GazeDx: Interactive Visual Analytics Framework for Comparative Gaze Analysis with Volumetric Medical Images

Hyunjoo Song,Jeongjin Lee,Tae Jung Kim,Kyoung Ho Lee,Bohyoung Kim,Jinwook Seo IEEE Computer Society 2017 IEEE transactions on visualization and computer gr Vol.23 No.1

<P>We present an interactive visual analytics framework, GazeDx (abbr. of GazeDiagnosis), for the comparative analysis of gaze data from multiple readers examining volumetric images while integrating important contextual information with the gaze data. Gaze pattern comparison is essential to understanding how radiologists examine medical images, and to identifying factors influencing the examination. Most prior work depended upon comparisons with manually juxtaposed static images of gaze tracking results. Comparative gaze analysis with volumetric images is more challenging due to the additional cognitive load on 3D perception. A recent study proposed a visualization design based on direct volume rendering (DVR) for visualizing gaze patterns in volumetric images; however, effective and comprehensive gaze pattern comparison is still challenging due to a lack of interactive visualization tools for comparative gaze analysis. We take the challenge with GazeDx while integrating crucial contextual information such as pupil size and windowing into the analysis process for more in-depth and ecologically valid findings. Among the interactive visualization components in GazeDx, a context-embedded interactive scatterplot is especially designed to help users examine abstract gaze data in diverse contexts by embedding medical imaging representations well known to radiologists in it. We present the results from two case studies with two experienced radiologists, where they compared the gaze patterns of 14 radiologists reading two patients' volumetric CT images.</P>

Therapeutic strategies for locally recurrent and metastatic de-differentiated liposarcoma with herpes simplex virus-thymidine kinase-expressing mesenchymal stromal cells

Lee, Hyunjoo,Jo, Eun Byeol,Kim, Su Jin,Yang, Heung Mo,Kim, You Min,Sung, Young Chul,Park, Jae Berm,Hong, Doopyo,Park, Hyojun,Choi, Yoon-La,Kim, Sung Joo Elsevier 2017 cytotherapy Vol.19 No.9

<P>Background aims. Major challenges in de-differentiated liposarcoma (DDLPS) therapy are the high rate of sequential recurrence (>80%) and metastasis (20-30%) following surgical removal. However, well-defined therapeutic strategies for this rare malignancy are lacking and are critically needed. Methods. We investigated a new approach to DDLPS therapy with mesenchymal stromal cells expressing herpes simplex virus thymidine kinase (MSC-TK). In an effort to evaluate this efficacy, in vitro cytotoxicity of MSC-TK against DDLPS cells was analyzed using an apoptosis assay. For pre-clinical study, the MSC-TK induced reduction in recurrence and metastasis was validated in a recurrent DDLPS model after the macroscopic complete resection and lung metastasis DDLPS model. Results. MSC-TK induced apoptosis in DDLPS cells by bystander effects via gap junction intracellular communication (GJIC) of toxic ganciclovir (GCV). Recurrent DDLPS models following no residual tumor/microscopic tumor resection and lung metastasis DDLPS models were established, which suggested clinical relevance. MSC-TK markedly reduced locoregional recurrence rates and prolonged recurrence-free survival, thus increasing overall survival in the recurrent DDLPS model. MSC-TK followed by GCV treatment yielded a statistically significant reduction in early and advanced-stage lung metastasis. Discussion. This therapeutic strategy may serve as an alternative or additional strategy by applying MSC-TK to target residual tumors following surgical resection, thus reducing local relapse and metastasis in these patients.</P>

Phosphorylation of human enhancer filamentation 1 (HEF1) stimulates interaction with Polo-like kinase 1 leading to HEF1 localization to focal adhesions

Lee, Kyung Ho,Hwang, Jeong-Ah,Kim, Sun-Ok,Kim, Jung Hee,Shin, Sang Chul,Kim, Eunice EunKyeong,Lee, Kyung S.,Rhee, Kunsoo,Jeon, Byeong Hwa,Bang, Jeong Kyu,Cha-Molstad, Hyunjoo,Soung, Nak-Kyun,Jang, Jae American Society for Biochemistry and Molecular Bi 2018 The Journal of biological chemistry Vol.293 No.3

<P>Elevated expression of human enhancer filamentation 1 (HEF1; also known as NEDD9 or Cas-L) is an essential stimulus for the metastatic process of various solid tumors. This process requires HEF1 localization to focal adhesions (FAs). Although the association of HEF1 with FAs is considered to play a role in cancer cell migration, the mechanism targeting HEF1 to FAs remains unclear. Moreover, up-regulation of Polo-like kinase 1 (Plk1) positively correlates with human cancer metastasis, yet how Plk1 deregulation promotes metastasis remains elusive. Here, we report that casein kinase 1δ (CK1δ) phosphorylates HEF1 at Ser-780 and Thr-804 and that these phosphorylation events promote a physical interaction between Plk1 and HEF1. We found that this interaction is critical for HEF1 translocation to FAs and for inducing migration of HeLa cells. Plk1-docking phosphoepitopes were mapped/confirmed in HEF1 by various methods, including X-ray crystallography, and mutated for functional analysis in HeLa cells. In summary, our results reveal the role of a phosphorylation-dependent HEF1–Plk1 complex in HEF1 translocation to FAs to induce cell migration. Our findings provide critical mechanistic insights into the HEF1–Plk1 complex–dependent localization of HEF1 to FAs underlying the metastatic process and may therefore contribute to the development of new cancer therapies.</P>

Beneficial Effects of Desalinated Magma Seawater in Ameliorating Thioacetamide-induced Chronic Hepatotoxicity

Hyunjoo Lee,In Soo Suh,Minji Woo,Mi Jeong Kim,Yong-Hwan Jung,Yeong Ok Song 한국생물공학회 2019 Biotechnology and Bioprocess Engineering Vol.24 No.1

Mineral water is valued for its potent health benefits. In this study, the hepatoprotective effects of desalinated magma seawater (DMS) containing minerals (9,987 mg/L) were investigated in thioacetamide (TAA)- injected rats. Chronic hepatotoxicity was induced via intraperitoneal injections of TAA (200 mg/kg bw), three times a week for 7 weeks. Rats (n = 10 per group) were allocated as TAA-treated groups fed either a normal chow diet (TAA group) or a chow diet containing 0.91% DMS (TAAL group), 2.05% DMS (TAAH group), or 0.05% silymarin (TAAS group). An additional normal group received the chow diet with vehicle (PBS) injections. Compared with the TAA group, the TAAL, TAAH, and TAAS groups had significantly higher body weights and food intake; however, the TAAH group had lower liver weights (P < 0.05). The TAAH and TAAS groups had higher expression levels of Nrf2, HO-1, and NQO1 proteins (P < 0.05) and lower levels of NF-κB, iNOS, and COX-2 than the TAA group (P < 0.05). Additionally, the protein expression levels of detoxification enzymes CYP2E1, MAT, and GST were higher in the TAAL, TAAH, and TAAS groups than in the TAA group (P < 0.05), as confirmed by histological examination. The severe TAAinduced nuclear damage and collagen accumulation in the hepatocytes improved in the DMS-administered groups, indicating that the hepatotoxicity was alleviated. In conclusion, the minerals in DMS likely ameliorate hepatotoxicity by elevating the liver’s antioxidative and anti-inflammatory status. These DMS effects were dose-dependent, with the effects of 2.05% DMS and 0.05% silymarin being comparable.

Clinical Value of Magnetic Resonance Spectroscopy in the Initial Evaluation of Patients with Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-Like Episodes

Hyunjoo Lee,Je Hee Shin,Ji-Hoon Na,Young-Mock Lee 대한소아신경학회 2021 대한소아신경학회지 Vol.29 No.3

Purpose: Magnetic resonance spectroscopy (MRS) is a diagnostic tool used to detect abnormal accumulation of lactate in the brain parenchyma in various metabolic diseases. This study evalu-ated the clinical roles of brain MRS in the initial assessment of mitochondrial encephalomyopa-thy, lactic acidosis, and stroke-like episodes (MELAS) caused by impairment of the mitochondrial respiratory chain. Methods: Twenty-five patients with the A3243G mutation among 34 MELAS patients referred to the pediatric neurology clinic of Gangnam Severance Hospital between January 2006 and De-cember 2020 were included. In this retrospective study, demographic, clinical, laboratory (serum lactate and lactate-to-pyruvate ratio), magnetic resonance imaging (MRI), and initial MRS (pres-ence of lactate peak and abnormal N-acetylaspartate [NAA]) data were reviewed. Results: Brain MRI showed cortical lesions in 24 of 25 genetically confirmed A3243G MELAS pa-tients with neurologic symptoms in this study. On MRS, 18 patients (72%) had increased lactate peaks, depicting anaerobic energy metabolism, and 17 patients (68%) had decreased NAA levels, indicating neuronal integrity. Ten patients underwent MRS in the acute stage (within 2 weeks of symptoms). Unlike patients who underwent MRS more than 2 weeks after symptom onset, a lac-tate peak on MRS was observed in all patients in the acute stage (P=0.011). Conclusion: Elevated lactate peaks in acute cerebral infarctions are highly suggestive of mito-chondrial encephalopathy. MRS alone is insufficient to diagnose MELAS, but it is valuable as a noninvasive supplemental diagnostic tool in combination with genetic testing.

Ionic Liquids as Electrolytes for Li Ion Batteries

Lee, Je Seung,Bae, Jin Yong,Lee, Hyunjoo,Quan, Nguyen Dinh,Kim, Hoon Sik,Kim, Honggon 한국공업화학회 2004 Journal of Industrial and Engineering Chemistry Vol.10 No.7

The electrolyte systems used for lithium ion batteries are briefly reviewed and the problems con-fronting current carbonate-based electrolytes are discussed in terms of following aspects including capacity, temperature limit, safety and hazard, and ion transport. Various efforts to apply room temperature ionic liquids for lithium ion battery electrolytes are introduced due to their excellent electrochemical properties such as non-flammability, non-volatility, chemical inertness, wide electrochemical windows, high conductivity, and wide thermal operating ranges.

The Effect of Government Hybrid Funds on IPO Underpricing in Emerging Markets : Evidence from the Korean Stock Market

Hyunjoo Lee,Jinho Jeong 한국재무학회 2016 한국재무학회 학술대회 Vol.2016 No.11

IPO underpricing has been a subject of great interest for researchers. Previous studies have focused on the underpricing of private venture capital-backed IPOs. However, underpricing in government-backed IPOs has been largely ignored by mainstream academic researchers. In this study, we aim to help fill this gap by investigating the pattern of IPO underpricing for government-backed IPOs in Korea. We analyzed the IPO price behavior of 278 newly listed firms on Korea Securities Dealers Automated Quotations during the period of 2009 through 2014. Empirical evidence shows that government sponsorship reduces the degree of asymmetric information in the IPO market by providing a certification role. In particular, the dual sponsorship of government and private VCs contributes most significantly to the reduction of information uncertainty in the IPO market.

Quantum Wormholes

Hyunjoo Lee 한국물리학회 2004 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.45 No.1

The two-dimensional dilaton gravity model which is generalized to include a ghost Klein-Gordon field is semiclassically modified by adding local covariant terms of one-loop order. The black hole and the wormhole solutions are given in the semiclassically corrected model. When a static traversible wormhole is used to transport matter or radiation, the stability of the wormhole is shown in semiclassical theory: the wormhole starts radiating when the matter arrives and finally return to a static one. A bulk of the ingoing matter energy is radiated and the unradiated energy is used to change of throat radius of the final static wormhole.

Quantum black holes and wormholes in exactly solvable model

Hyunjoo Lee,Won-Tae Kim,Sung-Won Kim 한국물리학회 2004 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.44 No.2

The two-dimensional dilaton gravity model is generalized to include a ghost Klein-Gordon eld, i.e., a negative gravitational coupling, which supports the existence of static traversible wormhole solutions, and is semiclassically modied by adding local covariant terms of one-loop order. In the semiclassically corrected model, the black hole and the wormhole solutions are given. When a static traversible wormhole is used to transport matter or radiation, we study the back-reaction of the transported matter on the wormhole and the end state of the wormhole in the semiclassical level and compare the results with the classical case. We show that the semiclassical wormhole is stable to such back-reaction.

Soft magnetic properties of Fe-based amorphous/nanocrystalline hybrid materials

Lee, Yeonjoo,Jeon, Jonggyu,Nam, Seungjin,Jang, Teasuk,Kim, Hwijun,Lee, Minwoo,Kim, Yongjin,Yang, Dongyeol,Min, Kyeongsik,Choi, Hyunjoo Elsevier 2018 Powder technology Vol.339 No.-

<P><B>Abstract</B></P> <P>In this study, we investigated the effect of crystalline structures on the magnetic properties of the Fe-based amorphous powder. We intentionally produced uniformly dispersed nanocrystallites inside the Fe-based amorphous powder using a combined process of mechanical milling and thermal annealing. In the case of powder produced after 30 min of ball milling followed by annealing at 400 °C, coercivity was decreased by 96.88% from 3698.73 to 115.49 A/m, and magnetization was increased 2.60% from 1.92 × 10<SUP>−4</SUP> to 1.97 × 10<SUP>−4</SUP> Wbm/kg. The simultaneous improvement of coercivity and magnetization can be attributed to the homogeneous generation of a small number of nanocrystallites as well as the release of residual stress.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The Fe-B-P-C-Nb-Hf amorphous powder was produced by gas-atomization. </LI> <LI> A uniform nanocrystallites was formed inside the Fe-based amorphous powder by thermal annealing and mechanical milling. </LI> <LI> Homogeneous generation of a small number of nanocrystallites improve coercivity and magnetization. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>