• Asian-Australasian Journal of Animal Sciences
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• 제23권1호
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• pp.106-115
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• 2010

Phosphorylated dextran (P-Dex) is an acidic polysaccharide that functions as an immune adjuvant. P-Dex is known to regulate immune response by maintaining a balance between Th1 and Th2 cells in vitro, and thus may also be important in the control of allergic reactions. In the current study, we report the optimum conditions required for the efficient phosphorylation of dextran without toxicity. We found that when dextran was heated at 160${^{\circ}C}$ for 24 h in phosphate buffer (pH 5.0), the resulting P-Dex demonstrated the highest phosphorus content (6.8%). We also report that P-Dex enhances mitogenic activity in mouse splenocytes and induces expression of CD69 and CD86 on the surface of B cells and dendritic cells (DC) in vitro. Oral administration of P-Dex to ovalubmin (OVA)-immunized mice was found to reduce antigen-induced cell proliferation and suppress the expression of CD86 on Th2-inducing DC via exogenous OVA stimulation. P-Dex was also found to increase IL-10 expression in the splenocytes of treated mice. These findings suggest that oral administration of P-Dex increases immunological tolerance and improves the specificity of immunological response to specific antigens.

• 한국결정학회지
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• 제4권1호
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• pp.6-10
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• 1993

11 β ,17 β -dihydroxy-9a-fluoro-l7a-methyl androst-4-en-3-one (Fluoxymesterone), CgoH29 FO,, orthorhombic, P2,2,2,, a=13.468(5) A, b= 19.554 (2)A, c=6.578(9)A, a=b=r=90˚, A (CuKa)=1.5406 A , Dm=1.289cm-3, Dc=1.299cm-3 and Z=4 at T=298k. The structure was solved by direct method using seminvariants of ggg Parity group and refined by the full-matrix least-square method, resulting model with reliability factor R=0.069 for 1098 unique reflection over 3σ . Ring A is an 1β-2a-half chair, 5 ring has a highly symmetrical chair conformation, C ring is in a distorted chair conformation and D ring is a 13aenveLope conformation. In the crystal structure, the molecules are packed with a hydrogen bond of 011-H23‥‥03(0.5+x, 1.5-y, 1.0-z) [1.94(9) A of H‥‥0.2.786(9)A of 0‥‥0 and 165(8) ˚ of

• 한국통신학회논문지
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• 제23권5호
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• pp.1310-1318
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• 1998

저주파의 아날로그 신호를 디지털 신호로 변환하기 위해 sigma-delta 아날로그-디지털 변환기의 이용이 용이하다. 이 변환기는 변조기와 디지털 필터로 구성되는데 여기에서는 변조기에 대해 언급한다. 14비트 분해능을 갖는 2차 sigma-delta 변조기를 설계하기 위한 변조기의 구성요소 즉 연산 증폭기, 적분기, 내부 ADC 및 DAC의 최대 허용 에러 범위를 규정하였다. 이를 위하여 먼저 이상적인 변조기를 모델링하고 다음으로 변조기의 성능을 저하시키는 여러 가지 에러 요인 즉 연산증폭기의 최대 출력 제한, DC 이득, slew rate, 축전기의 불일치에 의한 적분기 이득 에러와 내부 ADC 및 DAC의 에러 등을 이상적인 모델에 적용하여 성능을 검증하였다. 이러한 에러 허용 범위에 대한 조사를 바탕으로 sigma-delta 변조기 설계 시 요구되는 구성 요소의 사양을 결정 할 수 있으며, 제조과정에서 나타나는 에러 성분에 대한 한계를 규정하여 최종 제작될 변조기의 성능을 확신 할 수 있다.

• Archives of Plastic Surgery
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• 제35권4호
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• pp.367-372
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• 2008

Purpose: Prevention of acute rejection in skin allografts without continuous immunosuppression lacks reports in worldwide literature. Needs for chronic immunosuppression preclude the use of tissue allograft as a routine surgical reconstructive option. Recently dendritic cells(DC) gained considerable attention as antigen presenting cells that are also capable of immunologic tolerance induction. This study assesses the effects of alloantigen-pulsed dendritic cells in induction of survival increase in a rat skin allograft model. Methods: Recipient-derived dendritic cells were harvested from rat whole blood and cultured with GM-CSF(200 ng/mL) and IL-4(8 ng/mL) for 2 weeks. Then donor-specific alloantigen pulsed dendritic cells were reinjected into tail vein before skin graft. The rat dorsal skin allografts were transplanted in 5 subgroups. Groups: I) untreated, II) anti-lymphocyte serum(ALS, 0.5 mL), III) FK-506(2 mg/kg), IV) DCp, VI) DCp and FK-506. Graft appearance challenges were assessed postoperatively. Results: The group V(DC and FK-506 treated) showed longest graft survival rate(23.5 days) than other groups; untreated(5.8 days), ALS(7.2 days), FK-506 (17.5 days), DCp(12.2 days). Conclusion: Donor antigen pulsed host dendritic cell combined with short-term immunosuppression prolong skin allograft survival and has potential therapeutic application for induction of donor antigen specific tolerance.

• Applied Microscopy
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• 제34권1호
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• pp.51-59
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• 2004

주사전자현미경(SEM)에서 전자를 발생시키는 전자총 부분의 고압발생 장치를 설계 제작하고 그 안정성을 시험하였다. 고전압을 발생시키는 switching 주파수는 고압트랜스의 1차 측 임피던스와 인덕턴스에 matching 되는 주파수에서 최적의 전압 안정도가 유지되었다. 1차 측의 고압트랜스의 turn 수가 적으면 인덕턴스가 낮으므로 최적적인 matched switching 주파수가 높은 쪽으로 올라간다. 최대 출력 전압은 -30 kV 이상 출력되었으나 안정도는 출력전압이 -5 kV에서 10 kV 범위에서 가장 좋게 나타났다. 23.8 kHz에서 출력파형의 흔들림 없었고 DC 고전압 출력 또한 최고의 안정도을 보였다. 이때 도출된 전압 안정도는 ${\pm}0.002%$였다.

• Plant Resources
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• 제1권1호
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• pp.53-59
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• 1998

Laboratory experiments for the removal efficiency of heavy metals in land application of sludge, the accumulation and translocation of heavy metals in x plants after transplanting, and the responses of Minari growth with different ratio of land application of sludge were conducted to determine the potential ability of bioremediation with Minari plants. The removal rate and translocation of copper. zinc. lead. and cadmium in soil and plants were compared after transplanting the Minari plants to soil treated with different ratio of sludge. The removal efficiency of heavy metals in soil incorporated with sludge was different with application ratio, but increased with growing periods of Minari plants. The removal efficiency of Cu, Zn, Pb, and Cd ranged from 67 to 74% from 51% to 63%, from 37% to 71%. and from 15% to 25% after 45 days of transplanting. respectively. The amount removed the copper value. 65.9 mg/kg, observed to be highest in soil incorporated 3% sludge after 45 days. The translocation of Cu. Zn. Pb. and Cd from shoots to roots ranged from 18 to 53%, from 17 to 32%, from 14 to 49%, and from 23 to 38% over growing periods. respectively. In plant responses it appeared to be inhibited the plant growth in the treatment compared with the control at early stage of growth. However, the fresh weights of Minari plant increased from 12.5 to 62.5% in the sludge application after 45 days relative to the control. Therefore the Minari might play a useful role in bioremediation of Cu, Zn, Pb, and Cd in the land application of sludge.

• 한국화재소방학회논문지
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• 제23권5호
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• pp.153-160
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• 2009

본 연구에서는 건축 실내음향 특성파악에 이용되는 컴퓨터 시뮬레이션을 통해 비상경보설비의 음향장치에 공급되는 전압의 변동에 따른 비상경보설비음의 전달특성을 파악하였다. 현재 가장 널리 사용되고 있는 비상경보설비의 음향장치 음향파워레벨(정격전압 DC 24V)은 경종은 98.6dB, 전자식사이렌 스피커는 95.7dB 그리고 전자식사이렌 폰은 101.8dB로 측정되었다. 또한 경종은 주파수 증가에 따라 음항파워레벨이 증가하고 고주파 대역에서 피크 레벨을 보이는데 반해 전자사이렌의 폰형과 스피커형은 135~200Hz에서 최저음향파워레벨을 보이다가 이후 급격히 증가하는 패턴을 나타냈다. 컴퓨터 시뮬레이션을 통하여 비상경보설비와의 이격거리에 따른 전달특성을 살펴보면, 대상건물의 복도에서는 전체적으로 고른 분포를 보여주고 있다. 하지만 인접해 있는 강의실에서는 벽체 부분을 제외한 우회전달음의 영향으로 비상경보설비 음향장치의 주파수 특성에 따라 전달되는 음압레벨의 차가 크게 발생하였다. 향후 예측수법의 정확도와 타당성 검토을 통한 화재비상경보음의 전달특성을 건축물의 계획 시에 예측 비교한다면 화재 경보의 인지 가능성을 높일 수 있을 것으로 사료된다.

• 대한전자공학회논문지SD
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• 제47권8호
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• pp.23-28
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• 2010

본 논문에서는 각각 다른 캐리어 방향성을 가지는 strained-silicon PMOSFET에서 소자의 디지털 및 아날로그 성능을 비교 평가 하였다. 캐리어 방향이 <100>을 갖는 소자의 경우 이동도 향상에 의해서 <110> 방향의 소자 보다 우수한 드레인 구동 전류 및 출력저항 특성을 보이지만, NBTI 신뢰성과 소자의 matching 특성은 반대로 다소 열화 됨을 확인 하였다. 따라서 나노미터급 CMOSFET에서 캐리어 방향성을 이용한 이동도 향상 기술의 적용을 위해서는 DC 성능을 비롯한 신뢰성 및 아날로그 특성을 모두 고려하는 것이 반드시 필요하다고 할 수 있다.

• 전기전자학회논문지
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• 제20권3호
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• pp.279-284
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• 2016

This paper presents a two stage L-band power amplifier realized with a $0.32{\mu}m$ Silicon-On-Insulator (SOI) CMOS technology. To overcome a low breakdown voltage limit of MOSFET, stacked-FET structures are employed, where three transistors in the first stage amplifier and four transistors in the second stage amplifier are connected in series so that their output voltage swings are added in phase. The stacked-FET structures enable the proposed amplifier to achieve a 21.5 dB small-signal gain and 15.7 dBm output 1-dB compression power at 1.9 GHz with a 122 mA DC current from a 4 V supply. The amplifier delivers a 19.7 dBm. This paper presents a two stage L-band power amplifier realized with a $0.32{\mu}m$ Silicon-On-Insulator (SOI) CMOS technology. To overcome a low breakdown voltage limit of MOSFET, stacked-FET structures are employed, where three transistors in the first stage amplifier and four transistors in the second stage amplifier are connected in series so that their output voltage swings are added in phase. The stacked-FET structures enable the proposed amplifier to achieve a 21.5 dB small-signal gain and 15.7 dBm output 1-dB compression power at 1.9 GHz with a 122 mA DC current from a 4 V supply. The amplifier delivers a 19.7 dBm saturated output power with a 16 % maximum Power Added Efficiency (PAE). A bond wire fine tuning technology enables the amplifier a 23.67 dBm saturated output power with a 20.4 % maximum PAE. The die area is $1.9mm{\times}0.6mm$.

• 한국식품조리과학회지
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• 제25권4호
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• pp.406-414
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• 2009

This study was conducted to investigate the functional composition and antioxidant activity of Cirsium and Carduus genera based on different parts. Leaves of Cirsium setidens Nakai contained 23.66% protein and seeds of Carduus crispus L contained 25.30% lipid. Extraction yields of Cirsium and Carduus genera were higher in leaves than in any other parts of the plants. Total phenolics and total flavonoid content were abundant in extracts of leaves, steam and root of C. japonicum var. ussuriense, and the flower extract of C. setidens Nakai. Silymarin was not found in extracts of Cirsium and Carduus genera. Acacetin was identified in leaf or flower extracts of C. setidens Nakai, or in leaf and steam extracts of C. pendulum Fisch ex DC. Apigenin was identified in the flower extracts of Cirsium and Carduus genera and constituted 7.16 mg/g in C. japonicum var. ussuriense. Cynarin was present at 5.55 mg/g in the seed extract of C. setidens Nakai, and narirutin represented 19.56 mg/g and, 4.18 mg/g of the seed extracts of C. pendulum Fisch ex DC and, Carduus crispus L, respectively. 2,2-Diphenyl-1-2-picrylhydrazyl (DPPH) radical scavenger activity was higher in flower extracts of C. setidens Nakai than in the other genera. Photochemiluminescence activity was 2.3 nmol in leaves and flower extracts of C. setidens Nakai and flower extract of Carduus crispus L. Flowers and seeds of C. setidens Nakai shoe potential as new functional materials.