• 생태와환경
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• 제40권4호
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• pp.520-526
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• 2007

To select submerged macrophytes to suppress growth of Microcystis aeruginosa through releasing allelochemicals, we conducted growth experiments with water from patches of submerged macrophytes and with aqueous extracts of those submerged macrophytes. In the first experiment, growth rates of M. aeruginosa decreased as biomass of Myriophyllum spicatum and Hydrilla verticillata increased. In the second experiment, M. aeruginosa showed approximately 50% growth reduction with extracts from M. spicatum and 24% reduction with extracts from Ottelia alismoides. Both M. aeruginosa growth experiments with water and plant extracts suggest that M. spicatum would be the best candidate to reduce M. aeruginosa growth.

• Korea-Australia Rheology Journal
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• 제14권2호
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• pp.71-76
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• 2002

Metal thin films, which are indispensable constituents of ULSI (Ultra Large Scale Integration) circuits, have been fabricated by physical or chemical methods. However, these methods have a drawback of using expensive high vacuum instruments. In this work, the fabrication of tungsten metal film by spin coating was investigated. First of all, inorganic peroxopolytungstic acid (W-IPA) powder, which is soluble in water, was prepared by dissolving metal tungsten in hydrogen peroxide and by evaporating residual solvent. Then, the solution of W-IPA was mixed with organic solvent, which was spin-coated on wafers. And then, tungsten metal films, were obtained after reduction procedure. By selecting an appropriate organic solvent and irradiating UV, the sheet resistance of the tungsten metal film could be remarkably reduced.

• Genomics & Informatics
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• 제10권4호
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• pp.256-262
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• 2012

Most common complex traits, such as obesity, hypertension, diabetes, and cancers, are known to be associated with multiple genes, environmental factors, and their epistasis. Recently, the development of advanced genotyping technologies has allowed us to perform genome-wide association studies (GWASs). For detecting the effects of multiple genes on complex traits, many approaches have been proposed for GWASs. Multifactor dimensionality reduction (MDR) is one of the powerful and efficient methods for detecting high-order gene-gene ($G{\times}G$) interactions. However, the biological interpretation of $G{\times}G$ interactions identified by MDR analysis is not easy. In order to aid the interpretation of MDR results, we propose a network graph analysis to elucidate the meaning of identified $G{\times}G$ interactions. The proposed network graph analysis consists of three steps. The first step is for performing $G{\times}G$ interaction analysis using MDR analysis. The second step is to draw the network graph using the MDR result. The third step is to provide biological evidence of the identified $G{\times}G$ interaction using external biological databases. The proposed method was applied to Korean Association Resource (KARE) data, containing 8838 individuals with 327,632 single-nucleotide polymorphisms, in order to perform $G{\times}G$ interaction analysis of body mass index (BMI). Our network graph analysis successfully showed that many identified $G{\times}G$ interactions have known biological evidence related to BMI. We expect that our network graph analysis will be helpful to interpret the biological meaning of $G{\times}G$ interactions.

• Molecules and Cells
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• 제26권6호
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• pp.611-615
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• 2008

DNA methylation is an epigenetic mechanism for gene silencing. In Arabidopsis, MET1 is the primary DNA methyltransferase that maintains CG DNA methylation. Plants having an overall reduction of MET1 activity, caused by a met1 mutation or a constitutively expressed MET1 antisense gene, display genome hypomethylation, inappropriate gene and transposon transcription, and developmental abnormalities. However, the effect of a transient reduction in MET1 activity caused by inhibiting MET1 expression in a restricted set of cells is not known. For this reason, we generated transgenic plants with a MET1 antisense gene fused to the DEMETER (DME) promoter (DME:MET1 a/s). Here we show that DME is expressed in leaf primordia, lateral root primoridia, in the region distal to the primary root apical meristem, which are regions that include proliferating cells. Endogenous MET1 expression was normal in organs where the DME:MET1 a/s was not expressed. Although DME promoter is active only in a small set of cells, these plants displayed global developmental abnormalities. Moreover, centromeric repeats were hypomethylated. The developmental defects were accumulated by the generations. Thus, not maintaining CG methylation in a small population of proliferating cells flanking the meristems causes global developmental and epigenetic abnormalities that cannot be rescued by restoring MET1 activity. These results suggest that during plant development there is little or no short-term molecular memory for reestablishing certain patterns of CG methylation that are maintained by MET1. Thus, continuous MET1 activity in dividing cells is essential for proper patterns of CG DNA methylation and development.

• 농약과학회지
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• 제14권3호
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• pp.235-240
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• 2010

건조에 의한 마늘 중 농약의 잔류특성을 구명하기 위하여 마늘에 등록되어 사용 중인 azoxystrobin과 flutolanil의 표준희석 용액에 각각 1분과 5분간 침지한 후 동결 건조하였으며, 건조 전후 마늘 중 잔류농약은 GLC-ECD/NPD를 이용하여 분석하였다. 건조전후 마늘 중 시험농약의 회수율은 81.96-98.18%이었다. 건조 전 마늘 중 azoxystrobin과 flutolanil의 잔류량은 1분 침지에서 각각 0.34와 1.18 mg/kg, 5분 침지에서 0.44와 2.15 mg/kg이었으며, 건조 마늘 중 시험농약의 잔류량은 1분 침지에서 0.80과 4.51 mg/kg, 5분 침지에서 1.03과 5.28 mg/kg으로 건조 후 잔류농약의 농도는 증가하였다. Azoxystrobin의 가공계수는 1분과 5분 침지에서 각각 2.35와 2.34이었고, flutolanil의 가공계수는 1분과 5분 침지에서 각각 1.19와 1.17이었다. 건조전후 마늘 중 시험농약의 감소계수는 0.94-0.97 범위로서 동결건조 과정 중 시험농약은 거의 소실되지 않았다.

• Carbon letters
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• 제23권
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• pp.38-47
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• 2017

In this study, magnetite ($Fe_3O_4$) nanoparticles were electrochemically synthesized in an aqueous electrolyte at a given potential of -1.3 V for 180 s. Scanning electron microscopy revealed that dendrite-like $Fe_3O_4$ nanoparticles with a mean size of < 80 nm were electrodeposited on a glassy carbon electrode (GCE). The $Fe_3O_4/GCE$ was utilized for sensing chloramphenicol (CAP) by cyclic voltammetry and square wave voltammetry. A reduction peak of CAP at the $Fe_3O_4/GCE$ was observed at 0.62 V, whereas the uncoated GCE exhibited a very small response compared to that of the $Fe_3O_4/GCE$. The electrocatalytic ability of $Fe_3O_4$ was mainly attributed to the formation of Fe(VI) during the anodic scan, and its reduction to Fe(III) on the cathodic scan facilitated the sensing of CAP. The effects of pH and scan rate were measured to determine the optimum conditions at which the $Fe_3O_4/GCE$ exhibited the highest sensitivity with a lower detection limit. The reduction current for CAP was proportional to its concentration under optimized conditions in a range of $0.09-47{\mu}M$ with a correlation coefficient of 0.9919 and a limit of detection of $0.09{\mu}M$ (S/N=3). Moreover, the fabricated sensor exhibited anti-interference ability towards 4-nitrophenol, thiamphenicol, and 4-nitrobenzamide. The developed electrochemical sensor is a cost effective, reliable, and straightforward approach for the electrochemical determination of CAP in real time applications.

• Korean Chemical Engineering Research
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• 제47권2호
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• pp.163-168
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• 2009

본 연구에서는 양이온, 중심원소, 배위원소가 치환된 Keggin 형 및 Wells-Dawson 형 헤테로폴리산 촉매의 NDR(negative differential resistance) 거동을 STM(scanning tunneling microscopy)을 이용하여 살펴보았다. 헤테로폴리산 촉매의 NDR 전압과 산화환원능력 사이에는 일정한 상관관계가 있었다. 촉매의 구조적 차이에 상관없이 산화환원능력이 높은 헤테로폴리산 촉매는 보다 낮은 음전압에서 NDR 거동을 나타내었다. 이처럼 NDR 전압은 촉매의 산화환원능력을 대변하는 하나의 correlating parameter로 활용될 수 있었다.

• Journal of Korean Biological Nursing Science
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• 제4권2호
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• pp.127-137
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• 2002

The purpose of this study was to compare the hand disinfection effect of waterless alcohol gel hand washing agent with that of soap and water, 4% chlorhexidine gluconate, and 10% povidone-iodine. Hands of fourty subjects were artificially contaminated with Acinetobacter baumannii $5m{\ell}$ and randomly distributed to each hand washing methods. Samples were collected from gloved hand by glove juice sampling procedure. Mean log reduction after hand washing were compared with baseline values. Number of microorganisms were converted to log and tested by ANOVA in SPSSWIN 10.0. Mean log reduction of soap and water, alcohol gel, 4% chlorhexidine gluconate, 10% povidone-iodine were $2.76{\pm}0.62$, $2.97{\pm}0.56$, $4.66{\pm}1.70$, $4.60{\pm}0.91$, respectively. The bactericidal effect of alcohol gel was similar to that of soap and water, but the effect was much less than chlorhexidine gluconate and povidone-iodine(p<0.001). In terms of microorganism reduction, the efficacy of waterless alcohol gel was almost the same as soap and water hand washing. Further evaluation of the bactericidal effect of waterless alcohol gel is needed because waterless alcohol gel is simple, convenient, and non-irritating hand washing agent and also very effective in busy hospital environment.

• 한국환경보건학회지
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• 제32권5호
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• pp.478-484
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• 2006

There was no significant difference in the CADR (Clean Air Delivery Rate) between physical aerosols, NaCl and smoke, and biological aerosols, airborne MS2 virus and P. fluorescens, which implicate that the hybrid-type of air purifier, applying the unipolar ion emission and the radiant catalytic ionization, imposed identical reduction effect on both physical aerosol and bioaerosol. Ventilation decreases the efficiency of air cleaning by unipolar ionization because high ventilation diminishes the particle concentration reduction effect. The particle removal efficiency decreases with increase in the chamber volume because of the augmented ion diffusion and higher ion wall loss rate. Particle size affects the efficiency of air ionization. The efficiency is high for particles with very small diameter because reduction of charge increases with particle size. If there is no increasing supply of ions, the efficiency of air cleaning by unipolar ionization increases with respect to initial concentration of particles because of the large space charge effect at high particle concentration and amplified electric field.

• 생물정신의학
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• 제5권2호
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• pp.263-277
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• 1998

Conventional high-dose antipsychotics tend to result in more side effects, negative symptoms and dysphoria, and at the same time lower the cognitive function which is already impaired in most schizophrenics. Florid psychotic symptoms, negative symptoms and cognitive impairment greatly impede psychosocial performance and eventual reintegration into society. The reduction of symptom and the improvement of cognitive funtions and social skills are therefore central to the psychiatric rehabilitation process. The purpose of this study was to evaluate the dose-reduction effects of antipsychotics on chronic schizophrenics prescribed conventional high-dose antipsychotics more than 1,500mg equivalent of chlorpromazine. Fifty-one chronic schizophrenics who maintained high-dose antipsychotics for more than three months were randomly assigned to two groups : 20 patients comprised the dose-maintaining group and 31 patients made the dose-reduction group. Over a sixteen weekperiod Positive and Negative Syndrome Scale(PANSS), Extrapyramidal Symptom(EPS), Nurses' Observation Scale for Inpatient Evaluation(NOSIE-30), Continuous Performance Test(CPT), Quality of Life(QOL), and haloperidol/reduced haloperidol blood levels were determined at the base line and after 2, 4, 6, 8, 12, 16 weeks to evaluate the dose reduction effects of high-dose antipsychotics. The results were as follows : 1) Dose-reduction is highly effective in reducing positive and negative symptoms, and general psychopathology. Effects were most prominent at 8, 12, 16 weeks. Among the dose reduction group, positive symptoms in positive symptom group and negative symptoms in negative symptom group were more reduced. 2 Extrapyramidal symptoms showed no significant difference between two groups. But the EPS was reduced time after time within two groups. 3) Hit rates of Continuous Performance Test, which indicate attentional capacity, increased significantly after dose reduction. 4) Haloperidol and reduced haloperidol blood levels decreased until the 4th week, after which they were constant. 5) Total scores of Nurses' Observation Scale for Inpatient Evaluation were unchanged between the two groups. But among the indices, social interest and personal neatness were improved in the dose-reduction group and retardation was aggrevated in the dose-maintaining group. 6) Total quality of life scores were unchanged between two groups. But in the dose maintaining group, satisfaction scores of attention, autonomy, and interpersonal relationship decreased progressively. These findings suggest that the dose reduction of antipsychotics for chronic schizophrenics on programs of high-dose antipsychotics were effective. Dose reduction should therefore be implemanted to spread the rehabilitation and improve quality of life for chronic schizophrenics.