Periventricular white matter hyperintensities and the risk of dementia: a CREDOS study

Kim, Sangha,Choi, Seong Hye,Lee, Young Min,Kim, Min Ji,Kim, Young Don,Kim, Jin Young,Park, Jin Hong,Myung, Woojae,Na, Hae Ri,Han, Hyun Jeong,Shim, Yong S.,Kim, Jong Hun,Yoon, Soo Jin,Kim, Sang Yun,Kim Cambridge University Press 2015 INTERNATIONAL PSYCHOGERIATRICS - Vol.27 No.12

<B>ABSTRACT</B><B>Background:</B><P>Cerebral white matter hyperintensities (WMH) are prevalent incident findings on brain MRI scans among elderly people and have been consistently implicated in cognitive dysfunction. However, differential roles of WMH by region in cognitive function are still unclear. The aim of this study was to ascertain the differential role of regional WMH in predicting progression from mild cognitive impairment (MCI) to different subtypes of dementia.</P><B>Methods:</B><P>Participants were recruited from the Clinical Research Center for Dementia of South Korea (CREDOS) study. A total of 622 participants with MCI diagnoses at baseline and follow-up evaluations were included for the analysis. Initial MRI scans were rated for WMH on a visual rating scale developed for the CREDOS. Differential effects of regional WMH in predicting incident dementia were evaluated using the Cox proportional hazards model.</P><B>Results:</B><P>Of the 622 participants with MCI at baseline, 139 patients (22.3%) converted to all-cause dementia over a median of 14.3 (range 6.0-36.5) months. Severe periventricular WMH (PWMH) predicted incident all-cause dementia (Hazard ratio (HR) 2.22; 95% confidence interval (CI) 1.43-3.43) and Alzheimer's disease (AD) (HR 1.86; 95% CI 1.12-3.07). Subcortical vascular dementia (SVD) was predicted by both PWMH (HR 16.14; 95% CI 1.97-132.06) and DWMH (HR 8.77; 95% CI 1.77-43.49) in more severe form (≥ 10 mm).</P><B>Conclusions:</B><P>WMH differentially predict dementia by region and severity. Our findings suggest that PWMH may play an independent role in the pathogenesis of dementia, especially in AD.</P>

A Cautionary Tale of Singlet Fission

Woojae Kim(김우재) 한국고분자학회 2023 한국고분자학회 학술대회 연구논문 초록집 Vol.48 No.1

Change in ethanol and alcohol biomarker (EtG, EtS) under baterical conditions

Woojae Lee,Younghoon Jo,Soomin Kim,Songhie An,Hyunjee Kim,Mia Kwon 한국분석과학회 2021 학술대회논문집 Vol.2021 No.5

Development of Novel Breast Cancer Recurrence Prediction Model Using Support Vector Machine

Woojae Kim,김구상,이정언,노동영,김성원,정용식,박만영,박래웅 한국유방암학회 2012 Journal of breast cancer Vol.15 No.2

Purpose: The prediction of breast cancer recurrence is a crucial factor for successful treatment and follow-up planning. The principal objective of this study was to construct a novel prognostic model based on support vector machine (SVM) for the prediction of breast cancer recurrence within 5 years after breast cancer surgery in the Korean population, and to compare the predictive performance of the model with the previously established models. Methods: Data on 679 patients, who underwent breast cancer surgery between 1994 and 2002, were collected retrospectively from a Korean tertiary teaching hospital. The following variables were selected as independent variables for the prognostic model, by using the established medical knowledge and univariate analysis: histological grade, tumor size, number of metastatic lymph node, estrogen receptor, lymphovascular invasion, local invasion of tumor, and number of tumors. Three prediction algorithms, with each using SVM, artificial neural network and Cox-proportional hazard regression model, were constructed and compared with one another. The resultant and most effective model based on SVM was compared with previously established prognostic models, which included Adjuvant! Online, Nottingham prognostic index (NPI), and St. Gallen guidelines. Results: The SVM-based prediction model, named ‘breast cancer recurrence prediction based on SVM (BCRSVM),’ proposed herein outperformed other prognostic models (area under the curve=0.85, 0.71, 0.70, respectively for the BCRSVM, Adjuvant! Online, and NPI). The BCRSVM evidenced substantially high sensitivity (0.89), specificity (0.73), positive predictive values (0.75), and negative predictive values (0.89). Conclusion: As the selected prognostic factors can be easily obtained in clinical practice, the proposed model might prove useful in the prediction of breast cancer recurrence. The prediction model is freely available in the website (http://ami.ajou.ac.kr/bcr/).

Range-dependent geoacoustic inversion of vertical line array data using matched beam processing.

Kim, Kyungseop,Seong, Woojae,Lee, Keunhwa,Kim, Seongil,Shim, Taebo American Institute of Physics for the Acoustical S 2009 Journal of the Acoustical Society of America Vol.125 No.2

<P>This paper describes the results of range-dependent geoacoustic inversion using vertical line array data obtained from the 4th Matched Acoustic Properties and Localization Experiment conducted in the East Sea of Korea. The narrowband multitone continuous-wave signal from the towed source was analyzed to estimate the range-dependent geoacoustic properties along the radial track. The primary approach is based on the sectorwise inversion scheme. The inversion region up to 7.5 km from the vertical line array was divided into several segments, and the subinversions for each segment were performed sequentially. To reduce the dominance of low-angle arrivals, which bears little information for the bottom segment in question, matched beam processing with beam filtering was used for the cost function. The performance of proposed algorithm was tested using simulated data for an environment representative of the experimental site. The inversion results for the experimental data were consistent with the geophysical database and were validated from matched-field source localization using frequencies different from those used in the inversion.</P>

Visual Preference Assessment on Ultra-High-Definition Images

Kim, Haksub,Ahn, Sewoong,Kim, Woojae,Lee, Sanghoon [Institute of Electrical and Electronics Engineers 2016 IEEE transactions on broadcasting Vol.62 No.4

<P>With the recent evolution of ultra-high-definition (UHD) display technology, viewers can enjoy high-resolution content more realistically over TVs, virtual reality, portable, and wearable devices. To increase the visual attraction viewers perceive, post-processing of video content has been more powerfully conducted in such commercial devices. In this paper, we define a new terminology visual preference to quantify viewer perceptual preferences in a certain viewing environment with UHD images processed using sharpness and contrast enhancements. Viewers' visual preference for UHD images depends on the spatial resolution afforded by the UHD display, which in turn depends on the viewing geometry of the display resolution, display size, and viewing distance. In addition, viewers can perceive different degrees of quality and sharpness according to the content enhancement type and level, which leads to variation in the statistical dynamics of spatial image information. In this paper, we explore a novel methodology called the visual preference assessment model (VPAM) that accounts for content enhancement features, diverse viewing geometry, and statistical dynamics variation. The VPAM is a no-reference assessment method designed using an elaborate subjective preference assessment with support vector regression as the machine learning algorithm. The VPAM far outperforms previous methods in terms of correlation, 0.45-0.56, with the visual preference assessment.</P>

Exposure–outcome analysis in depressed patients treated with paroxetine using population pharmacokinetics

Kim, Jung-Ryul,Woo, Hye In,Chun, Mi-Ryung,Lim, Shinn-Won,Kim, Hae Deun,Na, Han Sung,Chung, Myeon Woo,Myung, Woojae,Lee, Soo-Youn,Kim, Doh Kwan Dove Medical Press 2015 Drug design, development and therapy Vol.9 No.-

<P><B>Purpose</B></P><P>This study investigated population pharmacokinetics of paroxetine, and then performed an integrated analysis of exposure and clinical outcome using population pharmacokinetic parameter estimates in depressed patients treated with paroxetine.</P><P><B>Patients and methods</B></P><P>A total of 271 therapeutic drug monitoring (TDM) data were retrospectively collected from 127 psychiatric outpatients. A population nonlinear mixed-effects modeling approach was used to describe serum concentrations of paroxetine. For 83 patients with major depressive disorder, the treatment response rate and the incidence of adverse drug reaction (ADR) were characterized by logistic regression using daily dose or area under the concentration–time curve (AUC) estimated from the final model as a potential exposure predictor.</P><P><B>Results</B></P><P>One compartment model was developed. The apparent clearance of paroxetine was affected by age as well as daily dose administered at steady-state. Overall treatment response rate was 72%, and the incidence of ADR was 30%. The logistic regression showed that exposure predictors were not associated with treatment response or ADR in the range of dose commonly used in routine practice. However, the incidence of ADR increased with the increase of daily dose or AUC for the patients with multiple concentrations.</P><P><B>Conclusion</B></P><P>In depressed patients treated with paroxetine, TDM may be of limited value for individualization of treatment.</P>

Extrapyramidal Signs and Risk of Progression from Mild Cognitive Impairment to Dementia: A Clinical Research Center for Dementia of South Korea Study

Woojae Myung,JinHong Park,SookYoung Woo,Seonwoo Kim,SangHa Kim,JaeWon Chung,HyoShin Kang,ShinnWon Lim,Junbae Choi,Duk L. Na,SeongYoon Kim,JaeHong Lee,SeolHeui Han,SeongHye Choi,SangYun Kim,Bernard J. 대한신경정신의학회 2017 PSYCHIATRY INVESTIGATION Vol.14 No.6

Objective-Extrapyramidal signs (EPS) are common in patients with mild cognitive impairment (MCI). However, few studies have assessed the effect of EPS on the clinical course of MCI. We aimed to evaluate whether patients with EPS show more frequent progression from MCI to Alzheimer’s disease (AD) and to other types of dementia. Methods-Participants (n=882) with MCI were recruited, and were followed for up to 5 years. The EPS positive group was defined by the presence of at least one EPS based on a focused neurologic examination at baseline. Results-A total of 234 converted to dementia during the follow-up period. The risk of progression to AD was lower in the patients with EPS after adjusting for potential confounders [hazard ratio (HR)=0.70, 95% confidence interval (CI)=0.53-0.93, p=0.01]. In contrast, the patients with EPS had a six-fold elevated risk of progression to dementia other than AD (HR=6.33, 95%CI=2.30–17.39, p<0.001). Conclusion-EPS in patients with MCI is a strong risk factor for progression of MCI to non-Alzheimer dementia. The careful neurologic examination for EPS in patients with MCI can yield important clinical information for prognosis.

Contour Integral Method for Crack Detection

Woojae Kim,Nohyu Kim,Seung-Yong Yang 한국비파괴검사학회 2011 한국비파괴검사학회지 Vol.31 No.6

In this paper, a new approach to detect surface cracks from a noisy thermal image in the infrared thermography is presented using an holomorphic characteristic of temperature field in a thin plate under steady-state thermal condition. The holomorphic function for 2-D heat flow field in the plate was derived from Cauchy Riemann conditions to define a contour integral that varies according to the existence and strength of a singularity in the domain of integration. The contour integral at each point of thermal image eliminated the temperature variation due to heat conduction and suppressed the noise, so that its image emphasized and highlighted the singularity such as crack. This feature of holomorphic function was also investigated numerically using a simple thermal field in the thin plate satisfying the Laplace equation. The simulation results showed that the integral image selected and detected the crack embedded artificially in the plate very well in a noisy environment.

Solvent and Structural Fluctuations Induced Symmetry-Breaking Charge Transfer in a Porphyrin Triad

Kim, Taeyeon,Kim, Woojae,Mori, Hirotaka,Osuka, Atsuhiro,Kim, Dongho American Chemical Society 2018 The Journal of Physical Chemistry Part C Vol.122 No.34

<P>This study aims to show that the symmetry-breaking charge transfer (SBCT) in a donor-acceptor-donor (DAD) porphyrin triad occurs via solvent and structural fluctuations measured by using femtosecond broadband fluorescence upconversion spectroscopy, which can directly trace the origin of the emitting state by monitoring its emission dipole moment as a function of time. While the emission dipole moment of the triad in the excited state remains nearly unchanged in nonpolar solvents such as cyclohexane and toluene, it is significantly reduced in polar solvents such as benzonitrile due to a change in the emitting state from quadrupolar (the exciton coupled state) to dipolar symmetry (the relaxed S<SUB>1</SUB> state). The latter state is formed by the SBCT process of DAD via a combination of solvent and structural fluctuations.</P> [FIG OMISSION]</BR>