Prognostic Implication of Right Ventricle Parameters Measured on Preoperative Cardiac MRI in Patients with Functional Tricuspid Regurgitation

Ahn Yura,Koo Hyun Jung,Kang Joon-Won,Choi Won Jin,Kim Dae-Hee,Song Jong-Min,Kang Duk-Hyun,Song Jae-Kwan,Kim Joon Bum,Jung Sung-Ho,Choo Suk Jung,Chung Cheol Hyun,Lee Jae Won,Yang Dong Hyun 대한영상의학회 2021 Korean Journal of Radiology Vol.22 No.8

Objective: To investigate the prognostic value of preoperative cardiac magnetic resonance imaging (MRI) for long-term major adverse cardiac and cerebrovascular events (MACCEs) in patients undergoing tricuspid valve (TV) surgery for functional tricuspid regurgitation (TR). Materials and Methods: The preoperative cardiac MR images, New York Heart Association functional class, comorbidities, and clinical events of 78 patients (median [interquartile range], 59 [51–66.3] years, 28.2% male) who underwent TV surgery for functional TR were comprehensively reviewed. Cox proportional hazards analyses were performed to assess the associations of clinical and imaging parameters with MACCEs and all-cause mortality. Results: For the median follow-up duration of 5.4 years (interquartile range, 1.2–6.6), MACCEs and all-cause mortality were 51.3% and 23.1%, respectively. The right ventricular (RV) end-systolic volume index (ESVI) and the systolic RV mass index (RVMI) were higher in patients with MACCEs than those without them (77 vs. 68 mL/m2, p = 0.048; 23.5 vs. 18.0%, p = 0.011, respectively). A high RV ESVI was associated with all-cause mortality (hazard ratio [HR] per value of 10 higher ESVI = 1.10, p = 0.03). A high RVMI was also associated with all-cause mortality (HR per increase of 5 mL/m2 RVMI = 1.75, p < 0.001). After adjusting for age and sex, only RVMI remained a significant predictor of MACCEs and all-cause mortality (p < 0.05 for both). After adjusting for multiple clinical variables, RVMI remained significantly associated with all-cause mortality (p = 0.005). Conclusion: RVMI measured on preoperative cardiac MRI was an independent predictor of long-term outcomes in patients who underwent TV surgery for functional TR.

Synthesis of Carbon Nanofibers Based on Resol Type Phenol Resin and Fe(III) Catalysts

Yura Hyun,Haesik Kim,이창섭 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.10

The carbon nanofibers (CNFs) used in this study were synthesized with an iron catalyst and ethylene as a carbon source. A concentration of 30 wt % iron(III) acetylacetonate was dissolved in resol type phenol resin and polyurethane foam was put into the solution. The sample was calendered after being cured at 80 °C in air for 24 h. Stabilization and carbonization of the resol type phenol resin and reduction of the Fe3+ were completed in a high-temperature furnace by the following steps: 1) heating to 600 °C at a rate of 10 °C/min with a mixture of H2/N2 for 4 h to reduce the Fe3+ to Fe; 2) heating to 1000 °C in N2 at a rate 10 °C/min for 30 minutes for pyrolysis; 3) synthesizing CNFs in a mixture of 20.1% ethylene and H2/N2 at 700 °C for 2 h using a CVD process. Finally, the structural characterization of the CNFs was performed by scanning electron microscopy and a synthesis analysis was carried out using energy dispersive spectroscopy and X-ray photoelectron spectroscopy. Specific surface area analysis of the CNFs was also performed by N2-sorption.

Synthesis of Carbon Nanofibers on Iron and Copper Catalysts by Chemical Vapor Deposition

Hyun, Yura,Kim, Haesik,Lee, Chang Seop Trans Tech Publications 2013 Advanced materials research Vol.750 No.-

<P>In this study, carbon nanofibers were synthesized on iron and copper catalysts by Chemical Vapor Deposition (CVD). Investigation was made with respect to variation on thickness and surface of fibers based on concentration of iron and copper. In order to prepare metal catalysts of respective synthesis, iron nitrate and copper nitrate were calculated in proportion to weight ratio and then dissolved into distilled water. Obtained catalyst precipitates were filtered and then dried for more than 24 hours at 110°C. Carbon nanofibers were composed by using ethylene gas of carbon source through CVD after pulverization of fully dried catalyst precipitates. Analysis through SEM was made in order to investigate structural characteristics of composed carbon nanofibers, and qualitative and quantitative analyses were conducted on elements through EDS. In addition, crystalline analysis was made on carbon nanofibers through XRD and Raman, and specific surface area measurement was carried on carbon nanofibers composed through BET.</P>

Characteristics and Electrochemical Performance of Si-Carbon Nanofibers Composite as Anode Material for Binder-Free Lithium Secondary Batteries

Hyun, Yura,Park, Heai-Ku,Park, Ho-Seon,Lee, Chang-Seop American Scientific Publishers 2015 Journal of Nanoscience and Nanotechnology Vol.15 No.11

Tricuspid Valve Imaging and Right Ventricular Function Analysis Using Cardiac CT and MRI

Ahn Yura,Koo Hyun Jung,Kang Joon-Won,Yang Dong Hyun 대한영상의학회 2021 Korean Journal of Radiology Vol.22 No.12

Cardiac computed tomography (CT) and cardiac magnetic resonance imaging (CMR) can reveal the detailed anatomy and function of the tricuspid valve and right ventricle (RV). Quantification of tricuspid regurgitation (TR) and analysis of RV function have prognostic implications. With the recently available transcatheter treatment options for diseases of the tricuspid valve, evaluation of the tricuspid valve using CT and CMR has become important in terms of patient selection and procedural guidance. Moreover, CT enables post-procedural investigation of the causes of valve dysfunction, such as pannus or thrombus. This review describes the anatomy of the tricuspid valve and CT and CMR imaging protocols for right heart evaluation, including RV function and TR analyses. We also demonstrate the pre-procedural planning for transcatheter treatment of TR and imaging of postoperative complications using CT.

Simultaneous Quantification of Oleins (triolein, diolein and monoolein) in Mouse Feces using Liquid Chromatography-Electrospray Ionization/Mass Spectrometry

( Jong Hyun Lim ),( Jeongae Lee ),( Yura Jang ),( Hesson Chung ),( Won-yong Lee ),( Bong Chul Chung ) 한국질량분석학회 2012 Mass spectrometry letters Vol.3 No.3

Fat malabsorption is an important cause of poor growth in infancy and childhood. Steatorrhea tests have been developed using various methods. Traditional measurements of stool fat, however, require large samples and it often takes as a week to complete the analysis. In this paper, a liquid chromatography-electrospray ionization/mass spectrometry (LC-ESI/MS) method was developed for simultaneous quantitative analysis of triacylglycerols, triolein, diolein and monoolein, in mouse feces. Moreover, the procedure was rapid, simple as well as compatible with LC-ESI/MS. Chloroform-isopropyl alcohol solution was used for fat-soluble sample extraction. After centrifugation and filtration, an analytical solution was prepared. Triolein, diolein and monoolein were separated using non-aqueous reversed-phase column with the mobile phase consisting of A (methanol) and B (acetone-isopropyl alcohol). The precision (% CV) and accuracy (% bias) of the assay were 3.8-14.7% and 85.2-114.9%, respectively. This method has been successfully applied to simultaneous determination of triolein, diolein and monoolein in feces from 30 mice. This method can therefore be applied to measure triacylglycerols in mouse feces accurately and precisely by LC-ESI/ MS, thereby helping to predictive biomarker in fat malabsorption and diagnostic research.

Impact of the Liver Imaging Reporting and Data System on Research Studies of Diagnosing Hepatocellular Carcinoma Using MRI

Ahn Yura,Choi Sang Hyun,Jang Jong Keon,Kim So Yeon,심주현,Lee Seung Soo,Byun Jae Ho 대한영상의학회 2022 Korean Journal of Radiology Vol.23 No.5

Objective: Since its introduction in 2011, the CT/MRI diagnostic Liver Imaging Reporting and Data System (LI-RADS) has been updated in 2014, 2017, and 2018. We evaluated the impact of CT/MRI diagnostic LI-RADS on liver MRI research methodology for the diagnosis of hepatocellular carcinoma (HCC). Materials and Methods: The MEDLINE, EMBASE, and Cochrane databases were searched for original articles reporting the diagnostic performance of liver MRI for HCC between 2011 and 2019. The MRI techniques, image analysis methods, and diagnostic criteria for HCC used in each study were investigated. The studies were classified into three groups according to the year of publication (2011–2013, 2014–2016, and 2017–2019). We compared the percentage of studies adopting MRI techniques recommended by LI-RADS, image analysis methods in accordance with the lexicon defined in LI-RADS, and diagnostic criteria endorsed by LI-RADS. We compared the pooled sensitivity and specificity between studies that used the LI-RADS and those that did not. Results: This systematic review included 179 studies. The percentages of studies using imaging techniques recommended by LI-RADS were 77.8% for 2011–2013, 85.7% for 2014–2016, and 84.2% for 2017–2019, with no significant difference (p = 0.951). After the introduction of LI-RADS, the percentages of studies following the LI-RADS lexicon were 0.0%, 18.4%, and 56.6% in the respective periods (p < 0.001), while the percentages of studies using the LI-RADS diagnostic imaging criteria were 0.0%, 22.9%, and 60.7%, respectively (p < 0.001). Studies that did not use the LI-RADS and those that used the LIRADS version 2018 showed no significant difference in sensitivity and specificity (86.3% vs. 77.7%, p = 0.102 and 91.4% vs. 89.9%, p = 0.770, respectively), with some difference in heterogeneity (I2 = 94.3% vs. 86.7% in sensitivity and I2 = 86.6% vs. 53.2% in specificity). Conclusion: LI-RADS imparted significant changes in the image analysis methods and diagnostic criteria used in liver MRI research for the diagnosis of HCC.

효율적인 몰입형 비디오의 부호화를 위한 적응적 패치 패킹 블록 크기 조절 기법

김현호(Hyun-Ho Kim),임성균(Sung-Gyun Lim),김유라(Yura Kim),김용환(Yong-Hwan Kim) 한국방송·미디어공학회 2023 한국방송공학회 학술발표대회 논문집 Vol.2023 No.11

최근 메타버스(Metaverse)에 대한 관심이 집중됨에 따라, 이를 구성하는 가상현실(VR), 증강현실(AR)과 같은 몰입형 미디어 관련 연구개발이 활발하게 진행되고 있다. 이를 돕기 위해, ISO/IEC MPEG (Moving Picture Experts Group) 표준화 그룹은 MPEG-I (Immersive) 그룹 내에서 다양한 종류의 몰입형 미디어 부호화 표준화를 진행중이다. 그 중에서도, 다수의 2D 비디오를 기반으로 3 자유도 이상을 제공하여 사용자에게 몰입감을 줄 수 있는 미디어의 압축 및 전송을 위한 MPEG-I Immersive Video (MIV) 표준화가 진행되고 있으며, 이러한 다시점 영상의 효과적인 부호화를 위한 테스트 모델인 Test Model for Immersive Video (TMIV)를 개발하였다. 현재 TMIV 내에서 사용되는 패치 패킹 블록 크기 값은 고정된 값을 사용하고 있으며, 이로 인해 몇몇 다시점 영상의 패치들이 전송되지 못하고 그대로 버려지는 상황이 발생한다. 이를 개선하고자, 본 논문에서는 TMIV 내 패치 패킹 블록크기를 Group of frames (GOF) 단위에서 적응적으로 조절하여, 버려지는 패치의 수를 최소화함으로써 최종 영상의 합성 성능을 높이는 기법을 제안한다. 제안 방식은 8 개의 테스트 영상에서 WS-PSNR 기준 평균 10.0% 이상, IVPSNR기준 평균 13.2% 이상의 BD-rate 이득을 보였다.

오일질량분률 측정용 정전용량센서 모듈

김유라(Yura Kim),나경환(Kyung Hwan Na),강현성(Hyun Sung Kang),임시형(Si-Hyung Lim) 대한기계학회 2015 대한기계학회 춘추학술대회 Vol.2015 No.11

The vest-collar as a rodent collar to prevent licking and scratching during experiments

Jang, Yura,Park, Ye Eun,Yun, Cheol-Won,Kim, Dae-Hyun,Chung, Hesson SAGE Publications 2016 Laboratory animals Vol.50 No.4

<P>Various types of restraint collars have been used for research animals, and the Elizabethan collar (E-collar) is the most commonly used. However, animals can be choked by the E-collar or they tend to remove it; furthermore, repeated rubbing and scratching of the collar may chafe the neck. We developed a new restraint collar with a vest to overcome these limitations. The vest-collar (V-collar) can be worn similarly to a vest, in contrast to the E-collar, which is fixed around the neck. A cone-shaped collar is attached to the vest in the V-collar and is made of Eva foam to surround the chest softly, accompanied by a transparent polyvinyl chloride (PVC) film for visibility. To evaluate the performance of the V-collar, we conducted experiments with mice wearing the V-collar and the E-collar. Both groups showed normal weight gain and food intake. Glucose and stress hormone levels showed no significant differences, and no stress-associated leukocyte profiles were observed during the experiments. However, despite the short experimental duration, more than half of the mice in the E-collar group showed injury to the skin on the neck, with increased thickness of the epidermal and keratin layers. Moreover, inflammatory cell counts were higher in the E-collar group than in the V-collar group. In conclusion, the V-collar, in contrast to the E-collar, does not cause skin injuries in animals and is thus beneficial for animals and investigators. Investigators can effectively use the V-collar to enhance laboratory animal welfare.</P>