• Clinical and Experimental Pediatrics
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• 제59권2호
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• pp.100-103
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• 2016

Patients with hemolytic-uremic syndrome (HUS) can rapidly develop profound anemia as the disease progresses, as a consequence of red blood cell (RBC) hemolysis and inadequate erythropoietin synthesis. Therefore, RBC transfusion should be considered in HUS patients with severe anemia to avoid cardiac or pulmonary complications. Most patients who are Jehovah's Witnesses refuse blood transfusion, even in the face of life-threatening medical conditions due to their religious convictions. These patients require management alternatives to blood transfusions. Erythropoietin is a glycopeptide that enhances endogenous erythropoiesis in the bone marrow. With the availability of recombinant human erythropoietin (rHuEPO), several authors have reported its successful use in patients refusing blood transfusion. However, the optimal dose and duration of treatment with rHuEPO are not established. We report a case of a 2-year-old boy with diarrhea-associated HUS whose family members are Jehovah's Witnesses. He had severe anemia with acute kidney injury. His lowest hemoglobin level was 3.6 g/dL, but his parents refused treatment with packed RBC transfusion due to their religious beliefs. Therefore, we treated him with high-dose rHuEPO (300 IU/kg/day) as well as folic acid, vitamin B12, and intravenous iron. The hemoglobin level increased steadily to 7.4 g/dL after 10 days of treatment and his renal function improved without any complications. To our knowledge, this is the first case of successful rHuEPO treatment in a Jehovah's Witness child with severe anemia due to HUS.

• 한국세라믹학회지
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• 제34권6호
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• pp.652-658
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• 1997

The phase stability in the interface of Sr-doped LaMnO3(LSM)/Gd-doped CeO2(CGO) was examined in this study in order to check the feasibility of using LSM as the cathode material in a low-temperature SOFC(solid oxide fuel cell) using CGO as the electrolyte. For the purpose, CGO powders of Ce0.82Gd0.18O0.91 and two LSM powders having different compositions, La0.9Sr0.1MnO3(LSM10) and La0.5Sr0.5MnO3(LSM50), were synthesized using Pechini method. Then, specimens having the LSM/CGO interface were prepared, heat-treated at 130$0^{\circ}C$ for up to 3 days, and analyzed by XRD and STEM/EDX. Face-centered cubic CGO powders of less than 10 nm size were obtained by calcination of polymeric precursor formed in the process at 45$0^{\circ}C$. Higher calcination temperature of $700^{\circ}C$ was necessary for monoclinic LSM10 and cubic LSM50 powders. LSM powders were coarser than CGO and observed to be in the range of 50~100 nm. No trace of LSM-CGO interaction product was found in the XRD pattern. Also it was known from the concentration profile in the vicinity of the interface that interdiffusion was occurred over only a small penetration depth of ~100 nm order.

• 한국재료학회지
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• 제19권5호
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• pp.233-239
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• 2009

The electrocatalytic behavior of the PtCo catalyst supported on the multi-walled carbon nanotubes (MWNTs) has been evaluated and compared with commercial Pt/C catalyst in a polymer electrolyte membrane fuel cell(PEMFC). A PtCo/MWNTs electrocatalyst with a Pt:Co atomic ratio of 79:21 was synthesized and applied to a cathode of PEMFC. The structure and morphology of the synthesized PtCo/MWNTs electrocatalysts were characterized by X-ray diffraction and transmission electron microscopy. As a result of the X-ray studies, the crystal structure of a PtCo particle was determined to be a face-centered cubic(FCC) that was the same as the platinum structure. The particle size of PtCo in PtCo/MWNTs and Pt in Pt/C were 2.0 nm and 2.7 nm, respectively, which were calculated by Scherrer's formula from X-ray diffraction data. As a result we concluded that the specific surface activity of PtCo/MWNTs is superior to Pt/C's activity because of its smaller particle size. From the electrochemical impedance measurement, the membrane electrode assembly(MEA) fabricated with PtCo/MWNTs showed smaller anodic and cathodic activation losses than the MEA with Pt/C, although ohmic loss was the same as Pt/C. Finally, from the evaluation of cyclic voltammetry(CV), the unit cell using PtCo/MWNTs as the cathode electrocatalyst showed slightly higher fuel cell performance than the cell with a commercial Pt/C electrocatalyst.

• 청정기술
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• 제2권2호
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• pp.51-59
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• 1996

Billions of tons of industrial waste are generated annually in industrialized countries. Managing and legally disposing of these wastes costs tens to hundreds of billions of dollars each year, and these costs have been increasing rapidly. The escalation is likely to continue as emission standards become even more stringent around the world. In the face of these rapidly rising costs and rapidly increasing performance standards, traditional end-of-pipe approaches to waste management have become less attractive. The most economical waste management alternatives in many cases have become recycling of the waste or the redesign of chemical processes and products so that wastes are prevented or put to productive use. These strategies of recycling or reducing waste at the source have collectively come to be known as pollution prevention. The engineering challenges associated with pollution prevention are substantial. This presentation will categorize the challenges in three levels. At the most macroscopic level, the flow of materials in our industrial economy, from natural resource extraction to consumer product disposal, can be redesigned. Currently, most of our raw materials are virgin natural resources that are used once, then discarded. Studies in what has come to be called industrial ecology examine the material efficiency of large-scale industrial systems and attempt to improve that efficiency. A second level of engineering challenges is found at the scale of individual industrial facilities, where chemical processes and products can be redesigned so that waste is reduced. Finally, on a molecular level, chemical synthesis pathways, combustion reaction pathways, and other material fabrication procedures can be redesigned to reduce emissions of pollution and unwanted by-products. All of these design activities, shown in Figure 1, have the potential to prevent pollution. All involve the tools of engineering, and in particular, chemical engineering.

• Journal of Magnetics
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• 제15권4호
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• pp.179-184
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• 2010

We have investigated the effects of post annealing on iron oxide nanoparticles synthesized by the novel hydrothermal synthesis method with the $FeSO_4{\cdot}7H_2O$. To investigate the post annealing effect, the as-synthesized iron oxide nanoparticles were annealed at different temperatures in a vacuum chamber. The morphological, structural and magnetic properties of the iron oxide nanoparticles were investigated with high resolution X-ray powder diffraction (XRD), high resolution transmission electron microscopy (HRTEM), Mossbauer spectroscopy, and vibrating sample magnetometer analysis. According to the XRD and HRTEM analysis results, as-synthesized iron oxide nanoparticles were only magnetite ($Fe_3O_4$) phase with face-centered cubic structure but post annealed iron oxide nanoparticles at $700^{\circ}C$ were mainly magnetite phase with trivial maghemite ($\gamma-Fe_2O_3$) phase which was induced in the post annealing treatment. The crystallinity of the iron oxide nanoparticles is enhanced by the post annealing treatment. The particle size of the as-synthesized iron oxide nanoparticles was about 5 nm and the particle shape was almost spherical. But the particle size of the post annealed iron oxide nanoparticles at $700^{\circ}C$ was around 25 nm and the particle shape was spherical and irregular. The as-synthesized iron oxide nanoparticles showed superparamagnetic behavior, but post annealed iron oxide nanoparticles at $700^{\circ}C$ did not show superparamagnetic behavior due to the increase of particle size by post annealing treatment. The saturation of magnetization of the as-synthesized nanoparticles, post annealed nanoparticles at $500^{\circ}C$, and post annealed nanoparticles at $700^{\circ}C$ was found to be 3.7 emu/g, 6.1 emu/g, and 7.5 emu/g, respectively. The much smaller saturation magnetization value than one of bulk magnetite can be attributed to spin disorder and/or spin canting, spin pinning at the nanoparticle surface.

• Advances in nano research
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• 제3권2호
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• pp.97-109
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• 2015

Citrate ion is a commonly used reductant in metal colloid synthesis, undergoes strong surface interaction with silver nanocrystallites. The slow crystal growth observed as a result of the interaction between the silver surface and the citrate ion makes this reduction process unique compared to other chemical and radiolytic synthetic methods. The antimicrobial effects of silver (Ag) ion or salts are well known, but the effects of citrate coated Ag nanoparticles (CAgNPs) are scant. Herein, we have isolated biofilm causative bacteria and fungi from drinking water PVC pipe lines. Stable CAgNPs were prepared and the formation of CAgNPs was confirmed by UV-visible spectroscopic analysis and recorded the localized surface plasmon resonance of CAgNPs at 430 nm. Fourier transform infrared spectroscopic analysis revealed C=O and O-H bending vibrations due to organic capping of silver responsible for the reduction and stabilization of the CAgNPs. X-ray diffraction micrograph indicated the face centered cubic structure of the formed CAgNPs, and morphological studies including size (average size 50 nm) were carried out using transmission electron microscopy. The hydrodynamic diameter (60.7 nm) and zeta potential (-27.6 mV) were measured using the dynamic light scattering technique. The antimicrobial activity of CAgNPs was evaluated (in vitro) against the isolated fungi, Gram-negative and Gram-positive bacteria using disc diffusion method and results revealed that CAgNPs with 170ppm concentration are having significant antimicrobial effects against an array of microbes tested.

• 한방안이비인후피부과학회지
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• 제27권2호
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• pp.1-13
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• 2014

Objective : The purpose of this study is to understand conspicuous features of geroderma with visceral manifestation theory(臟象論). Methods : We categorized skin aging into wrinkles, hyperpigmentation, dry skin and face flush. After investigating the reason, histological changes and mechanism of each classification in western medicine, we interpreted them according to the malfunction of five viscera(五臟) in Korean medicine. Result : The results are as follows. 1. Pathologic change of dermis and subcutaneous fat makes wrinkles. We consider wrinkles as the malfunction of the spleen(脾). 2. Irregular synthesis and disproportion of melanin makes hyperpigmentation. We consider hyperpigmentation as the malfunction of the liver(肝). 3. Dry skin is attributed to a subtle disorder of epidermal maturation. We consider dry skin as the malfunction of the lung(肺). 4. Facial flush is detected in rosacea and menopausal hot flush, which are both related with blood vessel abnormality. We consider facial flush as the malfunction of the heart(心) Conclusion : We interpreted the pathologic changes and mechanism of skin aging in western medicine as the decrease of five viscera(五臟) in visceral manifestation theory(臟象論) of Korean medicine. Further studies are needed to apply these hypothesis to clinical diagnosis and treatment.

• 정보보호학회논문지
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• 제30권6호
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• pp.1053-1065
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• 2020

최근 하드웨어의 성능과 인공지능 기술이 발달함에 따라 육안으로 구분하기 어려운 정교한 가짜 동영상들이 증가하고 있다. 인공지능을 이용한 얼굴 합성 기술을 딥페이크라고 하며 약간의 프로그래밍 능력과 딥러닝 지식만 있다면 누구든지 딥페이크를 이용하여 정교한 가짜 동영상을 제작할 수 있다. 이에 무분별한 가짜 동영상이 크게 증가하였으며 이는 개인 정보 침해, 가짜 뉴스, 사기 등에 문제로 이어질 수 있다. 따라서 사람의 눈으로도 진위를 가릴 수 없는 가짜 동영상을 탐지할 수 있는 방안이 필요하다. 이에 본 논문에서는 Bidirectional Convolutional LSTM과 어텐션 모듈(Attention module)을 적용한 딥페이크 탐지 모델을 제안한다. 본 논문에서 제안하는 모델은 어텐션 모듈과 신경곱 합성망 모델을 같이 사용되어 각 프레임의 특징을 추출하고 기존의 제안되어왔던 시간의 순방향만을 고려하는 LSTM과 달리 시간의 역방향도 고려하여 학습한다. 어텐션 모듈은 합성곱 신경망 모델과 같이 사용되어 각 프레임의 특징 추출에 이용한다. 실험을 통해 본 논문에서 제안하는 모델은 93.5%의 정확도를 갖고 기존 연구의 결과보다 AUC가 최대 50% 가량 높음을 보였다.

• 융합신호처리학회논문지
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• 제23권3호
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• pp.173-178
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• 2022

최근 인공지능, 빅데이터, IoT 등의 다양한 컴퓨팅 기술이 발달하고 있다. 특히 콘텐츠 및 의료 산업 등 여러 분야에서 인공지능 기반의 딥페이크(Deepfake) 기술이 다양하게 활용되고 있다. 딥페이크 기술이란 딥러닝과 fake의 합성어로, AI의 핵심기술인 딥러닝을 통해 사람의 얼굴이나 신체를 합성하여 억양, 목소리 등을 따라 하게 만드는 기술이다. 본 논문은 딥페이크 기술을 활용하여 애니메이션 모델과 실제 인물사진의 합성을 통한 가상 캐릭터생성을 연구한다. 이를 통해 애니메이션 제작과정에서 일어나는 여러 가지 비용 손실을 최소화하고 작가들의 작업을 지원할 수 있다. 또한, 딥페이크 오픈소스가 인터넷에 퍼짐에 따라 많은 문제들이 나타나면서 딥페이크 기술을 악용한 범죄가 성행하고 있다. 본 연구를 통해서 딥페이크 기술을 성인물이 아닌 아동물에 적용하여 이 기술에 대한 새로운 관점을 제시한다.

• 전기화학회지
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• 제11권2호
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• pp.109-114
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• 2008

에탄올이 이산화탄소가 생성되는 경로로 반응할 경우 12개의 전자를 발생시키게 되지만 실제로는 두 개의 탄소 원자사이의 결합력 때문에 완전 산화시키는 것이 쉽지 않다. 따라서 고성능 에탄을 산화촉매의 개발은 에탄을 연료전지 실용화에 필수적이다. 본 연구는 Pt에 Sn, Au을 첨가하여 이원계, 삼원계 촉매를 제조하여 에탄올에서의 활성과 촉매의 특성에 대한 분석을 수행하였다. 촉매합성은 modified polyol 방법을 이용하였으며 Vulcan XC-72R 담지체를 사용하여 20 wt%로 담지하였다. PtSn/c 합금촉매는 Pt : Sn의 비율이 1 : 0, 4 : 1, 3 : 1, 2 : 1, 1.5 : 1, 1 : 1, 1 : 1.5으로 합성하였으며, PtSnAu/C 합금촉매는 Pt : Sn : Au의 비율을 5 : 5 : 0, 5 : 4 : 1, 5 : 3 : 2, 5 : 2 : 3으로 합성하였다. 촉매특성은 XRD, TEM 분석을 통해 분석한 결과 $1.9{\sim}2.4\;nm$ 정도의 입자의 크기와 면심입방구조의 구조를 가지는 것으로 확인하였다. 에탄올 산화에 대한 합금촉매의 활성은 순환전류전압법으로 실험하였고, 그 중 가장 높은 성능을 가진 PtSn(1.5 : 1)/C와 PtSnAu(5 : 2 : 3)/C 합금촉매를 단위전지 성능평가륵 통해 실제 연료전지 구동환경에서 촉매의 활성을 측정하였다. 그 결과 에탄을 산화에 가장 높은 성능을 나타낸 촉매는 PtSn/c(1.5 : 1)이었고, 촉매의 안정성은 PtSnAu/C(5 : 2 : 3)에서 높게 나타났다.