• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVII)
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• pp.511-516
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• 2005

Sorbitan methacrylate was synthesized from sorbitan dehydrated from D-sorbitol using an immobilized lipase. To optimize the enzymatic synthesis of sorbitan methacrylate, response surface methodology was applied to determine the effects of five-level-four-factors and their reciprocal interactions on sorbitan methacrylate biosynthesis. A total of 30 individual experiments were performed, which were designed to study reaction temperature, reaction time, enzyme amount and substrate molar ratio. A statistical model predicted that the highest conversion yield of sorbitan methacrylate was 100%, at the following optimized reaction conditions: a reaction temperature of 43.06 $^{\circ}C$, a reaction time of 164.25 mins., an enzyme amount of 7.47%, and a substrate molar ratio of 3.98:1. Using these optimal factor values under experimental conditions in four independent replicates, the average conversion yield reached 98.7%${\pm}$1.2% and was well within the value predicted by the model.

• 분석과학
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• 제8권4호
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• pp.807-814
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• 1995

Accurate measurements of ozone precursors are required to understand the process and extent of ozone formation in rural and urban areas. Nonmethane hydrocarbons (NMHCs) have been identified as important ozone precursors. Identification and quantification of NMHCs are difficult because of the large number present and the wide molecular weight range encountered in typical air samples. A major plan of the research team of the Climate and Air Quality Taiwan Station (CATs) was the measurement of atmospheric nonmethane hydrocarbons. An analytical method has been development for the analysis of the individual nonmethane hydrocarbons in ambient air at ppb (v) and subppb(v) levels. The whole ambient air samples were collected in canisters and analyzed by GC-FID with $Al_2O_3$/KCl PLOT column. Our targeted for quantitative analysis 43 compounds that may be substantial contributors to ozone formation. The retention indices and molar response factors of some commercially available $C_2{\sim}C_{10}$ hydrocarbons were determined and used to identify and quantify air samples. A quality assurance program was instituted to ensure that good measurements were made by participating in the International Nonmethane Hydrocarbon Intercomparison Experiments (NOMHICE).

• 공업화학
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• 제32권6호
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• pp.621-626
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• 2021

MOF-801 합성공정의 최적화를 위해 순차적인 실험 계획법을 이용하였다. 먼저 screening을 위한 완전 2-요인 설계와 이후 반응표면 분석법 중에 하나인 중심합성 계획법을 연속적으로 사용하였다. 두 가지 반응변수인 MOF-801의 결정화도와 BET 비표면적 중에 실험계획법에 보다 적합한 변수를 선택하기 위하여 fumaric acid, dimethylformamide (DMF) 및 formic acid의 몰비를 이용한 2³ 요인 설계법을 수행하였다. MINITAB 19 소프트웨어에 따라 설계된 8번의 MOF-801 합성 실험을 수행한 이후 XRD 분석 및 질소흡착법을 이용하여 특성분석을 수행하였다. 두 가지 반응변수 중 결정화도의 R²이 0.999로 BET 비표면적보다 실험계획법에 보다 적합하였다. 분산 분석(ANOVA)을 통해 fumaric acid와 formic acid의 몰 비가 MOF-801의 결정화도를 결정하는 주요 인자임을 확인하였다. response optimization과 두 인자의 contour plot을 통해 최적의 몰비는 ZrOCl₂·8H₂O : fumaric acid : DMF : formic acid = 1 : 1: 39 : 35로 추정되었다. 이후 합성반응 공정의 최적화를 위해 도출된 전구체의 몰 비 조건에서 합성 기간과 온도에 대한 박스-벤켄설계법을 수행하였다. 설계된 9번의 합성실험을 통해 도출된 결과를 2차 모델 방정식을 이용하여 계산하였다. 이를 이용하여 MOF-801의 최대 결정화도는 합성시간 7.8 h 그리고 합성온도 123 ℃의 조건에서 얻을 수 있음을 예측하였다.

• Archives of Pharmacal Research
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• 제27권7호
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• pp.797-805
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• 2004

LPD vectors are non-viral vehicles for gene delivery comprised of polycation-condensed plasmid DNA and liposomes. Here, we described a novel anionic LPD formulation containing protamine-DNA complexes and pH sensitive liposomes composed of DOPE and cholesteryl hemisuccinate (Chems). Central composite design (CCD) was employed to optimize stable LPD formulation with small particle size. A three factor, five-level CCD design was used for the optimization procedure, with the weight ratio of protamine/DNA ($X_1$), the weight ratio of Chems/DNA ($X_2$) and the molar ratio of Chems/DOPE in the anionic liposomes ($X_3$) as the independent variables. LPD size ($Y_1$) and LPD protection efficiency against nuclease ($Y_2$) were response variables. Zeta potential determination was utilized to define the experimental design region. Based on experimental design, responses for the 15 formulations were obtained. Mathematical equations and response surface plots were used to relate the dependent and independent variables. The mathematical model predicted optimized $X_1-X_3$ levels that achieve the desired particle size and the protection efficiency against nuclease. According to these levels, an optimized LPD formulation was prepared, resulting in a particle size of 185.3 nm and protection efficiency of 80.22％.

• Environmental Engineering Research
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• 제24권1호
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• pp.24-30
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• 2019

The present study explores the applicability of response surface methodology (RSM) in conjunction with central composite design (CCD) matrix to statistically optimize ettringite crystallization process for the removal of sulphate from landfill leachate. A three factor-five coded level CCD with 20 runs, was performed to estimate the best fitted model. The RSM results indicated that the fitted quadratic regression model could be appropriate to predict sulfate removal efficiency. The pH was identified as the most dominant parameter affecting sulphate removal. 61.6% of maximum sulphate removal efficiency was obtained at pH of 11.06 for a 1.87 of $Ca/SO_4$ and 0.51 of $Al/SO_4$ molar ratios. The operating cost for ettringite crystallization at optimized conditions was calculated to be 0.52 $/$m^3$. The significance of independent variables and their interactions were tested by analysis of variance. Scanning electron microscope (SEM) and SEM coupled with energy dispersive X-Ray spectroscopy results confirmed the formation of ettringite crystal and were used to describe its morphology features.

• 대한치과교정학회지
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• 제30권3호
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• pp.317-333
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• 2000

급속 구개확장은 정중구개봉합을 이개하기 위하여 강한 힘을 치아에 가하게 된다. 확장후 정중구개봉합부에 존재하는 골모세포와 섬유모세포의 증식 활성도를 측정하여 정중구개확장이 생리적으로 진행되는지를 확인하고, 이때 개개 치아의 치주조직에서 나타나는 변화를 조사하기 위하여 약 10개월된 유성견 10마리를 대상으로 상악 제2소구치와 제1대구치에 Hyrak screw를 장착하였다. 실험동물은 대조군 1마리, 1주 확장한 군 3마리, 2주 확장한 군 3마리, 2주 확장후 2주 보정한 군 3마리로 구분하여, Screw를 1일 1/4회전시켜 확장하였고, 제2소구치, 제3소구치, 그리고 제 1대구치 부위의 정중구개봉합부와 치주조직을 절취하여 Soft X-ray로 관찰하고, 형태학적 및 면역조직화학적 변화를 광학현미경으로, 그리고 골개조를 편광현미경으로 관찰하여 다음과 같은 결과를 얻었다. 1. 편광현미경 소견에서는 대조군에 비하여 1주 확장군의 봉합부에서 골 형성과 흡수가 크게 증가되었으며, 2주 확장군에서 약간 감소를 보이다가, 보정군에서는 석회화가 크게 진행되었다. 2. 면역조직화학적 연구에서는 대조군에 비하여 1주 확장군의 봉합부에서 골모세포가 PCNA(Proliferating Cell Nuclear Antigen)에, 미분화 섬유모세포가 EGF(Epidermal Growth Factor)에 약간 증가된 양성 반응을 보였으며 EGF에 대한 골모세포의 반응은 낮았다. 2주 확장군에서는 섬유아세포와 골모세포에서 PCNA와 EGF에 대한 양성반응이 증가되었다. 보정군에서는 이들 PCNA와 EGF에 양성반응을 나타내는 세포들이 구개돌기 골단 주변에 집중되었다. 3. 확장기간 중 봉합부 주변에서 광범위한 골 흡수와 골형성을 동반한 골개조가 일어났으며, 보정군에서는 다소 감소하였다. 2주 확장군과 보정군의 제3소구치 와 제1대구치의 치근단에서 백악질 형성과 흡수가 나타났으며, 제1대구치의 협측 치경부에서 광범위한 초자양 변성대가 나타났다. 4. Soft X-ray소견에서 1주 확장군은 대조군에 비교하여 봉합부위의 여러부분에서 미세 파절과 저석회화된 결손부위를 보였다. 대조군과 보정군 사이 에는 정중구개봉합부의 석회화 정도에 별 차이 가 없었다. 2주 확장군과 보정군에서 제3소구치와 제1대구치는 협측으로 경사되는 경향을 보였다.

• International Journal of Oral Biology
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• 제41권4호
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• pp.225-230
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• 2016

Inflammation from chronic and acute infections of distal organs and tissues such as periodontitis is a risk factor for atherosclerotic vascular processes. Recently, a new model of atherosclerosis with vascular pathologies was developed in the Mongolian gerbil. In this study, we attempted to develop a model of ligature-induced periodontitis in gerbils and compared the characteristics of that periodontitis model with that in rats and mice. Each gerbil, rat, and mouse was randomly assigned to groups of control and periodontitis. A thread was placed around the cervix of the right and left first molars in the mandible with knots placed on the mesial side of each molar. At day 14 after the ligation, the animals were sacrificed and their mandibles were dissected. To measure alveolar bone loss along with inflammation, histopathological and micro-CT analyses were carried out. Gerbils showed tooth characteristics of deeper gingival crevice, longer cusp, longer root trunk and shorter root than those of rats and mice. The increased CEJ-ABC distance in distal and PDL area in furcation was also observed in ligated gerbils. An inflammatory response in the connective tissue under the junctional epithelium was also shown in all the animals. As a result, we confirmed the induction of periodontitis by ligature in the gerbils. We therefore consider the gerbil to be a useful model for investigating relationship between periodontitis and vascular disease in the same animal.

• 약학회지
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• 제42권3호
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• pp.296-301
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• 1998

To investigate the effects of ginsenosides from Panax ginseng on mitogenic responses in macrophages and splenocytes from murine, we examined the effects of representative protopanaxadiol and protopanaxatriol ginsenosides ($Rb_1,\;Rb_2,\;Re\;and\;Rg_1$) on tumor necrosis factor-${\alpha}$ (TNF-(${\alpha}$) production in murine macrophage cell line (RAW264.7 cells) stimulated by lipopolysaccharide (LPS) and T cell proliferation in splenocytes stimulated by concanavalin A (Con A). Among the ginsenosides tested, protopanaxadiol ginsenosides ($Rb_1\;and\;Rb_2$) significantly inhibited TNF-${\alpha}$ production in a dose-dependent manner. However, protoppanaxatriol ginsenosides (Re and $Rg_1$) showed little inhibitory activity. The molar concentrations of $Rb_1\;and\;Rb_2$ producing 50% inhibition ($IC_{50}$) of TNF-${\alpha}$ production were $55.8{\mu}g/ml\;(48.0{\mu}M)\;and\;31.8{\mu}g/ml (27.9{\mu}M)$, respectively. As a positive control, prednisolone also exhibited inhibitory activity with an $IC_{50}$ value of $21.7{\mu}M$. In T cell proliferation, $Rg_1$, was not effective but $Rb_1$ and Re or $Rb_2$ significantly increased or inhibited at high concentration, 75 and $100{\mu}g/ml$. In contrast, prednisolone showed potent inhibitory activity with an $IC_{50}$ value of 6.1nM. These results suggest that ginsenosides may take part in the mitogen-induced signaling pathway for TNF-${\alpha}$ production and T cell proliferation from macrophages and splenocytes.

• Korean Chemical Engineering Research
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• 제60권1호
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• pp.70-79
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• 2022

Biodiesel production has attracted attention as a sustainable source of fuel and is a competitive alternate to diesel engines. The glycerol that is produced as a by-product is generally discarded as waste and can be converted to green chemicals such as acetins to increase bio-diesel profitability. Acetins find application in fuel, food, pharmaceutical and leather industries. Batch experiments and analysis have been previously conducted for synthesis of acetins using glycerol esterification reaction aided by sulfated metal oxide catalysts (SO₄^2-/CeO₂-ZrO₂). The aim of this study was to optimize process parameters: effects of mole ratio of reactants (glycerol and acetic acid), catalyst concentration and reaction temperature to maximize glycerol conversion/acetin selectivity. The optimum conditions for this reaction were determined using response surface methodology (RSM) designed as per a five-level-three-factor central composite design (CCD). Statistica software 10 was used to analyze the experimental data obtained. The optimized conditions obtained were molar ratio - 1:12, catalyst concentration - 6 wt.% and temperature -90 ℃. A packed bed reactor was fabricated and column studies were performed using the optimized conditions. The breakthrough curve was analyzed.

• 대한치과교정학회지
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• 제28권1호
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• pp.113-122
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• 1998

본 연구는 조선대학교 부속 치과병원 교정과에 내원하여 교정치료를 시행하고 있는 환자중 Panadent 교합기 및 condylar position indicator(CPI)를 이용하여 중심위-중심교합 편위양을 측정한 결과, 전후방 및 수직적 편위양이 1.00mm이내, 측방편위양이 0.30mm 이내인 정상범주를 넘는 부정교합 환자 47명을 대상으로 하여 3개월간 교합안정장치를 24시간 장착하고, CPI 및 transcranial projection을 이용하여 교합안정장치 장착전과 장착후의 하악과두의 위치변화를 관찰한 결과 다음과 같은 결론을 얻었다. 1. CPI상의 모든 군에서 중심교합-중심위 사이에 통계적인 유의성이 있었다(p<0.001). 2. transcranial projection상의 superior joint space의 Rt와 Lt+Rt/2에서 중심교합-중심위 사이에 통계적인 유의성이 있었다(p<0.05). 3. CPI상의 모든 superior-inferior components군에서 교합안정장치 사용 전, 후의 중심교합-중심위 사이에 통계적인 유의성이 있었다(p<0.01). 4. transcranial projection상의 superior joint space의 Rt를 제외한 모든 군에서 교합안정장치 사용 전, 후의 중심교합-중심위 사이에 통계적인 유의성이 없었다. 이상의 결론을 종합해 볼 때 중심교합-중심위 사이의 변화를 평가하는데는 transcranial projection보다 CPI가 보다 유용하며, 교합안정장치는 하악과두의 전, 후방적 위치변화보다는 수직적 위치변화에 미치는 영향이 보다 큰 것으로 보인다.