• 한국토양비료학회지
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• 제14권3호
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• pp.117-129
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• 1981

토양(土壤)의 몇가지 물리적(物理的), 화학적성질(化學的成質)이 연초식물(煙草植物)의 생육(生育) 및 Ionic Balance에 어떤 영향을 미치고 있는가를 연구(硏究)하기 위하여 폿트실험을 하였다. 공시(供試)된 토양(土壤)은 pH를 3.5와 5.8인 두가지로 조정하였고 이에 2종류의 음(陰)이온을 ($NH_4Cl$의 Cl, $(NH_4)_2SO_4$의 $SO_4$) 처리하였고, 4수준(水準)의 pF치(値)(1.5-2.0-2.5-3.5)를 두었다. 그 결과(結果)를 요약(要約)하면 다음과 같디. 1. 산도(酸度)가 높은 토양(土壤)(pH3.5)에 $NH_4Cl$이 가(加)해진 경우 연초(煙草) Cl의 함량(含量)이 높았으며, $NH_4$와 Cl의 해작용(害作用)뿐아니라, Mn의 독작물(毒作用)까지 받았으므로 거의 생장(生長)하지 못하고 대단히 비정상적(非正常的)인 생육(生育)을 하였다. 한편 ($(NH_4)_2SO_4$를 많이 흡수하므로 Mg와 Ca의 결핍증(缺乏症)을 보였다. 그러나 산도(酸度)가 낮은 토양(pH5.8)에 가(加)해진 $NH_4-N$은 질산화작용(窒酸化作用)에 의하여 모두 $NO_3-N$로 변하였으며, $NH_4-N$와 함께 가(加)해진 Cl이나 $SO_4$에 관계없이 연초(煙草)는 건전한 생육(生育)을 하였으며 Cl 보다는 $SO_4$가 가(加)해진 토양(土壤)에서 자란 식물(植物)이 건물중(乾物重)도 더 높고 성숙도(成熟度)도 더 빨랐다. 2. 토양(土壤)의 수분함량(水分含量)은 식물(植物)이 인산(燐酸)을 흡수하는데 제한인자(制限因子)가 되는 것으로 생각되며, 지상부(地上部)와 뿌리의 건물수량(乾物收量)은 pF 1.5>2.0>2.5>3.5>의 순서이었고 pF3.5은 연초(煙草)의 일시계절점으로 생각되었다. 3. 연초식물(煙草植物)의 화학분석치(化學分析値)와 건물수량(乾物收量)은 이 식물(植物)이 정상적(正常的)인 (C-A) 개념(槪念)에 잘 적용된다는 것을 보여주었으며, 정상적(正常的)인 생육(生育)을 하고 있는 연초식물(煙草植物)에 있어서는 지상부(地上部)의 Carboxylate의 함량(含量)은 (C-A) 값과 거의 비슷함을 보여 주었다. 만약 식물체중(植物體中)에 $NH_4$함량(含量)이 상당히 많은 양(量)으로 존재(存在)한다면 $NH_4$를 분석(分析)하여 그 값을 (C-A)의 값을 계산하는데 사용해야 할것이다. Al은 가동성(可動性)이 매우 낮은 물질이므로 식물(植物)의 지상부(地上部)의 해(害)를 줄정도의 양(量)으로는 존재(存在)하지 않고 많은 양(量)이 뿌리의 내부나 그 주위에 존재(存在)한다. 식물체(植物體)가 Al을 많이 함유(含有)하고 있을 경우에도 (C-A) 값의 산출에 Al의 함량(含量)을을 고려해야 한다.

• Asian Pacific Journal of Cancer Prevention
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• 제16권3호
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• pp.1255-1258
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• 2015

Background: Locally advanced head and neck cancer is generally incurable and has a short survival rate. This study aimed to evaluate symptom relief, disease response, and acute toxicity after palliative hypo-fractionated radiotherapy and long-term survival in affected patients. Materials and Methods: Between January 2011 to December 2011, 80 patients who were histopathologically diagnosed as having stage III or stage IV head and neck squamous cell carcinoma based on Eastern Cooperative Oncology Group (ECOG) performance status 1-3, were offered palliative radiotherapy (20 Gy/5Fr/5 Days). Later these patients were evaluated on 30th day after completion of treatment for disease response based on World Health Organisation (WHO) criteria and palliation of symptoms using symptomatic response grading and acute toxicities by the Radiation Therapy Oncology Group (RTOG). Many patients were given post radiation therapy (RT) palliative chemotherapy for appropriate palliative care and a few patients were selected for further curative RT. The overall survival was also evaluated among this group of patients with last follow up date of 1st May, 2014. Results: The most common presenting complaint was pain followed by dysphagia. Most patients (60-70%) had appreciable relief in their presenting symptoms. A good response was observed in the majority following palliative RT; a few patients had progressive disease and some had stable and regressed disease. None of the patients experienced radiation toxicity that required hospital admission. Almost all showed grade one and two acute skin and mucosal toxicity one month after completion of treatment. The mean survival days for patients given only hypofractionated palliative RT was 307 days, those with post palliative RT and palliative chemotherapy was 390 days and patients who went on to receive further palliative RT and curative RT dose had significantly overall survival of 582 days. Conclusions: Advanced head and neck cancer should be identified for suitable palliative hypofractionated radiotherapy to achieve acceptable symptom relief in a great proportion of patients and should be followed by palliative chemotherapy or curative RT in suitable cases for long-term symptom-free survival.

• 공업화학
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• 제20권3호
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• pp.241-250
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• 2009

지난 수 년간 본 연구팀은 새로운 티탄염 응집제를 이용하여 폐수를 응집한 후 생산된 슬러지에서 산화티탄을 생산하는 연구를 진행하였다. 티탄염의 응집 효율은 일반적으로 많이 사용되는 철염과 알루미늄염 응집제와 비슷하였으며 슬러지를 소성하여 제조한 산화티탄은 상용 산화티탄보다 더 넓은 표면적과 높은 광촉매 활성을 나타내었다. 산화티탄의 광촉매 활성 향상과 pH를 높이기 위해 응집보조제로서 철, 알루미늄, 칼슘을 사용하여 광촉매 활성이 높은 Fe, Al, Ca 도핑 산화티탄을 제조하였다. 이 기술의 실제 적용 가능성을 확인하기 위하여 염색폐수 파일럿 장치에 적용한 결과, 우수한 유기물 제거 능력과 빠른 응집체 형성이 확인되었다. 염색폐수 슬러지에서 제조한 산화티탄은 높은 유기물 제거 광촉매 활성과 물 광분해에 의해 수소를 생성하였다. 티탄염 응집제와 슬러지에서 제조한 산화티탄의 독성을 D. magna로 조사한 결과, 낮은 독성을 확인할 수 있었다. 이 총설은 미래의 슬러지 재활용 기술로 높은 적용 가능성을 가지는 티탄염으로 제조한 산화티탄의 특성을 체계적으로 정리하였다.

• Ecology and Resilient Infrastructure
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• 제4권4호
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• pp.193-199
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• 2017

본 연구에서는 강산 및 강염기 유출사고가 발생하였을 때 육상생물의 생육에 영향을 미칠 수 있는 토양특성의 변화를 살펴보았다. 강산과 강염기 화학물질로 HCl과 NaOH을 선정하였으며 이들 물질을 토양과 반응시킨 후 토양의 토성, 비표면적, 유기물함량, pH, 양이온교환능력 및 치환성양이온 함량 변화를 측정하였다. 토양과 반응한 HCl 및 NaOH 농도가 각각 10 M과 1 M인 경우 (즉, 토양 1 g 당 50 mmol의 HCl이나 5 mmol의 NaOH가 유입된 경우) 유의한 수준의 토양 특성 변화가 관찰되었다. 10 M HCl 및 1 M NaOH 용액과 반응한 토양의 토성은 sandy loam에서 loamy sand로 변하였으며, 비표면적은 $5.84m^2/g$에서 각각 4.85 및 $1.92m^2/g$으로 감소하였다. 토양 유기물 함량은 3.23%에서 0.96 및 0.44%로 크게 감소하였으며, 반응 전 pH 5.05로 약산성인 토양의 pH는 각각 2.35 및 10.65로 변하였다. 토양 내 양이온교환능력은 10.27 cmol/kg에서 4.52 및 5.60 cmol/kg으로 크게 감소하였으며 $Na^+$을 제외한 알칼리성 양이온 ($K^+$, $Mg^{2+}$, $Ca^{2+}$)의 함량이 감소하였다. HCl과 반응한 경우 $Na^+$ 함량은 감소, $Al^{3+}$ 함량은 증가하였으나 반대로 NaOH와 반응한 경우 $Na^+$ 함량은 증가, $Al^{3+}$ 함량은 감소하였다. 높은 농도의 $Al^{3+}$과 $Na^+$은 각각 토양생물에게 직접적인 독성을 발현하거나 토양의 투수성을 감소시키고 중탄산염의 농도를 증가시켜 독성을 발현할 수 있다. 본 연구는 강산 및 강염기유출사고로 인하여 변화한 토양특성이 토양의 생태기능에 영향을 줄 수 있음을 보여준다.

• 대한환경공학회지
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• 제33권2호
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• pp.93-102
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• 2011

본 연구에서는 부산신항만 준설퇴적물에 포함된 중금속의 총농도, 이동성, 생체이용률, 독성을 알아보기 위하여 총함량분석과 연속추출실험을 실시하였다. 준설퇴적물의 중금속 총농도는 다음과 같이 비교적 낮았다: Al (2.36~2.96 wt.%), As (1.6~3.3 mg/kg), Ba (30.0~33.8 mg/kg), Cd (0.12~0.18 mg/kg), Cr (27.5~35.0 mg/kg), Cu (11.3~15.0 mg/kg), Fe (2.91~3.51 wt.%), Mn (324~408 mg/kg), Ni (18.8~23.8 mg/kg), Pb (23.8~31.3 mg/kg), Zn (70.0~86.3 mg/kg). 또한 대부분의 중금속이 residual fraction으로 존재하였는데, 이는 오염원이 자연발생적일 가능성이 높음을 의미한다: Al (87.5~95.9%), As (74.1~93.8%), Ba (71.8~77.6%), Cr (69.5~94.3%), Cu (50.0~78.7%), Fe (70.8~87.6%), Ni (64.5~75.3%), Pb (53.4~64.3%), Zn (62.5~81.7%). 반면에 Cd과 Mn은 주로 non-residual fraction으로 존재했다. 준설퇴적물의 유해중금속 농도가 낮고 residual fraction 비율이 높기 때문에, 이를 벽돌, 도로포장재료 등으로 재활용하는 것이 가능하다고 사료된다.

• 한국태양에너지학회 논문집
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• 제32권spc3호
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• pp.194-198
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• 2012

Crystalline silicon solar cell remains the major player in the photovoltaic marketplace with 80% of the market, despite the development of various thin film technologies. Silicon's excellent efficiency, stability, material abundance and low toxicity have helped to maintain its position of dominance. However, the cost of silicon materials remains a major barrier to reducing the cost of silicon photovoltaics. Using the crystalline silicon wafer with thinner thickness is the promising way for cost and material reduction in the solar cell production. However, the thinner the silicon wafer is, the worse bow phenomenon is induced. The bow phenomenon is observed when two or more layers of materials with different temperature expansion coefficiencies are in contact, in this case silicon and aluminum. In this paper, the solar cells were fabricated with different thicknesses of Al layer in order to reduce the bow phenomenon. With less amount of paste applications, we observed that the bow could be reduced by up to 40% of the largest value with 120 micron thickness of the wafer even though the conversion efficiency decrease by 0.5% occurred. Since the bowed wafers lead to unacceptable yield losses during the module construction, the reduction of bow is indispensable on thin crystalline silicon solar cell. In this work, we have studied on the counterbalance between the bow and conversion efficiency and also suggest the formation of enough back surface field (BSF) with thinner Al layer application.

• Journal of Periodontal and Implant Science
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• 제38권4호
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• pp.595-602
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• 2008

Purpose: Ti-6Al-4V alloy is widely used as an implant material because of its good biocompatibility and good mechanical property compared with commercial pure titanium. Otherwise, toxicity of aluminum and vanadium in vivo has been reported. Ti-8Ta-3Nb alloy is recently developed in the R&D Center for Ti and Special Alloys and it was reported that this alloy has high mechanical strength, no cytotoxicity and similar biocompatibility to commercial pure titanium, but many studies are needed for its clinical use. In these experiment, we carried out different surface treatment on each Ti-8Ta-3Nb alloy disks, then cultured cell on it and assessed biological response. Materials and Methods: cpTi, Ti-6Al-4V, Ti-8Ta-3Nb alloy disks were prepared and carried out sandblasting and acid etching (SLA) or alkali-heat treatment (AH) on the Ti-8Ta-3Nb alloy disks. We cultured primary rat calvarial cells on each surface and assessed early cell attachment and proliferation by scanning electron microscopy, cell proliferation, alkaline phosphatase activity. Result: The rates of cell proliferation on the cpTi, Ti-8Ta-3Nb AH disks were higher than others (p<0.05) and alkaline phosphatase activity was significantly enhanced on the Ti-STa-8Nb AH disks(p<0.05). Conclusion: Most favorable cell response was shown on the Ti-8Ta-3Nb AH surfaces. It is supposed that alkali-heat treatment of the Ti-8Ta-3Nb alloy could be induced earlier bone healing and osseointegration than smooth surface.

• 한국재료학회지
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• 제22권3호
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• pp.150-154
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• 2012

Ti-6Al-4V ELI (Extra Low Interstitial) alloy have been widely used as alternative to bone due to its excellent biocompatibility, although it still has many problems such as high elastic modulus and toxicity. Therefore, biomaterials with low elastic modulus and non toxic characteristics have to be developed. A novel ${\beta}$ Ti-35wt%Nb-7wt%Zr-Calcium pyrophosphate (CPP) composite that is a biocompatible alloy without elemental Al or V was fabricated by spark plasma sintering (SPS) at $1000^{\circ}C$ under 70 MPa using high energy mechanical milled (HEMM) powder. The microstructure and phases of the milled powders and the sintered specimens were studied using SEM, TEM, and XRD. Ti-35wt%Nb-7wt%Zr alloy was transformed from ${\alpha}$ phase to ${\beta}$ phase in the 4h-milled powder by sintering. The sintered specimen using the 4h-milled powder showed that all the elements were distributed very homogeneously and had higher density and hardness. ${\beta}$ Ti alloy-CPP composite, which has nanometer particles, was fabricated by SPS using HEMMed powder. During the sintering process, $CaTiO_3$, TixOy, and CaO were formed because of the reaction between Ti and CPP. The Vickers hardness of the composites increases with the increase of the milling time and the addition of CPP. The biocompatibility of the Ti-Nb-Zr alloys was improved by addition of CPP.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2012년도 춘계학술발표대회 논문집
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• pp.108-112
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• 2012

Crystalline silicon solar cell remains the major player in the photovoltaic marketplace with 90 % of the market, despite the development of a variety of thin film technologies. Silicon's excellent efficiency, stability, material abundance and low toxicity have helped to maintain its position of dominance. However, the cost of silicon photovoltaic remains a major barrier to reducing the cost of silicon photovoltaics. Using the crystalline silicon wafer with thinner thickness is the promising way for cost and material reduction in the solar cell production. However, the thinner thickness of silicon wafer is, the worse bow phenomenon is induced. The bow phenomenon is observed when two or more layers of materials of different temperature expansion coefficiencies are in contact, in this case silicon and aluminum. In this paper, the solar cells were fabricated with different thicknesses of Al layer in order to reduce the bow phenomenon. With lower paste applications, we observed that the bow could be reduced by up to 40% of the largest value with 130 micron thickness of the wafer even though the conversion efficiency decrease of 0.5 % occurred. Since the bowed wafers lead to unacceptable yield losses during the module construction, the reduction of bow is indispensable on thin crystalline silicon solar cell. In this work, we have studied on the counterbalance between the bow and conversion efficiency and also suggest the formation of enough back surface field (BSF) with thinner Al paste application.

• Biomolecules & Therapeutics
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• 제28권4호
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• pp.311-319
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• 2020

Middle East Respiratory Syndrome Coronavirus (MERS-CoV) is a newly emerging viral disease with fatal outcomes. However, no MERS-CoV-specific treatment is commercially available. Given the absence of previous structure-based drug discovery studies targeting MERS-CoV fusion proteins, this set of compounds is considered the first generation of MERS-CoV small molecule fusion inhibitors. After a virtual screening campaign of 1.56 million compounds followed by cell-cell fusion assay and MERS-CoV plaques inhibition assay, three new compounds were identified. Compound numbers 22, 73, and 74 showed IC₅₀ values of 12.6, 21.8, and 11.12 µM, respectively, and were most effective at the onset of spike-receptor interactions. The compounds exhibited safe profiles against Human embryonic kidney cells 293 at a concentration of 20 µM with no observed toxicity in Vero cells at 10 µM. The experimental results are accompanied with predicted favorable pharmacokinetic descriptors and drug-likeness parameters. In conclusion, this study provides the first generation of MERS-CoV fusion inhibitors with potencies in the low micromolar range.