• Elastomers and Composites
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• v.47 no.4
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• pp.355-363
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• 2012

A series of poly(hydroxyamide)s (PHAs) having trifluoromethyl group were prepared by direct polycondensation of aromatic diimide-dicarboxylic acids with 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane by thionyl chloride and triethyl amine in N-methyl-2-pyrrolidinone (NMP). The PHAs exhibited inherent viscosity in the range of 0.54-0.96 dL/g at $35^{\circ}C$ in DMAc solution. All PHAs were readily soluble in a variety of organic solvents, whereas the polybenzoxazoles (PBOs) were quite insoluble except partially soluble in sulfuric acid. PHAs were converted to PBOs by thermal cycling reaction with heat of endotherm. The maximum weight loss temperature of the PHAs occurred in the range of $559-567^{\circ}C$. The PBOs showed relatively high char yields in the range of 47-59%. Pyrolysis Combustion Flow Calorimeter (PCFC) results of the PBOs showed 12-19 W/g heat release rate (HRR), and 2.7-3.6 kJ/g total heat release (total HR). The HRR of PBO 1 showed the lowest value of 12 W/g, which was 37% lower than that of PBO 3 (19 W/g).

• Journal of the Society of Cosmetic Scientists of Korea
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• v.36 no.1
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• pp.71-77
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• 2010

The water fern Azolla belongs to the Azollaceae and forms a symbiotic association with a $N_2$-fixing cyanobacterium, referred to as Anabaena azollae, and this association has currently been demonstrated to have potential as a nitrogen source for rice production. Because of that, Azolla fern has been used not only as organic manure in southern China and northern Vietnam for a long time but also as food for animate creatures in the underwater and decontaminant in the water. However, the phenolic compounds and active materials of Azolla have not been examined in detail in the past studies. In the present study, anti-oxidant ability test and experiment to find a particular active material of Azolla imbricata and Azolla imbricata fraction (AIF) were performed. In anti-oxidant test such as DPPH test and lipoxygenase inhibition test, the value of test represented high activities compared with authentic sample - green tea and NDGA (nordihydroguaiaretic acid). In MMP-1 test, related to collagen protection and elasticity of skin, its inhibitory effect was measured over 75 %, and the phenolic compounds of AIF related with this activity were confirmed luteolin derivatives by using FT-IR spectroscopy, element analyzer (EA) and Liquid chromatography-MASS spectroscopy.

• Korean Journal of Food Science and Technology
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• v.54 no.1
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• pp.75-79
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• 2022

Fresh, washed ginseng can be contaminated with microorganism loads as high as 6.5 log CFU/g for total bacteria and 4.3 log CFU/g for mold. The goal of this study was to test eight antibacterial agents on ginseng. Immersing fresh ginseng washed in 1% (w/w) sodium citrate, sodium diacetate, sodium acetate, citric acid, and sodium lactate solution for 1 h resulted in a bactericidal effect of 31.0-97.5% for total bacteria. Among the organic acids, sodium citrate had the best antibacterial effect, with total bacteria reduced from 6.5 log to 4.9 log CFU/g. A 1% (w/w) vitamin B₁ lauryl sulfate solution with surfactant function by hydrophilic and hydrophobic sites can reduce 2.7 log CFU/g (99.8% inactivation) on total bacteria. In the 1% (w/w) calcium oxide solution, total bacteria were reduced by 3 log, showing an excellent inactivation effect of 99.9%. Calcium oxide is a highly useful material for inactivation of microorganisms in fresh ginseng.

• Applied Biological Chemistry
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• v.15 no.3
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• pp.213-219
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• 1972

In order to utilize sweet potatoes for the material of Takju, brewing experiments with raw sweet potatoes, sweet potato chips powder and its koji were conducted; and various tests were carried out on effect of the treatments of acid, alkali, polyphenol oxidase inhibitor, oxidizing and reducing agents upon the prevention against coloring of sweet potato chips by steaming, and on peeling effect of sweet potatoes by the alkali and heat treatments. The results obtained were as follows. 1) In the case of brewing with raw sweet potatose, each plot showed low acid and ethanol content, and its finished Takju had an undersirable color and odor. The plots which were mashed after peeling showed higher ethanol contents than the plots mashed without peeling. 2) In the case of brewing with sweet potato chips powder, each plot contained considerably more amount of ethanol than the plots brewed with raw sweet potatoes, white it contained less amount of acid. The ethanol contents of the plots using wheat bran koji were $10.5{\sim}11.4$ per cent 4 days after mashing, and were higher than those of the plots using malts powder. Their finished Takju was inferior in quality because of the lack of acid and being darkened gradually in process of time. 3) The kojies which were made of sweet potato chips powder with Neurospora sitophila or Aspergillus oryzae had good appearance, but the Takju mashes brewed with these contained remarkably less amount of ethanol. 4) Effect of the treatments of acid, alkali, polyphenol oxidase inhibitor and organic solvents such as ether and ethanol upon the prevention against coloring of sweet potato chips was not recognized. Alum and burnt alum were effective a little on the decolorization, and among the oxidizing and reducing agents tested, potassium permanganate was most effective. 5) Darkening of sweet potato chips powder in course of heating after mixing with water was not affected by pectin and amino acids, but by tannin. 6) Sweet potatoes were not peeled easily by friction after soaking in the boiling solution of 3 per cent alkali for 6 minutes and peeled in boiling water for 12 minutes. From the viewpoint of the results above mentioned, it seems to be necessary to study further on the isolation of microorganisms which are able to decompose the coloring substances and yeasts which are adequate for the fermentation of sweet potatoes in order to utilize sweet potatoes for Takju brewing, because brewing with raw sweet potatoes, sweet potato chips powder and its koji was unsuccessful, and effect of the various treatments on the decolorization of sweet potatoes was not recognized.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.10a
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• pp.111-124
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• 2003

Processes that cause immobilization of contaminants in soil are of great environmental importance because they may lead to a considerable reduction in the bioavailability of contaminants and they may restrict their leaching into groundwater. Previous investigations demonstrated that pollutants can be bound to soil constituents by either chemical or physical interactions. From an environmental point of view, chemical interactions are preferred, because they frequently lead to the formation of strong covalent bonds that are difficult to disrupt by microbial activity or chemical treatments. Humic substances resulting from lignin decomposition appear to be the major binding ligands involved in the incorporation of contaminants into the soil matrix through stable chemical linkages. Chemical bonds may be formed through oxidative coupling reactions catalyzed either biologically by polyphenol oxidases and peroxidases, or abiotically by certain clays and metal oxides. These naturally occurring processes are believed to result in the detoxification of contaminants. While indigenous enzymes are usually not likely to provide satisfactory decontamination of polluted sites, amending soil with enzymes derived from specific microbial cultures or plant materials may enhance incorporation processes. The catalytic effect of enzymes was evaluated by determining the extent of contaminants binding to humic material, and - whenever possible - by structural analyses of the resulting complexes. Previous research on xenobiotic immobilization was mostly based on the application of $^{14}$ C-labeled contaminants and radiocounting. Several recent studies demonstrated, however, that the evaluation of binding can be better achieved by applying $^{13}$ C-, $^{15}$ N- or $^{19}$ F-labeled xenobiotics in combination with $^{13}$ C-, $^{15}$ N- or $^{19}$ F-NMR spectroscopy. The rationale behind the NMR approach was that any binding-related modification in the initial arrangement of the labeled atoms automatically induced changes in the position of the corresponding signals in the NMR spectra. The delocalization of the signals exhibited a high degree of specificity, indicating whether or not covalent binding had occurred and, if so, what type of covalent bond had been formed. The results obtained confirmed the view that binding of contaminants to soil organic matter has important environmental consequences. In particular, now it is more evident than ever that as a result of binding, (a) the amount of contaminants available to interact with the biota is reduced; (b) the complexed products are less toxic than their parent compounds; and (c) groundwater pollution is reduced because of restricted contaminant mobility.

• Microbiology and Biotechnology Letters
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• v.35 no.2
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• pp.163-172
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• 2007

This study was designed to investigate that inorganic germanium $(GeO_2)$ did not exist in germanium-fortified yeast or obtained to non-detectable value by current analytical methods and equipments. For this purpose, we achieved $GeO_2$ qualitative analysis protocol which could be the scientific basis of the study. Since reddish brown precipitate was formed from the reaction of $GeO_2$ with 1 equiv $NaBH_4$, and dark brown precipitate was also formed from the reaction of $GeO_2$ with 2 equiv $NaBH_4$, $GeO_2$ was qualitatively analyzed by observing these particular colored-precipitates. Because no color change was showed from the reaction between $NaBH_4$ and $SiO_2$, the color change could be caused by charge transfer transition on Ge-O and B binding properties. The reaction between $NaBH_4$ and germanium-fortified yeast did not show any color change and precipitate formation which meant no $GeO_2$ existed in germanium-fortified yeast. The reaction between $NaBH_4$ and supernatant specimen collected from the outside of dialysis membrane (MWCO 1,200 dalton) did not show any color change and precipitate formation. Therefore, we considered that the both germaniums in and outside of the dialysis membrane were organic germaniums. Germanium-fortified yeast which was biosynthesized organic germanium can be applied not only as a new functional material for improving health, prevention and treatment of chronic degenerative diseases including cancers, and the regulation of immune system, but also as a new materials.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.3
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• pp.15-25
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• 2023

In this study, silicon sludge from semiconductor dicing process is recycled to fabricate silica nanoparticles, which are applied as dispersing materials for electro-responsive (ER) smart fluid. In specific, metal impurities are removed from silicon sludge by acid washing to obtain the high-purity silicon powder. And then, silica nanoparticles are synthesized by facile hydrothermal method employing the silicon powder as reactant material. To control the size of silica nanoparticles, the reaction time of hydrothermal method is varied as 8, 15, 20, and 30 hours are applied to control the size of silica nanoparticles. Sizes of silica nanoparticles are increased proportionally to the reaction time owing to the increased numbers of hydrolysis and condensation reactions. As-synthesized silica nanoparticles are prepared as electro-responsive smart fluids by dispersing into silicon oil. Silica nanoparticles synthesized by 30 hours of hydrothermal reaction (SiO₂-H30) exhibit the highest shear stress of 21.4 Pa under an applied electric field strength of 3.0kV mm^-1. Such enhancement in ER performance of SiO₂-H30 among various silica nanoparticles are attribute to the reinforcing effect originated from the mixed particle size, which allowing the formation of rigid chain-like structures. Accordingly, this study successfully propose a recycling method of silicon sludge to synthesize silica nanoparticles and their derived ER fluids, which may suggest new possibility to ESG management emphasizing the eco-friendliness.

• Food Science and Preservation
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• v.22 no.3
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• pp.353-360
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• 2015

Yakju, a Korean traditional alcoholic beverage, is made from rice and Nuruk. In this study, the fermentation characteristics of Yakju was investigated using rice and rice starch. Ingredients was classified into raw material (rice, rice starch) and starter (enzyme supplements, modified Nuruk, traditional Nuruk, and yellow rice koji) for fermentation. The crude protein content of rice, rice starch, and starter were determined as follows (%): rice 6.69, rice starch 0.44, enzyme supplements 7.84, modified Nuruk 15.29, traditional Nuruk 14.28, and yellow rice koji 7.28. The alcohol content of rice with traditional Nuruk ($20.13{\pm}0.12%$) was higher than other Yakju. The concentration of organic acids of rice starch-based Yakju (389.83~538.34 mg%) was higher than that of rice Yakju (259.27~357.70 mg%). The concentration of nitrogen compound of rice Yakju (498.38~5976.93 ppm) was higher than that of rice starch-based Yakju (600.43~4463.79 ppm). In line with these findings, further studies will be necessary for the quality analysis of the rice, rice starch and fermented starter (enzyme supplements, modified Nuruk, traditional Nuruk and yellow rice koji).

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.6
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• pp.836-842
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• 2009

The objectives of this study were to evaluate potential benefits of intercropping of corn with runner bean for a smallsized farming system, based on land equivalent ratio (LER) and silage yield and quality of corn intercropped with runner bean (Phaseolus vulgaris L.), in arid conditions of Turkey under an irrigation system. This experiment was established as a split-plot design in a randomized complete block, with three replications and carried out over two (consecutive) years in 2006 and 2007. Seven different mixtures (runner bean, B and silage corn sole crop, C, 10% B+90% C, 20% B+80% C, 30% B+70% C, 40% B+60%C, and 50% B+50%C) of silage corn-runner bean were intercropped. All of the mixtures were grown under irrigation. The corn-runner bean fields were planted in the second week of May and harvested in the first week of September in both years. Green beans were harvested three times each year and green bean yields were recorded each time. After the 3rd harvest of green bean, residues of bean and corn together were randomly harvested from a 1 $m^{2}$ area by hand using a clipper when the bean started to dry and corn was at the dough stage. Green mass yields of each plot were recorded. Silages were prepared from each plot (triplicate) in 1 L mini-silos. After 60 d ensiling, subsamples were taken from this material for determination of dry matter (DM), pH, organic acids, chemical composition, and in vitro DM digestibility of silages. The LER index was also calculated to evaluate intercrop efficiencies with respect to sole crops. Average pH, acetic, propionic and butyric acid concentrations were similar but lactic acid and ammonia-N levels were significantly different (p<0.05) among different mixtures of bean intercropped with corn. Ammonia-N levels linearly increased from 0.90% to 2.218 as the percentage of bean increased in the mixtures up to a 50:50 seeding ratio. While average CP content increased linearly from 6.47 to 12.45%, and average NDF and ADF contents decreased linearly from 56.17 to 44.88 and from 34.92 to 33.51%, respectively, (p<0.05) as the percentage of bean increased in the mixtures up to a 50:50 seeding ratio, but DM and OM contents did not differ among different mixtures of bean intercropped with corn (p>0.05). In vitro OM digestibility values differed significantly among bean-corn mixture silages (p<0.05). Fresh bean, herbage DM, IVOMD, ME yields, and LER index were significantly influenced by percentage of bean in the mixtures (p<0.01). As the percentage of bean increased in the mixtures up to a 50:50 seeding ratio, yields of fresh bean (from 0 to 24,380 kg/ha) and CP (from 1,258.0 to 1,563.0 kg/ha) and LER values (from 1.0 to 1.775) linearly increased, but yields of herbage DM (from 19,670 to 12,550 kg/ha), IVOMD (from 12,790 to 8,020 kg/ha) and ME (46,230 to 29,000 Mcal/ha) yields decreased (p<0.05). In conclusion, all of the bean-corn mixtures provided a good silage and better CP concentrations. Even though forage yields decreased, the LER index linearly increased as the percentage of bean increased in the mixture up to a 50:50 seeding ratio, which indicates a greater utilization of land. Therefore, a 50:50 seeding ratio seemed to be best for optimal utilization of land in this study and to provide greater financial stability for labor-intensive, small farmers.

• Economic and Environmental Geology
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• v.43 no.1
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• pp.13-20
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• 2010

Acid mine drainage (AMD) from abandoned mine sites typically has low pH and contains high level of various heavy metals, aggravating ground- and surface water qualities and neighboring environments. This study investigated removal of heavy metals in a biological treatment system, mainly focusing on the removal by adsorption on a substrate material. Bench-scale batch experiments were performed with a mushroom compost to evaluate the adsorption characteristics of heavy metals leached out from a mine tailing sample and the role of SRB in the overall removal process. In addition, adsorption experiments were perform using an artificial AMD sample containing $Cd^{2+}$, $Cu^{2+}$, $Pb^{2+}$ and $Zn^{2+}$ to assess adsorption capacity of the mushroom compost. The results indicated Mn leached out from mine tailing was not subject to microbial stabilization or adsorption onto mushroom compost while microbially mediated stabilization played an important role in the removal of Zn. Fe leaching significantly increased in the presence of microbes as compared to autoclaved samples, and this was attributed to dissolution of Fe minerals in the mine tailing in a response to the depletion of $Fe^{3+}$ by iron reduction bacteria. Measurement of oxidation reduction potential (ORP) and pH indicated the reactive mixture maintained reducing condition and moderate pH during the reaction. The results of the adsorption experiments involving artificial AMD sample indicated adsorption removal efficiency was greater than 90% at pH 6 condition, but it decreased at pH 3 condition.