• Title, Summary, Keyword: 가역성

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Effect of PCB on the Oocyte Maturation and Proges- terone Production of Frog, Rana dybowskii in Vitro

  • 고선근;이두표
    • Korean Journal of Environment and Ecology
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    • v.17 no.1
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    • pp.18-25
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    • 2003
  • In order to know the effects of PCB(Arochlor 1248) on the oocyte maturation and proges-terone(P$_4$) production by FPH(Frog pituitary homogenate: 0.01 p.e/$m\ell$) of frog in vitro, the oocytes were cultured for 20 hours in presence of the PCB at various concentrations and exam-ined their maturation(germinal vesicle breakdown: GVBD) rates and P$_4$ levels secreted by the oocyte in the culture medium. The results show that PCB concentration of 10 ppb suppressed the maturation of the oocytes and secretion of P$_4$. To examine the reversibility of the inhibitory effects, the oocytes were exposed to the PCB only for 3 hours, and then transferred to plain medium and cultured further for 17 hours. The oocytes were recovered from the toxic effect of the PCB when they were exposed to 2.5 ppb, but not to 5 ppb of the PCB. These results indi-cate that PCB suppress the maturation of oocytes and secretion of p, at low concentration, sug-gesting that the frog oocyte culture system can be used as a useful tool to evaluate the toxicity of the pollutants in the environment.

Reversible Watermarking based on Predicted Error Histogram for Medical Imagery (의료 영상을 위한 추정오차 히스토그램 기반 가역 워터마킹 알고리즘)

  • Oh, Gi-Tae;Jang, Han-Byul;Do, Um-Ji;Lee, Hae-Yeoun
    • KIPS Transactions on Software and Data Engineering
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    • v.4 no.5
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    • pp.231-240
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    • 2015
  • Medical imagery require to protect the privacy with preserving the quality of the original contents. Therefore, reversible watermarking is a solution for this purpose. Previous researches have focused on general imagery and achieved high capacity and high quality. However, they raise a distortion over entire image and hence are not applicable to medical imagery which require to preserve the quality of the objects. In this paper, we propose a novel reversible watermarking for medical imagery, which preserve the quality of the objects and achieves high capacity. First, object and background region is segmented and then predicted error histogram-based reversible watermarking is applied for each region. For the efficient watermark embedding with small distortion in the object region, the embedding level at object region is set as low while the embedding level at background region is set as high. In experiments, the proposed algorithm is compared with the previous predicted error histogram-based algorithm in aspects of embedding capacity and perceptual quality. Results support that the proposed algorithm performs well over the previous algorithm.

The Effects of Anticholinesterase Drugs on Gastric Motility (항콜린에스테라제 약물의 소화관 운동성에 대한 영향)

  • Choi, Hyoung-Chul;Kim, Jong-Ho;Ha, Jeoung-Hee;Lee, Kwang-Yoon;Kim, Won-Joon;Kwak, Dong-Suk;Kim, Sung-Hee;Song, Phil-Hyun;Yeo, Ji-Hyun
    • Yeungnam University Journal of Medicine
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    • v.16 no.2
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    • pp.318-325
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    • 1999
  • Background: Anticholinesterase drug inhibits acetylcholinesterase(AChE), induce accumulation of acetylcholine(ACh) near cholinergic receptors and cholinergic stimulation. This experiment was performed to study the effects of anticholinesterase drugs on gastric motility and the effect of ethanol on anticholinesterase drug-induced motility change. Materials and Methods: After excision of stomach, $2{\times}10mm$ circular muscle strips were made, which were then fixed to the isolated muscle chamber. An isometric tension transducer was used to measure the contraction change of the gastric smooth muscle strips after drug addition. Results: Fenthion, an irreversible anticholinesterase drug, increased ACh induced contraction of gastric smooth muscle strips and PAM, a cholinesterase activator, antagonized this action. Physostigmine, a reversible anticholinesterase drug, also increased the ACh induced contraction. The gastric motility was decreased by PAM. Ethanol, which is known to induce smooth muscle relaxation, inhibited the increase of contraction by fenthion. Conclusion: These results indicate that irreversible and reversible anticholinesterase drugs increase gastric motility and antagonized by cholinesterase activating drugs. And when exposed to both ethanol and anticholinesterase drug, gastric motility was decreased by the smooth muscle relaxation effect by ethanol.

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Study on the safety analysis method based on thermodynamic characteristics analysis for high capacity and high power lithium battery (고용량/고출력 리튬 이차 전지의 열역학적 특성 분석 기반의 안전성 분석 방법에 대한 연구)

  • Kang, Deokhun;Kim, Kyungjin;Kim, Sungkeun;Kim, Jonghoon
    • Proceedings of the KIPE Conference
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    • pp.37-39
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    • 2020
  • 리튬이온 배터리는 동작하는 과정에서 필연적으로 열이 발생하기 때문에 적절한 열 관리에 대한 전략이 필요하다. 배터리에서의 발열은 가역적인 발열과 비가역적인 발열로 분류될 수 있으며 배터리의 용도별, 동작 조건 별 발열 특성이 상이하기 때문에, 배터리의 열적 안전성 확보를 위해서는 열적 특성에 대한 분석이 필수적이다. 본 연구에서는 고용량/고출력 리튬이온 배터리의 전기적 특성 실험을 수행하고 열적 안전성 분석을 위하여 발열 특성 분석을 수행하였다. 고용량/고출력 배터리 특성에 따라 가역적 발열과 비가역적 발열이 나타나는 특성이 상이한 것으로 확인되었으며, 또한 온도 측정 정보로부터 배터리의 내부 상태 특성을 추정하고 고장 진단 및 수명 특성에 활용될 수 있음을 확인하였다.

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Study on the Urethane Restoration Filling Material and Adhesive for Stone Cultural Heritage (석조문화재 복원용 우레탄 메움제 및 접착제에 관한 연구)

  • Han, Won-Sik;Lee, Ho-Youn;Park, Gi-Jung;Hong, Tae-Kee;Wi, Koang-Chul
    • Journal of Conservation Science
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    • v.27 no.1
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    • pp.115-121
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    • 2011
  • A Urethane resin restoration material was made to be used in the restoration of stone cultural assets. The Urethane resin restoration material showed strong adhesive strength and tensile strength similar to epoxy recovery material, which had been mainly used for the recovery of stone cultural assets. The sealing property, anti-shrinking property and paint-ability of Urethane resin restoration material are also similar to existing epoxy system restoration materials. Especially, this Urethane resin restration material is expected to give permanence and continuous stability in the restoration of cultural assets made in stone by resolving the two big issues of existing epoxy recovery material, which are 'yellowing' and 'ir-reversibility'. This Urethane resin restration material had been directly applied as a filling material and adhesive and it was dissolved again. The Urethane resin, which had been used for the recovery, was able to be perfectly removed, which means that this Urethane resin recovery material has perfect reversibility. This Urethane resin restoration material also has enhanced convenience since user can adjust the working-life dependent on work environment. It is believed that this Urethane resin restoration material can also be used as a filling material or adhesive for other cultural assets made of ceramic or metal heritage, in addition to stone, since it has strong adhesive strength and tensile strength.

Nondestructive Evaluation of Remanent Life of Turbine Rotor Steel by Measuring Reversible Magnetic Permeability (가역투자율 측정에 의한 터빈로터강의 비파괴적 잔여수명 평가)

  • Ryu, Kwon-Sang;Nahm, Seung-Hoon;Kim, Yong-Il
    • Journal of the Korean Society for Nondestructive Testing
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    • v.23 no.4
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    • pp.315-321
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    • 2003
  • The integrity of the turbine rotors can be assessed by measuring the material properties at service temperature. In order to evaluate the remanent life of turbine rotor steel nondestructively, a measurement system of reversible magnetic permeability using an alternating perturbing magnetic field was constructed. We present a new non-destructive method to evaluate the remanent life of 1Cr-1Mo-0.25V steel using the value of reversible magnetic permeability. This method is based on the existence of reversible magnetic permeability in the differential magnetization around the coercive field strength. We measured the first harmonics voltage induced in a coil using a lock-in amplifier tuned to an exciting frequency. The Results of reversible magnetic Permeability and Wickers hardness on the aged samples show that the peak interval of reversible magnetic permeability (PIRMP) and Vickers hardness decreases as aging time increases. A softening curve is obtained from the correlation between Vickers hardness and the PIRMP. This curve can be used as a non-destructive method to evaluate the remanent life of turbine rotor steel.

Role of Redistribution and 24 Hour Reinjection Images to assess Myocardial Viability in Patients with Acute Myocardial Infarction (급성심근경색환자의 심근생존능 평가에 있어서 T1-201 재분포영상과 24시간 재주사영상의 역할)

  • Yoon, Seok-Nam;Pai, Moon-Sun;Park, Chan-H.;Yoo Myung-Ho;Choi, Byung-Il William
    • The Korean Journal of Nuclear Medicine
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    • v.32 no.4
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    • pp.325-331
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    • 1998
  • Purpose: We evaluated the importance of redistribution and 24 hour reinjection images in T1-201 SPECT assessment of myocardial viability after acute myocardial infarction (AMI). Materials and Methods: We performed dipyridamole stress-4 hour redistribution-24 hour reinjection T1-201 SPECT in 43 patients with recent AMI (4-16 days). The myocardium was divided into 16 segments and perfusion grade was measured visually with 4 point score from 0 to 3 (absent uptake to normal uptake). A perfusion defect with stress score 2 was considered moderate. A defect was considered severe if the stress score was 0 or 1 (absent uptake or severe perfusion decrease). Moderate defect on stress image were considered viable and segments with severe defect were considered viable if they showed improvement of 1 score or more on redistribution or reinjection images. We compared the results of viability assessment in stress-redistribution and stress-reinjection images. Results: On visual analysis, 344 of 688 segments (50%) had abnormal perfusion. Fifty two (15%) had moderate perfusion defects and 292 (85%) had severe perfusion defects on stress image. Of 292 severe stress defects, 53 were irreversible on redistribution and reversible on reinjection images, and 15 were reversible on redistribution and irreversible on reinjection images. Two hundred twenty four of 292 segments (76.7%) showed concordant results on stress-redistribution and stress-reinjection images. Therefore 24 hour reinjection image changed viability status from necrotic to viable in 53 segments of 292 severe stress defect (18%). However, myocardial viability was underestimated in only 5% (15/292) of severe defects by 24 hour reinjection. Conclusion: The 24 hour reinjection imaging is useful in the assessment of myocardial viability. It is more sensitive than 4 hour redistribution imaging. However, both redistribution and reinjection images are needed since they complement each other.

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A Study on the Chromatographic Separation of Proteins Using Fibrous Beds(I) -Adsorbent Fiber Manufactures and Data Handling- (섬유층을 이용한 단백질의 크로마토그래피적 분리에 관한 연구(I) -흡착성 섬유제조 및 자료처리-)

  • 박돈희;박주정
    • KSBB Journal
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    • v.9 no.2
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    • pp.98-103
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    • 1994
  • A bed configuration wherein sheets of modified fibrous polyethylene are potted within a Millipore Filter Cartridge matrix has been developed. Polyethylene fibers form sturdy beds but the native hydrophobicity and inertness of polyethylene have precluded their use in protein chromatography The polyethylene fibers used in this system were modified by plasma oxidation and further derivatization. The resulting fibers are hydrophilic, bind protein reversibly and serve as an anion-exchange stationary phase. Separation of Bovine Serum Albumin on this bed, as well as results of basic studies on capacity and reversibility of binding within a fibrous bed and experimental data handling system are shown.

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Distinguish Attack of block ciphers based on Reversible Cellular Automata (가역 셀룰러 오토마타 기반 블록 암호에 대한 취약점 분석)

  • Ryu, Han-Seong;Lee, Je-Sang;Lee, Chang-Hoon;Sung, Jae-Chul;Hong, Seok-Hie
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • pp.59-61
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    • 2008
  • 셀룰러 오토마타(CA:cellular automata)의 특징 중에서 확산(Diffusion)과 국소적인 상호 작용(Local Interaction)은 암호시스템을 설계하는데 적합하여 암호 알고리즘, 의사난수 생성기를 비롯한 암호시스템의 설계 논리로 활용되고 있다. 본 논문에서는 2004년에 제안된 가역 셀룰러 오토마타 기반 블록 암호(BCRCA)에 대한 취약점 분석을 소개한다. BCRCA는 224 비트의 안전성을 가져야 하지만, 균일한 키를 이용할 경우 통계적 취약점을 이용하여 191.8 비트의 안전성을 갖는다.

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An Advanced Watermarking Algorithm with Reversibility (개선된 가역 워터마킹 알고리즘)

  • Jung, Soo-Mok
    • Journal of the Korea Convergence Society
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    • v.9 no.2
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    • pp.151-156
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    • 2018
  • In this paper, an efficient reversible watermarking algorithm is proposed. By using the proposed algorithm, it is possible to increase the amount of copyright-related information to be embedded in cover image. Depending on the spatial locality and surface characteristics, it is possible to precisely predict the pixel value using neighboring pixels. If the predicted pixel value almost the same as the pixel value of the cover image, the differential value between the predicted pixel value and the pixel value of cover image is very small. So, the frequency is increased greatly at the peak point of histogram of difference sequence. Thus, it is possible to increase greatly the amount of secret data to be embedded in cover image. The experimental results show that the proposed watermarking algorithm is superior to the previous algorithms.