• 한국농공학회논문집
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• 제63권1호
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• pp.89-102
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• 2021

Soils in agricultural lands contain large amount of organic matter and nutrients due to the injected fertilizers and manure. During heavy rain, surface water and base runoff pollutants flows into a nearby stream or lake with eroded soil from agricultural lands. On the other hands, agricultural lands near the lake are inundated due to the increase of the water level in the lake, leading to organic matter and nutrient release from the inundated soil. In this study, releasing rates of nutrient salts and organic substances were analyzed for the soil in the agricultural land, where cultivation activities has been carried out and periodically flooded, to account for the possibility of contamination from the inundated agricultural land in reservoir areas The experiment results have shown that COD was released from the soil in anaerobic conditions, and T-P was released in both anaerobic and aerobic conditions. However, in the case of T-N, it was found that the runoff by soil was not made before the rainfall occurred, and when the soil was impound due to rainfall, the elution occurred under the aerobic conditions. Through the results of this study, it was possible to account for the effect of flooded agricultural lands on the water quality in the lake, and this could be reflected in an efficient agricultural non-point pollution management policy. In order to determine the precise releasing rate for each agricultural land, it is believed that the leaching experiment for paddy fields and grasslands are needed.

• The Korean Journal of Physiology and Pharmacology
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• 제26권2호
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• pp.125-133
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• 2022

Carbon monoxide (CO) is a known gaseous bioactive substance found across a wide array of body systems. The administration of low concentrations of CO has been found to exert an anti-inflammatory, anti-apoptotic, anti-hypertensive, and vaso-dilatory effect. To date, however, it has remained unknown whether CO influences atrial natriuretic peptide (ANP) secretion. This study explores the effect of CO on ANP secretion and its associated signaling pathway using isolated beating rat atria. Atrial perfusate was collected for 10 min for use as a control, after which high atrial stretch was induced by increasing the height of the outflow catheter. Carbon monoxide releasing molecule-2 (CORM-2; 10, 50, 100 μM) and hemin (HO-1 inducer; 0.1, 1, 50 μM), but not CORM-3 (10, 50, 100 μM), decreased high stretch-induced ANP secretion. However, zinc porphyrin (HO-1 inhibitor) did not affect ANP secretion. The order of potency for the suppression of ANP secretion was found to be hemin > CORM-2 >> CORM-3. The suppression of ANP secretion by CORM-2 was attenuated by pretreatment with 5-hydroxydecanoic acid, paxilline, and 1H-[1,2,4] oxadiazolo [4,3-a] quinoxalin-1-one, but not by diltiazem, wortmannin, LY-294002, or NG-nitro-L-arginine methyl ester. Hypoxic conditions attenuated the suppressive effect of CORM-2 on ANP secretion. In sum, these results suggest that CORM-2 suppresses ANP secretion via mitochondrial K_ATP channels and large conductance Ca²⁺-activated K⁺ channels.

• 한국산학기술학회논문지
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• 제17권11호
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• pp.640-647
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• 2016

형광 간섭 현상을 최소화시켜 상대적으로 민감한 측정이 가능한 aequorin기반 luminescence기술은 $G_{{\alpha}16}$ 단백질 도입을 통해 세포 내부의 칼슘 이동 신호를 감지하여 G 단백질 결합 수용체(G protein-coupled receptor, GPCR)의 기능 분석을 가능하게 하는 세포 기반 분석 기술로 수용체 및 G 단백질 유전자 전달의 최적화 과정이 필수적이다. 본 연구를 위해 corticotropin releasing factor receptor subtype 2(CRF2) 수용체를 모델 시스템으로 CRF2와 $G_{{\alpha}16}$ 단백질이 구축된 세 가지 안정화 세포주를 제작하였고, 이들을 이용한 서로 다른 세 가지 조건의 임시 발현 세포주에서 작용제(sauvagine)와 길항제(K41498)의 반응성을 분석하여 최적의 유전자 전달 방법을 도출하고자 하였다. 그 결과 sauvagine 및 K41498의 농도에 따른 반응에서 CRF2-$G_{{\alpha}16}$ 안정화 세포주가 임시 발현 세포주보다 10배 이상의 유효신호 비율을 나타내었고(z'=0.77) 임시 발현 세포주의 경우 $G_{{\alpha}16}$의 안정화 발현 이후에 CRF2를 전달하는 경우가 다른 임시 발현 조건보다 2배 이상 높은 효율을 보였다(z'=0.84). 따라서 임시 유전자 전달 기술을 GPCR 세포 기능 분석 시스템에 활용할 경우 $G_{{\alpha}16}$ 단백질에 대한 안정화 세포주를 우선적으로 구축하고, 목표하는 다양한 수용체들을 단계적으로 발현시키는 것이 최선의 방법이라 판단된다.

• 대한소아치과학회지
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• 제31권4호
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• pp.705-713
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• 2004

불소는 항우식 작용을 보이므로 치아의 우식 예방을 고려 한 진료가 이루어지면서 치면에 불화물을 도포하거나 불소 함유 구강세정액을 사용하거나 불소방출성의 수복재료를 적용하거나 하는 등의 우식억제 방법이 치과임상에서 빈번하게 적용되고 있다. 이에 본 연구는 불소 방출을 보이는 수복재료의 잇솔질 후 불소방출과 잇솔질로 인한 표면조도의 변화를 조사하기 위해 시행되었다. 7종의 불소를 방출하는 수복재료로 Fuji II LC Improved: FL, Compoglass F CG, Dyract AP: DR, F2000 : FT, Ariston: AT, Tetric: TR, 그리고 Gradia: GD를 연구재료로 사용하였다. 불소 방출은 10,000회의 잇솔질을 시행한 후 10일 동안의 방출량을 측정하였고, 표면조도는 40,000회의 잇솔질 후 중심선평균거칠기 Ra와 최대거칠기 Ry를 측정하였으며, 마모면은 주사전자현미경으로 관찰하였다. 잇솔질 후의 불소 방출량과 표면 관찰로부터 다음과 같은 결론을 얻었다. 1. 불소방출은 AT군, FL군 및 CF군의 경우에는 초기단계에 다량의 급격 한 방출을 보인 후 상대적으로 낮으면서도 지속적인 방출 양상을 보였지만, 나머지 시험군의 경우에는 초기단계로부터 낮으면서도 지속적인 방출을 보였다. 2. 불소방출은 약 40일 경과 후 안정적인 방출 양상을 나타냈으며, Tukey 분석 결과, AT군, 레진강화 GIC의 FL군, 콤포머군 전부 및 불소방출성 콤포짓트 레진의 GD군과 TC군 사이에서 통계학적으로 방출량의 유의한 차이를 보였다(P<0.05). 3. 표면조도는 FT군에서 가장 크고 CF군에서 가장 작은 값을 보였으며, Tukey 분석 결과, FT군, AL군 및 FL군과 TC군, DR군, GD군 및 CF군 사이에서 통계학적으로 유의한 차이를 보였다(P<0.05).

• 한국작물학회지
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• 제52권3호
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• pp.311-319
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• 2007

본 시험은 질소 용출 속도가 다른 3가지 피복요소가 포함된 완효성 복합비료를 관행 요소시비량의 80 및 100% 수준으로 시용하여 벼 건답직파 및 이앙재배에서 벼 생육, 수량 및 질소이용율을 알아보고 쌀의 품질에 미치는 영향을 조사하였다. 1. LCU의 제형별 $20^{\circ}C$ 및 $30^{\circ}C$에서 수중 용출 속도는 LCU40 > LCU80 > LCU혼합 > LCU100 순으로 빨랐다. 2. 벼 생육 및 수량은 건답직파 및 이앙재배 모두에서 LCU-복비100% > LCU-복비80% > 관행 순으로 높았다. 3. LCU-복비 시용에 의한 질소이용율은 요소시용에 비해 건답직파재배에서는 $4{\sim}7%$, 이앙재배에서는 $11{\sim}13%$ 향상되었으며, 표준시비량의 20%를 감비한 LCU-복비 80% 시용이 단위시비질소의 생산성이 가장 높았다. 4. 단백질 함량은 건답직파 및 이앙재배의 무질소구에서 6.3 및 6.6%로 가장 낮았고, 비료 처리간에는 LCU-복비 80% 시용구에서 각각 6.5 및 6.7%로 관행 요소시용 7.3 및 7.4%에 비해 낮았다. 5. 아밀로즈 함량 및 Mg/K 비는 모든 처리간에 유의성이 없었다. 또한 쌀의 호화특성 중 최고점도 및 강하점도는 LCU-복비 시용에 의해 다소 높았지만 통계적인 유의성은 없었다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.556-561
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• 2006

In this study, the failure of the automotive clutch disk was investigated. During the process of power transmission, clutch disk plates did repeated work of releasing and engaging the pressure plate. The effects of unbalance rotation in the abnormal vibration and torque amplitude under engaged state were measured from this experiment. In order to reduce the unbalance, a modified clutch disk shape was developed. With a three-dimensional model of the stopper pin, to predict fatigue fracture, finite element analysis was carried out and evaluated the improvement of the new clutch disk.

• 미생물학회지
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• 제29권2호
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• pp.117-122
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• 1991

In order to improve the removal ability of phosphate, Spheroplast fusions were performed among auxotrophic mutants of Aeromonas hydrophila isolated from waste water, named A13 and A14, Aci37 auxotrophic mutant of Acinetobactercalcoaceticus, and auxotrophic E. coli HR262/pCE27 carring pit gene. Eight fusants obtained from this experiment showed different biochemical characteristics. When the rate of phosphate uptake among fusants (F1-F8) was investigated in Phosphate Uptake Medium (PUM), F8 strain showed the highest rate for phosphate removal, 7 times as much as control after two hours incubation. The role of cations ($Mg^{++}$ ,$Ca^{++}$ , $K^{+}$ in phosphate uptade by F8 was also investigated in PUM without each salt. $K^{+}$ seemed to be crucial. Being compared with phosphate untake rate in PUM, that in PUM without $K^{+}$ was reduced 1.5 times. Therefore, by applying F8 strain and $K^{+}$ in practical environmental system, the increased efficiency in phosphate removal can be derived.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2001년도 춘계 학술대회논문집
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• pp.170-175
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• 2001

Fire inside light railway transit(LRT) was simulated for various fire scenarios using CFD analysis in order to assess the safety of passengers. Considered in the present paper are the effects of locations of fire, a fire size, an operation of ventilation system and an opening time of door on evolution of temperature and smoke concentration inside the LRT. For fire simulation, fire cells releasing heat and smoke corresponding to fire size were positioned at the location of fire. From the results, it is seen that the ventilation system and the opening time of door were the most important factors on temperature and smoke concentration inside the LRT

• 한국정밀공학회지
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• 제14권1호
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• pp.126-141
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• 1997

The purpose of this research is to develope a FEM program for analyzing solidification processes of axisymmetric casting, considering phase changes and the contact between the metal and mold. Tempera- ture recovery method is employed fro considering the phase changes releasing the latent heat and the coin- cident node method is used for calculating the amount of heat transfer between the metal and mold. Tan- gent modulus algorithm is adopted for calculating flow stress and a gap element is employed for modeling the interface between the mold and metal in finding deformed shapes. In order to verify the developed program, axisymmetric aluminum and steel casting processes are simulated. Temperature distribution, phase front position, and shrinkage and porosity creation are compared with measurements, FIDAP results, and good agreements are examined.

• Journal of Microbiology and Biotechnology
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• 제24권9호
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• pp.1291-1299
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• 2014

Recently, multifunctional nanomaterials have been developed as nanotherapeutic agents for cellular imaging and targeted cancer treatment because of their ease of synthesis and low cytotoxicity. In this study, we developed a multifunctional, two-component nanorod consisting of gold (Au) and nickel (Ni) blocks that enables dual-fluorescence imaging and the targeted delivery of small interfering RNA (siRNA) to improve cancer treatment. Fluorescein isothiocyanate-labeled luteinizing hormone-releasing hormone (LHRH) peptides were attached to the surface of a Ni block via a histidine-tagged LHRH interaction to specifically bind to a breast cancer cell line, MCF-7. The Au block was modified with TAMRA-labeled thiolated siRNA in order to knock down the vascular endothelial growth factor protein to inhibit cancer growth. These two-component nanorods actively targeted and internalized into MCF-7 cells to induce apoptosis through RNA interference. This study demonstrates the feasibility of using two-component nanorods as a potential theranostic in breast cancer treatment, with capabilities in dual imaging and targeted gene delivery.