• BMB Reports
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• 제46권3호
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• pp.151-156
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• 2013

Phylogenetic and amino acid sequence analysis indicated that rice allene oxide synthase-1 (OsAOS1) is CYP74, and is clearly distinct from CYP74B, C and D subfamilies. Regio- and stereo-chemical analysis revealed the dual substrate specificity of OsAOS1 for (cis,trans)-configurational isomers of 13(S)- and 9(S)-hydroperoxyoctadecadienoic acid. GC-MS analysis showed that OsAOS1 converts 13(S)- and 9(S)-hydroperoxyoctadecadi(tri)enoic acid into their corresponding allene oxide. UV-Visible spectral analysis of native OsAOS1 revealed a Soret maximum at 393 nm, which shifted to 424 nm with several clean isobestic points upon binding of OsAOS1 to imidazole. The spectral shift induced by imidazole correlated with inhibition of OsAOS1 activity, implying that imidazole may coordinate to ferric heme iron, triggering a heme-iron transition from high spin state to low spin state. The implications and significance of a putative type II ligand-induced spin state transition in OsAOS1 are discussed.

• 대한토목학회논문집
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• 제28권1B호
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• pp.149-152
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• 2008

철의 환원 특성에 관한 연구는 이미 널리 수행되었으며 특히 미네랄과 2가철의 반응 메커니즘은 2가철의 흡착이나 바운드를 통해 Fe(II)-Fe(III) (hydr)oxides를 생성하여 2가철이 3가철로 산화됨으로써 물질을 환원시키는 것으로 받아들여지고 있다. 그러나 2가철로 개질된 재강슬래그를 이용한 DS/S 실험과정에서 이러한 메커니즘으로 설명하기 힘든 현상을 발견하였다. 재강슬래그의 주요 성분중의 하나인 FeO와 Fe(II)만을 이용하여 TCE의 분해과정을 실험해 본 결과 초기 TCE의 분해가 이루어지지 않다가 급속히 분해되는 현상을 보였으며 이러한 시스템에서 TCE의 분해는 예상치 못한 결과였다. FeO/Fe(II) 시스템은 3가철이 존재하지 않기 때문에 기존의 Fe(II)-Fe(III) (hydr)oxides를 형성하는 환원 메커니즘으로는 설명할 수 없었다. 따라서 본 연구에서는 TCE의 분해실험과 분해 부산물의 측정, 2가철과 3가철을 확인함으로써 FeO/Fe(II) 시스템의 환원특성을 확인해 보고자 하였다. 실험 결과 2가철이 FeO에 흡착 또는 바운드 되는 것을 확인 할 수 는 있었으나 기존의 메커니즘으로 설명하기에는 부족한 부분이 있었다. 분해부산물들을 통해 환원으로 인한 TCE의 분해는 의심의 여지가 없었으나 FeO/Fe(II) 시스템이 새로운 species를 형성하는지, 혹은 FeO에 Fe(II)가 흡착 또는 바운드 되어 이제껏 알려지지 않은 형태의 새로운 미네랄 상을 형성하는지는 좀 더 상세한 연구가 필요하다.

• 자원리싸이클링
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• 제13권2호
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• pp.9-15
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• 2004

석유화학공정으로부터 폐기되는 폐산화철촉매를 이용하여 도금합성폐수중 크롬회수에 관한 연구를 회분식과 연속식으로 실시하였다. 도금합성제수 중 $CrO _{4}^{-2}$ 형태의 음이온으로 존재하는 6가 크롬은 폐산화철촉매의 등전점(pH 3.0)이하에서 폐촉매와 물리적 흡착을 한다. 한편, 6가 크롬은 pH 3.0 이상에서도 폐촉매의 수산화철과 산화환원반응에 의해 일부 환원되어 $Cr(OH)_3$로 침전한다. 컬럼을 이용한 크롬 연속회수실험에서 크롬합성폐수의 pH가 0.5∼2.0일 때 폐촉매의 크롬흡착량은 2.0∼2.3g/L이며, pH가 3.0에서는 1.5g/L이었다. 폐수 중 크롬농도가 50∼500mg/L로 높아질수록 폐촉매에 흡착한 크롬누적량은 1.29∼8.56g/L로 증가하지만, 유속이 30∼80 ml/mm으로 증가하여도 크롬 흡착누적량은 2.21∼2.49 mg/L로 거의 유사하였다.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2005년도 총회 및 춘계학술발표회
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• pp.13-16
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• 2005

Laboratory and field experiments were conducted to study the effectiveness of five adsorbents for the removal of arsenic. The adsorbents included activated alumina (AA), iron coated AA (ICAA), and granular ferric hydroxide (GFH), granular ferric oxide (GFO), and granular titanium dioxide (GTD). Laboratory experiments were conducted to investigate arsenic removal using challenge water prepared in accordance with NSF International Standards 53 (ANSl/NSF 53-2001). Field experiments were conducted using arsenic-contaminated groundwater In laboratory experiment, the treatment capacity decreased in the following order GTD > GFO > GFH. In contrast, the treatment capacity decreased in the following order GFO > GTD > GFH > ICAA > Ah in field experiments.

• Animal cells and systems
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• 제6권2호
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• pp.171-180
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• 2002

Nitric oxide has high affinity for iron, and thus it can cause intracellular iron loss. We tested the idea that intracellular iron can be the primary target of NO toxicity by comparing the signaling mechanisms involved in cell death caused by iron depletion and that caused by NO. Treatment of HL-60 cells with a NO donor, S-nitroso-N-acetyl-DL-penicillamine (SNAP), decreased the intracellular iron level rapidly as that observed with the iron chelator deferoxamine (DFO). Iron chelators such as DFO and mimosine could induce death of human leukemic HL-60 cells by a mechanism requiring activation of p38 kinase, c-Jun N-terminal kinase, caspase-3 and caspase-8. DFO and SNAP also caused release of cytochrome c from mitochondria. Inhibition of p38 kinase by a selective inhibitor, SB203580, abolished the NO and DFO-induced cell death, release of cytochrome c, and activation of caspase-3 and caspase-8, thus indicating that p38 kinase lies upstream in the cell death processes. In a parallel situation, the cells that are sensitive to NO showed similar sensitivity to DFO. Moreover, simultaneous addition of ferric citrate, an iron-containing compound, inhibited the SNAP and DFO-induced activation of caspases and also blocked the NO-mediated cell cycle arrest at $G_1$ phase. Collectively, our data implicate that the NO-induced cell death of tumor cells including HL-60 cells is mediated by depletion of iron and further suggest that activation of p38 kinase lies upstream of cytochrome c release and caspase activation involved in this apoptotic process.

• 대한화학회지
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• 제54권1호
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• pp.125-130
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• 2010

본 연구에서는 수용액 중에서 유해한 brilliant green (BG) 제거를 위한 탄소와 산화철 나노복합재료의 흡착특성을 살펴보았다. 탄소와 산화철 나노복합재료는 화학침전법과 $750^{\circ}C$에서 질산 철과 탄소를 열처리 함으로서 합성하였다. 그 생성물은 TEM, XRD, 그리고 TGA를 이용하여 확인하였다. 나노복합재료에 대한 BG의 흡착 연구는 열역학적 인자와 반응속도론적인자들을 이용하여 수행하였다. 흡착 속도식은 준 이차 속도식이 준 일차 속도식에 비해 잘 들어맞는다고 보여준다. 실험 결과는 Langmuir 과 Freundlich 흡착 등온선을 이용하여 분석하였다. 평형 데이터는 Langmuir모델에 잘 들어맞으며 최대 단일 층 흡착 용량 64.1 mg/g 을 갖는다. 열역학적 인자들은 나노복합재료에 BG의 흡착 으로부터 유도하며 흡착은 자발적이며 흡열 과정임을 확인하였다.

• 한국결정성장학회:학술대회논문집
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• 한국결정성장학회 1998년도 PROCEEDINGS OF THE 15TH KACG TECHNICAL MEETING-PACIFIC RIM 3 SATELLITE SYMPOSIUM SESSION 4, HOTEL HYUNDAI, KYONGJU, SEPTEMBER 20-23, 1998
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• pp.97-102
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• 1998

Transition metal Cr3+ and Fe3+ ion was diffused in white sapphire {0001}, {1010} crystal plane which were grown by the Verneuil method. It enhanced and changed the physical, electrical and optical properties of sapphires. After mixing the metallic oxide and metal powder, it were used for diffusion. Metallic oxide was synthesized by precipitation method and it's composition was mainly alumina which doped with chromium or ferric oxide. In case using metallic oxide, the dopping was slowly progressed and it needed the longer duration time and higher temperature, relatively. Metallic powder was vapoured under 1x10-4 torr of vacuum pressure at 1900(iron metal) and 2050(chromium)℃, first step. Diffusion condition were kept by 6atm of N2 accelerating pressure at 2050∼2150℃. Each surface density of sapphire crystal are 0.225(c) and 0.1199atom/Å2(a). The color of the Cr-doped sapphires was changed to red. Dopping reaction was come out more deep in th plane of {1010} than {0001}. It was speculated that the planar density was one of the factors to determine diffusion effect.

• 한국재료학회지
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• 제6권8호
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• pp.768-778
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• 1996

결정 성장 조절체를 이용하여 수용액 중에서 직접 $\alpha$산화철을 제조하였으며, 염기도에 따른 생성물의 입자 특성과 반응기구, $\alpha$산화철의 생성 과정과 침상형 입자의 생성 반응 기구를 고찰하였다. pH 9.0이하에서는 hexagonalgudxo, pH 10.75-11.75범위에서는 ellipsoidal 또는 rectangular 형태의 $\alpha$-${Fe}_{2}{O}_{3}$입자로 각각 생성되었으며, pH12.50이상에서는 acicular 형태의 $\alpha$-FeOOH입자가 생성되었다. pH 10.75-11.75범위에서 제조된 생성물의 염기도는 결정 성장 조절제의 해리에 의해 생성된 수산기 이온(OH-) 때문에 반응물의 염기도에 대비해 약간 증가하는 현상을 나타내었다. 결정 성장 조절제로 사용한 구연상은 제이철 수산화물에 구연산 음이온(R-COO-) 형태로 흡착되어 생성물인 $\alpha$산화철의 입자 형태를 침상 형태로 유도하였다.

• Nuclear Engineering and Technology
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• 제40권6호
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• pp.497-504
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• 2008

In a study of the optimum operational condition for a melting decontamination, the effects of the basicity, slag type and slag composition on the distribution of depleted uranium were investigated for radioactively contaminated metallic wastes of iron-based metals such as stainless steel (SUS 304L) in a direct current graphite arc furnace. Most of the depleted uranium was easily moved into the slag from the radioactive metal waste. The partitioning ratio of the depleted uranium was influenced by the amount of added slag former and the slag basicity. The composition of the slag former used to capture contaminants such as depleted uranium during the melt decontamination process generally consists of silica ($SiO_2$), calcium oxide (CaO) and aluminum oxide ($Al_2O_3$). Furthermore, calcium fluoride ($CaF_2$), magnesium oxide (MgO), and ferric oxide ($Fe_2O_3$) were added to increase the slag fluidity and oxidative potential. The partitioning ratio of the depleted uranium was increased as the amount of slag former was increased. Up to 97% of the depleted uranium was captured between the ingot phase and the slag phase. The partitioning ratio of the uranium was considerably dependent on the basicity and composition of the slag. The optimum condition for the removal of the depleted uranium was a basicity level of about 1.5. The partitioning ratio of uranium was high, exceeding $5.5{\times}10^3$. The slag formers containing calcium fluoride ($CaF_2$) and a high amount of silica proved to be more effective for a melt decontamination of stainless steel wastes contaminated with depleted uranium.

• 대한핵의학회지
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• 제1권2호
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• pp.41-59
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• 1967

This study was aimed; firstly to observe various clinical symptomatology with reiation to the number of Ancylostoma duodenale larvae orally given to the human beings, secondly to evaluate the effects of some drugs like steroid hormones, antihistaminic3 and antitussives, and, thirdly to study the influences of some iron compounds in prevention and treatment of anemia of such origin. Ten healthy volunteers free from the previous history of hookworm infection were divided into 4 groups, to whom various numbers of actively moving filariform Ancylostoma duodenale larvae were orally given; 500 to 4 cases, 250 to 3 cases and 100 to 3 cases. Following were the results: 1. Clinical symptomatology 1. The most frequently encountered symptoms and signs were general malaise, cough and hoar seness. The tracheal itching and pain low back pain, arthralgia, sputum and salivation, acid belching, loss of appetite, abdominal pain and vomiting were also noted. 2. If the larger number of the larvae was given, the clinical symtomatology was more severe. 3. Prednisolone medication caused some improvement of such symptomatology, while the antihistaminics and antitussives like codeine or ephedrine were ineffective. 4. In volunteers whose nutritional conditions were rather poor appeared to show more severe symptomatology. 2. Effects of iron compounds 1. The oral administration of ferrous fumarate induced a slight increase of serum iron levels in the initial stage of the infection, then a decrease from $15{\sim}20$ days later and a recovery after 2 months. 2. The intravenous administration of saccharated ferric oxide induced a steady upkeep of the serum iron levels. 3. The hemoglobin contents also showed the upkeeps after either the oral or intravenous administration of the iron compounds. 4. The iron compounds, therefore, are considered to have the preventive as well as the therapeutic effects on hookworm anemia, which may strongly suggest that hookworm anemia is essentially the iron deficiency type. 3. Hematological changes 1. The severity of hookworm anemia generally correlated with the number of larvae given. 2. The moderate leucocytosis was observed in all cases regardless of the number of larvae given, which reached to a peak in $25{\sim}35$ days. 3. Eosinophilia was observed in all cases, but was more severe in cases given larger number of larvae, which was slightly less evident after the medication of prednisolone. 4. Red cell survival time The red cell survival time determined by $^{51}Cr$ was generally in the normal ranges except for the severe anemia patients.