• Title, Summary, Keyword: DSA

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Three-Dimensional Digital Subtraction Angiographic Evaluation of Aneurysm Remnants after Clip Placement

  • Ahn, Soon-Seob;Kim, Young-Don
    • Journal of Korean Neurosurgical Society
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    • v.47 no.3
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    • pp.185-190
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    • 2010
  • Objective : The aneurysm remnants rate was evaluated via three-dimensional digital subtraction angiography (3D-DSA) in the postoperative evaluation of clipped aneurysms. Methods : Data on surgically clipped aneurysms of anterior circulation obtained via postoperative 3D-DSA from February 2007 to March 2009 were gathered. The results of the postoperative 3D-DSA and of two-dimensional digital subtraction angiography (2D-DSA) for the detection of aneurysm remnants were compared, and an investigation was performed as to why 2D-DSA had missed some aneurysm remnants that were detected in the 3D-DSA. Various surgical factors that revealed aneurysm remnants in the 3D-DSA were also evaluated. Results : A total of 39 neck remnants of 202 clipped aneurysms (19.3%) were confirmed in 3D-DSA, and these were classified according to Sindou's classification of aneurysm remnants. Patients with only a neck remnant found in the 3D-DSA represented 17.3% (35/202 aneurysms) of the whole series, and those with a residuum of neck plus sac found in the 3D-DSA represented 1.9% (4/202 aneurysms). The causes of aneurysm remnants were no full visualization (14/39, 35.9%), parent and perforator artery protection (10/39, 25.6%), clip design problems (8/39, 20.5%), and broadnecked aneurysm (7/39, 17.9%). Conclusion : Patients with ${\leq}2$mm aneurysm remnants showed an increased risk of undetectable aneurysm remnants in the 2D-DSA. The most frequent location of the missed aneurysm in 2D-DSA was the anterior communicating artery. 3D-DSA showed more aneurysm remnants than what is indicated in the existing literature, the 2D-DSA.

An Updated Review of Recent Studies on Dimensionally Stable Anodes (DSA) (불용성 산화 전극(DSA)의 최신 연구 동향)

  • Park, Su-Ryeon;Park, Jin-Soo
    • Journal of the Korean Electrochemical Society
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    • v.23 no.1
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    • pp.1-10
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    • 2020
  • DSA (Dimensionally Stable Anode) electrodes are physically, thermally and electrochemically stable and are mainly Ti electrodes coated by Ru, Ir and Ta. DSA electrodes have been used in many industrial fields such as chlor-alkali, electrochemical water treatment, water electrolysis, etc. This review paper summarizes the study on the applications using DSA electrodes published in the recent 5 years. It suggests that the researches are intensively required on effective screening of electrodes materials, optimal designing of electrode structures and economical manufacturing of large area electrodes. It is expected that these studies will contribute to the further research and development on advanced DSA electrodes. In addition, the enhancement of DSA electrodes significantly leads to expand the type of the application using electrochemical processes in industry.

A Review of Chlorine Evolution Mechanism on Dimensionally Stable Anode (DSA®) (DSA 전극에서 염소 발생 메커니즘)

  • Kim, Jiye;Kim, Choonsoo;Kim, Seonghwan;Yoon, Jeyong
    • Korean Chemical Engineering Research
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    • v.53 no.5
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    • pp.531-539
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    • 2015
  • Chlor-alkali industry is one of the largest electrochemical processes which annually producing 70 million tons of sodium hydroxide and chlorine from sodium chloride solution. $DSA^{(R)}$ (Dimensionally Stable Anodes) electrodes such as $RuO_2$ and $IrO_2$, which is popular in chlor-alkali process, have been investigated to improve the chlorine generation efficiency. Although DSA electrode has been developed with various researches, understanding of the chlorine evolution mechanism is essential to the development of highly efficient DSA electrode. In this review paper, chlorine generation mechanisms are summarized and that of key factors are identified to systematically understand the chlorine generation mechanism. Rate determining step, effect of pH, reaction intermediate, and electrode crystal structure were intensively overviewed as key factors of the chlorine mechanism.

Performance Analysis of Dynamic Spectrum Allocation in Heterogeneous Wireless Networks

  • Ha, Jeoung-Lak;Kim, Jin-Up;Kim, Sang-Ha
    • ETRI Journal
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    • v.32 no.2
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    • pp.292-301
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    • 2010
  • Increasing convergence among heterogeneous radio networks is expected to be a key feature of future ubiquitous services. The convergence of radio networks in combination with dynamic spectrum allocation (DSA) could be a beneficial means to solve the growing demand for radio spectrum. DSA might enhance the spectrum utilization of involved radio networks to comply with user requirements for high-quality multimedia services. This paper proposes a simple spectrum allocation algorithm and presents an analytical model of dynamic spectrum resource allocation between two networks using a 4-D Markov chain. We argue that there may exist a break-even point for choosing whether or not to adopt DSA in a system. We point out certain circumstances where DSA is not a viable alternative. We also discuss the performance of DSA against the degree of resource sharing using the proposed analytical model and simulations. The presented analytical model is not restricted to DSA, and can be applied to a general resource sharing study.

Effects of Motivational Activation on Processing Positive and Negative Content in Internet Advertisements

  • Lee, Seungjo;Park, Byungho
    • Science of Emotion and Sensibility
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    • v.15 no.4
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    • pp.517-526
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    • 2012
  • This study investigated the impact of individual differences in motivational reactivity on cognitive effort, memory strength (sensitivity) and decision making (criterion bias) in response to Internet ads with positive and negative content. Individual variation in trait motivational activation was measured using the Motivational Activation Measurement developed by A. Lang and her colleagues (A. Lang, Bradley, Sparks, & Lee, 2007). MAM indexes an individual's tendency to approach pleasant stimuli (ASA, Appetitive System Activation) and avoid unpleasant stimuli (DSA, Defensive System Activation). Results showed that individuals higher in ASA exert more cognitive effort during positive ads than individuals lower in ASA. Individuals higher in DSA exert more cognitive effort during negative ads compared to individuals lower in DSA. ASA did not predict recognition memory. However, individuals higher in DSA recognized ads better than those lower in DSA. The criterion bias data revealed participants higher in ASA had more conservative decision criterion, compared to participants lower in ASA. Individuals higher in DSA also showed more conservative decision criterion compared to individuals lower in DSA. The theoretical and practical implications are discussed.

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An Efficient DSA Signature Scheme Resistant to the Fault Analysis Attack (오류 분석 공격에 대응하는 효율적인 DSA 서명 기법)

  • Bae, Ki-Seok;Baek, Yi-Roo;Moon, Sang-Jae;Ha, Jae-Cheol
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.20 no.5
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    • pp.49-57
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    • 2010
  • The fault cryptanalysis is a physical attack in which the key stored inside of the device can be extracted by occurring some faults when the device performs cryptographic algorithm. Since the international signature standard DSA(Digital Signature Algorithm) was known to be vulnerable to some fault analysis attacks, many researchers have been investigating the countermeasure to prevent these attacks. In this paper we propose a new countermeasure to compute DSA signature that has its immunity in the presence of faults. Since additional computational overhead of our proposal is only an inverse operation in signature process, the proposed DSA scheme can be implemented more efficiently compared to previous countermeasures.

The Comparison of Usefulness between MDCT Angiography and DSA in the Diagnosis of Intracranial Aneurysm (뇌 동맥류 진단에 있어 디지털 감산 혈관조영술과 다중검출기 전산화단층촬영 혈관조영술의 유용성 비교)

  • Khang, Hyun-Soo;Seo, Sun-Youl;Han, Dong-Kyoon;Kwon, Soo-Il;Shim, Su-Jung;Cho, Sam-Ju
    • Progress in Medical Physics
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    • v.22 no.4
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    • pp.184-189
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    • 2011
  • The purpose of this study was to compare the image between DSA and MDCT Angiography and to examine whether MDCT Angiography could be useful as a screening test for the diagnosis of cerebral aneurysm in patients who were diagnosed with cerebral aneurysm on DSA. Of patients who were diagnosed with cerebral aneurysm DSA at University Hospital, 194 patients who concomitantly underwent MDCT Angiography were enrolled in the current retrospective study. The methods for analyzing cerebral aneurysm were to analyze the presence of cerebral aneurysm on DSA and MDCT Angiography. In cases in which it exceeded 1, the corresponding cases were classified as narrow-neck aneurysms. In otherwise cases, they were classified as wide-neck aneurysms. Thus, a comparative analysis could be performed to ascertain if cases were narrow-neck or wide-neck aneurysms. As compared with DSA, the sensitivity of MDCT Angiography for cerebral aneurysm was measured to be 97.4%. The degree of consistency between narrow-neck and wide-neck aneurysms was 90.2% and the proportion of undetectable an at MDCT Angiography was 2.54%. mean size was 2.4 mm. It is expected that a non-invasive diagnostic modality for a screening test for cerebral aneurysm, MDCT Angiography might be a very useful regimen as compared with an invasive one, DSA.

Usefulness of 3-Dimensional Gadolinium-enhanced MR Angiography for the Evaluation of Pedal Artery. : Comparison with digital subtraction angiography (족부혈관 평가에 있어서의 3차원 Gadolinium 조영증강 자기공명혈관조영술의 유용성 : 디지털 감산 혈관조영술과의 비교)

  • Ji, Youn-Sang;Lee, Bong-Jae
    • Journal of radiological science and technology
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    • v.24 no.2
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    • pp.23-28
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    • 2001
  • The purpose of this study is to compare the 3-dimensional MR angiography(MRA) with digital subtraction angiography(DSA) for the evaluation of pedal artery. MR angiography was performed using three-dimensional FISP acquisition before, and four sequential acquisitions after the injection of gadolinium(0.2 mmol/kg, 3 ml/sec). MRA was compared with DSA for a correct identification of the arterial segment. Out of 168 segments, 32 segmints were invisible in both MRA and DSA. At the level of ankle, 48 segments were visible in both examinations, and 18 segments were visible only in MRA. In the foot area, 34 segments were visible in MRA, but not in DSA. Three arterial segments were visible only in DSA. 3D MRA is comparable to DSA for the evaluation of pedal artery, thus it gives additional Information for the planning of treatment in lower extremity artery.

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Electrochemical Characteristics of Assembled-Graphite/DSA Electrode for Redox Flow Battery (Redox Flow Battery용 일체화된 흑연/DSA 전극의 전기화학적 특성)

  • Kim, Hyung-Sun
    • Journal of the Korean Electrochemical Society
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    • v.13 no.2
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    • pp.123-127
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    • 2010
  • An assembled-graphite/DSA(Dimensionally Stable Anode) was prepared using graphite powder to increase durability and energy efficiency of redox flow battery and investigated its electrochemical properties in vanadium-based electrolyte. The cyclic voltammetry (CV) was carried out in the voltage range of -0.7V and 1.6V vs. SCE at 5 mV/sec scan rate to analyze vanadium redox reaction. From the CV results, the assembled-graphite/DSA electrode showed a fast couple reaction and good reversibility in 2M $VOSO_4$ + 2.5 M $H_2SO_4$ electrolyte. Therefore, it has been expected that this electrode increases power density as well as energy density of redox flow battery.

Influences of Coating Cycles and Composition on the Properties of Dimensionally Stable Anode for Cathodic Protection

  • Yoo, Y.R.;Chang, H.Y.;Take, S.;Kim, Y.S.
    • Corrosion Science and Technology
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    • v.5 no.2
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    • pp.45-51
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    • 2006
  • Properties of the anode for cathodic protection need low overvoltage for oxygen evolution and high corrosion resistance. It is well known that DSA (Dimensionally Stable Anode) has been the best anode ever since. DSA is mainly composed of $RuO_2$, $IrO_2$, $ZrO_2$, $Co_2O_3$, and also $Ta_2O_5$, $TiO_2$, $MnO_2$ are added to DSA for better corrosion resistance. The lifetime of DSA for cathodic protection is also one of the very important factors. $RuO_2$, $IrO_2$, $RhO_2$, $ZrO_2$ are well used for life extension, and many researches are focused on life extension by lowering oxygen evolution potential and minimizing dissolution of oxide coatings. This work aims to evaluate the influence of constituents of MMO and coating cycles and $ZrO_2$ coating on the electrochemical properties and lifetime of DSA electrodes. From the results of lifetime assessment in the anodes coated with single component, $RuO_2$ coating was more effective and showed longer lifetime than $IrO_2$ coating. Also, an increased coating cycle and an electrochemically coated $ZrO_2$ could enhance the lifetime of a DSA.