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  1. Article: Comparison of two laboratory-based systems for evaluation of halos in intraocular lenses.

    Carson, Daniel / Lee, Sangyeol / Alexander, Elsinore / Wei, Xin / Lee, Shinwook

    Clinical ophthalmology (Auckland, N.Z.)

    2018  Volume 12, Page(s) 385–393

    Abstract: Purpose: Multifocal intraocular lenses (IOLs) can be associated with unwanted visual phenomena, including halos. Predicting potential for halos is desirable when designing new multifocal IOLs. Halo images from 6 IOL models were compared using the ... ...

    Abstract Purpose: Multifocal intraocular lenses (IOLs) can be associated with unwanted visual phenomena, including halos. Predicting potential for halos is desirable when designing new multifocal IOLs. Halo images from 6 IOL models were compared using the Optikos modulation transfer function bench system and a new high dynamic range (HDR) system.
    Materials and methods: One monofocal, 1 extended depth of focus, and 4 multifocal IOLs were evaluated. An off-the-shelf optical bench was used to simulate a distant (>50 m) car headlight and record images. A custom HDR system was constructed using an imaging photometer to simulate headlight images and to measure quantitative halo luminance data. A metric was developed to characterize halo luminance properties. Clinical relevance was investigated by correlating halo measurements to visual outcomes questionnaire data.
    Results: The Optikos system produced halo images useful for visual comparisons; however, measurements were relative and not quantitative. The HDR halo system provided objective and quantitative measurements used to create a metric from the area under the curve (AUC) of the logarithmic normalized halo profile. This proposed metric differentiated between IOL models, and linear regression analysis found strong correlations between AUC and subjective clinical ratings of halos.
    Conclusion: The HDR system produced quantitative, preclinical metrics that correlated to patients' subjective perception of halos.
    Language English
    Publishing date 2018-02-21
    Publishing country New Zealand
    Document type Journal Article
    ISSN 1177-5467
    ISSN 1177-5467
    DOI 10.2147/OPTH.S152201
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article: Optical bench performance of a novel trifocal intraocular lens compared with a multifocal intraocular lens.

    Lee, Shinwook / Choi, Myoung / Xu, Zaiwei / Zhao, Zeyu / Alexander, Elsinore / Liu, Yueai

    Clinical ophthalmology (Auckland, N.Z.)

    2016  Volume 10, Page(s) 1031–1038

    Abstract: Purpose: The purpose of this study is to compare the optical characteristics of the novel PanOptix presbyopia-correcting trifocal intraocular lens (IOL) and the multifocal ReSTOR +3.0 D IOL, through in vitro bench investigations.: Methods: The ... ...

    Abstract Purpose: The purpose of this study is to compare the optical characteristics of the novel PanOptix presbyopia-correcting trifocal intraocular lens (IOL) and the multifocal ReSTOR +3.0 D IOL, through in vitro bench investigations.
    Methods: The optical characteristics of AcrySof(®) IQ PanOptix™ (PanOptix) and AcrySof(®) IQ ReSTOR +3.0 D (ReSTOR +3.0 D) IOLs were evaluated by through-focus Badal images, simulated headlight images, and modulation transfer function (MTF) measurements which determine resolution, photic phenomena, and image quality. Through-focus Badal images of an Early Treatment of Diabetic Retinopathy Study chart were recorded at both photopic and mesopic pupil sizes. Simulated headlight images were taken on an MTF bench with a 50-μm pinhole target and a 5.0 mm pupil at the distance focus of the IOL. MTF curves were measured with a 3.0 mm pupil, and spatial frequencies equivalent to 20/40 and 20/20 visual acuities were recorded to illustrate the through-focus MTF curves. Far-, intermediate-, and near-focus MTF values were obtained.
    Results: Bench Badal image testing and MTF measurements showed that PanOptix has a near focus at a distance of 42 cm and an additional intermediate focus at a distance of about 60 cm. The near focus for ReSTOR +3.0 D is at 45 cm. PanOptix and ReSTOR +3.0 D have comparable photopic distances and near MTF values. Additionally, PanOptix provided a substantial continuous range of vision from distance to intermediate and to near compared with ReSTOR +3.0 D. The halo propensity for PanOptix was slightly higher than that for ReSTOR +3.0 D.
    Conclusion: Laboratory-based in vitro simulations showed that PanOptix trifocal IOL has comparable resolution and image quality performance in distance and near foci compared with ReSTOR +3.0 D IOL. PanOptix showed better resolution and image quality performance at the intermediate focus than ReSTOR +3.0 D IOL.
    Language English
    Publishing date 2016-06-02
    Publishing country New Zealand
    Document type Journal Article
    ISSN 1177-5467
    ISSN 1177-5467
    DOI 10.2147/OPTH.S106646
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article: A Finite Element Analysis Study of Edentulous Model with Complete Denture to Simulate Masticatory Movement.

    Lee, Jeong-Hyeon / Seo, Jeong-Hee / Park, Shin-Wook / Kim, Won-Gi / Jung, Tae-Gon / Lee, Sung-Jae

    Bioengineering (Basel, Switzerland)

    2024  Volume 11, Issue 4

    Abstract: The purposes of this study are to establish and validate a finite element (FE) model using finite element analysis methods and to identify optimal loading conditions to simulate masticatory movement. A three-dimensional FE model of the maxillary and ... ...

    Abstract The purposes of this study are to establish and validate a finite element (FE) model using finite element analysis methods and to identify optimal loading conditions to simulate masticatory movement. A three-dimensional FE model of the maxillary and mandibular cortical bone, cancellous bone, and gingiva was constructed based on edentulous cone-beam-computed tomography data. Dental computer-aided design software was used to design the denture base and artificial teeth to produce a complete denture. Mesh convergence was performed to derive the optimal mesh size, and validation was conducted through comparison with mechanical test results. The mandible was rotated step-by-step to induce movements similar to actual mastication. Results showed that there was less than a 6% difference between the mechanical test and the alveolar bone-complete denture. It opened 10° as set in the first stage, confirming that the mouth closed 7° in the second stage. Occlusal contact occurred between the upper and lower artificial teeth as the mouth closed the remaining angle of 3° in the third stage while activating the masseter muscle. These results indicate that the FE model and masticatory loading conditions developed in this study can be applied to analyze biomechanical effects according to the wearing of dentures with various design elements applied.
    Language English
    Publishing date 2024-03-29
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2746191-9
    ISSN 2306-5354
    ISSN 2306-5354
    DOI 10.3390/bioengineering11040336
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: 1.4kW high peak power generation from an all semiconductor mode-locked master oscillator power amplifier system based on eXtreme Chirped Pulse Amplification(X-CPA).

    Kim, Kyungbum / Lee, Shinwook / Delfyett, Peter

    Optics express

    2009  Volume 13, Issue 12, Page(s) 4600–4606

    Abstract: The concept of eXtreme Chirped Pulse Amplification (X-CPA) is introduced as a novel method to overcome the energy storage limit of semiconductor optical amplifiers in ultrashort pulse amplification. A colliding pulse mode-locked semiconductor laser is ... ...

    Abstract The concept of eXtreme Chirped Pulse Amplification (X-CPA) is introduced as a novel method to overcome the energy storage limit of semiconductor optical amplifiers in ultrashort pulse amplification. A colliding pulse mode-locked semiconductor laser is developed as a master oscillator and generates 600fs pulses with 6nm bandwidth at 975nm. Using a highly dispersive chirped fiber Bragg grating (1600ps/nm) as an extreme pulse stretcher and compressor, we demonstrate ~16,000 times extreme chirped pulse amplification and recompression generating optical pulses of 590fs with 1.4kW of peak power. These pulses represent, to our knowledge, the highest peak power generated from an all semiconductor ultrafast laser system.
    Language English
    Publishing date 2009-08-08
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1491859-6
    ISSN 1094-4087 ; 1094-4087
    ISSN (online) 1094-4087
    ISSN 1094-4087
    DOI 10.1364/opex.13.004600
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Donor fat-to-muscle ratio and kidney transplant outcomes: A proposition of metabolic memory.

    Kee, Youn Kyung / Lee, Juhan / Nam, Bo Young / Joo, Young Su / Kang, Shin-Wook / Huh, Kyu Ha / Park, Jung Tak

    Diabetes/metabolism research and reviews

    2024  Volume 40, Issue 2, Page(s) e3781

    Abstract: Aims: The impact of donor abdominal fat-to-muscle ratio (FMR) on kidney transplant (KT) outcomes was assessed. Given the transient nature of the donor's metabolic environment in transplant recipients, this study investigated the capacity of body ... ...

    Abstract Aims: The impact of donor abdominal fat-to-muscle ratio (FMR) on kidney transplant (KT) outcomes was assessed. Given the transient nature of the donor's metabolic environment in transplant recipients, this study investigated the capacity of body composition to induce metabolic memory effects.
    Materials and methods: KT patients (n = 895) who received allografts from living donors (2003-2013) were included. Donor fat and muscle were quantified using pre-KT abdominal computed tomography scans. Patients were categorised into donor FMR tertiles and followed up for graft outcomes. Additionally, genome-wide DNA methylation analysis was performed on 28 kidney graft samples from KT patients in the low- and high-FMR groups.
    Results: Mean recipient age was 42.9 ± 11.4 years and 60.9% were males. Donor FMR averaged 1.67 ± 0.79. Over a median of 120.9 ± 42.5 months, graft failure (n = 127) and death-censored graft failure (n = 109) were more frequent in the higher FMR tertiles. Adjusted hazard ratios for the highest versus lowest FMR tertile were 1.71 (95% CI, 1.06-2.75) for overall graft failure and 1.90 (95% CI, 1.13-3.20) for death-censored graft failure. Genome-wide DNA methylation analysis identified 58 differentially methylated regions (p < 0.05, |Δβ| > 0.2) and 35 genes showed differential methylation between the high- (FMR >1.91) and low-FMR (FMR <1.27) groups.
    Conclusions: Donors with increased fat and reduced muscle composition may negatively impact kidney allograft survival in recipients, possibly through the transmission of epigenetic changes, implying a body-composition-related metabolic memory effect.
    MeSH term(s) Male ; Humans ; Adult ; Middle Aged ; Female ; Kidney Transplantation/adverse effects ; Retrospective Studies ; Graft Survival/physiology ; Living Donors ; Muscles
    Language English
    Publishing date 2024-02-17
    Publishing country England
    Document type Journal Article
    ZDB-ID 1470192-3
    ISSN 1520-7560 ; 1520-7552
    ISSN (online) 1520-7560
    ISSN 1520-7552
    DOI 10.1002/dmrr.3781
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: eXtreme chirped pulse oscillator operating in the nanosecond stretched pulse regime.

    Lee, Shinwook / Mandridis, Dimitrios / Delfyett, Peter J

    Optics express

    2008  Volume 16, Issue 7, Page(s) 4766–4773

    Abstract: An eXtreme Chirped Pulse Oscillator (XCPO) implemented with a Theta cavity and based on a semiconductor optical amplifier (SOA) is presented for generating 10 ns frequency-swept pulses and 3.6 ps compressed pulses directly from the oscillator. In this ... ...

    Abstract An eXtreme Chirped Pulse Oscillator (XCPO) implemented with a Theta cavity and based on a semiconductor optical amplifier (SOA) is presented for generating 10 ns frequency-swept pulses and 3.6 ps compressed pulses directly from the oscillator. In this experiment, we show the two distinct characteristics of the XCPO which are the scalability of the output energy and the mode-locked spectrum. By using these characteristics, we obtain a pulse energy of 58.4 pJ from the stretched pulse and a mode-locked optical bandwidth of 14.6 nm (10 dB) directly from the oscillator. The laser cavity design allows for low repetition rate operation <100 MHz, as well. The cavity, significantly, reduces nonlinear carrier dynamics, integrated self phase modulation (SPM), and fast gain recovery in an SOA. Due to the laser's ability to generate directly frequency-swept pulses from the oscillator, this oscillator can be used for high speed frequency-swept optical coherence tomography (OCT) and time-stretched photonic analog to digital converters (P-ADC).
    MeSH term(s) Amplifiers, Electronic ; Equipment Design ; Equipment Failure Analysis ; Lasers, Semiconductor ; Nanotechnology/instrumentation ; Oscillometry/instrumentation ; Signal Processing, Computer-Assisted/instrumentation
    Language English
    Publishing date 2008-03-12
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 1491859-6
    ISSN 1094-4087 ; 1094-4087
    ISSN (online) 1094-4087
    ISSN 1094-4087
    DOI 10.1364/oe.16.004766
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  7. Article ; Online: Insomnia in patients on incident maintenance dialysis and the risk of major acute cardio-cerebrovascular events and all-cause mortality.

    Kim, Hyung Woo / Heo, Ga Young / Kim, Hyo Jeong / Kang, Shin-Wook / Park, Jung Tak / Lee, Eun

    Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association

    2023  Volume 39, Issue 5, Page(s) 830–837

    Abstract: Background: Insomnia is a known risk factor for cardio-cerebrovascular disease in the general population; however, its effect on cardio-cerebrovascular outcomes in end-stage kidney disease patients is unclear. Therefore, this study aimed to investigate ... ...

    Abstract Background: Insomnia is a known risk factor for cardio-cerebrovascular disease in the general population; however, its effect on cardio-cerebrovascular outcomes in end-stage kidney disease patients is unclear. Therefore, this study aimed to investigate the association between cardio-cerebrovascular outcomes and insomnia in patients who initiated maintenance dialysis.
    Methods: This study used nationwide Korean health insurance claims data to analyze 79 420 patients who initiated maintenance dialysis from January 2009 to December 2017. Insomnia was defined using claim codes and sleep medication prescription data. Patients were categorized according to the presence of insomnia before and after dialysis initiation: (i) no insomnia, (ii) insomnia before dialysis only (improved insomnia), (iii) insomnia after dialysis only (developed insomnia) and (iv) insomnia in both periods (persistent insomnia). The primary and secondary outcomes were major adverse cardiac and cerebrovascular events (MACCE) and all-cause mortality, respectively. The outcome risks were estimated by Cox regression models with inverse probability of treatment weighting.
    Results: The mean age was 61.4 ± 13.4 years, and 39.7% were women. During the transition period from pre-dialysis to maintenance dialysis, 13.2% experienced insomnia. The insomnia groups showed significantly higher risks for MACCE [weighted hazard ratios (95% confidence intervals): developed insomnia, 1.26 (1.25-1.28); improved insomnia, 1.31 (1.29-1.33); persistent insomnia, 1.39 (1.37-1.41)] and higher all-cause mortality risks than the no insomnia group. The insomnia-related cardio-cerebrovascular disease risk elevation was more prominent in younger and male patients.
    Conclusions: Insomnia may increase cardio-cerebrovascular disease and all-cause mortality risk among end-stage kidney disease patients who initiate maintenance dialysis.
    MeSH term(s) Humans ; Male ; Female ; Middle Aged ; Renal Dialysis/adverse effects ; Sleep Initiation and Maintenance Disorders/complications ; Kidney Failure, Chronic/therapy ; Kidney Failure, Chronic/mortality ; Kidney Failure, Chronic/complications ; Cerebrovascular Disorders/mortality ; Cerebrovascular Disorders/etiology ; Cerebrovascular Disorders/epidemiology ; Cardiovascular Diseases/mortality ; Cardiovascular Diseases/etiology ; Risk Factors ; Republic of Korea/epidemiology ; Aged ; Cause of Death ; Incidence ; Retrospective Studies
    Language English
    Publishing date 2023-11-07
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 90594-x
    ISSN 1460-2385 ; 0931-0509
    ISSN (online) 1460-2385
    ISSN 0931-0509
    DOI 10.1093/ndt/gfad231
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  8. Article ; Online: Machine Learning-Aided Chronic Kidney Disease Diagnosis Based on Ultrasound Imaging Integrated with Computer-Extracted Measurable Features.

    Lee, Sangmi / Kang, Myeongkyun / Byeon, Keunho / Lee, Sang Eun / Lee, In Ho / Kim, Young Ah / Kang, Shin-Wook / Park, Jung Tak

    Journal of digital imaging

    2022  Volume 35, Issue 5, Page(s) 1091–1100

    Abstract: Although ultrasound plays an important role in the diagnosis of chronic kidney disease (CKD), image interpretation requires extensive training. High operator variability and limited image quality control of ultrasound images have made the application of ... ...

    Abstract Although ultrasound plays an important role in the diagnosis of chronic kidney disease (CKD), image interpretation requires extensive training. High operator variability and limited image quality control of ultrasound images have made the application of computer-aided diagnosis (CAD) challenging. This study assessed the effect of integrating computer-extracted measurable features with the convolutional neural network (CNN) on the ultrasound image CAD accuracy of CKD. Ultrasound images from patients who visited Severance Hospital and Gangnam Severance Hospital in South Korea between 2011 and 2018 were used. A Mask regional CNN model was used for organ segmentation and measurable feature extraction. Data on kidney length and kidney-to-liver echogenicity ratio were extracted. The ResNet18 model classified kidney ultrasound images into CKD and non-CKD. Experiments were conducted with and without the input of the measurable feature data. The performance of each model was evaluated using the area under the receiver operating characteristic curve (AUROC). A total of 909 patients (mean age, 51.4 ± 19.3 years; 414 [49.5%] men and 495 [54.5%] women) were included in the study. The average AUROC from the model trained using ultrasound images achieved a level of 0.81. Image training with the integration of automatically extracted kidney length and echogenicity features revealed an improved average AUROC of 0.88. This value further increased to 0.91 when the clinical information of underlying diabetes was also included in the model trained with CNN and measurable features. The automated step-wise machine learning-aided model segmented, measured, and classified the kidney ultrasound images with high performance. The integration of computer-extracted measurable features into the machine learning model may improve CKD classification.
    MeSH term(s) Male ; Humans ; Female ; Adult ; Middle Aged ; Aged ; Machine Learning ; Neural Networks, Computer ; Ultrasonography ; Computers ; Renal Insufficiency, Chronic/diagnostic imaging
    Language English
    Publishing date 2022-04-11
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1033897-4
    ISSN 1618-727X ; 0897-1889
    ISSN (online) 1618-727X
    ISSN 0897-1889
    DOI 10.1007/s10278-022-00625-8
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  9. Article: Metabolically Abnormal Non-Obese Phenotype Is Significantly Associated with All-Cause Mortality in Hemodialysis Patients.

    Lee, Jin Hyeog / Yun, Hae-Ryong / Kim, Hyung Woo / Park, Jung Tak / Han, Seung Hyeok / Kim, Yong-Lim / Kim, Yon Su / Yang, Chul Woo / Kim, Nam-Ho / Kang, Shin-Wook / Yoo, Tae-Hyun

    Journal of clinical medicine

    2024  Volume 13, Issue 4

    Abstract: The association between obesity and all-cause mortality in patients undergoing kidney failure with replacement therapy (KFRT) has shown conflicting results. This study aimed to evaluate whether metabolic abnormalities (MA) increase the risk of all-cause ... ...

    Abstract The association between obesity and all-cause mortality in patients undergoing kidney failure with replacement therapy (KFRT) has shown conflicting results. This study aimed to evaluate whether metabolic abnormalities (MA) increase the risk of all-cause mortality in these patients. Between 2009 and 2015, 1141 patients undergoing KFRT were recruited from the Clinical Research Center for End-Stage Renal Disease dataset. Patients were divided into four groups according to the presence of obesity and MA. Multivariate Cox proportional hazard analysis was performed to determine the association between the phenotypes and all-cause mortality. During a mean follow-up of 4.2 years, all-cause mortality was observed in 491 (43.0%) patients. Obesity had a 24% decreased risk of all-cause mortality compared with non-obesity. In contrast, the presence of MA showed a 1.53-fold increased risk of all-cause mortality. There was a significant interaction between obesity and MA (
    Language English
    Publishing date 2024-02-13
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2662592-1
    ISSN 2077-0383
    ISSN 2077-0383
    DOI 10.3390/jcm13041059
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  10. Article ; Online: Association between progression of coronary artery calcification and development of kidney failure with replacement therapy: Findings from KNOW-CKD study.

    Park, Cheol Ho / Kim, Hyung Woo / Park, Jung Tak / Chang, Tae Ik / Yoo, Tae-Hyun / Park, Sue Kyung / Lee, Kyu Beck / Jung, Ji Yong / Jeong, Jong Cheol / Oh, Kook-Hwan / Kang, Shin-Wook / Han, Seung Hyeok

    Atherosclerosis

    2024  , Page(s) 117563

    Abstract: Background and aims: High coronary artery calcification (CAC) burden is a significant risk factor for adverse cardiovascular and kidney outcomes. However, it is unknown whether changes in the coronary atherosclerotic burden can accompany changes in ... ...

    Abstract Background and aims: High coronary artery calcification (CAC) burden is a significant risk factor for adverse cardiovascular and kidney outcomes. However, it is unknown whether changes in the coronary atherosclerotic burden can accompany changes in kidney disease progression. Here, we evaluated the relationship between CAC progression and the risk of kidney failure with replacement therapy (KFRT).
    Methods: We analyzed 1173 participants with chronic kidney disease (CKD) G1 to G5 without kidney replacement therapy from the KoreaN Cohort Study for Outcomes in Patients With Chronic Kidney Disease (KNOW-CKD). Participants were categorized into three groups according to the change in the CAC score between enrollment and year 4 (non-progressors, ≤0 AU; moderate progressors, 1-199 AU; and severe progressors, ≥200 AU). The primary outcome was the development of KFRT.
    Results: During a follow-up period of 4690 person-years (median, 4.2 years), the primary outcome occurred in 230 (19.6 %) participants. The incidence of KFRT was 37.6, 54.3, and 80.9 per 1000 person-years in the non-, moderate, and severe progressors, respectively. In the multivariable cause-specific hazard model, the hazard ratios (HRs) for the moderate and severe progressors were 1.71 (95 % confidence interval [CI], 1.02-2.87) and 2.55 (95 % CI, 1.07-6.06), respectively, compared with non-progressors. A different definition of CAC progression with a threshold of 100 AU yielded similar results in a sensitivity analysis.
    Conclusions: CAC progression is associated with an increased risk of KFRT in patients with CKD. Our findings suggest that coronary atherosclerosis changes increase the risk of CKD progression.
    Language English
    Publishing date 2024-04-23
    Publishing country Ireland
    Document type Journal Article
    ZDB-ID 80061-2
    ISSN 1879-1484 ; 0021-9150
    ISSN (online) 1879-1484
    ISSN 0021-9150
    DOI 10.1016/j.atherosclerosis.2024.117563
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