• Macromolecular Research
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• v.11 no.4
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• pp.283-290
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• 2003

Organic drugs including aspirin, omeprazole, and naproxen with three different levels of octanol/water partition coefficient were examined for their release behavior from the amphiphilic PCL-b-PEO-b-PCL (PCEC) matrix. Scanning electron micrograph (SEM) of PCEC illustrated a well defined two-phase morphology consisted of dispersed poly(ethylene oxide) (PEO) domain and continuous polycaprolactone (PCL) phase. Differential scanning calorimetry (DSC) and X-ray diffractometry (XRD) experiments veri tied that three model drugs are dissolved as a molecular dispersion in PCEC matrix. The release of hydrophilic aspirin closely followed the water absorption profile of the matrix indicating that its major fraction is present in PEO domain. However, substantial amount of aspirin present in less hydrophilic region displayed discontinuous biphasic release pattern. In the case of omeprazole with intermediate hydrophobicity consistent release behavior was observed for a period of 24 hrs after the rapid liberation of ca. 10% of the drug presumably partitioned in PEO phase. It was ascribed to the fact that the progressive hydration of PCEC matrix gradually increased the chance of drug/water exposure to compensate the exhaustion of device. Naproxen with the highest octanol/water distribution coefficient among three model drugs exhibited a limited release of 35% for 24 hrs. Finally, hydroxypropyl methylcellulose phthalate (HPMCP)/PCEC blend matrix demonstrated an accelerated and quantitative release of hydrophobic naproxen by generating high porosity and thereby expanding polymer/water interface.

• Bulletin of the Korean Chemical Society
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• v.35 no.1
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• pp.103-110
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• 2014

Sisal fiber, an agricultural resource abundantly available in china, has been used as raw material to prepare activated carbon with high surface area and huge pore volume by chemical activation with zinc chloride. The orthogonal test was designed to investigate the influence of zinc chloride concentration, impregnation ratio, activation temperature and activation time on preparation of activated carbon. Scanning electron micrograph, Thermo-gravimetric, $N_2$-adsorption isotherm, mathematical models such as t-plot, H-K equation, D-R equation and BJH methods were used to characterize the properties of the prepared carbons and the activation mechanism was discussed. The results showed that $ZnCl_2$ changed the pyrolysis process of sisal fiber. Characteristics of activated carbon are: BET surface area was $1628m^2/g$, total pore volume was $1.316m^3/g$ and ratio of mesopore volume to total pore volume up to 94.3%. These results suggest that sisal fiber is an attractive source to prepare mesoporous high-capacity activated carbon by chemical activation with zinc chloride.

• Preventive Nutrition and Food Science
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• v.12 no.1
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• pp.40-45
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• 2007

The effects of drying methods on the physicochemical properties of chaga (Inonotus obliquus) mushroom powder were investigated. Scanning electron micrograph revealed that freeze drying produced smaller particle- sized samples which in turn resulted in higher porosity than did vacuum and hot-air drying. Samples prepared by freeze drying showed a significantly higher L*-value as compared with those prepared by hot-air drying and vacuum drying (p<0.05). The lightness (L*-value) significantly decreased with increasing relative humidity and storage temperature regardless of drying method (p<0.05). The yellowness (b*-value) increased significantly with increasing relative humidity (p<0.05). Browning index was significantly lower in samples prepared by freeze drying (p<0.05) but not significantly different between samples dried by hot-air and vacuum drying. Freeze dried sample exhibited a significantly higher degree of rehydration than other samples (p<0.05) probably due to the small particle size. Water solubility of the freeze dried sample was higher than those of the other methods while swelling ratio of the same sample appeared to be lower than those of others. Freeze dried chaga mushroom powder contained significantly lower amount of total phenolics and total sugar as compared to other samples (p<0.05).

• Proceedings of the SCSK Conference
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• 2003.09b
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• pp.319-329
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• 2003

Ursolic acid (UA) and oleanolic acid (OA) are pentacyclic triterpenoids which are widely distributed in plants, and their derivatives are aglycones of many naturally occurring saponins. It is known that pentacyclic acids may possibly enhance the mechanical barrier functions of cell membranes in plants. Recently, it has been reported that OA and UA have interesting biological activities on skin, such as anti-inflammatory and anti-wrinkle activities. Since triterpenoids are extremely insoluble and their solubility problem limits skin-care application, OA and UA were encapsulated in liposomes via micelle-to-vesicle transition to overcome poorly soluble property and enhance biological efficacy. Optimal molar ratio of OA to lecithin was found to exist for producing liposomes of small hydrodynamic size and liposomal suspensions without recrystallized precipitation of OA. From electron micrograph and dynamic light scattering studies, reconstituted OA-containing liposomes without severe mechanical treatment showed small hydrodynamic size about 150 nm. Wide-angle X-ray diffraction coupled with dynamic light scattering revealed that optimal amount of OA in liposome was 25.4 mole %. In biological evaluation, OA-containing liposome significantly increased filaggrin and transglutaminase as markers of keratinocyte differentiation in epidermal layer of hairless mouse, whereas ursolic acid-containing liposome did not show noticeable increase of filaggrin and transglutaminase compared to empty liposome. It is concluded that nano-scaled liposomes containing triterpenoids were spontaneously prepared by vesicular transition from mixed micelle and liposomal triterpenoids can enhance skin absorption of triterpenoid and biological efficacy.

• Journal of Microbiology and Biotechnology
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• v.22 no.12
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• pp.1605-1612
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• 2012

The present study concerned the identification and characterization of a novel bacterial strain isolated from entomopathogenic nematodes collected from different regions in Korea. The bacterial isolate M1021 was Gramnegative, bioluminescent, and produced red colonies on MacConkey agar medium. A rod-shaped structure was confirmed by the electron micrograph. Fatty acid composition was analyzed by using the Sherlock MIDI system. The identification was further supported by 16S rDNA sequence analysis, which revealed 96-99% sequence homology with strains of Photorhabdus temperata. The location of the isolated strain of P. temperata in the phylogenetic tree was confirmed and it was named P. temperata M1021. P. temperata M1021 exhibited catalase, protease, and lipase activities when grown on appropriate media supplemented with respective substrates. The culture of P. temperata M1021 exhibited insecticidal activity against the larvae of Galleria mellonella and the activity was the highest after 3-4 days of cultivation with agitating at $28^{\circ}C$ under 220 rpm. Antibacterial activity was also observed against Salmonella Typhimurium KCTC 1926 and Micrococcus luteus KACC 10488.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.145-148
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• 2006

The protocrystalline silicon (pc-Si:H) multilayer solar cell is very promising owing to its fast stabilization with low degradation against light irradiation. However, the pc-Si:H multi layers have not extensively been investigated in detail on its material characteristics yet. We present the material characteristics of pc-Si:H multilayer using a transmission electron microscopy(TEM), and Raman spectroscopy. In addition, we present the superior light-soaking behavior of the pc-Si:H mutt i layer solar cell. A TEM micrograph shows that a pc-Si:H multilayer has a repeatedly layered structure and crystalline-like objects in a-Si:H matrix. A Raman spectra introduces improved short-range-order and medium-range-order in pc-Si:H multilayer. As a result the excellent metastability of the pc-Si:H multilayer solar cell is primarily due to the repeatedly layered structure that improves a structural order in absorber layer.

• Textile Coloration and Finishing
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• v.31 no.3
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• pp.127-134
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• 2019

Cotton fabrics were treated with gelatin to improved their dyeability, color strength toward cochineal dye. Gelatin were used as the protein. Gelatin is containing a large number of hydrophilic groups. Pad-dry-cure method was used for the treatment process(10g/L concentration). The scanning electron micrograph showed the gelatin was deposited on the surface of cotton. Pretreated fabrics were mordanted with 10%(owf) alum. Then the fabrics were dyed with cochineal. Compared with original cotton fabric the K/S value with cochineal dyes was significantly improved on gelatin modified cotton. Treating cotton with 10g/L concentration gelatin offered higher cochineal adsorption. The dyeability of pH 4 yielded the highest color strength. In dyebaths of a ratio of ethanol and water such as; 10:0, 9:1, 8:2, 7:3, 6:4, 5:5, 4:6, 3:7, 2:8, 1:9, 0:10, fabrics were dyed. The ratio of ethanol and water had powerful effects on solution polarity. Cochineal dye uptake showed maximum value, when the proportion of ethanol and water was 9:1. Dyeing at increased temperatures and with increased time resulted in higher dye uptake and reddish-purple color(5RP). The washing fastness was 1-2grade, and the fastness to light was 2-3grade.

• Elastomers and Composites
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• v.30 no.3
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• pp.185-194
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• 1995

Membrane process has been employed to separate a specific substance from gas or liquid mixture, and treat wastewater. This is due to the fact that the substance of mixture can be permeated and separated selectively by membrane. Since Initial equipment and operation costs are not expensive, membrane process has been adopted in various fields such as petroleum Industry, chemistry, polymer, electronics, foods, biochemical industry and wastewater treatment. In this study, $CaCO_3$ particles impregnated in silicone rubber network were extracted by using supercritical carbon dioxide and pore distribution of silicone $rubber-CaCO_3$ was investigated with varying amount of extract. Silicone rubber has excellent mechanical properties such as heat-resistance, cold-resistance etc. and $CaCO_3$ has microporous structure. It is possible to make silicone $rubber-CaCO_3$ composite sheets via work-intensive kneading processes. In so doing $CaCO_3$ particles become distributed and impregnated in silicone rubber network. Supercritical carbon dioxide diffuse through composite sample, then sample is swollen. $CaCO_3$ in silicone rubber network Is dissolved in supercritical carbon dioxide, and its sites become pores. Pore distribution, pore shape and surface area are observed by SEM(scanning electron microscope) micrograph and BET surface area analyzer examination respectively. Pore characteristics of membrane suggest the possibilities that the membrane can be used for process of mixture separation and wastewater treatment.

• The Korean Journal of Food And Nutrition
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• v.30 no.2
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• pp.282-289
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• 2017

This study was conducted to investigate the noodle-making characteristics of a noodle dough with konjac powder added. The water-binding capacity was significantly increased by increasing amounts of the konjac powder. When the weight and volume of the noodles were measured after cooking, there was no difference between the control and konjac powder groups. Turbidity was significantly reduced in a concentration-dependent manner. Chromaticity, in the case of raw noodle lightness (L), decreased significantly, while redness (a) and yellowness (b) significantly increased. Cooked noodles also showed the same pattern of results, however, as a whole, the results were lower when compared to wet noodles. The texture characteristics of hardness and chewiness significantly increased by increasing concentrations of the konjac powder. Cohesiveness was determined to not be significantly different by observing the surface of the noodle with a scanning electron microscope. In a sensory evaluation of the cooked noodle, no significant differences in gloss, taste, hardness, springiness or overall acceptability were observed between the control and konjac powder groups. This study indicates the that addition of 1.5% konjac powder to noodle dough may improve the functionality and preference of noodles.

• The Korean Journal of Zoology
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• v.28 no.4
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• pp.257-278
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• 1985

The effect of aromatic amino acids such as phenylalaine, tryptophan and tyrosine on somitogenesis at the early stage of chick embryo has been investigated morphologically using light and electron microscopy. Micrographs of aromatic amino acid injected chick embryo showed that an incomplete somite segmentation occurred and some decremental effect on the nervous system were observed. Somites were poorly developed and their size were variable. Electron micrograph of somatic cells from aromatic amino acid injected chick embryo showed that chromatins were coagulated, some of mitochondria were damaged, and nucleus were transformed considerably in some cases. The protein and nucleic acid levels and some enzyme activities of 15-day chick embryo which received the injection of 1mg of aromatic amino acid in 0.05 ml of saline 24 hours after the incubation were analyzed. Protein, DNA and RNA levels of the test group were not lowered significantly but the activities of enzymes for basic metabolism, such as lactate dehydrogenase, succinate dehydrogenase, malate dehydrogenase and glucose 6-phosphate dehydrogenase were considerably lowered as compared with those of control. From the present expeerimental results, it was tentatively suggested that the administration of amino acid might slow down the yolk granule degradation probably by feed back mechanism resulting in the disturbance of amino acid balance in the cell, which might give rise to impair normal metabolic pattern leading to abnormal somitogenesis to chick embryo at very early stage of development.