• Korean Chemical Engineering Research
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• v.49 no.6
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• pp.816-822
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• 2011

Pervaporation is known to be a low energy consumption process since it needs only an electric power to maintain the permeate side in vacuum. Also, the pervaporation is an environmentally clean technology because it does not use the third material such as an entrainer for either an azeotropic distillation or an extractive distillation. In this study, Silicalite-1 particles are hydrothermally synthesized and polydimethylsiloxane(PDMS)-zeolite composite membranes are prepared with a mixture of synthesized Silicalite-1 particles and PDMS-polymer. They are used to separate n-butanol from its aqueous solution. Pervaporation characteristics such as a permeation flux and a separation factor are investigated as a function of the feed concentration and the weight % of Silicalite-1 particles in the membrane. A 1,000 $cm^3$ aqueous solution containing butanol of low mole fraction such as order of 0.001 was used as a feed to the membrane cell while the pressure of the permeation side was kept about 0.2~0.3 torr. When the butanol concentration in the feed solution was 0.015 mole fraction, the flux of n-butanol significantly increased from 14.5 g/ $m^2$/hr to 186.3 g/$m^2$/hr as the Silicalite-1 content increased from 0 wt% to 10 wt%, indicating that the Silicalite-1 molecular sieve improved the membrane permselectivity from 4.8 to 11.8 due to its unique crystalline microporous structure and its strong hydrophobicity. Consequently, the concentration of n-butanol in the permeate substantially increased from 0.07 to 0.15 mole fraction. This composite membrane could be potentially appliable for separation of n-butanol from insitu fermentation broth where n-butanol is produced at a fairly low concentration of 0.015 mole fraction.

• Korean Chemical Engineering Research
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• v.44 no.2
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• pp.187-192
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• 2006

The preparation and characterization of new polymer composite membranes containing polyphenylene oxide (PPO) thin films with hetropoly acid (HPA) are presented. PPO thin films with phosphotungstic acid (PWA) or phosphomolybdic acid (PMA) have been prepared by using the solvent mixture. The PWA and PPO can be blended using the solvent mixture, because PPO and PWA are not soluble in the same solvent. In this study, methanol was used as a solvent dissolving PWA and chloroform was used as a solvent dissolving PPO. PPO-PWA solutions were cast onto a glass plate with uniform thickness. The composite membranes were prepared by casting Nafion mixture on porous PPO-PWA films. The morphology and structure of these PPO-PWA films were observed with scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). The composite membranes were characterized by measuring their ion conductivity and methanol permeability. The performance was evaluated with composite membranes as electrolytes in fuel cell conditions. The methanol cross-over of composite membranes containing PPO-PWA barrier films in the DMFC reduced by 66％.

• Korean Chemical Engineering Research
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• v.46 no.4
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• pp.727-731
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• 2008

Mesoporous Pt-Au alloy films were successfully fabricated on ITO-coated glass by electrodeposition method using tri-blockcopolymer (P123) as a templating agent. The electrolyte consisted of 10 mM hydrogen hexachloroplatinate ($H_2PtCl_6$), 10 mM hydrogen tetrachloroaurate ($HAuCl_4$), and proper amount of P123. For comparison, control samples were electrodeposited without $HAuCl_4$ and P123. Film composition was determined by EDS(Energy Dispersive X-ray Spectroscopy), and the mesoporous structure was confirmed by TEM(Transmission Electron Microscopy). SEM(Scanning Electron Microscopy) was utilized to examine surface morphology, and it was observed that the addition of P123 affected the particle growth, resulting in the significant change of surface morphology. Methanol oxidation and CO oxidation were carried out to investigate electrocatalytic activities of synthesized samples. It was observed that the catalytic activity was strongly dependent on the film compositions. Compared with nonporous electrode prepared without P123 templating, mesoporous films prepared with P123 templating showed much higher catalytic activities and stability for both methanol oxidation and CO oxidation. These enhanced electrocatalytic activities were due to the high surface area and facilitated charge transfer of mesoporous films.

• BMB Reports
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• v.33 no.6
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• pp.454-462
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• 2000

Interleukin-4(IL-4) is known to be a major cytokine regulating immunoglobulin E(IgE) response by the induction of IgE production and type II IgE receptor(IgER II: CD23) expression. Recently, however, the role of neuroendocrine factors has been implicated in modulating the IgE response. Among various neuroendocrine growth factors, we investigated the effects of the insulin-like growth factor-1(IGF-1) since IL-4 and IGF-1 share common intracellular signaling molecules, such as the insulin receptor substrate-1/2(IRS-1/2) to induce a specific cellular response. In the human peripheral blood mononuclear cell (PBMC) cultures, IGF-1 was capable of inducing a substantial level of IgE production in a dose-dependent manner. It also noticeably upregulated the IL-4-induced or IL-4 plus anti-CD40-induced IgE production. Similarly, the IGF-1-induced IgE production was enhanced by IL-4 or anti-CD40 in an additive manner, which became saturated at high concentrations of IGF-1. Although IGF-1 alone did not induce IgER II (CD23) expression, it augmented the IL-4-induced surface CD23 expression in a manner similar to the action of anti-CD40. These results imply that IGF-1 is likely to utilize common signaling pathways with IL-4 and anti-CD40 to induce IgE and IgER II expression. In support of this notion, we observed that IGF-1 enhanced the IL-4-induced signal transducers and activators of transcription 6(STAT6) activation and independently induced $NF-{\kappa}B$ activation. Both of these bind to the IgE(C) or IgER II (CD23) promoters. Together, our data suggest that IL-4 and IGF-1 work cooperatively to activate STAT6 and $NF-{\kappa}B$. This leads to the subsequent binding of these transcription factors to the $C{\varepsilon}$ and CD23 promoters to enhance the expression of IgE and IgER II. The observed differential ability of IGF-1 on the induction of IgE vs. IgER II is discussed based on the different structure of the two promoters.

• Korean Journal of Plant Taxonomy
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• v.47 no.2
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• pp.137-153
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• 2017

Fruit and seed morphological characteristics were investigated in 36 taxa of 20 genera of Korean Ranunculaceae. As a result, fruits were classified as the achene, berry, or follicle type. In the taxa with achene, the presence of trichomes and stoma on the surface of the fruit and a feature in which the endocarp distinctively develops into a one-layer sclereid were considered as useful characteristics. Moreover, in the taxa with follicles, the composition of the seed coat (bitegmic vs. unitegmic), the cell shape of the seed coat, the presence of trichomes, and the type of seed coat were useful for taxonomic characteristics in Korean Ranunculaceae. Based on the fruit and seed characteristics, Adonis is likely to be classified into Helleboroideae rather than Ranunculoideae, as it has bitegmic ovules. In addition, Enemion is similar to Eranthis in unitegmic ovule and the seed coat structure which has non-sclereid exotesta; therefore, it is reasonable to be placed in Helleboroideae. According to the results of this study, more in-depth research is needed regarding the taxonomic positions of Callianthemum and Actaea, which has the only berry fruit type.

• Archives of Pharmacal Research
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• v.29 no.8
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• pp.666-676
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• 2006

Gangliosides are widely distributed in mammalian cells and play important roles in various functions such as cell differentiation and growth control. In addition, diabetes and obesity cause abnormal development of reproductive processes in a variety of species. However, the mechanisms underlying these effects, and how they are related, are not fully understood. This study examined whether the differential expression of gangliosides is implicated in the abnormal follicular development and uterine architecture of streptozotocin (STZ)-induced and db/db diabetic mice. Based upon the mobility on high-performance thin-layer chromatography, mouse ovary consisted of at least five different ganglioside components, mainly gangliosides GM3, GM1, GD1a and GT1b, and diabetic ovary exhibited a significant reduction in ganglioside expression with apparent changes in the major gangliosides. A prominent immunofluorescence microscopy showed a dramatic loss of ganglioside GD1a expression in the primary, secondary and Graafian follicles of STZ-induced and db/db diabetic mice. A significant decrease in ganglioside GD3 expression was also observed in the ovary of db/db mice. In the uterus of STZ-induced diabetic mice, expression of gangliosides GD1a and GT1b was obviously reduced, but gangliosides GM1, GM2 and GD3 expression was increased. In contrast, the uterus of db/db mice showed a significant increase in gangliosides GM1, GD1a and GD3 expression. Taken together, a complex pattern of ganglioside expression was seen in the ovary and uterus of normoglycemic ICR and $db/^+$ mice, and the correspoding tissues in diabetic mice are characterized by appreciable changes of the major ganglioside expression. These results suggest that alterations in ganglioside expression caused by diabetes mellitus may be implicated in abnormal ovarian development and uterine structure.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.31 no.2
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• pp.103-115
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• 2009

In vertebrates, the face is mainly formed with neural crest derived neural crest cells by the inherent programs and the interactive environmental factors. Extracellular signaling-regulated kinase (Erk) is one of such programs to regulate the various cellular functions. And retinoic acid (RA) also plays an important role as a regulator in differentiation process at various stages of vertebrate embryogenesis. We wanted to know that the segregation as well as the patterning of maxillary and mandibular structure is greatly influenced by the maxillomandibular cleft (MMC) and the failure of this development may result in the maxillomandibular fusion (syngnathia) or other patterning related disorder. It has been well documented that the epithelium at this cleft region has significant expression of Fibroblast growth factor (Fgf) 8, and it is essential for the patterning of the first arch derived structures. By the morphological, skeletal, cell proliferation and apoptotic, and hybridization analysis, we checked the effects of Erk inhibition and/or RA activation onto MMC and could observe that Erk and RA signaling is individually and synergically involved in the facial patterning in terms of FGF signaling pathway via Barx-l. So RA and Erk signaling work together for the MMC patterning and the segregation of maxilla-mandible by controlling the Fgf-related signaling pathways. And the abnormality in MMC brought by aberrant Fgf signaling may result in the disturbances of maxillary-mandibular segregation.

• Journal of Plant Biology
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• v.5 no.3
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• pp.5-10
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• 1962

Studies on the anatomical observation of Bamboos distributed in East-South Asia for systematic botany were scarecely reported except for the morphological studies on Bamboos, which was investigated by Dr. Hiroshi Usui, present author and others. Recently it has been certain that it could be hardly classify some species of bamboo family without this work. For this reason the author reported the anatomical studies on Korean bamboos in 1959, and furthermore the author intended to identify the two species of Pleioblastum Simoni Nakai in Korean bamboos by studying the characteristics of internal structure and qualitative assay of free amino acid containg in Pleioblastus Simoni Nakai(1), (2). In view of fact that there is some differences between two species, it is likely to be identifiable completely different species one another. Furthermore, a lot of characteristics surveyed by the author were as follow: It was reassumed that two species cultivated under same conditions for three years were different alternately in the species of Pleioblastus Simoni Nakai. At the same time, these studies could clarify some evolutional processes of bamboo family. On the other hand, it was found that two species had not only the obvious difference in aerenchyma, the size of thickwalled parenchyma and bulliform cell, but also the internode of Pleioblastus Simoni Nakai(1) is longer than the other, the speed of growing is more rapid, the leaf of former is narrow and that of latter is wide. The free amino acids containg in each species were found as 18 kinds, especially Pleioblastus Simoni Nakai (2) had not Histidine in spite of containg in Pleioblastus Simoni Nakia(1). From the characteristics and the experiments described above, it seemed to the author that Pleioblasus Simoni Nakai (1) which was growing at the region of Ulsan in Korea.

• Korean Journal of Agricultural Science
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• v.41 no.3
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• pp.163-167
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• 2014

The average temperatures for year and winter season have been risen by $0.7{\circ}C$ and $1.4{\circ}C$, respectively, during the last 30 years. Recently abnormal climate phenomena occurred frequently results in severe loss of vegetable crops grown in Korea. Specially, Chinese cabbages grown in the southern area of Korea are often significantly affected by sudden cold waves during winter season before harvest. This experiment was conducted to find out a potential role of covering materials on the protection of frost damage of 'Bularm' chinese cabbage in the winter season. The lowest temperature was $-15.8^{\circ}C$ in non-covering, $-8.1^{\circ}C$ in the PE film covering and $-4.6^{\circ}C$ in the non-woven fabric covering with PE film, respectively. The cumulative times below $4.0^{\circ}C$ were 145.5 hours for the non-covering treatment, 94 hours in the PE film covering and 14.5 hours in the non-woven fabric covering with PE film, respectively. The symptoms of frost damage were severe at non-covering chinese cabbages compared to polyethylene film (PE) non-woven fabric with PE covering ones. Microscopic studies showed the normal anatomical structure of palisade and spongy tissue of cabbage leaves covered with non-woven fabric with PE film. Leaf cells, however, were slightly damaged in cabbages covered with PE film alone, and both palisade and spongy cells were were completely collapsed in uncovered cabbages. The result of this study suggests that chinese cabbages is required to be covered with non-woven fabric with PE film to minimize the frost damage by sudden cold wave below $-7^{\circ}C$.

• Journal of the Korean Vacuum Society
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• v.19 no.2
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• pp.128-133
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• 2010

ZnO:Al films were deposited by DC-pulsed magnetron sputtering using a two-step process involving the control of the oxygen pressure. The seed layers were prepared with various Ar to oxygen flow ratios and the bulk layers were deposited under pure Ar. As the oxygen pressure during the deposition of the seed layer increased, the crystallinity and degree of (002) texturing increased. The resistivity gradually decreased with increasing crystallinity from $4.7\times10^4\Omega{\cdot}cm$ (no seed) to $3.7\times10^4\Omega{\cdot}cm$ (Ar/$O_2$ = 9/1). The etched surface showed a crater-like structure and an abrupt morphology change appeared as the crystallinity was increased. The sample deposited at an Ar/$O_2$ flow ratio of 9/1 showed a very high haze value of 88% at 500 nm, which was explained by the large feature size of the craters, as shown in the AFM image.