Identification of progressive mild cognitive impairment patients using incomplete longitudinal MRI scans

Thung, Kim-Han,Wee, Chong-Yaw,Yap, Pew-Thian,Shen, Dinggang Springer Science + Business Media 2016 BRAIN STRUCTURE AND FUNCTION Vol. No.

<P>Distinguishing progressive mild cognitive impairment (pMCI) from stable mild cognitive impairment (sMCI) is critical for identification of patients who are at risk for Alzheimer's disease (AD), so that early treatment can be administered. In this paper, we propose a pMCI/sMCI classification framework that harnesses information available in longitudinal magnetic resonance imaging (MRI) data, which could be incomplete, to improve diagnostic accuracy. Volumetric features were first extracted from the baseline MRI scan and subsequent scans acquired after 6, 12, and 18 months. Dynamic features were then obtained using the 18th month scan as the reference and computing the ratios of feature differences for the earlier scans. Features that are linearly or non-linearly correlated with diagnostic labels are then selected using two elastic net sparse learning algorithms. Missing feature values due to the incomplete longitudinal data are imputed using a low-rank matrix completion method. Finally, based on the completed feature matrix, we build a multi-kernel support vector machine (mkSVM) to predict the diagnostic label of samples with unknown diagnostic statuses. Our evaluation indicates that a diagnosis accuracy as high as 78.2 % can be achieved when information from the longitudinal scans is used-6.6 % higher than the case using only the reference time point image. In other words, information provided by the longitudinal history of the disease improves diagnosis accuracy.</P>

Insertional mutations exhibiting high cell-culture density HCD phenotypes are enriched through continuous subcultures in Chlamydomonas reinhardtii

Thung, Leena,He, Jing,Zhu, Qingling,Xu, Zhenyu,Liu, Jianhua,Chow, Yvonne The Korean Society of Phycology 2018 ALGAE Vol.33 No.1

Low efficiency in microalgal biomass production was largely attributed to the low density of algal cell cultures. Though mutations that reduced the level of chlorophyll or pigment content increased efficiency of photon usage and thus the cell-culture density under high-illumination growth conditions (e.g., >$500{\mu}mol\;photon\;m^{-2}\;s^{-1}$), it was unclear whether algae could increase cell-culture density under low-illumination conditions (e.g., ${\sim}50{\mu}mol\;photon\;m^{-2}\;s^{-1}$). To address this question, we performed forward genetic screening in Chlamydomonas reinhardtii. A pool of >1,000 insertional mutants was constructed and subjected to continuous subcultures in shaking flasks under low-illumination conditions. Complexity of restriction fragment length polymorphism (RFLP) pattern in cultures indicated the degree of heterogeneity of mutant populations. We showed that the levels of RFLP complexity decreased when cycles of subculture increased, suggesting that cultures were gradually populated by high cell-culture density (HCD) strains. Analysis of the 3 isolated HCD mutants after 30 cycles of subcultures confirmed that their maximal biomass production was 50-100% higher than that of wild type under low-illumination. Furthermore, levels of chlorophyll content in HCD mutant strains were similar to that of wild type. Inverse polymerase chain reaction analysis identified the locus of insertion in two of three HCD strains. Molecular and transcriptomic analyses suggested that two HCD mutants were a result of the gain-of-function phenotype, both linking to the abnormality of mitochondrial functions. Taken together, our results demonstrate that HCD strains can be obtained through continuous subcultures under low illumination conditions.

Conversion and time-to-conversion predictions of mild cognitive impairment using low-rank affinity pursuit denoising and matrix completion

Thung, Kim-Han,Yap, Pew-Thian,Adeli, Ehsan,Lee, Seong-Whan,Shen, Dinggang Elsevier 2018 Medical image analysis Vol.45 No.-

<P><B>Abstract</B></P> <P>In this paper, we aim to predict conversion and time-to-conversion of mild cognitive impairment (MCI) patients using multi-modal neuroimaging data and clinical data, via cross-sectional and longitudinal studies. However, such data are often heterogeneous, high-dimensional, noisy, and incomplete. We thus propose a framework that includes sparse feature selection, low-rank affinity pursuit denoising (LRAD), and low-rank matrix completion (LRMC) in this study. Specifically, we first use sparse linear regressions to remove unrelated features. Then, considering the heterogeneity of the MCI data, which can be assumed as a union of multiple subspaces, we propose to use a low rank subspace method (i.e., LRAD) to denoise the data. Finally, we employ LRMC algorithm with three data fitting terms and one inequality constraint for joint conversion and time-to-conversion predictions. Our framework aims to answer a very important but yet rarely explored question in AD study, i.e., when will the MCI convert to AD? This is different from survival analysis, which provides the probabilities of conversion at different time points that are mainly used for global analysis, while our time-to-conversion prediction is for each individual subject. Evaluations using the ADNI dataset indicate that our method outperforms conventional LRMC and other state-of-the-art methods. Our method achieves a maximal pMCI classification accuracy of 84% and time prediction correlation of 0.665.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Longitudinal MRI, PET and cognitive data are used jointly for pMCI prediction. </LI> <LI> MCI subjects exhibit biological heterogeneity, and the data are incomplete and noisy. </LI> <LI> Low rank affinity-pursuit denoising is used to denoise incomplete heterogeneous data. </LI> <LI> Label and conversion time are predicted jointly using low rank matrix completion. </LI> <LI> Best pMCI classification acc. is 84%, conversion time prediction correlation is 0.67. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

비관적 견해 : 차이나 쇼크위기 ; 더 이상 "창업의 섬" 아니다 中 의존도 심화로 빈부격차 등 사회 문제 확산

Thung Hong Lin 포스코경영연구원 2014 CHINDIA Plus Vol.92 No.-

Insertional mutations exhibiting high cell-culture density HCD phenotypes are enriched through continuous subcultures in Chlamydomonas reinhardtii

Leena Thung,Jing He,Qingling Zhu,Zhenyu Xu,Jianhua Liu,Yvonne Chow 한국조류학회I 2018 ALGAE Vol.33 No.1

Low efficiency in microalgal biomass production was largely attributed to the low density of algal cell cultures. Though mutations that reduced the level of chlorophyll or pigment content increased efficiency of photon usage and thus the cell-culture density under high-illumination growth conditions (e.g., >500 µmol photon m-2 s-1), it was unclear whether algae could increase cell-culture density under low-illumination conditions (e.g., ~50 µmol photon m-2 s-1). To address this question, we performed forward genetic screening in Chlamydomonas reinhardtii. A pool of >1,000 insertional mutants was constructed and subjected to continuous subcultures in shaking flasks under low-illumination conditions. Complexity of restriction fragment length polymorphism (RFLP) pattern in cultures indicated the degree of heterogeneity of mutant populations. We showed that the levels of RFLP complexity decreased when cycles of subculture increased, suggesting that cultures were gradually populated by high cell-culture density (HCD) strains. Analysis of the 3 isolated HCD mutants after 30 cycles of subcultures confirmed that their maximal biomass production was 50-100% higher than that of wild type under low-illumination. Furthermore, levels of chlorophyll content in HCD mutant strains were similar to that of wild type. Inverse polymerase chain reaction analysis identified the locus of insertion in two of three HCD strains. Molecular and transcriptomic analyses suggested that two HCD mutants were a result of the gain-of-function phenotype, both linking to the abnormality of mitochondrial functions. Taken together, our results demonstrate that HCD strains can be obtained through continuous subcultures under low illumination conditions.

The implementation of spherical acoustical holography

Yong Thung Cho(조용성),J. Stuart Bolton,Yong-Joe Kim(김용조) 한국소음진동공학회 2002 한국소음진동공학회 심포지엄 Vol.2002 No.1

The implementation of spherical acoustical holography

Yong Thung Cho(조용성),J. Stuart Bolton,Yong-Joe Kim(김용조) 한국소음진동공학회 2002 한국소음진동공학회 학술대회논문집 Vol.2002 No.11

미세한 공혈을 통한 소음의 저감을 위한 접착 테이프 별 삽입손실 특성

조용성 ( Yong Thung Cho ) 한국복합재료학회 2024 Composites research Vol.37 No.3

접착용 테이프는 다양한 기계적 강도를 요구하는 재료와 특유의 접착 물질을 결합시켜 편리하게 다양한 용도로 사용할 수 있다. 그 중 덕트 테이프(duct tape)는 대개 쉽게 구할 수 있고, 널리 사용되는 접착 테이프로 뽑을 수 있다. 덕트 테이프는 일반 테이프와 달리 섬유 소재를 함유하고 있는 복합재료이고 기계적 강도가 우수하다. 그 외에도 전선의 절연 용도로 사용되는 전기 절연테이프도 매우 오랜 기간 동안 사용되었고 실제로는 절연용도 외에도 전선의 기계적 강도 보강 및 댐핑 역할을 한다. 최근에는 다양한 종류의 폼 테이프(foam tape) 및 양면 테이프도 여러 용도로 널리 사용되고 있다. 하지만, 이러한 테이프의 소음 차단 효과에 대해서는 기존 자료에 명확하게 나타나 있지 않다. 본 연구에서는 미세한 공혈(hole)을 이용하여 다양한 테이프의 삽입손실을 측정하여 소음 차단 효과를 나타내었고, 그 중에서도 양면 폼 테이프의 소음 차단 효과가 가장 좋게 나타났다. Adhesive tapes can be conveniently used for various applications by combination of materials requiring diverse mechanical strength and specific adhesives. Duct tape is usually readily available and one of the most widely used adhesive tapes. Duct tapes are composite materials with good mechanical strength consisted of fiber material, which is different from other tapes. In addition, electrical insulation tapes are used for very long period of time for insulating cables, and are also used for reinforcement of mechanical strength and increasing damping of cable in practice. Recently, variety of foam tapes and double-sided tapes are widely used in diverse applications. However, there is no previous work readily available clearly illustrating noise isolation performance of tapes. In present work, noise isolation performance of tapes is presented by measurement of insertion loss of variety of tapes on a small hole. Double-side foam tapes presented the best noise isolation performance among adhesive tapes measured in present work.

건물 내 방 문을 통한 실내 소음 전파 특성 분석

조용성(Cho, Yong Thung) 한국생태환경건축학회 2018 한국생태환경건축학회 학술발표대회 논문집 Vol.18 No.2

음향 홀로그래피를 이용한 건물 내 방 문 소음 전파 특성 가시화 방안

조용성(Cho, Yong Thung) 한국생태환경건축학회 2019 한국생태환경건축학회 학술발표대회 논문집 Vol.19 No.2