the incineration process were sampled using an air sampling pump and bags for 160 minutes and then the components and concentrations of the VOCs were analyzed by a CC-MS. The most prominent chemical structure of the Vous identified from incineration of the papers was furans and then furans were followed by aromatics and aliphatic alkenes. About 40% of the identified VOCs contained double bonds, which have relatively a high ozone (ground level) formation potential, within their molecular structure. Also, some cancer suspecting compounds like benzene, dichlorormethane and chloroform were identified.

• Clean Technology
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• v.21 no.1
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• pp.62-67
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• 2015

We have developed a versatile method for the preparation of chemically linked graphene/multi-walled carbon nanotubes (MWNTs) hybrid materials via simple acid-catalyzed dehydration reaction between graphene oxide (GO) and amine-functionalized MWNTs (af-MWNTs). In this condition, ketone (-C=O) groups in GO and primary amine (-NH₂) moieties in af-MWNTs readily react to form imine (-C=N-) linkage. The chemical structures of graphene/MWNTs hybrid materials have been investigated using various microscopic and spectroscopic measurements. As a result of the synergetic effects of hybrid materials such as improved surface area and the superior structural restoration of graphitic networks, the hybrid materials demonstrate improved capacitance with excellent long-term stability. Furthermore, controlled experiments were conducted to optimize the weight ratio of graphene/MWNTs in hybrid materials. The highest capacitance of 132.4 F/g was obtained from the GM7.5 material, in which the weight ratio between graphene and MWNTs was adjusted to 7.5/1, in 1M KOH electrolyte at a scan rate of 100 mV/s.

• Transactions of the Korean hydrogen and new energy society
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• v.25 no.2
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• pp.151-160
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• 2014

CL-SPEEK/Cs-TPA/$CeO_2$ composite membrane was prepared for polymer electrolyte membrane water electrolysis (PEMWE). In order to improve the electrochemical, mechanical, durabilities and electrocatalytic characteristics, engineering plastic of polyether ether ketone (PEEK) as polymer matrix was sulfonated and the organic-inorganic blend composite membranes was prepared by loading cesium-substituted tungstophosphoric acid (Cs-TPA) by titration method with cross-linking agent contents of 0.01mL. Ceria ($CeO_2$) was used to scavenge free radicals which attack the membrane in the PEMWE circumstance and to increase the duration of the membrane. CL-SPEEK/$Cs_{(1)}$-TPA/CeriaIn conclusion, 1% membrane showed the optimum results such as 0.119 S/cm at $80^{\circ}C$ of proton conductivity and 62MPa of tensile strength.

• Journal of odor and indoor environment
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• v.16 no.1
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• pp.54-63
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• 2017

The Automobile HVAC system is a habitat for odor-associated fungal communities. We investigated the odor-associated fungal community in an automobile HVAC system using a high-throughput DNA sequencing method. The fungal community structure was evaluated via metagenome analysis. At the phylum level, Ascomycota and Basidiomycota were detected, accounting for 43.41% and 56.49% of the fungal community in the HVAC system, respectively. Columnosphaeria (8.31%), Didymella (5.60%), Davidiella (5.50%), Microxyphium (4.24%), unclassified Pleosporales (2.90%), and Cladosporium (2.79%) were abundant at phylum of Ascomycota and Christiansenia (36.72%), Rhodotorula (10.48%), and Sporidiobolus (2.34%) were abundant at phylum of Basidiomycota. A total of 22 genera of fungi were isolated and identified from the evaporators of the HVAC systems which support fungal growth and biofilm formation. Among them, Cladosporium, Penicillium, Aspergillus, and Alternaria are the most representative odor-associated fungi in HVAC systems. They were reported to form biofilm on the surface of HVAC systems with other bacteria by hypha. In addition, they produce various mVOCs such as 3-methyl-1-butanol, acetic acid, butanoic acid, and methyl isobutyl ketone. Our findings may be useful for extending the understanding of odor-associated fungal communities in automobile HVAC systems.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.7 no.1
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• pp.71-85
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• 1997

The purpose of this study was to evaluate concentrations of organic solvent mixtures in air of rotogravure printing workplaces. Qualitative and quantitative analysis of organic solvents contained in the gravure inks used at rotogravure factories had been done. The results obtained were as follows: 1. The gravure inks mainly consist of toluene, methyl ethyl ketone(MEK), and ethyl acetate(EA), and traces of isopropyl alcohol(IPA), xylene, 2-butanol, cyclohexane, cellosolve etc were also contained in them. 2. Thinner used as a diluent consist of toluene, MEK, and EA. 3. Geometric mean concentration of toluene in ambient air were 23.81 ppm at gravure printing of packing material, 42.10 ppm at gravure printing of wallpaper, 16.95 ppm at gravure printing of plastic bottle for beverage and 4.31 ppm at gravure printing of plywood printing or floor covering. Concentrations of toluene in ambient air showed statistically significant difference between types of printing. 4. Concentrations of MEK in ambient air were 12.43 ppm at gravure printing of packing material, 5.47 ppm at gravure printing of wallpaper, 16.78 ppm at gravure printing of plastic bottle for beverage and 16.44 ppm at gravure printing of plywood printing or floor covering. MEK concentrations in ambient air showed no significant difference. 5. Conentrations of EA were 14.30 ppm at gravure printing of packing material, 1.92 ppm at gravure printing of wallpaper and 21.12 ppm at gravure printing of plywood printing or floor covering. EA concentrations in ambient air shown significant difference. 6. Percentage of the workplaces where the ambient air concentration of organic solvent mixtures exceeded the Korean Permissble Exposure Level(KPEL) amounted to 18.03%. 7. Toluene concentrations in ambient air of rotogravure printing workplaces ranged from 0.69 to 156.02 ppm and urinary hippuric acid excretion ranged from 0.10 to $1.32g/{\ell}$.

• Korean Journal of Food Science and Technology
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• v.27 no.4
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• pp.464-470
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• 1995

Volatile flavor components from various edible portions of Commelina communis L. were collected by simultaneous steam distillation-extraction(SDE) method using diethyl ether as solvent. Essential oils were analyzed by gas chromatography(GC) and combined gas chromatography-mass spectrometry(GC-MS). Eighty nine volatile flavor components, including 33 hydrocarbons, 4 aldehydes, 9 ketones, 23 alcohols, 6 esters, 10 acids and 4 miscellaneous ones were confirmed in whole samples. Twenty three components, including 14 hydrocarbons, 7 alcohols and 2 esters were confirmed in leaves. Six components, including 3 hydrocarbons and 3 alcohols were confirmed in stems, and 18 components, including 13 hydrocarbons, 1 ketone, 3 alcohols and 1 acid were confirmed in roots. The kinds and amounts of volatile flavor components revealed different patterns depending upon various edible portions. Relatively greater numbers of volatile flavor components were identified in leaves compared with other portions of this wild plant.

• Journal of the Korean Chemical Society
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• v.37 no.12
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• pp.987-994
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• 1993

Inductive and resonance effects play an important role in determining carbony) stretching frequencies of ketones. Hydrogen bonding, dielectric effects, and steric effects are all factors which determine the carbonyl stretching frequency, νC=O of ketones in solution. The $ν_{C=O}$ frequencies were shifted by approximately 27$cm^{-1}$ each by substituting to a phenyl group for a methyl group in acetone. The $ν_{C=O}$ frequency for ketones shifted differently in various solvents and increased with increasing the volume ratio of the ketones in water solutions. The $ν_{C=O}$ frequency for ketones shifts continously at constant concentration of ketone in solutions of $(CH_3)_2SO/CCl_4$and$CHCl_3/CCl_4$ with changing of the mole ratio of two solvents. The $ν_{C=O}$ frequency was also affected by changing concentration in either $CCl_4$ or $(CH_3)_2SO$ solution and in either $CCl_4$or $CHCl_3$ solution.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.2
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• pp.236-242
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• 2005

To develop a new detection method using irradiation-induced volatile marker compounds of red pepper powder (RP), the volatile compounds of irradiated RP (0, 1, 3, 5, and 10 kGy) were analyzed by purge and trap (P&T)/solid phase microextraction (SPME)/gas chromatography/mass spectrometry (GC/MS) methods. A total of 51 and 31 compounds were detected in IRP by SPME and P&T methods, respectively. Among these, 25 compounds, which were composed of 4 hydrocarbons, 7 aldehydes, 1 ketone, 3 alcohols, 4 aromatic compounds, 2 esters and 4 miscellaneous compounds, showed irradiation dependent manner with significant positive correlation (p<0.01 or p<0.05) between irradiation dose and relative concentration. However, all compounds except 1,3-bis(1,1-dimethylethyl)benzene were not suitable as marker compounds because of their low determination coefficients ($R^2$<0.80) between irradiation dose and their concentrations, and detectablilty in nonirradiated sample. Therefore, only one compound, 1,3-bis(1,1-dimethylethyl)benzene, was tentatively identified as a volatile marker compound to detect irradiated RP.

• Clinical Nutrition Research
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• v.12 no.3
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• pp.169-176
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• 2023

Glucose transporter type 1 (GLUT1) deficiency syndrome (DS) is a metabolic brain disorder caused by a deficiency resulting from SLC2A1 gene mutation and is characterized by abnormal brain metabolism and associated metabolic encephalopathy. Reduced glucose supply to the brain leads to brain damage, resulting in delayed neurodevelopment in infancy and symptoms such as eye abnormalities, microcephaly, ataxia, and rigidity. Treatment options for GLUT1 DS include ketogenic diet (KD), pharmacotherapy, and rehabilitation therapy. Of these, KD is an essential and the most important treatment method as it promotes brain neurodevelopment by generating ketone bodies to produce energy. This case is a focused study on intensive KD nutritional intervention for an infant diagnosed with GLUT1 DS at Gangnam Severance Hospital from May 2022 to January 2023. During the initial hospitalization, nutritional intervention was performed to address poor intake via the use of concentrated formula and an attempt was made to introduce complementary feeding. After the second hospitalization and diagnosis of GLUT1 DS, positive effects on the infant's growth and development, nutritional status, and seizure control were achieved with minimal side effects by implementing KD nutritional intervention and adjusting the type and dosage of anticonvulsant medications. In conclusion, for patients with GLUT1 DS, it is important to implement a KD with an appropriate ratio of ketogenic to nonketogenic components to supply adequate energy. Furthermore, individualized and intensive nutritional management is necessary to improve growth, development, and nutritional status.