• 농약과학회지
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• 제3권2호
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• pp.47-53
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• 1999

원예작물중 농약잔류물을 인위적으로 경감시키기 위하여 몇몇 감광제 (photosensitizer, PS)의 활성을 조사하였다. 살균제 iprodione, bitertanol, chlorothalonil, myclobutanil, 및 dichlofluanid를 사과와 오이에 살포한 후 선발된 감광제를 살포하고, 살포 후 0, 1, 3, 7, 15일에 시료를 채취하여 그 잔류량을 분석하였다. 감광제로는 PS-1 (방향족 ketone), PS-2 (방향족 amine), PS-3 (quinone), PS-4 (무기화합물), PS-5 (유기산염) 및 PS-6(반도체 광촉매)이 선발되었다. 사과에 살포된 iprodione의 경우 감광제 PS-1을 처리한 후 15일에 그 잔류량은 대조구의 74%로 감소하였고, bitertanol은 감광제 PS-1를 처리한 후 15일에 그 잔류량은 대조구의 78%로 감소하였으며, chlorothalonil의 경우 감광제 PS-1과 PS-2를 처리한 후 1일에 그 잔류량은 각각 대조구의 56과 54%로 감소하였다. 한편 오이에 살포된 iprodione의 경우 감광제 PS-1과 PS-2를 처리한 후 3일에 그 잔류량은 각각 대조구의 44와 67%로 감소하였고, myclobutanil의 경우 감광제 PS-6을 처리한 후 15일에 그 잔류량은 대조구의 45%로 감소하였으며, dichlofluan김의 경우 감광제 PS-1를 처리한 후 3일에 그 잔류량은 대조구의 44%로 감소하였다. 결과로 미루어 볼 때 방향성 ketone인 감광제 PS-1은 사과와 오이에 잔류하는 농약잔류물의 광분해에 그 효과가 탁월하였다.

• 한국자기공명학회논문지
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• 제21권3호
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• pp.78-84
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• 2017

Pseudin is a naturally occurring 24 amino-acid-residue antimicrobial peptide derived from the skin of paradoxical frog Pseud's paradoxa. It shows potency against the bacteria and antibiotic-resistant bacteria strain, but has high cytotoxicity against mammalian cell. In our previous study, substitution of $Pro^{11}$ for Gly (Ps-P) increased bacterial cell selectivity but decreased the antibacterial activity of pseudin. In this study, we designed pseudin analogue, Ps-4K-P with increased cationicity up to +7 in Ps-P by substituting Glu14, Gln10, Gln24, and Leu18 with Lys. Ps-4K-P showed improved potent antibacterial activity with high bacterial cell selectivity. We determined the tertiary structure of Ps-4K-P in the presence of DPC micelles by NMR spectroscopy and it has a hinge structure at $Pro^{11}$ followed by three turn helices from $Pro^{11}$ to $Val^{23}$ at the C-terminus. Amphipathicity with increased cationicity as well as helix-hinge-helix structural motif provided by introduction of a Pro at position $Gly^{11}$ are the crucial factors which confer antibacterial activity with bacterial cell selectivity to Ps-4K-P.

• Macromolecular Research
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• 제15권4호
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• pp.285-290
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• 2007

Ag nanoparticles were distributed onto polystyrene nanoparticle (PS-Ag) beads using two synthetic methodologies. In the first methodology, polystyrene (PS) beads were prepared via emulsion polymerization, with Ag nanoparticles subsequently loaded onto the surface of the PS beads. The polymerization of styrene was radiolytically induced in an ethanol (EtOH)/water medium, generating PS beads. Subsequently, Ag nanoparticles were loaded onto the PS beads via the reduction of Ag ions. The results from the morphological studies, using field emission transmission electron microscopy (FE-TEM), reveal the PS particles were spherical and nanosized, and the average size of the PS spherical particles decreased with increasing volume % of water in the polymerization medium. The size of the PS spherical particles increases with increasing radiation dose for the polymerization. Also, the amount of Ag nanoparticle loading could be increased by increasing the irradiation dose for the reduction of the Ag ions. In the second methodology, the polymerization of styrene and reduction of Ag ions were simultaneously performed by irradiating a solution containing styrene and Ag ions in an EtOH/water medium. Interestingly, the Ag nanoparticles were preferentially homogeneously distributed within the PS particles (not on the surface of the PS particles). Thus, Ag nanoparticles were distributed onto the surface of the PS particles using the first approach, but into the PS clusters of the particles via the second. The antimicrobial efficiency of a cloth coated with the Ag-PS composite nanoparticles was tested against bacteria, such as Staphylococcus aureus and Klebsiella pneumoniase, for 100 water washing cycles.

• 한국환경농학회지
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• 제19권2호
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• pp.116-121
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• 2000

재배중인 고추표면의 농약잔류물을 인위적으로 경감시키기 위하여 몇몇 감광제 (photosensitizer, PS)의 활성을 조사하였다. 살균제 dithianon, triflumizole 및 triforine을 고추에 4회 살포한 후 선발된 감광제를 1회 살포하고, 감광제 살포 후 0, 1, 3, 7, 15일에 시료를 채취하여 그 잔류량을 분석하였다. 회수율은 $76.6{\sim}78.3%$인 dithianon 외에는 $90.7{\sim}98.5%$로서 양호하였다. Dithianon의 경우, PS-1 (10 ppm) 살포 후 1일에 그 잔류량은 대조구의 76%이었다. Triflumizole의 경우, PS-4 (50 ppm) 살포 후 1일에 잔류량은 대조구의 48%이었다. Triforine의 경우, PS-3 (100 ppm) 살포 후 1일에 잔류량은 대조구의 55%이었다. 이들 결과로 미루어 볼 때 감광제의 작용은 농약의 종류 및 농약이 잔류해 있는 매체에 따라 달라짐을 알 수 있었다.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.191-191
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• 2006

The structures of the mesophases and their subunits of PS-b-P4VP in a toluene solution were studied by using SAXS, TEM and GIFT methods. The hierarchical structures of PS-b-P4VP, such as the individual micelle, the face-centered cubic (fcc) and body-centered cubic (bcc) structures and the lamellar structure, were identified for the first time. The diameter of the micelle core was ${\sim}80\;%$ of the most extended chain length of the core chain, suggesting that the core chains were quite stretched. The stretched chain in the core caused the core of the micelle to be not homogenous with a higher density at the center than at the outer part. As the concentration level increases, the fcc and both fcc and bcc appear for the packing of the micelles of PS(3.3k)-b-P4VP(4.7K) and PS(12K)-b-P4VP(11.8K), respectively. The lamellar structure was also identified, with a further increase in the concentration for PS(3.3k)-b-P4VP(4.7K). These hierarchical structures were also identified via TEM images.

• 한국미생물·생명공학회지
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• 제33권2호
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• pp.117-122
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• 2005

Beijerinckia indica를 통한 Heteropolysaccharide-7(PS-7)생산 최적화를 위해 다양한 탄소원과 질소원을 첨가하여 다른 배지 조성들이 PS-7에 미치는 영향을 조사하였다. 높은 C/N ratio에서 PS-7 생산을 배양 40시간까지 효과적으로 증가시킬 수 있었으며 낮은 C/N ratio에선 탄소원으로 첨가한 glucose가 균체의 생산에 사용되었을뿐 PS-7의 생산은 낮았다. 하지만, 높은 C/N ratio에서는 배양액의 점도로 균체의 생산이 정체하는 것으로 보아 본 실험에서는 20g/l glucose와 $NH_{4}NO_3$ 7.5 mM으로 33.3의 C/N ratio가 PS-7 생산에 적절한 비율인 것으로 관찰되었다. 다양한 탄소원을 첨가한 결과, B. indica는 PS-7 생산을 위하여 탄소원으로 hexose 또는 glucose-generating 당을 효율적으로 이용할 수 있었다. Beijerinckia indica를 이용한 PS-7 생산을 위해 첨가한 다양한 탄소원 중 sucrose 농도가 최고의 PS-7(6.96 g/L)을 생산 하였다. 51 배양기를 이용한 배양에서 탄소원 20 g/L glucose, 질소원 7.5 mM $NH_{4}NO_3$이 포함된 MSM 배지내 배양된 B. indica의 세포 농도가 최고 2.5 g/L이였고, 생산된 최고 PS-7농도는 7.5 g/L(35174 cp)으로 나타났다. 질소원이 완전히 소모된 12시간 이후, 7.5 mM의 $NH_{4}NO_3$, glutamine, glutamate을 첨가한 MSM 배지에서의 B. indica 배앙 결과, 질소원이 B. indica 내에서 탄소원 대사를 조절하는 역할을 하는 것을 관찰할 수 있었으며 최종적으로 PS-7의 생산을 조절할 수 있었다.

• 콘크리트학회지
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• 제8권4호
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• pp.76-85
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• 1996

• Carbon letters
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• 제24권
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• pp.73-81
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• 2017

Interconnected meso/microporous activated carbons were prepared from pumpkin seeds using a simple chemical activation method. The porous carbon materials were prepared at different temperatures (PS-600, PS-700, PS-800, and PS-900) and demonstrated huge surface areas ($645-2029m^2g^{-1}$) with excellent pore volumes ($0.27-1.30cm^3g^{-1}$). The well-condensed graphitic structure of the prepared activated carbon materials was confirmed by Raman and X-ray diffraction analyses. The presence of heteroatoms (O and N) in the carbon materials was confirmed by X-ray photoemission spectroscopy. High resolution transmission electron microscopic images and selected area diffraction patters further revealed the porous structure and amorphous nature of the prepared electrode materials. The resultant porous carbons (PS-600, PS-700, PS-800, and PS-900) were utilized as electrode material for supercapacitors. To our delight, the PS-900 demonstrated a maximum specific capacitance (Cs) of $303F\;g^{-1}$ in 1.0 M $H_2SO_4 $ at a scan rate of 5 mV. The electrochemical impedance spectra confirmed the poor electrical resistance of the electrode materials. Moreover, the stability of the PS-900 was found to be excellent (no significant change in the Cs even after 6000 cycles).

• Macromolecular Research
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• 제14권2호
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• pp.194-198
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• 2006

Polystyrene, PS, particles of 450 nm diameter and poly(styrene-co-styrene sulfonate), PSS, particles of 140-160 nm diameter were prepared by emulsifier-free emulsion polymerization. The surfaces of the PS and PSS particles were coated with Ag nanoparticles for the application of antimicrobial agents by reduction of Ag ions using ${\gamma}$-irradiation. The Ag-PS and Ag-PSS were characterized by High-Resolution Transmittance Electron Microscopy (HR-TEM), Field-Emission Scanning Electron Microscopy (FE-SEM), and Energy Dispersive X-ray Spectroscopy (EDXS). The HR-TEM and EDXS data showed that the Ag nanoparticles were loaded on the surface of the PS and PSS particles, respectively. The antimicrobial efficiency of the Ag-PS and Ag-PSS particles (0.4 g) with ca. 100 ppm Ag, which was coated onto yam (KS K 0905-1996 rule), was tested against Staphylococcus aureus ATCC 6538 and Klebsiella pneumoniae ATCC 4352 after 100 washing cycles (KS K 0432-1999 rule). The antimicrobial efficiency of the Ag-PS particles against Staphylococcus aureus ATCC 6538 and Klebsiella pneumoniae ATCC 4352 was 99.9% after 100 cycles washing., confirming that the Ag-PS particles can be used as antimicrobial agents.

• 한국유기농업학회지
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• 제4권1호
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• pp.13-28
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• 1995

This study analyzed marketing activities of producers' organization on organic farming products(O.F.Ps), and was inquired into direction of consumption increase by it. As a result, in order to raise marketing efficiency and to increase consumption of O.F.Ps, the present questions and issues which are to be solved is as follows: Consumer's confidence for O.F.Ps should be obtained broadly and formally. Particulary, the use of brand such as 'no pollution' or ' no pesticides' should be forbidden without institutional certification. Thus cosumers should be able to distinguish O.F.Ps from general farming products(G.F.Ps) by the brand. Also physical marketing is inefficient since many items are marketed in small amount, and marketing cost is spendedtoo much relatively. Physical marketing center to cut down this expenses should be constructed under government support largely. And the consumers' price of O.F.Ps tends to be fixed all the year round. Owing to this feature, the consumers' price of G.F.Ps have severely influece upon at once demand and supply of O.F.Ps. The associations of consumer and producer should allow O.F.Ps price to fluctuate in proportion to G.F.Ps price. Besides, both should vary marketing patterns. Finally, government should help both associations legally and institutionally to improve all economic activities.