• BMB Reports
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• 제38권5호
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• pp.507-516
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• 2005

Antimicrobial peptides (AMPs) have been isolated and characterized from tissues and organisms representing virtually every kingdom and phylum. Their amino acid composition, amphipathicity, cationic charge, and size allow them to attach to and insert into membrane bilayers to form pores by 'barrel-stave', 'carpet' or 'toroidal-pore' mechanisms. Although these models are helpful for defining mechanisms of AMP activity, their relevance to resolving how peptides damage and kill microorganisms still needs to be clarified. Moreover, many AMPs employ sophisticated and dynamic mechanisms of action to carry out their likely roles in antimicrobial host defense. Recently, it has been speculated that transmembrane pore formation is not the only mechanism of microbial killing by AMPs. In fact, several observations suggest that translocated AMPs can alter cytoplasmic membrane septum formation, reduce cell-wall, nucleic acid, and protein synthesis, and inhibit enzymatic activity. In this review, we present the structures of several AMPs as well as models of how AMPs induce pore formation. AMPs have received special attention as a possible alternative way to combat antibiotic-resistant bacterial strains. It may be possible to design synthetic AMPs with enhanced activity for microbial cells, especially those with antibiotic resistance, as well as synergistic effects with conventional antibiotic agents that lack cytotoxic or hemolytic activity.

• 한국학교수학회논문집
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• 제7권1호
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• pp.121-138
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• 2004

본 논문에서는 제7차 교육과정의 특색중의 하나인 교과재량활동시간의 효율적 운영에 관하여 연구하였다. 교과재량 활동시간에 '함께가자! 우리' 프로그램의 운영을 통하여 다양한 수학에 대한 경험, 실생활을 소재로 한 수학문제, 수준별 협동학습 수학에 대한 흥미를 유발시켰으며, 1:1 맞춤학습에 의한 부담 없는 질문과 학습의 분위기 조성 등이 학생들의 자기주도적 학습력을 향상시키는데 많은 도움을 주었음을 알 수 있다.

• 보건교육건강증진학회지
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• 제29권5호
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• pp.49-59
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• 2012

Objectives: Physical activity provides economic benefits and contributes in improving health and quality of life. Opportunities for physical activity continue to decrease with the increasing prevalence of sedentary lifestyles. In various settings, there have been many efforts to enhance physical activity to prevent chronic disease for people of all ages. This study was performed to define competencies of physical activity specialists in health promotion and compare with those of health education specialists. Methods: The study employed official data and manuals of health promotion programs that have been published and uploaded on public websites. Results: Competencies for physical activity in health promotion included needs assessment, analysis of data and scientific information, planning and evaluation, developing strategies and materials, management, building healthy environment, research. To compare with the competency of health education specialists, competencies of physical activity were almost similar to that except the developing individual-based physical activity program in exercise science. Conclusions: Physical activity programs for health promotion should be planned and implemented throughout various health topics and in coordination with multiple sectors. To increase efficiency of the utilization of human resources in health promotion, health education specialists needs to participate in physical activity programs and would require empowerment in exercise science.

• Bulletin of the Korean Chemical Society
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• 제31권2호
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• pp.339-343
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• 2010

A series of $Ce_1Mg_xZr_{1-x}O_2$ (CMZO) mixed metal oxide with different molar ratio were prepared by simple co-precipitation method. The prepared materials were tested for their catalytic activity performance using Knoevenagel condensation of various aromatic aldehydes with barbituric acid under solvent-free condition in microwave. The best catalytic activity was obtained with CMZO (1:0.6:0.4). The synthesized materials were characterized by using XRD, FT-IR, SEM-EDS techniques.

• Restorative Dentistry and Endodontics
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• 제22권1호
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• pp.305-324
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• 1997

Numerous materials such as amalgam, IRM, SuperEBA, dessicated ZOE, and Ketac-Silver have been used as a root-end filling material or to repair furcation perforations. But so far no material has been found to satisfy all of the requirements of an ideal restorative material. Recently, mineral trioxide aggregate (MTA) has been suggested for use as a root end filling material and for the repair of furcation perforations. The purpose of this study was to compare the effect of MTA on the proliferation of MC3T3/E1 osteoblastic cell, formation of bone nodule, alkaline phosphatase activity, and finally the tissue reaction of bone with those of amalgam, IRM, SuperEBA, dessicated ZOE, and Ketac-Silver. The following conclusions were drawn within the limits of the experimental results : 1. MTA showed a excellent proliferation of osteoblastic cell and Ketac-Silver showed moderate proliferation of osteoblastic cell. The rest of test materials showed no proliferation of osteoblastic cell. 2. Many of definite bone nodules were found in the MTA group. In contrast, Ketac-Silver group showed no definite bone formation but only showed mild sign of bone formation. 3. Alkaline phosphatase activity of Ketac-Silver and MTA showed similar results. But both of them showed higher activity than that of other materials (p<0.005). 4. The tissue reaction to implanted MTA in the calbarium of mouse was milder than that observed with other materials. The tissue reaction of dessicated ZOE showed the worst results among the test materials.

• 한국재료학회지
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• 제30권5호
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• pp.217-222
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• 2020

The design and fabrication of catalysts with low-cost and high electrocatalytic activity for the oxygen evolution reaction (OER) have remained challenging because of the sluggish kinetics of this reaction. The key to the pursuit of efficient electrocatalysts is to design them with high surface area and more active sites. In this work, we have successfully synthesized a highly stable and active NiCo₂S₄ nanowire array on a Ni-foam substrate (NiCo₂S₄ NW/NF) via a two-step hydrothermal synthesis approach. This NiCo₂S₄ NW/NF exhibits overpotential as low as 275 mV, delivering a current density of 20 mA cm^-2 (versus reversible hydrogen electrode) with a low Tafel slope of 89 mV dec^-1 and superior long-term stability for 20 h in 1 M KOH electrolyte. The outstanding performance is ascribed to the inherent activity of the binder-free deposited, vertically aligned nanowire structure, which provides a large number of electrochemically active surface sites, accelerating electron transfer, and simultaneously enhancing the diffusion of electrolyte.

• 한국표면공학회지
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• 제51권5호
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• pp.332-336
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• 2018

Alkaline oxygen electrocatalysis, targeting anion exchange membrane alkaline-based metal-air batteries has become a subject of intensive investigation because of its advantages compared to its acidic counterparts in reaction kinetics and materials stability. However, significant breakthroughs in the design and synthesis of efficient oxygen reduction catalysts from earth-abundant elements instead of precious metals in alkaline media still remain in high demand. One of the most inexpensive alternatives is carbonaceous materials, which have attracted extensive attention either as catalyst supports or as metal-free cathode catalysts for oxygen reduction. Also, carbon composite materials have been recognized as the most promising because of their reasonable balance between catalytic activity, durability, and cost. In particular, heteroatom (e.g., N, B, S or P) doping on carbon materials can tune the electronic and geometric properties of carbon, providing more active sites and enhancing the interaction between carbon structure and active sites. Here, we focused on boron and nitrogen doped nanocarbon composit (BNC nanocarbon) catalysts synthesized by a solution plasma process using the simple precursor of pyridine and boric acid without further annealing process. Additionally, guidance for rational design and synthesis of alkaline ORR catalysts with improved activity is also presented.

• 한국세라믹학회지
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• 제50권4호
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• pp.269-274
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• 2013

ACF and ZnO modified $TiO_2$ composite materials (ZnO-ACF/$TiO_2$) were prepared by a sol-gel method. The composites were characterized by X-ray diffraction (XRD), energy dispersive X-ray (EDX) analysis and scanning electron microscope (SEM) analysis. A methyl orange (MO) solution under visible light irradiation was used to determine the photocatalytic activity. The degradation of the MO was determined using UV spectrophotometers. An increase in the photocatalytic activity was observed and attributed to an increase of the photo-absorption effect by the ZnO and the cooperative effect of the ACF.

• 대한금속재료학회지
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• 제50권1호
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• pp.45-51
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• 2012

Thermodynamics of carbon in manganese alloy melts is important in manufacturing low carbon ferromanganese and silico-manganese alloys. In order to predict the carbon solubility in liquid $Mn-Si-Fe-C_{sat}$ alloys as a function of melt composition and temperature, thermodynamic interactions among carbon, silicon and iron in carbon saturated liquid manganese should be known. In the present study, the effects of silicon and iron on the carbon solubility in Mn-Si, Mn-Fe and Mn-Si-Fe melts were measured in the temperature range from 1673 to 1773 K. The carbon solubility decreases significantly as silicon and iron contents increase in liquid manganese alloy. The interaction parameters among carbon, silicon and iron in carbon saturated liquid manganese were determined from the carbon solubility data and the Lupis' relation for the interaction coefficient at constant activity.

• 한국축산식품학회지
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• 제25권3호
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• pp.344-349
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• 2005

Two different NokJoongTangs were prepared by boiling antler and various oriental medicinal materials. The phenolic contents and free radical scavenging effects against DPPH(1,1-diphenyl-2-picrylhydrazyl) radical and hydroxyl radical of the NokJoongTangs which are used as the health supplement foods, were investigated. NokJoongTang-II prepared dried antler with various oriental medicinal materials, had higher phenolic content than that of NokJoongTang-I prepared 1mm raw antler with the same materials. In addition, NokJoongTang-II exhibited higher scavenging activities than these of NokJoongTang-I against DPPH radical and hydroxyl radical. These result indicate that free radical scavenging activity of NokJoongTang showed a difference by using raw and dry antler for NokJoongTang preparation, and that the findings also show a positive correlation between radical scavenging activity and total phenolic contents.