• Journal of the Korean Chemical Society
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• v.27 no.6
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• pp.449-456
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• 1983

The facile route of preparing S-2-(${\omega}$-aminoalkylamino) ethyl dihydrogen phosphorothioates, potential chemical radioprotectants, have been studied. Intermediate 3-(2-phthalimidoethyl)-2-oxazolidinone was prepared by a reaction of potassium phthalimide and 3-(2-bromoethyl)-2-oxazolidinone, which was obtained through the alkaline ring closure of a mixture of carbonate and 2,2'-dibromo diethylamine prepared from diethanolamine. This was converted to N-[2-(2-bromoethylamino)ethyl] phthalimide hydrobromide by 30% HBr(gas) in acetic acid and N-(2-bromoethyl)-1,2-ethanediamine dihydrobromide was obtained by reacting the hydrobromide with a solution of HBr-HOAc. N-(2-bromoethyl)-1,3-propanediamine dihydrobromide could be prepared through the Cortese treatment of 2-(3-aminopropylamino) ethanol, which was prepared by a reaction of 1,3-diaminopropane and 2-chloroethanol. These dihydrobromides were treated by sodium thiophosphate in DMF to result S-2-(${\omega}$-aminoalkylamino) ethyl dihydrogen phosphorothioates. The characteristics of each reaction path were discussed in regards to reaction conditions and overall yields and a facile route of preparing each derivative was proposed.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.454-454
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• 2014

Silicon microwire array is one of the promising platforms as a means for developing highly efficient solar cells thanks to the enhanced light trapping efficiency. Among the various fabrication methods of microstructures, deep reactive ion etching (DRIE) process has been extensively used in fabrication of high aspect ratio microwire arrays. In this presentation, we show precisely controlled Si microwire arrays by tuning the DRIE process conditions. A periodic microdisk arrays were patterned on 4-inch Si wafer (p-type, $1{\sim}10{\Omega}cm$) using photolithography. After developing the pattern, 150-nm-thick Al was deposited and lifted-off to leave Al microdisk arrays on the starting Si wafer. Periodic Al microdisk arrays (diameter of $2{\mu}m$ and periodic distance of $2{\mu}m$) were used as an etch mask. A DRIE process (Tegal 200) is used for anisotropic deep silicon etching at room temperature. During the process, $SF_6$ and $C_4F_8$ gases were used for the etching and surface passivation, respectively. The length and shape of microwire arrays were controlled by etching time and $SF_6/C_4F_8$ ratio. By adjusting $SF_6/C_4F_8$ gas ratio, the shape of Si microwire can be controlled, resulting in the formation of tapered or vertical microwires. After DRIE process, the residual polymer and etching damage on the surface of the microwires were removed using piranha solution ($H_2SO_4:H_2O_2=4:1$) followed by thermal oxidation ($900^{\circ}C$, 40 min). The oxide layer formed through the thermal oxidation was etched by diluted hydrofluoric acid (1 wt% HF). The surface morphology of a Si microwire arrays was characterized by field-emission scanning electron microscopy (FE-SEM, Hitachi S-4800). Optical reflection measurements were performed over 300~1100 nm wavelengths using a UV-Vis/NIR spectrophotometer (Cary 5000, Agilent) in which a 60 mm integrating sphere (Labsphere) is equipped to account for total light (diffuse and specular) reflected from the samples. The total reflection by the microwire arrays sample was reduced from 20 % to 10 % of the incident light over the visible region when the length of the microwire was increased from $10{\mu}m$ to $30{\mu}m$.

• Herbal Formula Science
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• v.24 no.2
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• pp.80-99
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• 2016

Objectives : Instrumental chemical analysis was utilized to investigate the effect of Add-Omit-Saenghyeoryunbu-eum(AO-SHU) on diabetic treatment. One of the most exciting, yet also controversial, arguments is the safety and biological mechanisms of the natural medicine on human body. Therefore, the aim of this study is to provide a better understanding on bioactive chemical components, hazards of heavy metal contamination and biological mechanism of the diabetic medicine composed of 12 different natural herbs. Methods : To study bioactive compound and metallic component in the diabetic medicine in detail, LC-MS/MS (Liquid Chromatography-Mass/Mass), GC (Gas Chromatography) and ICP (Inductively Coupled Plasma) were utilized to characterize the extract of the diabetic medicine and the result was compared with 18 marker substances selected from literature survey. In addition, in vitro assay experiments including GPR 119 activity and human DGAT-1 inhibition, and OGTT (Oral Glucose Tolerance Test) were performed to verify the effectiveness of this medicine on diabetic treatment. Results : Out of 18 marker substances, 9 bioactive compounds were identified from LC-MS/MS analysis which include Citruline, Catalpol, Berberine, Ginsenoside Rb1, Ginsenoside Rg1, Oleanolic acid, β-Sitosterol, Mangiferin, and Schizandrin. ICP study on 245 residual pesticides revealed that 239 species were not detected but 6 species, Dimethomorph, Trifloxystrobin, Pyraclostrobin, Isoprocarb, Carbaryl and Flubendiamide, while the amounts are trace levels, below permitted concentrations. The biological activity was observed in vitro assay and Oral Glucose Tolerance Test(OGTT), which are consistent with a preliminary clinical test result, a drop in blood sugar level after taking this herbal medicine. Conclusions : Instrumental chemical analysis using LC-MS/MS, GC, and ICP was conducted successfully to identify bioactive compounds in AO-SHU for the treatment of diabetes, finding 9 bioactive compounds. Furthermore, in vitro assay experiments and OGTT show that AO-SHU has its biological activities, which imply that it can be a candidate for the future diabetes remedy.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.10
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• pp.1579-1585
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• 2005

The aim of this study was to propose utilization of tofu whey concentrates separated by ultrafiltration (UF) for yogurt production. The curd yogurt was prepared from whole milk added with skim milk Powder in which UF powder was substituted 0$\%$, 6.25$\%$, 12.5$\%$ or 25$\%$ for skim milk powder. The quality characteristics of yogurt in terms of pH, titratable acidity, viscosity, color and viable cell counts were evaluated. There were no significant differences in pH and titratable acidity between control (yogurt added with only skim milk powder) and yogurt added with UF powder after 24 hr of fermentation at 37$^{\circ}C$. Apparent viscosity of yogurt added with UF powder was lower (2,623 $\∼$ 3,189 cps) than that of the control yogurt (3,196 cps). Lightness and redness value of yogurt added with UF powder were not significantly different from control yogurt, while yellowness value increased as the amount of UF powder increased. Addition of UF powder stimulated the growth of lactic acid bacteria. Gas chromatographic analysis detected acetaldehyde, diacetyl, and organic acids, and more volatile compounds were detected in yogurt added with UF powder. Sensory analysis showed that yogurt added with UF powder were evaluated as acceptable as control yogurt. Therefore, UF powder could be substituted for skim milk powder without depressing yogurt qualify.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.5
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• pp.695-701
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• 2015

This study was conducted to evaluate the effects of drying and extraction methods on antioxidant activity and total phenol content of Gnaphalium affine D. DON (GA). Hot-air, shade-drying, and freeze-drying were used for drying, after which magnetic stirring and ultrasonification were applied. Extracting solvents were water, 80% ethanol, and 80% methanol. Total phenol content was highest in 80% ethanol extract of freeze-dried and stirred GA. Total flavonoid content was highest in 80% methanol extract of freeze-dried and stirred GA. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity was higher in 80% methanol and 80% ethanol extracts than in water extract. 2,2-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity was highest in 80% ethanol extract of shade-dried and ultrasonicated GA. Reducing power was generally higher in 80% methanol extract than in 80% ethanol and water extracts of GA. Total phenol and total flavonoid contents were highly correlated with DPPH radical scavenging activity and reducing power, respectively. This result implies that the antioxidant activity of GA can be attributed to phenol compounds such as flavonoids. Conclusively, phenol compounds such as flavonoids are responsible for the antioxidant activity of GA, and there was no significant effect of drying and stirring conditions on antioxidant activity of 80% ethanol. Meanwhile, DPPH radical scavenging activity of water extract and reducing power of 80% methanol extract were higher in hot-air and shade-dried GAs than in freeze-dried GA.

• Journal of the Korean Chemical Society
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• v.26 no.1
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• pp.36-42
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• 1982

Filters were evaluated to use in the collection of ammonia and ammonium salts in the atmosphere. Ammonia from standard gas generator was collected on a glass fiber filter impregnated with a mixture of 3% boric acid and 25% glycerin. The collection efficiency by the impregnated filter was 96.4${\pm}$2.15% in pH control method and 97.4${\pm}$1.06% in the atmosphere for five measurements, respectively. Adsorption and desorption of gaseous ammonia were compared using three commercially available filters; glass fiber, quartz fiber and polycarbonate filters. Both glass and quartz fiber filters indicated some loss of ammonium salts and adsorption of ammonia, respectively. However, polycarbonate filter was found to be satisfactory for the collection of ammonium salts in the atmosphere. The minimum measurable concentration of ammonia was 0.83ppb (ca. 0.63${\mu}g$/$m^3$) by spectrophotometry of the indophenol method for the sample collected by 47mm${\phi}$ filter(20l/min, 60min). The sensitivity of the present method is about 20 folds higher than that of conventional method of bubbler collection followed by spectrophotometry, so that this method makes it possible to measure thevariation of ammoniacal concentrations in the atmosphere for a short time period of about 60 min.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.17 no.2
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• pp.81-88
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• 2007

The aim of this study was to investigate whether the exposure to vinyl chloride monomer(VCM) induces lipid peroxidation in workers by evaluating the concentration of malondialdehyde(MDA) in the urine in order to assess worker's oxidative stress due to exposure of vinyl chloride monomer. The subjects investigated in the study were divided into the experimental group; 18 workers exposed to VCM, and the control group; 19 workers unexposed to VCM. A gas chromatography/pulsed flame photometric detector(GC/PFPD) was utilized to analyze thiodiglycolic acid(TDGA), which was methylated with trimethylsilyldiazomethane (2.0M in diethyl ether) in urine and the urinary MDA, the product of lipid peroxidation, was determined by high-performance liquid chromatography/ultraviolet-visible detector after derivatized with 2,4-dinitrophenylhydrazine(DNPH). The concentrations of urinary TDGA in controls and VCM exposure workers were 0.13(2.01)mg/g Cr. GM(GSD) and 0.35(1.96)mg/gCr. GM(GSD), respectively. The concentrations of urinary MDA were $0.12(2.21){\mu}mol/gCr$. GM(GSD) in controls and $1.35(1.79){\mu}mol/gCr$. GM(GSD) in VCM exposure workers. As a result of simple regressions analysis between urinary concentration of TDGA and MDA in VCM exposure workers, it was found that the $R^2$ value was 0.261 (p=0.03) and the drinking and smoking did not affect their level. In conclusion, the workers exposed to VCM have a potentially to suffered by oxidative stress due to VCM exposure and the urinary MDA can be applicable to the marker of effect to assess the level of worker's VCM exposure.

• Journal of the Korean Wood Science and Technology
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• v.42 no.6
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• pp.747-757
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• 2014

Since the air contamination by air pollutants from indoor construction materials and daily supplies has been increased in recent decades, the public interest of using environmentally friendly products and improving indoor air quality also attracted much attention. As known as effects of phytoncide, it has been used in construction materials and daily supplies with various method. In this study, hinoki cypress (Chamaecyparis obtusa) was used because of its high contents of phytoncide. The leaves of hinoki cypress (C. obtusa), which generated by pruning, were extracted by steam distillation, and then used as humidification water source. Volatile organic compound (VOC) from C. obtusa were characterized by GC-MS (Gas chromatograph-Mass spectrophotometry) in order to evaluate effects and risks of using C. obtusa extracts. Total 86 types and 116 types of VOC were detected from distilled water (DI water) and C. obtusa extracts, respectively. Aromatic compounds (DI water: 13 types, 53%; C. obtusa extracts: 13 types, 38%) and terpenoids (DI water: 16 types, 23%; C. obtusa extracts: 23 types, 33%) were detected more diverse types and higher amount than other compound categories. No additional aromatic compounds were found from C. obtusa extracts, so C. obtusa extracts did not affect on aromatic compounds emission. However, in terpenoids, total amount of emission from C. obtusa extracts increased to 33% from 23% (DI water) and 7 more types of compounds were found from C. obtusa extracts. Especially, from C. obtusa extracts, terpinen-4-ol was emitted 71 times higher than DI water. During the humidification with C. obtusa extracts, emitted terpenoid compounds were well known for higher anti-bacterial, anti-insect, and anti-septic functions, but also these had anti-hypertensive and anti-cancer activities. Therefore, terpenoids from C. obtusa extracts can help to improve public health by using humidifier.

• Journal of Life Science
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• v.26 no.12
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• pp.1438-1445
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• 2016

Yeast can be post-contaminated by the equipment, producer, or air, and this can degrade yogurt quality. This study aimed to demonstrate the yeast inhibiting effect in fermented milk by adding Lactobacillus paracasei and Lactobacillus rhamnosus along with current fermenting lactic acid bacteria such as Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus. A certain amount of yeast was added to fermented milk samples that were soon after stored at variable temperatures, and the number of yeast cells was counted periodically. The swelling phenomenon caused by the gas produced by the yeast in fermented products was also observed. In the two experiments, compared to the control, the L. paracasei- and L. rhamnosus-added-groups showed much slower rate of yeast appearance and lower frequency of swelling phenomena. This suggests that using a mixture of L. paracasei and L. rhamnosus in fermented milk inhibits the growth of yeast. Furthermore, if the products are stored at $10^{\circ}C$, post-acidification is rarely seen in the experimental group compared to the control group. This means that the organoleptic flavor can be kept consistent from the production day till the expiration day, resulting in improved organoleptic quality for customers. In other words, the use of L. paracasei and L. rhamnosus in fermented milk will result in the following positive effects: improvement in storage stability by delaying yeast appearance, increase in quality consistency by inhibiting post-acidification, and improved organoleptic quality by enhancing texture and flavor.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.1
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• pp.18-25
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• 2008

Pseudomonas sp. PRGB06, a bacterial strain isolated from diamondback moth (Plutella xylostella) gut, was examined for its plant growth promotion and biofertilizing traits. The bacteria growth was observed under various conditions of carbon sources, temperature, pH and salt concentrations. In addition, the mechanisms of antagonism and phosphate solubilization were investigated. The bacterial strain PRGB06, grew well using most of the tested carbon sources. The best growth was observed at $30^{\circ}C$ and pH 7. The inhibition of the pathogenic fungi was likely due to the volatile antifungal metabolite and ammonia gas produced by the bacteria. A significant positive relationship was found between the phosphate solubilization and acid production. When inoculated with PRGB06 in vitro and in gnotobiotic condition, red pepper and maize showed increase in root length, seedling vigor and dry bio-mass.