• Title/Summary/Keyword: MD&A

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Molecular Simulations for Anti-amyloidogenic Effect of Flavonoid Myricetin Exerted against Alzheimer’s β-Amyloid Fibrils Formation

  • Choi, Young-Jin;Kim, Thomas Donghyun;Paik, Seung R.;Jeong, Karp-Joo;Jung, Seun-Ho
    • Bulletin of the Korean Chemical Society
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    • v.29 no.8
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    • pp.1505-1509
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    • 2008
  • Comparative molecular simulations were performed to establish molecular interaction and inhibitory effect of flavonoid myricetin on formation of amyloid fibris. For computational comparison, the conformational stability of myricetin with amyloid $\beta$ -peptide (A$\beta$ ) and $\beta$ -amyloid fibrils (fA$\beta$) were traced with multiple molecular dynamics simulations (MD) using the CHARMM program from Monte Carlo docked structures. Simulations showed that the inhibition by myricetin involves binding of the flavonoid to fA$\beta$ rather than A$\beta$ . Even in MD simulations over 5 ns at 300 K, myricetin/fA$\beta$ complex remained stable in compact conformation for multiple trajectories. In contrast, myricetin/A$\beta$ complex mostly turned into the dissociated conformation during the MD simulations at 300 K. These multiple MD simulations provide a theoretical basis for the higher inhibitory effect of myricetin on fibrillogenesis of fA$\beta$ relative to A$\beta$ . Significant binding between myricetin and fA$\beta$ observed from the computational simulations clearly reflects the previous experimental results in which only fA$\beta$ had bound to the myricetin molecules.

Clinical Features of Symptomatic Meckel's Diverticulum in Children: Comparison of Scintigraphic and Non-scintigraphic Diagnosis

  • Rho, Jung Hee;Kim, Jae Sook;Kim, Sang Yong;Kim, Soon Ki;Choi, Yoon Mi;Kim, Sung Min;Tchah, Hann;Jeon, In Sang;Son, Dong Woo;Ryoo, Eell;Cho, Kang Ho;Choi, Deok Young;Kim, Yoon Mi
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • v.16 no.1
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    • pp.41-48
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    • 2013
  • Purpose: Meckel's diverticulum (MD) has various clinical manifestations, and diagnosis or selectection of proper diagnostic tools is not easy. This study was conducted in order to assess the clinical differences of MD diagnosed by scintigraphic and non-scintigraphic methods and to find the proper diagnostic tools. Methods: We conducted a retrospective review ofthe clinical, surgical, radiologic, and pathologic findings of 34 children with symptomatic MD, who were admitted to Gachon University Gil Medical Center, Inha University Hospital, and The Catholic University of Korea, Incheon St. Mary's Hospital between January 2000 and December 2012. The patients were evaluated according to scintigraphic (12 cases; group 1) and non-scintigraphic (22 cases; group 2) diagnosis. Results: The male to female ratio was 7.5: 1. The most frequent chief complaint was lower gastrointestinal (GI) bleeding in group 1 and nonspecific abdominal pain in group 2, respectively. The most frequent pre-operative diagnosis was MD in both groups. Red blood cell (RBC) index was significantly lower in group 1. MD was located at 7 cm to 85 cm from the ileocecal valve. Four patients in group 1 had ectopic gastric tissues causing lower GI bleeding. The most frequent treatment modality was diverticulectomy in group 1 and ileal resection in group 2, respectively. Conclusion: To diagnose MD might be delayed unless proper diagnostic tools are considered. It is important to understand indications of scintigraphic and non-scintigraphic methods according to clinical and hematologic features of MD. Scintigraphy would be weighed in patients with anemia as well as GI symptoms.

A Study on the Control System of Maximum Demand Power Using Neural Network and Fuzzy Logic (신경망과 퍼지논리를 이용한 최대수요전력 제어시스템에 관한연구)

  • 조성원
    • Journal of the Korean Institute of Intelligent Systems
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    • v.9 no.4
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    • pp.420-425
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    • 1999
  • The maximum demand controller is an electrical equipment installed at the consumer side of power system for monitoring the electrical energy consumed during every integrating period and preventing the target maximum demand (MD) being exceeded by disconnecting sheddable loads. By avoiding the peak loads and spreading the energy requirement the controller contributes to maximizing the utility factor of the generator systems. It results in not only saving the energy but also reducing the budget for constructing the natural base facilities by keeping thc number of generating plants ~ninimumT. he conventional MD controllers often bring about the large number of control actions during the every inteyating period and/or undesirable loaddisconnecting operations during the beginning stage of the integrating period. These make the users aviod the MD controllers. In this paper. fuzzy control technique is used to get around the disadvantages of the conventional MD control system. The proposed MD controller consists of the predictor module and the fuzzy MD control module. The proposed forecasting method uses the SOFM neural network model, differently from time series analysis, and thus it has inherent advantages of neural network such as parallel processing, generalization and robustness. The MD fuzzy controller determines the sensitivity of control action based on the time closed to the end of the integrating period and the urgency of the load interrupting action along the predicted demand reaching the target. The experimental results show that the proposed method has more accurate forecastinglcontrol performance than the previous methods.

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Optimization of supplementation with maltodextrin and grape seed extract for improving quality of shredded Korean cabbage (Brassica rapaL. ssp. Pekinensis) during salting process (절임 공정 중 절단 배추의 품질 향상을 위한 maltodextrin과 grape seed extract 첨가조건 최적화)

  • Park, Sang-Un;Choi, Eun Ji;Chung, Young Bae;Han, Eung Soo;Park, Hae Woong;Chun, Ho Hyun
    • Food Science and Preservation
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    • v.23 no.7
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    • pp.913-922
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    • 2016
  • The aim of this study was to develop a new salting condition that included added maltodextrin (MD) and grape seed extract (GSE) to ensure the microbiological safety and quality of salted shredded Korean cabbage. Response surface methodology (RSM) was used to analyze the effects of four independent variables (NaCl concentration, salting duration, MD concentration, and GSE concentration). The following response variables were evaluated: reduction in total aerobic bacteria, yeast, and mold counts; weight loss and salt content; and taste, texture, and overall acceptability of salted shredded Korean cabbage. The optimal salting conditions include a combination of 10.09~10.32% NaCl, 9.45~10.00% MD, and 234~300 ppm GSE in a ternary salting solution and a salting duration of 5.68~5.94 hr. This optimal combination reduced total aerobic bacterial and yeast/molds counts by 3.33 and 1.45 log CFU/g, respectively, while maintaining high sensory scores for taste, texture, and overall acceptability of the salted shredded Korean cabbage. In addition, the optimal conditions yielded more acceptable weight loss and salt content characteristics. The results suggest that use of the optimized combination of salting conditions can improve the microbiological safety and quality of salted shredded Korean cabbage used for commercial kimchi production.

The Magnitude Distribution method of U/V decision (음성신호의 전폭분포를 이용한 유/무성음 검출에 대한 연구)

  • 배성근
    • Proceedings of the Acoustical Society of Korea Conference
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    • 1993.06a
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    • pp.249-252
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    • 1993
  • In speech signal processing, The accurate detection of the voiced/unvoiced is important for robust word recognition and analysis. This algorithm is based on the MD in the frame of speech signals that does not require statistical information about either signal or background-noise to decide a voiced/unvoiced. This paper presents a method of estimation the Characteristic of Magnitude Distribution from noisy speech and also of estimation the optimal threshold based on the MD of the voiced/unvoiced decision. The performances of this detectors is evaluated and compared to that obtained from classifying other paper.

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A Study of Dynamic Properties of Graphene-Nanoribbon Memory (그래핀 나노리본 메모리의 동적 특성에 대한 연구)

  • Lee, Jun Ha
    • Journal of the Semiconductor & Display Technology
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    • v.13 no.2
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    • pp.53-56
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    • 2014
  • In this work, we investigate the operational properties of this proposed device in detail via classical MD simulations. The bi-stability of the GNF(Graphene Nano-flake) shuttle encapsulated in bi-layer GNR could be achieved from the increase of the attractive energy between the GNRs when the GNF approached the edges of the GNRs. This result showed the potential application of the nano-electromechanical GNR memory as a NVRAM.

ADP-Ribosylation: Activation, Recognition, and Removal

  • Li, Nan;Chen, Junjie
    • Molecules and Cells
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    • v.37 no.1
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    • pp.9-16
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    • 2014
  • ADP-ribosylation is a type of posttranslational modification catalyzed by members of the poly(ADP-ribose) (PAR) polymerase superfamily. ADP-ribosylation is initiated by PARPs, recognized by PAR binding proteins, and removed by PARG and other ADP-ribose hydrolases. These three groups of proteins work together to regulate the cellular and molecular response of PAR signaling, which is critical for a wide range of cellular and physiological functions.

A Theoretical Investigation of FCO and $FCO^+$

  • Sung, Eun-Mo;Lee, Ho-Soon
    • Bulletin of the Korean Chemical Society
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    • v.11 no.6
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    • pp.511-515
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    • 1990
  • Ab initio calculations with MP3 and CISD method were performed for the FCO and $FCO^+$. The equilibrium geometry of FCO shows the reasonable agreement with experimental values. $FCO^+$ has a linear geometry with $R_{CF}=1.213\;and\;R_{CO}=1.118{\AA}$. The quadratic force constants of $FCO^+$ are 23.21 md ${\AA}^{-1}$ for CO stretch and 12.38 md ${\AA}^{-1}$ for CF stretch. The cubic force constants and the other molecular constants are also calculated.

A Study on Secure Query/Response System using Pseudonoise Sequence in DNS (DNS상에서 Pseudonoise Sequence를 사용한 안전한 질의/응답 시스템에 관한 연구)

  • 석우진;이만희;최홍진;변옥환
    • Proceedings of the Korean Information Science Society Conference
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    • 1998.10a
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    • pp.612-614
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    • 1998
  • DNS는 인터넷상에서 도메인 네임과 IP 주소간의 상호 전환의 동작을 수행하는 시스템이다. DNS상에서 도메인 네임이나 IP 주소를 요청하는 질의나 이에 대한 응답은 네트워크상에서 UDP를 사용한 메시지 형식으로 전송한다. 이때 제 3자의 개입에 의한 조작의 가능성이 있다. 이러한 질의와 응답 메시지의 조작을 방지하고자 RFS2065에서는 RSA 공개키 방식을 사용하였다. RSA 공개키 방식은 현제 국내에서 직접사용하기에는 많은 애로 사항이 있으며 속도 측면에서 좋지 않은 면을 보여준다. 본 논문에서는 Pseudonoise Sequence와 MD5를 사용하여 DNS 상에서의 안전한 질의 응답을 가능하게 하고자 한다. Pseudonoise Sequence와 MD5를 사용함으로써 메시지를 암오화하지않아도 되며 또한 많은 계산을 요구하지 않는다. 메시지에 Pseudonoise Sequence를 기입하고, 그 메시지의 MD5를 송수신 측에서 검사함으로써 제 3자 개입에 의한 조작 방지와 메시지 데이터의 무결성을 보할 수 있다.

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Application of Mahalanobis Taguchi System for Analysis of Multivariate System (Mahalanobis Taguchi System을 이용한 다변량 시스템의 해석에 관한 연구)

  • Hong, Jeong-Eui;Kim, Yong-Beom
    • Proceedings of the Safety Management and Science Conference
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    • 2005.11a
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    • pp.300-310
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    • 2005
  • Mahalanobis Taguchi System (MTS) is developed by Genishi Taguchi as a part of his quality engineering methodology. The basic idea of Taguchi's quality engineering is looking for the way of effectiveness of analyzing multivariate system. In the MTS, with the standardized variables of healthy normal data, Mahalanobis Distance(MD) calculated and that can be discriminate between normal and abnormal objects. If this discrimination process is successful, next step is optimization which is try to reduce number of attributes by neglecting less effective attributes to MD. Orthogonal Array (OA) and Signal to Noise ratio (S/N) are used to evaluate the amount contribution of each attribute to the MD. Wisconsin Breast Cancer study, from machining learning repository at University of California at Irvine, used for examining the discriminant ability of MTS.

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