• 대한바이러스학회지
• /
• 제30권1호
• /
• pp.83-99
• /
• 2000

A defective HIV-1 helper virus DNA, pHyPC, was assembled by deleting the RNA packaging signal, env, nef and the 3'LTR sequences. HIV-1 like virus particles that carry the HIV-1 receptor, CD4 were generated by co expression of pHyPC and plasmid DNAs encoding different chimeric CD4 proteins. The CD4 particles, sharing the CD4 ectodomain, precisely fused to different membrane anchors. CD4(+) particles specifically bound to HIV-1 Env expressing cells, but any signs of infection into these cells were not detected. Binding was only partially blocked by either polyclonal anti-CD4 antibodies or by high concentrations of soluble CD4. Surprisingly, CD4(+) particles also adsorbed to HeLa, CHO, NIH3T3 and COS-7 cells in the absence of HIV-1 Env expression. Adsorption was comparable in strength and speed to the highly specific CD4-Env interaction. CD4(-) particles exhibited only background levels of binding. Cell binding was CD4. dependent, but it was independent of the cell type from which the CD4(+) particles originated. Interestingly, CD4-dependent/Env-independent binding was only found when CD4 was present on virus particles. This suggests that the micro-environment of CD4 on virus particles uniquely expose this new cell binding activity. Its high affinity could explain in part why infection of Env(+) cells by CD4(+) particles was not detected. Further experiments will be required to evaluate whether this strong membrane interaction could represent one step in the multiple-step viral entry process.

• Archives of Pharmacal Research
• /
• 제27권11호
• /
• pp.1183-1187
• /
• 2004

This study was designed to develop crosslinking of $\beta$-cyclodextrin ($\beta$-CD), and determine the optimum conditions of different factors (mixing time, mixing temperature, and mixing speed) on cholesterol reduction from milk. Crosslinked $\beta$-CD was prepared with epichlorohydrin. When milk was treated with different conditions, the cholesterol removal rate was in the range of 79.4 to 83.3% with 1 % crosslinked $\beta$-CD addition, which were not significantly different among treatments. After cholesterol removal from milk, the used crosslinked $\beta$-CD was washed for cholesterol dissociation and reused. For recycling study, the cholesterol removal rate in first trial was 81.8%, which was mostly same as that using new crosslinked $\beta$-CD. With five trials repeatedly using the same sample, the mean cholesterol removal rate was 81.2%. The present study indicated that the optimum conditions on cholesterol removal using crosslinked $\beta$-CD were 10 min mixing with 400 rpm speed at $5^{\circ}C$ with about 80% cholesterol removal. In addition, crosslinked $\beta$-CD resulted in the effective recycling efficiency almost 100%.

• 한국식품위생안전성학회지
• /
• 제27권2호
• /
• pp.133-140
• /
• 2012

본 연구는 중금속이 함유된 식이를 섭취 시 생체 내에서의 중금속 동태 및 함량을 구명하고자 Cd 오염 지역에서 생산된 현미를 첨가한 식이로 12주간 흰쥐를 사육하여 성장 특성과 혈액, 간 및 신장 조직의 Cd, Zn 및 Cu의 함량을 분석한 결과는 다음과 같다. 식이에 따른 일일 증가체중은 BR 및 PBR 100% 식이 군에서 0.22-0.26 g/day이었고, FE식이 군은 1.08-1.26 g/day로 식이 원에 따른 체중변화 차이가 뚜렷하였다. 식이 내 중금속 일일 섭취량은 BR+PBR 50% 및 PBR 100% 군은 10.77 및 22.36 ${\mu}g/rat$ 이고, FE+PBR 50% 군은 8.83 ${\mu}g/rat$로 식이 중 Cd 농도에 따라 일일 Cd 섭취량이 증가 되었다. 12주간 섭취한 중금속은 전체적으로 식이 중 Cd 함량이 높아지면 이들 총 섭취량도 증가되었다. BR+PBR 50% 군 및 FE+PBR 50% 군의 간과 신장의 무게는 FE 식이 군에서 2.64배 및 2.27배 높은 무게를 나타냈다. 혈액 중 Cd 함량은 BR 식이 섭취량이 많을수록 증가되었고, Zn 및 Cu 함량은 감소되었다. 동일 Cd 농도 식이 군에서 FE+PBR 50% 군은 BR+PBR 50%로 조제한 식이군보다 혈액 중 Cd 함량이 1.27배 높았다. 간에서 BR, BR+PBR 50% 및 PBR 100% 식이 군은 Cd 농도가 높으면 간 중 Cd 함량이 증가되는 현상이 뚜렷하였다. 동일 수준 농도에서 BR+PBR 50% 및 FE+PBR 50%의 Cd 축적은 BR 식이가 높았다. 신장 중 BR, BR+PBR 50% 및 PBR 100% 식이 군에서 Cd 함량의 축적이 높아지면 신장 중 Zn 및 Cu 함량이 증가하였고, 식이군의 Cd 농도가 같은 수준에서 FE와 BR 첨가 차이는 BR 첨가식이 군이 FE로 조제한 식이군보다 3.11배가 높은 Cd 함량을 나타냈다. 이와 같은 결과는 오염된 식이의 섭취량과 Cd 농도 수준에 의존한 결과로서 Zn 및 Cu 함량과도 깊은 관계가 있음을 확인하였다.

• 한국미생물·생명공학회지
• /
• 제19권5호
• /
• pp.444-449
• /
• 1991

Pullulanase의 역반응능을 이용하여 maltose와 $\beta$-cyclodextrin으로부터 maltosyl-$\beta$-cyclodextrin을 중합합성하기 위한 최적효소반응조건을 검토하였다. Maltose와 $\beta$-CD를 기질로 maltosyl-$\beta$-CD을 합성하였을 경우, 기질의 농도 70( w/w, 70g/100ml $H2_O$ ), malto-loigo당 /$\beta$-CD의 혼합비 12.7, 그리고 사용효소량 350 units/100ml일 때 최대전융인 43(w/w, g branched-CD/g CD)를 얻었고, 생성량은 2.31g/100ml였다. Maltosyl-$\beta$-CD의 효소합성의 적정 pH 및 온도는 각각 4.9와 $60^{\circ}C$ 였다. 또한 maltose와 $\alpha ,\beta$-그리고 $\gamma$-CD 각각을 기질로하여 maltosyl $\Alpha, \beta$ 그리고 $\gamma$-CD를 합성하였을 경우 전환율은 51.8, 42.6, 그리고 48.1로써, 생성량은 각각 2.8, 2.3 그리고 2.6g/100ml였다.

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제8권2호
• /
• pp.87-91
• /
• 2003

본 연구는 산업시설에서 배출되는 대기오염물질이 인접한 주거지역에 영향을 미칠 것으로 예상되는 시화공업단지 주변의 공단지역, 주거지역 및 녹지지역의 토양을 대상으로 As, Cd, Co, Cr, Cu, Hg, Ni, Pb 및 Zn 함량을 조사하였다. 토양 중 중금속 함량의 범위는 As 0.58~3.81, Cd ND~0.91, Co 0.15~6.33, Cr ND~1.86, Cu 0.14~110.27, Hg ND~l.17, Ni 0.04~10.59, Pb 1.16~86.48 및 Zn 1.83~212.65 mg/kg으로서 전 지역에서 토양환경보전법의 토양오염기준이나 식물독성 유발기준에 비하여 매우 낮은 값을 나타내었다. As 함량은 전 지역에 걸쳐 비슷하였으나, Cd와 Cr 함량은 공단지역이 주거지역이나 녹지지역보다 각각 약 10배 및 5배정도 높았으며, 주거지역과 녹지지역은 비슷한 경향이었다. Co, Cu, Hg, Ni, Pb 및 Zn 함량은 공단지역이 주거지역이나 녹지지역보다 약 2~3배정도 높았으며, 주거지역과 녹지지역은 비슷한 경향이었다.

• Transactions on Electrical and Electronic Materials
• /
• 제12권4호
• /
• pp.164-168
• /
• 2011

Nanocrystalline cadmium sulphide (CdS) thin films were prepared using chemical bath deposition (CBD), and the structural, optical and photoconductive properties were investigated. The crystal structure of CdS thin film was studied by X-ray diffraction. The crystallite size, dislocation density and lattice constant of CBD CdS thin films were investigated. The dislocation density of CdS thin films initially decreases with increasing film thickness, and it is nearly constant over the thickness of 2,500 ${\AA}$. The dislocation density decreases with increasing the crystallite size. The Urbach energies of CdS thin films are obtained by fitting the optical absorption coefficient. The optical band gap of CdS thin films increases and finally saturates with increasing the lattice constant. The Urbach energy and optical band gap of the 2,900 A-thick CdS thin film prepared for 60 minutes are 0.24 eV and 2.83 eV, respectively. The activation energies of the 2,900 ${\AA}$-thick CdS thin film at low and high temperature regions were 14 meV and 31 meV, respectively. It is considered that these activation energies correspond to donor levels associated with shallow traps or surface states of CdS thin film. Also, the value of ${\gamma}$ was obtained from the light transfer characteristic of CdS thin film. The value of ${\gamma}$ for the 2,900 A-thick CdS thin film was 1 at 10 V, and it saturates with increasing the applied voltage.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2000년도 제18회 학술발표회 논문개요집
• /
• pp.83-83
• /
• 2000

MBE법으로 성장시킨 Cd1-xMgxTe 박막을 조성비 (x=0, 0.23, 0.32, 0.43)에 따라 타원편광 분석기로 측정하여 연구하였다. E0 critical point energy 아래에서 나타나는 간섭무늬를 제거하기 위해 multilayer calculation을 수행했고 ellipsometric data를 2번 미분하여 계산하는 Critical Point Parabolic Band(CPPB) model을 사용하여 E0, E0+Δ0, E1, E1,+Δ1, and E0'critical point energy 들을 구할 수 있었다. 특히 E2 peak region 에서는 종전의 고상시료 (bulk)에서 측정 발표된 값보다도 매우 높고 명확한 <$\varepsilon$2>값이 측정되어, E2와 E、0 peak가 명확하게 분리되는 것을 볼 수 있었다. 또한 Mg의 조성비에 따라 critical point energy 가 linear 하게 변화됨이 관측되었다.

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제14권3호
• /
• pp.32-39
• /
• 2009

우리나라 토양 중 중금속 자연배경농도를 비교 평가함으로써 토양오염기준 설정을 위한 과학적 근거를 마련하고자 전국 주요 지질단위인 대동층군, 백악기화강암, 옥천층군, 조선누층군, 평안층군, 경상누층군, 쥬라기화강암, 화산암, 변성암등 산림지역 총 92개 지점에 대한 표토를 0.1N 염산 가용성 시험방법 및 왕수 시험방법으로 분석한 결과, 왕수시험방법에 의한 자연함유량 평균값(mg/kg)은 Cd 0.287, Cu 15.26, Pb 18.43, Cr 25.36, Zn 54.27, Ni 17.68, As 6.83으로 조사되었으며, 가용성 시험결과 평균농도(mg/kg)는 Cd 0.040, Cu 0.48, Pb 3.06, Cr 0.09, Zn 1.54, Ni 0.27, As 0.089로 나타났다. 이들 시료의 가용성 평균 농도는 왕수 시험방법의 평균농도에 비하여 각각 Cd 13.9%, Cu 3.1%, Pb 16.6%, Cr 0.4%, Zn 2.8%, Ni 1.5%, As 1.3% 수준으로 낮게 평가되었다. 또한 가용성 시험방법과 왕수 시험방법에 의한 중금속 측정값 간의 상관계수는 0.24~0.88의 범위로 나타났으며 Cd > Pb > Cu > Ni > Cr > Zn $\approx$ As의 순으로 감소하였다.

• Advances in nano research
• /
• 제1권2호
• /
• pp.83-91
• /
• 2013

The synthesis of semiconductor nanoparticles is a growing research area due to the prospective applications for the development of novel technologies. In this paper we have reported the biosynthesis of Cadmium sulfide nanoparticles (CdSNPs) by reduction of cadmium sulphate solution, using the bacteria of Serratia nematodiphila. The process for the synthesis of CdS nanoparticles is fast, novel and ecofriently. Formation of the CdS nanoparticles was confirmed by surface Plasmon spectra using UV-Vis spectrophotometer and absorbance strong peak at 420 nm. The morphology of crystalline phase of nanoparticles was determined from Scanning Electron Microscopy (SEM), Energy Dispersive X-ray spectroscopy and X-ray diffraction (XRD) spectra. The average size of CdS nanoparticles was in the range of 12 nm and the observed morphology was spherical. The results indicated that the proteins, which contain amine groups, played a reducing and controlling responsibility during the formation of CdS nanoparticles in the colloidal solution. Antibacterial activity against some bacteria such as Bacillus subtilis, Klebsiella planticola. CdS nanoparticles exhibiting good bactericidal activity.

• Journal of Dairy Science and Biotechnology
• /
• 제25권1호
• /
• pp.9-13
• /
• 2007

The present study was carried out to examine the effect of crosslinked ${\beta}$-cyclodextrin(${\beta}$-CD) made by adipic acid on cholesterol removal rate and find the structural change after recycling on SEM observation. The size reduction and morphological changes were found during the recycling process and the profound changes were observed at 8th time reuse. After cholesterol removal in milk, the used crosslinked ${\beta}$-CD was washed for cholesterol dissociation and reused. In recycling study, the cholesterol removal rate at first trial was 92.5% in milk, which was mostly same as that using new crosslinked ${\beta}$-CD(92.4%). With repeated 10th reuse of crosslinked ${\beta}$-CD resulted in 81.4% of cholesterol removal in milk. Similar trend was found in cream and cholesterol removal was 91.5% at 1st trial and 83.4% at 10th trial. In both milk and cream samples, the removal rate at 1st reuse was not significantly different from that at 6th reuse(p>0.05). The present study indicated that crosslinked ${\beta}$-CD made by adipic acid resulted in the effective recycling efficiency, especially up to 6th reuse and morphological modifications were not distinguishable up to 8th reuse.