의료용 초음파 B-모드 영상을 위한 신호처리

송태경 한국비파괴검사학회 2000 한국비파괴검사학회지 Vol.20 No.6

초음파 영상은 의료진단을 위한 영상기기 중 가장 널리 쓰이고 있는 방법으로 전자공학에 있어서 DSP 및 VLSI 분야의 기술발전에 힘입어 보다 효율적이고 복잡한 기법들이 적용이 가능하여져 90년대에 이르러 시스템의 성능이 매우 빠르게 발달되었다. 본 논문은 의료진단용 초음파 영상장치에서 사용되는 주요 디지털 신호처리 기법과 시스템 구현 기술에 대하여 기술하였다. 구체적으로는 일반적인 초음파 영상장치의 구조 및 신호처리 기법을 소개하고, 90년대에 개발된 디지털 초음파 영상장치의 기술적인 내용을 그 기술 동향과 전망과 함께 다루었다. 특히 초음파 영상의 화질을 결정하는 가장 중요한 요소인 해상도를 증대하기 위한 모든 초음파 집속 기법을 표현할 수 있는 통합 합성 구경 모형을 제시하고, 이론적인 해석을 통하여 초음파 영상을 위한 어레이 신호처리 기법들을 구분하고 각 방법들에 대한 특성을 조사하였다. 본 논문에서 소개된 신호처리 기법들은 초음파를 이용한 비파괴 검사 분야에 유용하게 적용될 수 있는 것 들이다. Ultrasonic imaging is the most widely used modality among modern imaging debices for medical diagnosis and the system performance has been improved dramatically since early 90's due to the rapid advances in DSP performance and VLSI technology that made it possible to employ more sophisticated algorithms. This paper describes "main stream" digital signal processing functions along with the associated implementation considerations in modrn medical ultrasound imaging systems. Topics covered include signal processing methods for resloution improvement. ultrasound imaging system architectures, rolse and necessity of the applications of DSP and VLSI technology in the development of the medical ultrasound imaging systems, and array signal processing techniques for ultrasound focusing.

Heterocyclic Compounds from Chrysanthemum coronarium L. and Their Inhibitory Activity on hACAT-1, hACAT-2, and LDL-Oxidation

Song, Myoung-Chong,Yang, Hye-Joung,Jeong, Tae-Sook,Kim, Kyong-Tai,Baek, Nam-In 대한약학회 2008 Archives of Pharmacal Research Vol.31 No.5

The aerial parts of Chrysanthemum coronarium L. were extracted with MeOH, and the concentrated extract was partitioned using EtOAc, n-BuOH, and $H_2O$, successively. Repeated column chromatography of the EtOAc and n-BuOH fractions gave a new heterocycle, 5,5'-dibuthoxy-2,2'-bifuran (1) along with five known compounds: methyl trans-ferulate (2), prunasin (3), sambunigrin (4), pterolactam (5), and adenosine (6), which were identified by several spectroscopic methods including NMR and MS. This paper is the first report on the isolation of these compounds from C. coronarium L. The $IC_{50}$ values of compound 1 for human Acyl-CoA:cholesterol acyltransferase (hACAT)-1 and hACAT-2 were 0.16 mM and 0.19 mM, respectively. Compound 2 inhibited low-density lipoprotein (LDL) oxidation with an $IC_{50}$ value of $7.7\;{\mu)M$.

INHIBITION OF ATP - INDUCED [ Ca2+ ] RISE BY HISTAMINE - MEDIATED PKA ACTIVATION IN HL60 PROMYELOCYTES

Sook Keun Song,Byung Chang Suh,Kyong Tai Kim 생화학분자생물학회 1996 생화학분자생물학회 춘계학술발표논문집 Vol.- No.-

의료기관 BSC 전개의 성공요인에 관한 사례연구

김태경(Kim, Tai Kyong),김정원(Kim, Jung Won),송경수(Song, Kyung Soo) 한국인적자원관리학회 2011 인적자원관리연구 Vol.18 No.4

최근 병원조직에서도 경영성과를 평가하기 위한 방법으로 균형적 성과관리 측정도구라 할 수 있는 BSC(Balanced Scorecard) 기법을 도입하고 있다. 이에 따라 본 연구는 국내ㆍ외 의료 기관에의 BSC의 도입이나 적용 사례를 조사ㆍ비교ㆍ평가함으로써 의료 기관에의 최적의 BSC 도입 및 전개를 위한 방법, 고려사항, 그리고 시사점을 제시하고자 한다. 의료기관의 주요 보직자로서 의사 또는 병원장은 결정권자로서의 큰 권력을 가지고 있는 반면, 관리자나 경영자로서의 능력이 부족할 수 있다. 이러한 의료기관의 조직 특성은 BSC의 원활한 도입과 운영을 저해시킬 위험성이 크다. 이런 점에서 의료기관이 BSC를 도입하고 원활하게 운영하기 위해서는 조직의 최고경영자 또는 최고행정책임자의 의지와 리더십이 무엇보다 중요하다. 아무리 합리적이고 객관적인 성과 평가 체계라 할지라도, 조직원의 협조가 없다면 성과 개선은 기대할 수 없기 때문이다. BSC 도입 성공 병원 사례를 벤치마킹하고, 전문가 그룹을 구성 전략을 모색해 나가기에 앞서 BSC 도입의 필요성을 모든 조직원들에게 충분히 설명하고 이해시키는 일이 무엇보다 중요하다. 그리고 병원의 특성에 맞는 BSC 전략을 모색하고, 구축된 안은 정기적인 내부 교육과 네트워크 구성으로 정기적으로 보완하며 정보의 교류에 힘쓴다면 효율적 운영 및 추진이 가능할 것이다. 비록 사례 연구의 한계점은 가지고 있으나 다양한 검색 도구를 사용하여 자료를 수집하고자 노력하였다. 본 연구결과를 통해 우리나라 병원 조직에서 성과주의 시스템의 체계화를 촉진시키고 성과관리체계의 합리적 도입과 운영을 위한 실무적 차원에서의 정책적 시사점을 제시할 수 있을 것으로 기대한다. With drastic changes in the medical environment due to the opening up of the medical market and intensifying competition among hospitals, the need for efficiency in management has increased, and, in recent years, hospitals have adopted, as a means of evaluating business performance, the balanced scorecard(BSC) technique, which is a balanced performance management tool through financial and non-financial performance indices. The number of hospitals that wish to adopt BSC is expected to increase. However, in comparison with reports on BSC at public and private enterprises, those on BSC at medical institutions including ways of applying BSC to the management of medical institutions and aspects to be taken into consideration before the adoption of BSC are not many. The present researcher therefore seeks to explore the methods for introducing and deploying BSC in medical institutions, considerations, and implications by examining, comparing, and evaluating cases of the introduction (application) of BSC into medical institutions at home and abroad. Since the data used in the present study concern only several hospitals in South Korea, USA and Japan, there are limitations to objectifying its results. Some cases of the hospitals might be missing although the date were collected by searching tools for literature such as PubMed, due to the access limitations to medical institutes, the failure of adopting BSC to hospitals, or the omission of hospitals’ data. It is therefore difficult to apply the results of the present study to all hospitals.

Generalised dynamic decimation method using polyphase MACs for ultrasound imaging

Hyungil Kang,Jeeun Kang,Tai-Kyong Song IET 2015 Electronics letters Vol.51 No.6

<P>In medical ultrasound imaging, the focused echo signal is decimated with a finite impulse response filter by a rational factor <I>M</I>/<I>L</I>, the frequency response of which dynamically changes over time. Presented is, an efficient structure for dynamic decimation by a programmable rational factor that use a fixed number of polyphase multiplier-accumulators (MACs) regardless of the values of <I>M</I> and <I>L</I>. The proposed structure uses the minimum number of MAC units operating at the input data rate to minimise both power consumption and hardware complexity.</P>

Ultrasonic sector imaging using plane wave synthetic focusing with a convex array transducer

Bae, Sua,Kim, Pilsu,Song, Tai-kyong Acoustical Society of America 2018 Journal of the Acoustical Society of America Vol.144 No.5

A new synthetic aperture focusing method to suppress the diffraction of ultrasound

Jin Ho Chang,Tai-Kyong Song IEEE 2011 and Frequency Control Vol.58 No.2

<P>Spatial resolution of an ultrasound image is limited by diffraction of ultrasound as it propagates along the axial direction. This paper proposes a method for reducing the diffraction spreading effect of ultrasound by using a synthetic aperture focusing (SAF) method that uses plane waves instead of spherical waves. The new method performs data acquisition and beamforming in the same manner as conventional SAF methods. The main difference is that all array elements are used on each firing to generate a plane wave, the traveling angle of which varies with the position of a receive subaperture. On reception, each scan line is formed by synthesizing RF samples acquired by relevant receive subapertures with delays to force the plane waves to meet at each imaging point. Theoretical analysis and computer simulation with infinite transmit aperture show that the proposed method is capable of suppressing the diffraction of ultrasound and especially causing the lateral beam width to remain unchanged beyond a certain depth determined by the size of a receive subaperture and the maximum traveling angle of plane waves. It is demonstrated that the proposed method is realizable using a linear array transducer. It is also shown that the lateral radiation pattern produced by the proposed method has smaller beam width than that using conventional SAF methods in the region of interest because it suppresses the diffraction of ultrasound.</P>

하모닉 직교 방식의 초음파 고조파 영상화 기법

김상민,송재희,송태경,Kim, Sang-Min,Song, Jae-Hee,Song, Tai-Kyong 대한의용생체공학회 2009 의공학회지 Vol.30 No.1

A harmonic quadrature demodulation method to extract the second harmonic component from focused ultrasound signals after a single transmit-receive event is proposed. In the proposed method, the focused ultrasound signal is converted into baseband inphase and quadrature components by multiplying with sine and cosine signals both having twice the center frequency of the transmitted signal and filtering the two modulated signals. The quadrature component is then passed through a Hilbert filter to be added to the inphase component, which leaves only the envelope of the second harmonic component. A novel phase estimation technique is employed in the proposed method to avoid the phase mismatch between the focused signal and the two modulating signals. The proposed method is verified through both theoretical analysis and computer simulations. It is shown that compared to the pulse inversion scheme the proposed method provides almost the same results for stationary targets and significantly improved harmonic to fundamental ratio for moving targets.

Synthesis of Ibuprofen Conjugated Molecular Transporter Capable of Enhanced Brain Penetration

Biswas, Goutam,Kim, Wanil,Kim, Kyong-Tai,Cho, Junhwi,Jeong, Dongjun,Song, Keon-Hyoung,Im, Jungkyun Hindawi Limited 2017 Journal of chemistry Vol.2017 No.-

<P>Based on the strong evidences between inflammation and neurodegeneration, nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, are considered as effective agents to reduce the risk of Alzheimer’s and Parkinson’s disease. However, the clinical use of NSAIDs in these diseases is limited by low brain distribution. In this study, we had synthesized ibuprofen conjugate which has good brain penetration.<I> S</I>-(+)-Ibuprofen was covalently attached to a molecular transporter having FITC and eight terminal guanidine groups. This conjugate showed good cellular uptake property in live cells. It was also injected into a mouse and the distribution of the compound was examined in each organ. The conjugate was well delivered to mouse brain indicating the conjugate is able to cross the blood-brain barrier. Our novel synthetic ibuprofen conjugate will hopefully deliver other NSAIDs into brain and is therefore applicable to the neurodegenerative diseases treatment or prevention.</P>

Vaccinia-Related Kinase 2 Controls the Stability of the Eukaryotic Chaperonin TRiC/CCT by Inhibiting the Deubiquitinating Enzyme USP25

Kim, Sangjune,Lee, Dohyun,Lee, Juhyun,Song, Haengjin,Kim, Hyo-Jin,Kim, Kyong-Tai American Society for Microbiology 2015 Molecular and cellular biology Vol.35 No.10

<P>Molecular chaperones monitor the proper folding of misfolded proteins and function as the first line of defense against mutant protein aggregation in neurodegenerative diseases. The eukaryotic chaperonin TRiC is a potent suppressor of mutant protein aggregation and toxicity in early stages of disease progression. Elucidation of TRiC functional regulation will enable us to better understand the pathological mechanisms of neurodegeneration. We have previously shown that vaccinia-related kinase 2 (VRK2) downregulates TRiC protein levels through the ubiquitin-proteasome system by recruiting the E3 ligase COP1. However, although VRK2 activity was necessary in TRiC downregulation, the phosphorylated substrate was not determined. Here, we report that USP25 is a novel TRiC interacting protein that is also phosphorylated by VRK2. USP25 catalyzed deubiquitination of the TRiC protein and stabilized the chaperonin, thereby reducing accumulation of misfolded polyglutamine protein aggregates. Notably, USP25 deubiquitinating activity was suppressed when VRK2 phosphorylated the Thr<SUP>680</SUP>, Thr<SUP>727</SUP>, and Ser<SUP>745</SUP> residues. Impaired USP25 deubiquitinating activity after VRK2-mediated phosphorylation may be a critical pathway in TRiC protein destabilization.</P>