• BMB Reports
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• 제45권2호
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• pp.71-78
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• 2012

Bdellovibrio bacteriovorus is a predatory bacterium which attacks and consumes other bacterial strains, including the well known pathogens E. coli O157 : H7, Salmonella typhimurium and Helicobacter pylori. This remarkable activity has been the focus of research for nearly five decades, with exciting practical applications to medical, agriculture and farming practices recently being published. This article reviews many of the exciting steps research into this bacterium, and similar bacteria, has taken, focusing primarily on their use as both an antibiotic to remove harmful and pathogenic bacteria and as a probiotic to help curb and control the bacterial populations within the intestinal tract. Owing to the unique and dual nature of this bacterium, this review proposes the use of "amphibiotic" to describe these bacteria and their activities.

• International Journal of Computer Science & Network Security
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• 제24권6호
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• pp.17-22
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• 2024

Software cost and schedule estimation is usually based on the estimated size of the software. Advanced estimation techniques also make use of the diverse factors viz, nature of the project, staff skills available, time constraints, performance constraints, technology required and so on. Usually, estimation is based on an estimation model prepared with the help of experienced project managers. Estimation of software cost is predominantly a crucial activity as it incurs huge economic and strategic investment. However accurate estimation still remains a challenge as the algorithmic models used for Software Project planning and Estimation doesn't address the true dynamic nature of Software Development. This paper presents an efficient approach using the contemporary Constructive Cost Model (COCOMO) augmented with the desirable feature of fuzzy logic to address the uncertainty and flexibility associated with the cost drivers (Effort Multiplier Factor). The approach has been validated and interpreted by project experts and shows convincing results as compared to simple algorithmic models.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 추계학술대회논문집
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• pp.44-47
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• 2004

Although bulk metallic glasses have many outstanding aspects in their chemical, mechanical or functional properties, some critical problems still hinder their wide application. The most important one is the brittle nature of them, which is the serious problem to structural application. So, to use viscous flow is now the only competent way to form bulk metallic glass. In this study, we investigated the basic nature of viscous flow of Zr-base bulk metallic glass, vitrelloy 1, in terms of process variables. The results were used to design the thermo-mechanical process composed of heating, holding, pressing, and cooling, which have unique influence on the glass transition and crystallization behavior. We adopted small load scale and dies with nano/micro patterns on them. The results were evaluated using several analytical methods.

• 한국과학교육학회지
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• 제17권4호
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• pp.359-371
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• 1997

The purpose of this investigation was to examine and compare pre-service and in-service secondary tearchers' beliefs about STS, particulary beliefs about the nature of science and technology and their interaction within society. For this study, a belief was defined as something that people believe and accept as true. Instrument used in this investigation was empirically developed multiple-choice instrument entitled the Tearchers' Belief about Science - Technology - Society(TBA-STS) by Peter A. Rubba and William L. Harkness. The result of survey showed that large percentages of the preservice and in-service secondary science teachers in the two samples held misconception about the nature of science and technology and their interactions within society. And there was no apparent difference between the samples on their beliefs about STS interactions.

• 대한화학회지
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• 제68권2호
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• pp.107-116
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• 2024

본 연구의 목적은 테크놀로지를 활용한 모델의 평가와 수정 과정에서 나타난 예비화학교사들의 모델의 본성에 대한 인식 변화를 분석하는 것이다. 모델의 본성에 대한 인식 변화는 선행연구에서 예비화학교사들에게 부족하다고 판단된 표상적 측면의 함축화와 간단화, 설명적 측면의 해석, 추론, 설명, 정량화를 중심으로 분석하였다. 이를 위하여 충청북도에 있는 사범대학의 3학년 예비화학교사 19명을 대상으로 테크놀로지를 활용하여 개발한 보일 법칙 관련 모델을 평가하고, 평가 결과를 바탕으로 모델을 수정하여 최종 평가하도록 요구하였다. 연구 결과, 표상적 측면의 간단화, 설명적 측면의 해석, 설명, 정량화에 대한 예비화학교사들의 인식이 모델의 평가와 수정 과정을 통해 긍정적으로 변화되었음을 확인할 수 있었다. 따라서 모델의 본성에 대한 인식이 변화하기 위해서는 모델의 평가와 수정 과정이 핵심적인 역할을 하는 것을 알 수 있었다. 하지만 표상적 측면의 함축화와 설명적 측면의 추론에 대한 인식 변화는 거의 나타나지 않았다. 이러한 요소들에 대한 인식은 다른 요소들의 인식보다 변화하기 어려운 것으로 볼 수 있다. 이러한 문제를 해결하기 위해서는 예비화학교사들을 위한 보다 정교한 교육 설계가 필요하다.

• 대한화장품학회지
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• 제33권3호
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• pp.165-173
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• 2007

선구 연구로부터 저자들은 제주 자생 식물 추출물의 항산화 및 세포보호 효과에 대한 결과의 일부를 이미 보고하였으며, 본 연구에서는 제주도에서 자생하는 나머지 37종의 식물 추출물에 대한 항산화, 미백 그리고 주름생성억제 효과를 측정하였다. 항산화 효과는 1,1-diphenyl-2-picrylhydrazyl radical(DPPH)을 이용한 free radical 소거 활성 측정, $Fe^{3+}-EDTA/H_2O_2$ 계에서 생성된 활성산소종으로 인한 luminol의 화학발광을 이용한 소거 활성, 사람 적혈구를 대상으로 하여 rose-bengal로 증감된 활성산소에 대한 세포보호 효과를 측정하였다. 미백 및 주름억제 효과측정으로는 각각 tyrosinase, elastase의 활성 저해 효과를 측정하였다. 실험결과, free radical의 소거 활성($FSC_{50}$)은 소귀나무 수피(Myrica rubra, 5 ${\mu}g/mL$), 광대싸리 수피(Securinega suffruticosa, 8 ${\mu}g/mL$)에서 높게 나타났고, 활성산소 소거 활성($OSC_{50}$)은 상수리나무 잎(Quercus acutissima)과 광대싸리 수피(Securinega suffruticosa)에서 0.009 ${\mu}g/mL$로 높게 나타났으며, 세포보호 효과(${\tau}_{50}$)는 50 ${\mu}g/mL$에서 광대싸리 수피(Securinega suffruticosa, 895 min), 버드나무 줄기(Salix koreensis, 640 min)에서 크게 나타났다. 200 ${\mu}g/mL$에서 tyrosinase의 활성 저해 효과($IC_{50}$)는 소귀나무 수피(Myrica rubra, 77.8%), elastase의 활성 저해 효과($IC_{50}$)는 버드나무 줄기(Salix koreensis, 76.2%)에서 큰 효과가 나타났다. 결론적으로 광대싸리 수피, 소귀나무 수피, 상수리나무 잎, 버드나무 줄기, 동백나무 잎/줄기 추출물은 기능성 화장품 제조를 위한 원료로 사용하기에 충분한 가능성이 있음을 확인할 수 있었으며, 향후에 제품화를 위하여 좀 더 다양한 연구들이 필요하다고 사료된다.

• 한국응용과학기술학회지
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• 제26권2호
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• pp.117-123
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• 2009

Caprylic/Capric triglyceride-in-water emulsions stabilized by Nikkol HCO-60 and HCO-10 were prepared using emulsion inversion point method at different HLB values. Emulsions with various droplet sizes were formed, and emulsion inversion point was detected by electrical conductivity. The change in emulsion droplet sizes and long term stability were monitored using laser scattering method and visual method. The droplet sizes and stability of emulsions were affected by HLB of surfactant. At emulsion inversion point, the water volume fraction increased as the HLB of surfactants decreased. According to our analysis, this resulted from a tendency of forming the W/O (water-in-oil) emulsion as the HLB of surfactants was decreased. The emulsion inversion point was clearly detected by the microscope and the electric conductivity meter. Nanometer-sized emulsion was obtained at the optimum HLB by using emulsion inversion point method. The main pattern of instability of emulsions in HLB 12 and 13 systems was Ostwald ripening. However, The patterns of instability of emulsions below 11 of HLB systems were Ostwald ripening and coalescence. All emulsions produced with surfactants in the range of HLB 8-13, creaming caused by density difference between water phase and oil phase.

• 대한음성학회지:말소리
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• 제spc1호
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• pp.24-32
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• 2002

• 한국응용과학기술학회지
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• 제26권3호
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• pp.269-278
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• 2009

In this study, the anti oxidative effects, inhibitory effects on elastase, and components of Securinega suffruticosa extracts were investigated. The free radical (1,1-diphenyl-2-picrylhydrazyl, DPPH) scavenging activities ($FSC_{50}$) and reactive oxygen species ROS) scavenging activities ($OSC_{50}$) of extract/fractions from Securinega suffruticosa were measured. The aglycone fraction ($9.04\;{\pm}\;0.51\;{\mu}g/mL$) and 50 % ethanol extract ($1.05\;{\pm}\;0.41\;{\mu}g/mL$) showed the most effective scavenging activities. The protective effects on the rose-bengal sensitized photohemolysis of human erythrocytes were investigated. The aglycone fraction exhibited the most prominent cellular protective effect (${\tau}_{50},\;102.77\;{\pm}\;5.37$ min at $10{\mu}g/mL$). The inhibitory effect of ethyl acetate fraction on tyrosinase were of examined ($210.0\;{\pm}\;1.02\;{\mu}g/mL$). The inhibitory effect of aglycone fraction on elastase were also investigated ($17.6\;{\pm}\;1.26\;{\mu}g/mL$). These results indicate that extract/fractions of Securinega suffruticosa can function as antioxidants in biological systems, particularly skin exposed to UV radiation by scavenging $^1O_2$ and other ROS, and protect cellular membranes against ROS. Securinega suffruticosa extract could be used as a new cosmeceutical ingredient for whitening and anti-wrinkle products.

• 한국환경복원기술학회지
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• 제9권4호
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• pp.36-51
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• 2006

Although the demand and necessity for the facilities of nature environmental conservation and its utilization have been increased recently, the local governments has been experiencing difficulties to launch the facilities since there are no confirmed principles or guidelines for the direction of the facility and distinctions from the ordinary parks. In this regard, the aim of this paper is to provide the overall framework for establishing the facility by equipping checklists from planning to operational stage. The stages are disengaged into 5 steps of siting feasibility, planning, preliminary environmental assessment and environmental impact assessment, design, construction, and operation. This paper also include the recommendations to vitalize the existing facilities, of which expansion of educational program development; utilization of various manpower; provision of appropriate settings; strengthened monitoring; and increased public relations. Furthermore, it is suggested to consider the strengthened local characteristics, reviewing management plan at the stage of applying a new facility establishment to the concerned authority, fostering experts, and expansion of the facilities through restoration of environmentally damaged areas for a new facility.