• Journal of the Korean Wood Science and Technology
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• 제30권3호
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• pp.26-33
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• 2002

The seven strains, Pseudomonas paucimobilis, Pseudomonas cepacia, Staphylococcus auricularis, Staphylococcus saprophyticus, Acidovorax spp., Acinetobacter calcoaceticus, and Actinobacillus capsulatus were tested with three slimicides. Most of the tested bacteria were inhibited with slimicide K (an isothiazolin based compound), even at its low concentration, except for Actinobacillus capsulatus and Staphylococcus auricularis. Both slimicides B (an organic bromine based compound) and S (aldehydes) also couldn't prevent these two strains even at their highest concentration. Five different sizes of plasmid DNA were isolated from Actinobacillus capsulatus. Staphylococcus auricularis, a gram-positive bacteria, showed the slimy substances around its cell distinctively. The results suggest that two strains, Actinobacillus capsulatus, Staphylococcus auricularis, have presumably developed a resistance to the slimicide, by plasmid DNA or slimy substance. Our findings also suggest that not only gram-negative bacteria, but also gram-positive bacteria should not be neglected

• Journal of Ginseng Research
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• 제13권1호
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• pp.49-55
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• 1989

정상 wistar rat strain의 체중 및 장기무게 변화 그리고 사료, 물 섭취량의 변화 등을 조사함으로써 polyacetylene 화합물들의 투여량에 따른 독성변수(toxicological parameter)의 범위를 추정하고자 하였다. 또한, ICR mouse strain의 Sarcoma-180으로 유도되는 고형암의 억제와 관련해서 polyacetylene 화합물들의 투여량에 따른 독성변수(toxicological parameter)와의 관계를 관찰하고자 하였다. Panaxydol 40$\mumoles/kg b.w.을 3일간 연속 복강 투여했을때 wistar rat의 체중증가율은 대조군보다 약 17% 감소하였으나, polyacetylene 의 투여를 중지하면 약 4일 경과후부터 체중증가율이 정상으로 회복되었다. 이 투여량을 20$\mumoles/kg b.w.로 줄이면 대조군과의 체중증가율의 차이는 약 10% 정도로 완화되며 그 체중감소율은 panaxydol, panaxynol, panaxytriol의 순으로 증가하였다. 이때 장기무게의 관찰 결과는 대조군과 polyacetylene 화합물들 투여군 사이에 의미있는 차이가 없는 것으로 나타났다. 또한 정상 mice의 간세포에 대한 electron micrograph 관찰결과, panaxydol 40$\mumoles/kg b.w./day 투여시에도 대조군에 비하여 별다른 미세조직의 변화가 관찰되지 않았다.

• Applied Microscopy
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• 제38권3호
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• pp.195-204
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• 2008

본 연구는 UVB 조사로 인해 손상된 피부에 있어서 자초추출물의 유효성을 검증하기 위해 시도되었다. 생후 6주령된 제모한 C57BL/6 마우스를 대상으로 대조군, UVB 조사군(UVB군), UVB조사 후 자초추출물처치군(UVB+Le군)으로 구분하여 24시간, 48시간, 72시간, 120시간, 168시간의 시간대별로 관찰하였다. 경표피수분손실량을 측정한 결과, UVB+Le군이 UVB군 보다 시간이 경과함에 따라 TEWL이 감소하였다. 특히 168시간군에서 유의하게 낮게 나타났다(p<0.05). 멜라닌 양 측정 결과, UVB+Le군이 UVB군 보다 낮게 나타났으나 통계학적으로 유의성은 없게 나타났다(p>0.05). 홍반 지수 측정 결과, UVB+Le group 24시간, 48시간, 72시간군에서 UVB group 보다 유의하게 낮게 나타났다(p<0.05). 주사전자현미경적 관찰 결과, UVB group 24시간군에서는 UVB group보다 팽윤현상이 완화되었다. 48시간군에서는 가피형성, 72시간군에서는 규칙적인 판상구조, 120시간군에서 새로운 각질세포 생성, 168시간군에서는 얇은 섬유망으로 덮혀 있는 것이 관찰되었다. 투과전자현미경적 관찰 결과, UVB+Le group은 층판소체의 증가와 층판소체의 재형성이 UVB group보다 모든 군에서 촉진되었다. 특히 165시간군에서는 지질이중막의 구조가 거의 회복되어졌다. 이상의 모든 실험결과를 통해 자초추출물이 UVB 조사로 손상된 생쥐 피부를 회복시키는 효과가 있는 것으로 사료된다.

• Applied Microscopy
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• 제20권1호
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• pp.17-35
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• 1990

Effect of 5-hydroxytryptamine(5-HT, serotonin) and its precursor tryptophan on the cell proliferation of brain and somite parts of 4 day chick embryo in Dulbeco's modified essential medium was examined morphologically at cellular level. It was realized that the externally added 5-HT and/or tryptophan disturbed cell proliferation and severve necrosis occured. Electron micrograph showed that the development of cell organelles were greatly impaired. The activities of both acetylcholine esterase and $Mg^{2+}$ -dependent ATPase of the brain tissues of 5 day chick embryo, which received 1mg of tryptophan and/or 0.1mg of 5-HT at primitive streak stage after 24 hrs incubation of the fertilized egg, were much lower(about 20-25%) than those of control group. These results were supported by the electron micrographs of chemically treated cells. Control cells showed clear densed bands of acetylcholine esterase activity around nucleus and rough endoplasmic reticulum but tryptophan or 5-HT treated groups showed discontinued activity bands. In the case of $Mg^{2+}$-ATPase, the control groups showed clear continuous activity bands but tryptophan and/or 5-HT treated groups were discontinuous. From the previous and present studies, it seems that the intracelluar 5-HT level is very important for the cell proliferation and normal morphogenesis.

• 상하수도학회지
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• 제19권4호
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• pp.455-461
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• 2005

This study was designed to investigate the fundamental aspects of a possible recovery of phosphorus strategy from wastewater by using the zirconium mesoporous structured materials as a new type of ion exchangers. Zirconium mesoporous structure material was synthesized by hydro-thermal synthesis. The synthesized zirconium mesoporous structure was examined by X-ray diffraction (XRD) and Transmission electron micrograph (TEM). From the results of XRD and TEM, it was found out that hexagonal mesoporous structure, pore size was about $47{\AA}$, was synthesized. Experimental results showed that the complex of zirconium sulfate tetrahydrate and surfactant micelles had very high ability for capture of phosphorus. The amount of phosphate ions exchanged into the solid was as great as 3.4mmol/g-ZS. And the ion exchange reaction was occurred between $PO_4{^{3-}}$ and $SO_4{^{2-}}$ and also between $PO_4{^{3-}}$ and $OH^-$. Therefore, it is possible to get the higher removal efficiency than other ion exchange media and adsorbent.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2177-2181
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• 2007

In this paper, effective thermal conductivities of water-based $Al_2O_3$-nanofluids with low concentration from 0.01 vol. % to 0.3 vol. % are experimentally obtained by transient hot wire method (THWM). The water-based $Al_2O_3$-nanofluids are manufactured by two-step method which is widely used. To examine suspension and dispersion characteristics of the water-based $Al_2O_3$-nanofluids, Zeta potential as well as transmission electron micrograph (TEM) is observed. We confirm the manufactured $Al_2O_3$-nanofluids have good suspension and dispersion. The effective thermal conductivities of the water-based $Al_2O_3$-nanofluids with low concentration are enhanced up to 1.64% compared with that of DI water at $21^{\circ}C$. In addition, experimental results are compared with theoretical results from Jang and Choi model.

• 한국생산제조학회지
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• 제22권5호
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• pp.806-811
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• 2013

In this study, to prevent the nonhomogeneity of fiber orientation during the molding of GFRP composites, GFRP prepreg was fabricated using roving fiber and polypropylene resin. Analyses on the degree of impregnation, tensile strength, and microstructure were conducted on the fabricated prepregs. A lower pulling speed, higher resin temperature, and longer die length showed a greater degree of impregnation of the prepreg. The scanning electron microscope (SEM) micrograph showed, a homogeneous fiber orientation. As a result, fundamental techniques for improved productivity were suggested for the manufacturing field.

• 한국전기전자재료학회논문지
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• 제25권12호
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• pp.1009-1014
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• 2012

Hydrogenated amorphous silicon (${\alpha}$-Si:H) layers deposited by plasma enhanced chemical vapor deposition (PECVD) are investigated for use in silicon hetero-junction solar cells employing n-type crystalline silicon (c-Si) substrates. The optical and structural properties of silicon hetero-junction devices have been characterized using spectroscopy ellipsometry and high resolution cross-sectional transmission electron micrograph (HRTEM). In addition, the effective carrier lifetime is measured by the quasi-steady-state photocoductance (QSSPC) method. We have studied on the correlation between the order of ${\alpha}$-Si:H and the passivation quality at the interface of ${\alpha}$-Si:H/c-Si. Base on the result, we have fabricated a silicon hetero-junction solar cell incorporating the ${\alpha}$-Si:H passivation layer with on open circuit voltage ($V_{oc}$) of 637 mV.

• Advances in materials Research
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• 제3권4호
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• pp.233-242
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• 2014

Magnetic and conducting aniline sulfide resin cross-linked (ASC-Fe3O4) nanocomposite has been prepared in the presence of aniline sulfide resin (ASR), aniline, $Fe_3O_4$ coated by polyethylene glycol (PEG) and initiator. The magnetic properties of the resulting composites showed ferromagnetic behavior, such as high-saturated magnetization (Ms= 41 emu/g), and coercive force (Hc=1.5 Oe). The saturated magnetization was increased by increasing of $Fe_3O_4$ content and decreased by increasing aniline ratio. The transmission electron micrograph (TEM) and X-ray diffraction proved that nanometer-sized about 20-30 nm $Fe_3O_4$ in the composite. The average size of ASC-$Fe_3O_4$ nanocomposite with core-shell structure was about 50-60 nm, and polydisperse. This approach may also be extended to the synthesis and modification of other polymers. Electrical conductivity of aniline sulfide resin cross-linked (ASC) nanocomposite has been studied by four-point probe method and produced $3.3{\times}10^{-4}S/cm$ conductivity for it. The conductivity of the composites at room temperature depended on the $Fe_3O_4$, aniline ratio and doping degree. The thermogravimetry analysis (TGA) results showed that this resin is thermal resistance near of $500^{\circ}C$. So, It can be used for resistance thermal coating for military applications. $Fe_3O_4$-PASC nanocomposite has been flexible structure with electrical and magnetic properties.

• Advances in nano research
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• 제6권2호
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• pp.183-200
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• 2018

In the present study silver nanoparticles (AgNPs) were successfully synthesized using aqueous extract of Sargassum muticum. The aqueous extract (10%) treated with 1 mM silver nitrate solution resulted in the formation of AgNPs and the surface plasmon resonance (SPR) of the formed AgNPs was recorded at 360 nm using UV-Visible spectrophotometer. The molecules involved in the formation of AgNPs were identified by Fourier transform infrared spectroscopy (FT-IR), surface morphology was studied by using scanning electron microscopy (SEM), SEM micrograph clearly revealed the size of the AgNPs was in the range of 40-65 nm with spherical, hexagonal in shape and poly-dispersed nature, and X-ray diffraction spectroscopy (XRD) was used to determine the crystalline structure. High positive Zeta potential (36.5 mV) of formed AgNPs indicates the stability and XRD pattern revealed the crystal structure of the AgNPs by showing the Bragg's peaks corresponding to (111), (200), (311) and (222) planes of face-centered cubic crystal phase of silver. The synthesized AgNPs exhibited effective anticancerous activity (at doses 25 and $50{\mu}g/ml$ of AgNPs) against Breast cancer cell line (MCF7).