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Ulsan, South Korea

The University of Ulsan was founded on February 19, 1969 as the Ulsan Institute of Technology. The University was promoted to a full-fledged University on March 1, 1985. The university is located in Mugeo-dong, Ulsan, South Korea. The University currently has approximately 10,500 students enrolled.The city of Ulsan has been recognized as the Korean city which was built around the corporate base of the multinational Hyundai conglomerate. Thus, the Hyundai Conglomerate announced its plan to give 40 billion won to assist a variety of university-industry cooperation projects.This corporate relationship has helped turn the University into one of South Korea's top rated institutions for graduate job placement, as well as increasing its reputation more broadly as one of the top private universities outside of Seoul. Wikipedia.

Han J.,Sanford Burnham Institute for Medical Research | Han J.,150 West Medical Center Drive | Back S.H.,150 West Medical Center Drive | Back S.H.,University of Ulsan | And 13 more authors.
Nature Cell Biology | Year: 2013

Protein misfolding in the endoplasmic reticulum (ER) leads to cell death through PERK-mediated phosphorylation of eIF2α, although the mechanism is not understood. ChIP-seq and mRNA-seq of activating transcription factor 4 (ATF4) and C/EBP homologous protein (CHOP), key transcription factors downstream of p-eIF2α, demonstrated that they interact to directly induce genes encoding protein synthesis and the unfolded protein response, but not apoptosis. Forced expression of ATF4 and CHOP increased protein synthesis and caused ATP depletion, oxidative stress and cell death. The increased protein synthesis and oxidative stress were necessary signals for cell death. We show that eIF2α-phosphorylation-attenuated protein synthesis, and not Atf4 mRNA translation, promotes cell survival. These results show that transcriptional induction through ATF4 and CHOP increases protein synthesis leading to oxidative stress and cell death. The findings suggest that limiting protein synthesis will be therapeutic for diseases caused by protein misfolding in the ER. © 2013 Macmillan Publishers Limited. All rights reserved.

Kim J.H.,University of Ulsan
Transplantation Proceedings | Year: 2014

When the Organ Transplantation Act came into effect in 2000 in South Korea, living organ donations were legalized and the Korean Network for Organ Sharing (KONOS) had a duty to approve the application of donation. The number of living organ donors has increased and the waiting time of recipients has been steady or decreased. The Organ Transplantation Act mainly focuses on the informed consent process of donations, so unrelated directed donations are permitted unless there is a suspicion of organ trafficking. But the annual reports show that directed donations of unrelated and related donors may have an ethical concern about organ sales. The donations of family members show another ethical concern. The numbers of ABO-incompatible transplantations have steadily increased since 2008, and lineal descendants, including minors, comprised 61% of living liver donors in 2012. Addressing the unethical practices without inhibiting living organ donations is the current task in South Korea. Private agencies have actively operated the living organ donations programs. The web-based computerized organ exchange program has been cooperatively run by hospital-based organizations. The strict legal regulations that could decrease living organ donations are hard to adopt. In the current situation, the functions of the official system need to be more developed. A national organ exchange program run by KONOS could be an option which could reduce ABO-incompatible transplantations and relieve the ethical concern of organ sales in unrelated directed donations.

Harskamp R.E.,VU University Amsterdam | Park D.-W.,University of Ulsan
Current Cardiology Reports | Year: 2015

For decades, coronary artery bypass grafting (CABG) has been the choice of revascularization strategy for significant left main coronary artery (LMCA) disease. However, with marked technological advances in less invasive percutaneous strategies, such as drug-eluting stents, and potent adjunctive pharmacology, percutaneous coronary intervention (PCI) has been increasingly accepted as an alternative to CABG for selected cases with LMCA disease. The available evidence from randomized clinical trials and adequately sized, real-world registries suggest that hard clinical endpoints (death, myocardial infarction, or stroke) were comparable between two treatment strategies at short- and mid-term follow-up, while higher rate of repeat revascularization are observed after PCI. Current guidelines state that PCI for LMCA disease is reasonable in patients with low to intermediate anatomic complexity and those who are at increased surgical risk. Ongoing large-sized clinical trials comparing newer-generation drug-eluting stents and CABG would provide important clinical insights to guide optimal strategy for patients with significant LMCA disease in the (near) future. © 2015, Springer Science+Business Media New York.

Chu S.J.,University of Ulsan
Journal of Mechanical Science and Technology | Year: 2013

The present study investigates the cause of the loosening of the lock nut in a forklift drive axle. Structural analysis of the wheel shaft assembly revealed that the slippage on the contact surface of the lock nut was considerable, especially when the preloads on the bearing set were lacking. Macroscopic observation of the worn out contact surface revealed that circular scratches were formed whose radii were nearly the same as the slippage distance in the structural analysis results. Experimental simulation of the loosening of the lock nut was successfully carried out. © 2013 The Korean Society of Mechanical Engineers and Springer-Verlag Berlin Heidelberg.

Lee Y.J.,Dankook University | Han S.R.,Dankook University | Kim N.Y.,Dankook University | Lee S.-H.,University of Ulsan | And 2 more authors.
Gastroenterology | Year: 2012

Background & Aims: Carcinoembryonic antigen (CEA) is expressed by many types of cancer cells; its overexpression induces cell adhesion, increases resistance to anoikis, and promotes hepatic metastasis of colon cancer cells. The amino acid sequence PELPK in its hinge region, between the N and A1 domains, is required for migration of cancer cells to the liver. We sought to identify ligands of this domain for use in diagnosis and therapy. Methods: We screened for RNA aptamers against the domain of CEA required for metastasis using systematic evolution of ligands by exponential enrichment. The specificity and affinity of the aptamer for CEA protein were characterized by mobility shift, uptake, and surface plasmon resonance assays. We analyzed the effects of the aptamer on metastatic properties of cells, as well as metastasis of colon cancer cells in mice. Results: Using systematic evolution of ligands by exponential enrichment, we identified an RNA aptamer that bound to the PELPK sequence in CEA with high affinity and specificity. The isolated aptamer bound specifically to CEA-positive cells and inhibited interactions between CEA and heterogeneous nuclear ribonucleoprotein M4. The aptamer inhibited homotypic aggregation, migration, and invasion by CEA-positive cancer cells, but did not affect adhesion of endothelial cells. The aptamer induced colon cancer cell anoikis by interrupting the interaction between death receptor 5 and CEA. The aptamer prevented metastasis of human colon cancer cells to the livers of mice. Conclusions: An RNA aptamer that binds to the PELPK sequence in CEA inhibits its interactions with heterogeneous nuclear ribonucleoprotein M4 and death receptor 5, migration and invasion by colon cancer cells, and hepatic metastasis of colon cancer cells in mice. It promoted cancer cell anoikis and might be used to identify CEA-positive tumors in patients or be developed as an anti-cancer reagent. © 2012 AGA Institute.

Song J.-K.,University of Ulsan
Herz | Year: 2011

Non-invasive tomographic imaging modalities have recently contributed to identifying aortic intramural hematoma, a variant form of classic dissection, which is characterized by the absence of an intimal tear and thus the absence of direct flow communication, and which represents an important disease entity in acute aortic syndrome. Clinical investigations have revealed that intramural hematoma has characteristic clinical features and that the natural remodeling process of hematoma is different from that of classic aortic dissection. These findings suggest that intramural hematoma is not just a precursor to aortic dissection, but may be a unique disease entity with a more favorable prognosis compared to aortic dissection. There is regional heterogeneity regarding the relative incidence of this hematoma, with higher incidence seen in Eastern countries. Due to favorable outcomes with medical treatment in Asian patients with type A intramural hematoma, a tailored or individualized approach based on risk stratification using initial clinical information and including imaging studies and timely surgical repair has been suggested in hemodynamically stable patients; however, these results need to be confirmed in other patient populations. The concept of a "micro-tear" which cannot be easily visualized using conventional imaging modalities has been raised: "echo-free space" on transesophageal echocardiography and "focal contrast enhancement" on ultra-fast computerized tomography have drawn many physicians' attention, and the possibility of a pathophysiologic link between classic aortic dissection and intramural hematoma has been discussed. Further investigations are needed to test whether intramural hematoma begins with an initial intimal tear and a different aortic status-characterized by a more rigid and non-compliant aorta associated with old age or long-standing hypertension - and results in an apparently absent intimal flap. © 2011 Urban & Vogel, Muenchen.

Hong J.H.,University of Ulsan | Kim I.Y.,Urologic
Korean Journal of Urology | Year: 2014

After the introduction of prostate cancer screening with the prostate-specific antigen (PSA) test, we have witnessed a dramatic stage migration. As a result, an increasing number of patients are diagnosed at earlier stages and receive local treatments including surgery or radiation. When these local treatments fail by the definition of increasing PSA levels, patients are usually treated with androgen-deprivation therapy. A fraction of these patients will finally reach a state of castration-resistant prostate cancer (CRPC) even without radiological evidence of metastasis, which is referred to as nonmetastatic CRPC (NM-CRPC). Most men with advanced or metastatic prostate cancer initially respond to various types of androgen ablation, but a considerable portion of them eventually progress to NM-CRPC. Among patients with NM-CPRC, about one-third will develop bone metastasis within 2 years. In these patients, PSA kinetics is the most powerful indicator of progression and is usually used to trigger further imaging studies and enrollment in clinical trials. Although CRPC remains largely driven by the androgen receptor, the benefit of second-line hormonal manipulations, including first-generation antiandrogens, adrenal synthesis inhibitors, and steroids, has not been investigated in men with NM-CRPC. To date, denosumab is the only agent that has been shown to delay the onset of bone metastasis. However, overall survival did not differ. In treating NM-CRPC patients, physicians should recognize the heterogeneity of the disease and acknowledge that the recently approved second-line treatments have been studied only in advanced stages of the disease. © The Korean Urological Association, 2014.

Khang Y.-H.,University of Ulsan | Kim H.R.,Korea Institute for Health and Social Affairs
Journal of Women's Health | Year: 2010

Aims: We aimed to examine whether pain-inducing musculoskeletal disorders might explain the gender difference in the strength of the self-rated health (SRH)-mortality association. Methods: We pooled data from two National Health and Nutrition Examination Surveys (conducted in 1998 and 2001), which were linked to national mortality data of Korea using 13-digit unique personal identification numbers. There were 9,912 study participants, and 456 deaths were recorded (average length of follow-up=5.7 years). Using a checklist of chronic conditions, the prevalences of major pain-causing musculoskeletal disorders (arthritis, sciatica, and herniated intervertebral disc) were obtained. Results: The relative risk (RR) of mortality for the poor and very poor categories of SRH tended to be greater in men than in women. Compared with those without musculoskeletal disorders, the RR for those with musculoskeletal disorders was similar in men but lower in women. Women had a greater prevalence of musculoskeletal disorders than men, and women with musculoskeletal disorders reported poorer health than did men with these disorders. In individuals without major musculoskeletal disorders, the strength of the SRH-mortality association was reduced in men but increased in women. Similar patterns in RRs for SRH by gender were observed when sociodemographic characteristics (education and marital status), number of severe chronic illnesses, and health behaviors (cigarette smoking, alcohol consumption, and regular physical exercise) were additionally adjusted for. Conclusions: Nonfatal musculoskeletal disorders may explain gender differences in the SRH-mortality association. Larger prospective studies in different cultural settings may help advance our understanding of the role of pain and pain-inducing musculoskeletal disorders in explaining gender differences in the SRH-mortality association. Copyright 2010, Mary Ann Liebert, Inc.

Kim J.S.,University of Ulsan
Frontiers of Neurology and Neuroscience | Year: 2014

Transient ischemic attack (TIA) is a cerebrovascular disease with temporary (<24 h) neurological symptoms. The symptoms of TIA patients are largely similar to those of ischemic stroke patients and include unilateral limb weakness, speech disturbances, sensory symptoms, visual disturbances, and gait difficulties. As these symptoms are transient, they are frequently evaluated based on patients' subjective reports, which are less precise than those of patients with stroke whose longer-lasting symptoms and signs can be reliably assessed by physicians. Some symptoms, such as monocular blindness, are much more common in TIA than in stroke, and limb shaking occurs almost exclusively in TIA patients. On the other hand, symptoms like hemivisual field defects or limb ataxia are underappreciated in TIA patients. These transient neurological symptoms are not necessarily caused by cerebrovascular diseases, but can be produced by a variety of non-vascular diseases. Careful history taking, examination, and appropriate imaging tests are needed to differentiate these TIA mimics from TIA. Each TIA symptom has a different specificity and sensitivity, and there has been an effort to assess the outcome of the patients through the use of specific clinical features. On top of this, recent developments in imaging techniques have greatly enhanced our ability to predict the outcomes of TIA patients. Perception or recognition of TIA symptoms may differ according to the race, sex, education, and specialty of physicians. Appropriate education of both the general population and physicians with regard to TIA symptoms is important as TIAs need emergent evaluation and treatment. Copyright © 2014 S. Karger AG, Basel.

The growing disparity between the number of liver transplant candidates and the supply of deceased donor organs has motivated the development of living donor liver transplantation (LDLT). Over the last two decades, the operation has been markedly improved by innovations rendering modern results comparable with those of deceased donor liver transplantation (DDLT). However, there remains room for further innovation, particularly in adult living donor liver transplantation (ALDLT). Unlike whole-size DDLT and pediatric LDLT, size-mismatching between ALDLT graft and recipient body weight and changing dynamics of posttransplant allograft regeneration have remained major challenges. A better understanding of the complex surgical anatomy and physiologic differences of ALDLT helps avoid small-for-size graft syndrome, graft congestion from outflow obstruction and graft hypoperfusion from portal flow steal. ALDLT for high-urgency patients (Model for End-Stage Liver Disease score >30) can achieve results comparable to DDLT in high volume centers. Size limitations of partial grafts and donor safety issues can be overcome with dual grafts and modified right-lobe grafts that preserve the donor's middle hepatic vein trunk. Extended application of LDLT for unresectable hepatocellular carcinoma above Milan criteria is an optional strategy at the cost of slightly compromised survival. ABO-blood group incompatibility obstacles have been broken down by introducing a paired donor exchange program and refined peri-operative management of ABO-incompatible ALDLT. This review focuses on recent innovations of surgical techniques, safe donor selection, current strategies to expand ALDLT with broadened patient selection criteria and important aspects of teamwork required for success. Expanding a successful adult living donor liver transplantation program requires a better understanding of the physiologic differences between living donor and deceased donor liver transplantation, technical innovation, broadened recipient acceptance criteria, and consistently safe donor selection criteria. Companion videos demonstrating the techniques described in this comprehensive review can be found in the AJT Video Library at amjtransplant.com. © Copyright 2014 The American Society of Transplantation and the American Society of Transplant Surgeons.

Lim Y.S.,University of Ulsan
The Korean journal of hepatology | Year: 2010

Acute liver failure (ALF) is a rare condition in which rapid deterioration of liver function results in altered mentation and coagulopathy in individuals without previously recognized liver disease. The outcomes of patients with ALF vary greatly according to etiology, and the etiology of ALF varies markedly by geographical region. In Korea, about 90% of ALF are associated with etiologies that usually result in poor outcomes, including hepatitis B virus (HBV) infection and herbal remedies. The main causes of death in patients with ALF are increased intracranial pressure, systemic infection, and multi-organ failure. Recent advances in the intensive care of patients with ALF have contributed to a marked improvement in their overall survival. Emergency adult to adult living-donor liver transplantation (LDLT) can be performed expeditiously and safely for patients with ALF, and greatly improves survival rate as well as deceased-donor transplantation. As the window during which transplantation is possible is limited, emergency adult LDLT should be considered to be one of the first-line treatment options in patients with ALF, especially in regions in which ALFs are caused by etiologies associated with poor outcome and the supply of organs is very limited.

Yoo H.,University of Ulsan
Electronics Letters | Year: 2013

In high-magnetic magnetic resonance imaging (MRI) systems (7 T and above), the radio frequency (RF) field shows greater inhomogeneity compared with clinical MRI systems (1.5 and 3.0 T). In multichannel RF coils, driving each coil element with convex optimisation can reduce non-uniformity of the RF field in a region of interest. In this Letter, a periodic compressed method (PCM) and a PCM after averaging are proposed in order to reduce RF coil control time at high fields. Simulation results were obtained using a human head model in 7 and 9.4 T systems, and the results are discussed in detail. © 2013 Institution of Engineering and Technology.

Suh Y.S.,University of Ulsan
Sensors (Switzerland) | Year: 2014

An off-line smoother algorithm is proposed to estimate foot motion using an inertial sensor unit (three-axis gyroscopes and accelerometers) attached to a shoe. The smoother gives more accurate foot motion estimation than filter-based algorithms by using all of the sensor data instead of using the current sensor data. The algorithm consists of two parts. In the first part, a Kalman filter is used to obtain initial foot motion estimation. In the second part, the error in the initial estimation is compensated using a smoother, where the problem is formulated in the quadratic optimization problem. An efficient solution of the quadratic optimization problem is given using the sparse structure. Through experiments, it is shown that the proposed algorithm can estimate foot motion more accurately than a filter-based algorithm with reasonable computation time. In particular, there is significant improvement in the foot motion estimation when the foot is moving off the floor: the z-axis position error squared sum (total time: 3.47 s) when the foot is in the air is 0.0807 m2(Kalman filter) and 0.0020 m2 (the proposed smoother). © 2014 by the author; licensee MDPI, Basel, Switzerland.

Son Y.-J.,Soonchunhyang University | Song E.K.,University of Ulsan
European Journal of Cardiovascular Nursing | Year: 2013

Background: The most desirable outcome in heart failure (HF) management is to improve health-related quality of life (HRQoL) as a patient-centred health outcome. Nutrition is assumed to be important in HF management, whereas there is little evidence that nutritional risk affects HRQoL, except for sodium. Purpose: We aimed to determine whether nutritional risk is associated with worse HRQoL after controlling for daily sodium intake. Methods: A total of 134 consecutive patients with HF [age 63]11 years, 35% female, 45% New York Heart Association (NYHA) class III/IV, ejection fraction (EF) 33]13%] completed the Nutrition Screening Initiative (NSI) to assess nutritional risk and a 24-h urine sodium excretion assessment to estimate daily sodium intake at baseline. The Minnesota Living with HF Questionnaire was used to evaluate HRQoL at baseline and 6 months later. Hierarchical linear regressions were used to determine whether nutritional risk predicted HRQoL at baseline and 6 months later. Results: Seventy-eight (58.2%) patients had high nutritional risk as indicated by a total NSI score ≥6. Increased nutritional risk was independently associated with worse HRQoL at baseline and 6 months later (β=0.33, p<0.001; β=0.35, p<0.001, respectively), after controlling for age, gender, aetiology, body mass index, NYHA class, EF, total comorbidity score, prescribed medications, and daily sodium intake. Conclusion: These findings show that higher nutritional risk beyond sodium intake affects worse HRQoL in patients with HF. Further work is required to provide specific dietary guidelines to improve health outcomes for patients with HF. © The European Society of Cardiology 2012.

Cho S.,University of Ulsan | Lee J.,Ulsan National Institute of Science and Technology | Tong M.,University of California at Santa Barbara | Seo J.H.,University of California at Santa Barbara | Yang C.,Ulsan National Institute of Science and Technology
Advanced Functional Materials | Year: 2011

As a characteristic feature of conventional conjugated polymers, it has been generally agreed that conjugated polymers exhibit either high hole transport property (p-type) or high electron transport property (n-type). Although ambipolar properties have been demonstrated from specially designed conjugated polymers, only a few examples have exhibited ambipolar transport properties under limited conditions. Furthermore, there is, as yet, no example with 'equivalent' hole and electron transport properties. We describe the realization of an equivalent ambipolar organic field-effect transistor (FET) by using a single-component visible-near infrared absorbing diketopyrrolopyrrole (DPP)-benzothiadiazole (BTZ) copolymer, namely poly[3,6-dithiene-2-yl-2,5-di(2- decyltetradecyl)-pyrrolo[3,4-c]pyrrole-1,4-dione-5',5''-diyl-alt-benzo-2,1, 3-thiadiazol-4,7-diyl] (PDTDPP-alt-BTZ). PDTDPP-alt-BTZ shows not only ideally balanced charge carrier mobilities for both electrons ( e = 0.09 cm 2V -1s -1) and holes ( h = 0.1 cm 2V -1s -1) but also its inverter constructed with the combination of two identical ambipolar FETs exhibits a gain of ∼35 that is much higher than usually obtained values for unipolar logic. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ruminski A.M.,Lawrence Berkeley National Laboratory | Jeon K.-J.,Lawrence Berkeley National Laboratory | Jeon K.-J.,University of Ulsan | Urban J.J.,Lawrence Berkeley National Laboratory
Journal of Materials Chemistry | Year: 2011

The carbon dioxide storage capacity of magnesium oxide (MgO) particles was examined as a function of particle size, shape, and surface area. Two types of MgO nanocrystals (5 nm spheres and 23 nm disks) were synthesized and compared against commercially available MgO (325 mesh/44 μm and 40 mesh/420 μm). The surface area of the four types of particles was determined by N2 gas adsorption. Carbon dioxide capture was measured at 60 °C and 600 °C using thermogravimetric analysis, with results indicating enhanced CO 2 capacity correlating with increased surface area. © 2011 The Royal Society of Chemistry.

Hung T.N.,University of Ulsan
Sensors (Basel, Switzerland) | Year: 2013

Two feet motion is estimated for gait analysis. An inertial sensor is attached on each shoe and an inertial navigation algorithm is used to estimate the movement of both feet. To correct inter-shoe position error, a camera is installed on the right shoe and infrared LEDs are installed on the left shoe. The proposed system gives key gait analysis parameters such as step length, stride length, foot angle and walking speed. Also it gives three dimensional trajectories of two feet for gait analysis.

Nguyen T.-T.,University of Ulsan
Sensors (Basel, Switzerland) | Year: 2014

This paper proposes a practical low-complexity MAC (medium access control) scheme for quality of service (QoS)-aware and cluster-based underwater acoustic sensor networks (UASN), in which the provision of differentiated QoS is required. In such a network, underwater sensors (U-sensor) in a cluster are divided into several classes, each of which has a different QoS requirement. The major problem considered in this paper is the maximization of the number of nodes that a cluster can accommodate while still providing the required QoS for each class in terms of the PDR (packet delivery ratio). In order to address the problem, we first estimate the packet delivery probability (PDP) and use it to formulate an optimization problem to determine the optimal value of the maximum packet retransmissions for each QoS class. The custom greedy and interior-point algorithms are used to find the optimal solutions, which are verified by extensive simulations. The simulation results show that, by solving the proposed optimization problem, the supportable number of underwater sensor nodes can be maximized while satisfying the QoS requirements for each class.

Hyun Kim S.,University of Ulsan
Journal of the Franklin Institute | Year: 2014

This paper is devoted to the robust stabilization problem for a class of MJLSs with mode transition probabilities taken to be partly known, unknown, and unknown but with known bounds. To meet the needs of less conservative stabilization conditions, this paper proposes a valuable approach that (1) can express the conditions in terms of matrix inequalities with homogeneous polynomial dependence on partly unknown transition probabilities and (2) can include all possible slack variables related to transition probability constraints in the relaxation process coupled with deriving a finite set of linear matrix inequalities (LMIs). Finally, two numerical examples are reported to illustrate the effectiveness of the derived stabilization conditions. © 2014 The Franklin Institute. Published by Elsevier Ltd. All rights reserved.

Kim S.H.,University of Ulsan
IEEE Transactions on Fuzzy Systems | Year: 2014

This paper investigates the nonquadratic output-feedback stabilization problem for nonlinear systems in Takagi-Sugeno's (T-S) form. To achieve improved performance in the H sense, this paper provides two kinds of relaxation techniques: one for the case where all premise variables are measurable and one for the case where the premise variables are immeasurable. In particular, the emphasis of the second technique is the use of estimated premise variables for nonquadratic Lyapunov functions. © 2014 IEEE.

Pasten C.,University of Chile | Shin H.,University of Ulsan | Carlos Santamarina J.,Georgia Institute of Technology
Journal of Geotechnical and Geoenvironmental Engineering | Year: 2014

Repetitive loading can induce volumetric and shear strain accumulation in soils and affect the long-term performance of engineered and natural geosystems.Ahybrid numerical scheme based on theFEMis implemented to analyze problems where a very large number of cycles is involved. The numerical approach combines a classical mechanical constitutive model to simulate the static load and the first load cycle and empirical accumulation functions to track the accumulation of deformations during repetitive loading. The hybrid model captures fundamental characteristics of soil behavior under repetitive loading, such as threshold strains, terminal density, and ratcheting response; it also predicts volumetric and shear strains as a function of the static stress obliquity, the number of load cycles, and the plastic strain during the first load cycle. The proposed numerical scheme is used to analyze shallow foundations subjected to repetitive loads. Results show the evolution of vertical settlement, horizontal displacement, footing rotation, and stress redistribution within the soil mass as the number of load cycles increases. Displacements and rotation are more pronounced as the static factor of safety decreases and the cyclic load amplitude increases. © 2013 American Society of Civil Engineers.

Shin H.,University of Ulsan | Santamarina J.C.,Georgia Institute of Technology
Geotechnique Letters | Year: 2011

The formation of open-mode discontinuities is a common occurrence in soils. This family of discontinuities includes hydraulic fractures, gas-driven fractures, desiccation cracks, ice and hydrate lenses, and even roots. These discontinuities can be analysed at the particle scale or at the macroscale using constitutive models that are consistent with the effective stress-dependent behaviour of soils. Both analyses show that the medium is in compression everywhere and that growth is intimately related to unloading and expansion ahead of the tip. While these observations appear to be common to the development of all open-mode fractures in soils, there are pronounced invasion differences between miscible fluids and immiscible phases.

Jo K.,University of Ulsan
Neurocomputing | Year: 2015

In recent years, light-emitting diodes dot-matrix text (LED text) is being widely used for displaying information and announcements. However, there is currently no text detection system that is capable of handling LED text. Unlike general printed text, it is not easy to detect and recognize LED text due to its discontinuity. A character of the LED is generally displayed with a matrix of segments and composed with them to generate the text. Furthermore, it is necessary to detect each character from a line of LED text for creating a robust text detection system. Thus, this paper proposes a method for LED text detection and recognition in natural scene images. To perform this goal of detection and recognition of a character and text, it consists of two main steps with the following steps: the first step, a Canny edge was used to detect character pixels which appear in LED display area from scene images. The center points of edge segments are calculated. These points are merged based on their properties to generate a character candidate. In order to obtain character feature, the spatial information such as a centroid and orientation of the character candidate are used. These values are then analyzed using a k-nearest neighbor approach for classifying the character candidate as a certain alphanumeric. In the second step, the recognized characters are later combined into a text line based on the similarity of their characteristics such as width, height, aspect ratio and color. The post-processing of text line generating is then applied for rectifying the falsely recognized characters. In experiments, our proposed method achieves 68.8% and 47% for detection and recognition rate, respectively. These results show the robustness and effectiveness of the proposed method for detecting and recognizing the LED text in natural scene images that has filled the vacancy that the printed and dense text detection system has not covered. © 2014 Elsevier B.V.

Shin H.-W.,Chung - Ang University | Chung S.J.,University of Ulsan
Journal of Clinical Neurology (Korea) | Year: 2012

Drug-induced parkinsonism (DIP) is the second-most-common etiology of parkinsonism in the elderly after Parkinson's disease (PD). Many patients with DIP may be misdiagnosed with PD because the clinical features of these two conditions are indistinguishable. Moreover, neurological deficits in patients with DIP may be severe enough to affect daily activities and may persist for long periods of time after the cessation of drug taking. In addition to typical antipsychotics, DIP may be caused by gastrointestinal prokinetics, calcium channel blockers, atypical antipsychotics, and antiepileptic drugs. The clinical manifestations of DIP are classically described as bilateral and symmetric parkinsonism without tremor at rest. However, about half of DIP patients show asymmetrical parkinsonism and tremor at rest, making it difficult to differentiate DIP from PD. The pathophy-siology of DIP is related to drug-induced changes in the basal ganglia motor circuit secondary to dopaminergic receptor blockade. Since these effects are limited to postsynaptic dopaminergic receptors, it is expected that presynaptic dopaminergic neurons in the striatum will be intact. Dopamine transporter (DAT) imaging is useful for diagnosing presynaptic parkinsonism. DAT uptake in the striatum is significantly decreased even in the early stage of PD, and this characteristic may help in differentiating PD from DIP. DIP may have a significant and longstanding effect on patients' daily lives, and so physicians should be cautious when prescribing dopaminergic receptor blockers and should monitor patients' neurological signs, especially for parkinsonism and other movement disorders. © 2012 Korean Neurological Association.

Kim Y.S.,University of Ulsan
Journal of the Korean Surgical Society | Year: 2012

Parathyroid carcinoma is a rare disease in pediatric patients. We present a case of a 13-year-old girl who presented to the Thyroid Department for an asymptomatic palpable neck mass for 1 year. The high levels of calcium, ionized calcium, and parathyroid hormone level along with parathyroid scintigraphy studies suggested primary hyperparathyroidism. Parathyroid carcinoma was confirmed by biopsy and pathologic examination after resection. Six months postoperatively, persistent hypercalcemia and multiple lung metastases were found on computed tomography. Bilateral lung wedge resection was performed. En bloc resection for primary parathyroid carcinoma and aggressive resection of metastatic disease is the most effective treatment to control hypercalcemia. Copyright © 2012, the Korean Surgical Society.

Hong J.T.,University of Ulsan
Korean journal of ophthalmology : KJO | Year: 2012

To evaluate the effect of the scanning laser ophthalmoscope (SLO) guided re-test mode on short- and long-term measurement variability of peripapillary retinal nerve fiber layer (RNFL) thickness obtained by spectral domain-SLO optical coherence tomography (SD-SLO/OCT). Seventy five healthy eyes were scanned 3 times per day (intra-session variability) by both the SLO guided re-test mode and the independent mode of SD-SLO/OCT. Subjects were scanned 3 times by both modes at visits within a 2-week interval (inter-session variability). For testing longitudinal variability, 3 separate exams were performed over 6 months by both modes. The coefficient of variation (CV), reproducibility coefficient (RC) and intraclass correlation coefficient of RNFL thickness were compared between the two modes. The intra-session RC and CV ranged from 5.4 to 12.9 microns and 1.76% to 5.72% when measured by independent mode and 5.4 to 12.5 microns and 1.75% to 5.58% by re-test mode, respectively. The inter-session RC and CV ranged from 5.8 to 13.3 microns and 1.89% to 5.78% by independent mode and 5.8 to 12.7 microns and 1.90% to 5.54% by re-test mode, respectively. Intra-session and inter-session variability measurements were not significantly different between the two modes. The longitudinal RC and CV ranged from 8.5 to 19.2 microns and 2.79% to 7.08% by independent mode and 7.5 to 14.4 microns and 2.33% to 6.22% by re-test mode, respectively. Longitudinal measurement variability was significantly lower when measured by the re-test mode compared to the independent mode (average, p = 0.011). The SLO guided re-test mode for RNFL thickness measurement in SD-SLO/OCT employing a tracking system improved long-term reproducibility by reducing variability induced by inconsistent scan circle placement.

Goo H.W.,University of Ulsan
European Journal of Radiology | Year: 2010

Whole-body MRI (WBMRI) is an emerging imaging method that has a great potential in pediatric oncologic imaging. It appears useful in staging and monitoring neuroblastoma although its clinical impact has not been thoroughly evaluated. Among various imaging techniques currently available for WBMRI, coronal and sagittal STIR imaging with a quadrature body coil at 1.5T MR system is recommended for a standard protocol. Nevertheless, further technical improvements are anticipated at 3.0T MR system and multi-channel surface coil system. Scan time of WBMRI is reasonably short ranging from 20 min to 60 min. In localized neuroblatoma, WBMRI may help in predicting surgical risks by evaluating image-defined risk factors accurately. In addition, WBMRI is quite useful in detecting distant metastasis, assessing initial treatment responses, and identifying tumor recurrence of neuroblastoma. We should understand limitations of WBMRI in the evaluation of lymph node involvement, in the differentiation between viable tumor and non-viable residual lesion, and in the detection of calcified lesion. Diffusion-weighted imaging may improve diagnostic accuracy of WBMRI. Complementary use of WBMRI and other metabolic imaging method such as MIBG scintigraphy or PET probably increases diagnostic accuracy and, subsequently, improves clinical outcome of children with neuroblastoma. © 2009 Elsevier Ireland Ltd. All rights reserved.

Kim S.H.,University of Ulsan
Journal of the Franklin Institute | Year: 2015

This paper investigates the problem of stochastic stability analysis for a class of discrete-time singular Markovian jump systems with time-varying delays and incomplete (i.e., unknown and uncertain) transition probabilities. To derive an improved delay-range-dependent stability criterion under the incomplete transition descriptions, a relaxation scheme is proposed with consideration of the free-weighting matrix method compatible with the delay partitioning technique, and its purpose is accomplished (1) by making full use of the available boundary information on incomplete transition probabilities, and (2) by employing novel slack variables that allow some useful equality constraints to be exploited. © 2014 The Franklin Institute.

Choi C.M.,University of Ulsan
Tuberculosis and Respiratory Diseases | Year: 2013

Many attempts have been made to find genetic abnormalities inducing carcinogenesis after the development of epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor targeting EGFR in lung cancer. New target therapies have been already commercialized and studied along with the recent discovery of gene rearrangement involved in the carcinogenic process of non-small cell lung cancer. This study aims to investigate anplastic lymphoma kinase, c-ros oncogene 1, and receptor tyrosine kinase, in particular. © 2013 The Korean Academy of Tuberculosis and Respiratory Diseases. All rights reserved.

Yim J.H.,University of Ulsan
Annals of Plastic Surgery | Year: 2015

BACKGROUND: The inverted nipple is a relatively common aesthetic problem seen by plastic surgeons. The etiologies of an inverted nipple include insufficiency of supporting tissues, hypoplasia of the lactiferous ducts, and retraction caused by fibrous bands at the base of the nipple. Many different surgical techniques have been described, either individually or in combination, but none represents a landmark strategy. In our present study, we report our experience of spontaneous improvement immediately after nipple-sparing mastectomy with simple buried interrupted sutures to maintain nipple base in inverted nipple patients. METHODS: We describe our 10 yearsʼ experience in using a simple approach to correct inverted nipples after nipple-sparing mastectomy with pedicled transverse rectus abdominis myocutaneous flap reconstruction. Between January 2001 and August 2010, we observed 23 inverted nipples after nipple-sparing mastectomy by using only a buried baseline suture to tighten the base of the nipple. The follow-up period ranged from 3 to 13 years. RESULTS: After nipple-sparing mastectomy with tightening of the base of the nipple, improvements were seen in 18 of the 23 patients. No complications associated with surgery occurred, such as infection, depigmentation, sensory disturbance, or nipple necrosis. CONCLUSIONS: The simple method of baseline suturing that only tightens the nipple base with nipple-sparing mastectomy has been used in our center over a 10-year period in patients with breast cancer and an inverted nipple. The retractile duct or fibrous cord was completely cut with nipple-sparing mastectomy, and over 70% of inverted nipples in the patients were improved and maintained with only the tightening of the base of the nipple. Our results show that inverted nipple is caused by tight fibrous band or short duct rather than a lack of subareolar tissue. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.

Goo H.W.,University of Ulsan
Korean Journal of Radiology | Year: 2012

In keeping with the increasing utilization of CT examinations, the greater concern about radiation hazards from examinations has been addressed. In this regard, CT radiation dose optimization has been given a great deal of attention by radiologists, referring physicians, technologists, and physicists. Dose-saving strategies are continuously evolving in terms of imaging techniques as well as dose management. Consequently, regular updates of this issue are necessary especially for radiologists who play a pivotal role in this activity. This review article will provide an update on how we can optimize CT dose in order to maximize the benefit-to-risk ratio of this clinically useful diagnostic imaging method.

Kim Y.,University of Ulsan | Park S.,Hoseo University | Kim N.-S.,Soonchunhyang University | Lee B.-K.,Korea Industrial Health Association
Journal of Preventive Medicine and Public Health | Year: 2013

Objectives: The inherent nature of the Korean National Health and Nutrition Examination Survey (KNHANES) design requires special analysis by incorporating sample weights, stratification, and clustering not used in ordinary statistical procedures. Methods: This study investigated the proportion of research papers that have used an appropriate statistical methodology out of the research papers analyzing the KNHANES cited in the PubMed online system from 2007 to 2012. We also compared differences in mean and regression estimates between the ordinary statistical data analyses without sampling weight and design-based data analyses using the KNHANES 2008 to 2010. Results: Of the 247 research articles cited in PubMed, only 19.8% of all articles used survey design analysis, compared with 80.2% of articles that used ordinary statistical analysis, treating KNHANES data as if it were collected using a simple random sampling method. Means and standard errors differed between the ordinary statistical data analyses and design-based analyses, and the standard errors in the design-based analyses tended to be larger than those in the ordinary statistical data analyses. Conclusions: Ignoring complex survey design can result in biased estimates and overstated significance levels. Sample weights, stratification, and clustering of the design must be incorporated into analyses to ensure the development of appropriate estimates and standard errors of these estimates. © 2013 The Korean Society for Preventive Medicine.

Ahn S.-H.,Seoul National University | Chun D.-M.,University of Ulsan | Chu W.-S.,Seoul National University
International Journal of Precision Engineering and Manufacturing | Year: 2013

The International Symposium of Green Manufacturing and Applications (ISGMA) 2012 was successfully held in Jeju Island, Korea from 27 to 29, August 2012. In this Symposium, the topics of green manufacturing such as design and manufacturing of sustainable products, energy saving and pollution/waste reduction in manufacturing processes, energy/environmentally-friendly materials, and new/renewable energy systems were discussed. As a perspective on green manufacturing and applications, several issues are drawn for energy and material savings as well as exploration to new technologies. © 2013 Korean Society for Precision Engineering and Springer-Verlag Berlin Heidelberg.

Lim O.T.,University of Ulsan
International Journal of Automotive Technology | Year: 2013

The HCCI combustion mode poses its own set of narrow engine operating by knocking. In order to solve this, inhomogeneity method of mixture and temperature is suggested. The purpose of this research is to get fundamental knowledge about the effect of thermal stratification on HCCI combustion of n-Heptane/iso-Octane-Air mixture. The temperature stratification is made by buoyancy effect in combustion chamber of RCM. The analysis items are pressure, temperature of incylinder gas and combustion duration. In addition, the structure of flames using the two dimensional chemiluminescence's images by a framing camera are analyzed. Under stratification, the LTR starting time and the HTR starting time are advanced than that of homogeneous. Further, the LTR period of homogeneous conditions became shorter than that of the stratified conditions. With the case of homogeneous condition, the luminosity duration becomes shorter than the case of stratified condition. Additionally, under stratified condition, the brightest luminosity intensity is delayed longer than at homogeneous condition. © 2013 The Korean Society of Automotive Engineers and Springer-Verlag Berlin Heidelberg.

Choi Y.-R.,University of Ulsan
European Journal of Mechanics, A/Solids | Year: 2013

In this study, the cross section of an air-inflated heavy membrane structure anchored at two points on an inclined foundation is examined. Novel general solutions obtained in a previous study for air-inflated membrane structures are used to solve the problem in this work. By imposing boundary conditions on the general solutions, unknown values are formulated as solutions to algebraic equations. The shape and characteristic values are mathematically expressed in closed form. The cross-sectional area is also evaluated analytically. Some results for the characteristic values and shapes are ultimately presented. © 2013 Elsevier Ltd. All rights reserved.

Lee J.,University of Washington | Lee J.,University of Ulsan | Storch G.A.,University of Washington
Pediatric Infectious Disease Journal | Year: 2014

Background: Multiplex molecular assays now make it possible for clinical laboratories to detect human coronaviruses (HCoVs). We investigated the clinical characteristics of HCoV-OC43 and HCoV-NL63 in patients <5 years of age during a recent coronavirus season. Methods: Respiratory viruses were detected using a multiplex molecular assay at St. Louis Children's Hospital starting in November 2012. We analyzed demographic and clinical data from all patients <5 years of age with solo detection of HCoV-OC43 (n = 52) and HCoV-NL63 (n = 44) and for comparison, samples of children with respiratory syncytial virus, parainfluenza virus and picornaviruses. Results: During the study period, HCoV-OC43 (4%) was the 5th and HCoVNL63 the 8th (2%) most common respiratory virus. Coinfections were detected in 35% and 38% of children with HCoV-OC43 and HCoV- NL63, respectively. Croup was more common with HCoV-NL63 (30%) than with HCoV-OC43 (2%). Lower respiratory tract infection occurred in 33% of children with HCoV-OC43 and 25% of children with HCoV-NL63. Severe illness was less common in HCoV-NL63, HCoV-OC43 and parainfluenza virus (14%, each) compared with respiratory syncytial virus (30%) and picornaviruses (26%; P = 0.055 for HCoVs combined compared with the other respiratory viruses) and occurred mainly in those with underlying medical conditions. Conclusions: Infections caused by HCoV-OC43 and HCoV-NL63 are common and include some with lower respiratory tract involvement and severe disease, especially in children with underlying medical conditions. Overall, a substantial burden of disease associated with both HCoV-OC43 and HCoV-NL63 was observed for hospitalized children <5 years of age. Copyright © 2014 by Lippincott Williams & Wilkins.

Son S.,University of Ulsan | Lynett P.J.,University of Southern California
Coastal Engineering | Year: 2014

A set of depth-integrated equations describing combined wave-current flows is derived and validated. To account for the effect of turbulence induced by interactions between waves and currents with arbitrary horizontal vorticity, new additional stress terms are introduced. These stresses are functions of a parameter b that relates the relative importance of wave radiation stress and bottom friction stress to the wave-current interaction. To solve the equations, a fourth-order MUSCL-TVD scheme with an approximate Riemann solver is adopted. As a first-order check of the model, the Doppler shift effect and wave dispersion over linearly sheared currents are analytically shown to be retained appropriately in the equation set. The model results are then validated through comparisons with three experimental data sets. First, based on the experiments of Kemp and Simons (1982, 1983), a reasonable functional form of b is estimated. Second, simulations examining the propagation of a weakly dispersive wave over a depth-uniform or linearly sheared current are performed. Finally, the model is applied to a more complex configuration where bichromatic waves interact with spatially varying currents. Simulated results indicate that the model is capable of predicting nearshore interactions of waves with currents of arbitrary vertical structure. One of the unique properties of the developed model is its ability to assimilate an external current field from any source, be it from a circulation model or an observation, and predict the interaction of a nonlinear and dispersive wave field with that current. •Examine nonlinear waves interacting with a current of arbitrary vertical structure•Employ depth-integrated, Boussinesq-type approach•The model accurately predicts the combined wave-current velocity structure.•The approach can assimilate external current field from any source. © 2014 Elsevier B.V.

This study aimed to determine optimal strength of sinogram-affirmed iterative reconstruction (SAFIRE) and to evaluate image quality (IQ) of low-dose chest computed tomography (LDCT) using SAFIRE compared with iterative reconstruction in image space (IRIS) and filtered back projection (FBP). Thirty patients underwent LDCT. Computed tomography (CT) was reconstructed using 5 strengths of SAFIRE (S1-S5), IRIS, and FBP. Objective noise of CT was measured. Two radiologists evaluated CT for subjective IQ, beam-hardening artifacts, and overall IQ. Measured noise was highest in FBP, followed by S1, S2, S3, IRIS, S4, and S5. S2 and S3 demonstrated significantly higher overall IQ scores than the other strengths (P < 0.05). Overall IQ and beam-hardening artifacts of S2 and S3 were significantly better than those in FBP and IRIS (P < 0.001). S2 or S3 strengths of SAFIRE can be used practically in clinical routines and may have more potential than IRIS and FBP for LDCT with improved IQ.

Kim B.H.,University of Ulsan
International Journal of Precision Engineering and Manufacturing | Year: 2013

Advancements in nanoscale precision engineering require an in-depth understanding of energy transport. The thermal properties of fluids containing nano-particles significantly depend on the particle/fluid volume ratio at high interface thermal resistance lengths (Kapitza lengths). However, there is a lack of fundamental understanding of nano-scale thermal transport based on the continuum mechanics. In nano-scale thermal transport, the molecular structure of the liquid and surfaces and their interactions on atomic length scales are indispensable. In this study, a molecular level investigation of the thermal resistance at the silicon-argon interface is implemented using molecular dynamics (MD) simulations. This research investigates the interface thermal resistance between liquid argon and silicon surfaces with a perfect crystalline structure. Silicon and argon are chosen due to their broad use in nano-technology applications. Layering of argon liquid molecules on the silicon solid interface was evident for weak wall/fluid interaction strength and bin sizes smaller than the molecular diameter. A recently developed interface thermal resistance (Kapitza resistance) model is used in this study (Kim et al., Journal of Chemical Physics, 129, 174701, 2008). Interactive thermal wall (ITW) model can significantly reduce the computational cost for silicon crystal walls. However, the ITW model needs to properly model thermal interactions with argon molecules using modified liquid/solid interaction strength and thermal oscillation frequency. Our simulation result matches with the case for the ITW model for the similar liquid/solid interaction strength. © 2013 Korean Society for Precision Engineering and Springer-Verlag Berlin Heidelberg.

Nguyen T.D.,Ho Chi Minh City University of Technology | Lee H.-H.,University of Ulsan
IEEE Transactions on Industrial Informatics | Year: 2014

A new space vector modulation (SVM) process for use in an indirect matrix converter (IMC) has been proposed in this paper to reduce the common-mode voltage (CMV) in a high voltage transfer ratio. The principles of selecting suitable active vectors and then properly arranging the switching sequence in the inverter stage of the IMC are described. The IMC with the new SVM method significantly reduces the peak-to-peak voltage of the CMV without any extra hardware. The new SVM method has some other advantages such as a lower total harmonic distortion of line-to-line output voltage and a reduced switching loss at the inverter stage through a minimum number of switching commutations as compared to the conventional reduced CMV-SVM method. The proposed modulation can be easily implemented in software without any additional hardware modifications. Both simulation and experimental results are shown to demonstrate that the new SVM method can generate good performance of the input/output waveforms and provide CMV reduction. © 2005-2012 IEEE.

Zheleznyak L.,University of Rochester | Kim M.J.,University of Ulsan | MacRae S.,University of Rochester | Yoon G.,University of Rochester
Journal of Cataract and Refractive Surgery | Year: 2012

Purpose: To measure the impact of corneal aberrations on the through-focus image quality of presbyopia-correcting intraocular lenses (IOLs) using an adaptive optics IOL metrology system. Setting: Flaum Eye Institute, University of Rochester, Rochester, New York, USA. Design: Experimental study. Methods: An adaptive optics IOL metrology system comprising a model eye, wavefront sensor, deformable mirror, and an image-capturing device acquired through-focus images of a letter chart with 3.0 mm and 5.0 mm pupil diameters. The system was used to induce corneal astigmatism and higher-order aberrations (HOAs) in previously measured pseudophakic presbyopic eyes. A single-optic accommodating IOL (Crystalens HD (HD500), an apodized (Restor +3.0 diopter [D] SN6AD1) and full-aperture (Tecnis ZM900) diffractive multifocal IOL, and a monofocal IOL (Acrysof SN60AT) were evaluated. Image quality was quantified using the correlation-coefficient image-quality metric. Results: The single-optic accommodating IOL and monofocal IOL performed similarly; however, with a 3.0 mm pupil, the former had better intermediate (1.50 D) image quality. The multifocal IOLs had bimodal through-focus image quality trends. Corneal astigmatism reduced through-focus image quality and depth of focus with all IOLs; however, the multifocal IOLs had the most severe decline in depth of focus. Ocular spherical aberration had the strongest impact on image quality when typical pseudophakic corneal HOAs were present. Conclusions: The uncorrected corneal astigmatism and HOAs in pseudophakic eyes significantly affected through-focus performance of presbyopia-correcting IOLs. Although multifocal IOLs significantly increased depth of focus, this benefit diminished when more than 0.75 D astigmatism remained uncorrected. Residual ocular spherical aberration had a significant effect on image quality in the presence of other corneal HOAs. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned. © 2012 ASCRS and ESCRS Published by Elsevier Inc.

Roh J.-L.,University of Ulsan | Wang X.V.,Dana-Farber Cancer Institute | Wang X.V.,Harvard University | Manola J.,Dana-Farber Cancer Institute
Clinical Cancer Research | Year: 2013

Purpose: Promoter hypermethylation is a well-documented mechanism for tumor-specific alteration of suppressor gene activity in human malignancy including head and neck cancer (HNC). The abrogation of specific suppressor gene activity may influence tumor behavior and clinical outcome. In this study we examined methylation of DCC, KIF1A, EDNRB, and p16INK4a in a large cohort of HNC patients from Eastern Cooperative Group (ECOG) 4393/Radiation Therapy Oncology Group (RTOG) 9614 to identify clinical correlates of methylation of these genes. Experimental Design: Methylation was assessed by quantitative methylation-specific PCR in DNA from tumor specimens and was considered as a continuous and a binary variable. Clinical data including demographics, stage, risk factor exposure, treatment, and outcome were collected by ECOG and RTOG. Methylation status was also correlated with mutation of TP53 (previously reported) and human papilloma virus status. Results: Methylation results were available for 368 cases, 353 of which also have p53 mutation status. At least one methylation event was present in all tumors. In multivariate analysis of the entire cohort, methylation of p16 was associated with decreased survival (HR = 1.008; P = 0.045). However, in tumors with disruptive TP53 mutation (poor prognostic group), the additional presence of methylation of p16 was protective (P = 0.019 considering p16 methylation as a continuous variable). Conclusion: Methylation of tumor-related genes contributes to the biological behavior of HNC and influences overall survival in conjunction with other known prognostic molecular events. ©2013 AACR.

Choi Y.J.,University of Ulsan
Korean journal of ophthalmology : KJO | Year: 2010

Retrobulbar hemorrhage and permanent visual loss are rare presentations following traumatic asphyxia. In this case, bilateral permanent visual disturbance developed in a woman after chest-crushing trauma without direct trauma to the orbits. A computed tomography scan confirmed bilateral retrobulbar hemorrhages. An ophthalmologic exam revealed bilateral subconjunctival hemorrhages and severe lid edema. Despite high-dose steroid therapy, visual recovery was limited, and optic nerve atrophy developed. Ischemia of the optic nerve associated with retrobulbar hemorrhage may be postulated as one of the causes of permanent visual impairment following traumatic asphyxia.

Kweon S.,Centers for Disease Control and Prevention | Kim Y.,Centers for Disease Control and Prevention | Jang M.-J.,Centers for Disease Control and Prevention | Kim K.,Centers for Disease Control and Prevention | And 5 more authors.
International Journal of Epidemiology | Year: 2014

The Korea National Health and Nutrition Examination Survey (KNHANES) is a national surveillance system that has been assessing the health and nutritional status of Koreans since 1998. Based on the National Health Promotion Act, the surveys have been conducted by the Korea Centers for Disease Control and Prevention (KCDC). This nationally representative cross-sectional survey includes approximately 10 000 individuals each year as a survey sample and collects information on socioeconomic status, health-related behaviours, quality of life, healthcare utilization, anthropometric measures, biochemical and clinical profiles for non-communicable diseases and dietary intakes with three component surveys: health interview, health examination and nutrition survey. The health interview and health examination are conducted by trained staff members, including physicians, medical technicians and health interviewers, at a mobile examination centre, and dieticians' visits to the homes of the study participants are followed up. KNHANES provides statistics for health-related policies in Korea, which also serve as the research infrastructure for studies on risk factors and diseases by supporting over 500 publications. KCDC has also supported researchers in Korea by providing annual workshops for data users. KCDC has published the Korea Health Statistics each year, and microdata are publicly available through the KNHANES website (http://knhanes.cdc.go.kr). © The Author 2014.

Kim S.-Y.,University of Ulsan | Park S.-P.,Kyungpook National University
Journal of Headache and Pain | Year: 2014

Background: Headache chronicity has been known to elicit deleterious effects on quality of life (QOL). We evaluated the contribution of headache chronicity to QOL in relation to clinical, psychiatric, and psychosocial variables in patients with migraine.Methods: Subjects were recruited from a headache clinic and completed self-report questionnaires including the Migraine Disability Assessment (MIDAS), Beck Depression Inventory (BDI), Beck Anxiety Inventory (BAI), and Migraine-Specific Quality of Life (MSQoL). We obtained predictors of MSQoL by multiple regression analyses. A path analysis model was constructed to analyze interrelationships between the variables.Results: Among 251 eligible patients, 183 (72.9%) had episodic migraine (EM) and 68 (27.1%) had chronic migraine (CM). Patients with CM had more serious clinical, psychiatric, and poor QOL than did patients with EM. The strongest predictor of the MSQoL score in all patients with migraine was the BDI score (β = -0.373, p < 0.001), followed by the MIDAS score (β = -0.223, p < 0.001), female gender (β = -0.192, p < 0.001), attack duration (β = -0.159, p = 0.001), and headache chronicity (β = -0.130, p = 0.012). Headache chronicity had a direct effect on the MSQoL score and exerted an indirect effect on the MSQoL score through the MIDAS and the BDI scores.Conclusions: Chronic migraine appears to impair QOL directly as well as indirectly by provoking disability and depression. © 2014, Kim and Park; licensee Springer.

Seo D.W.,University of Ulsan
Gut and Liver | Year: 2010

Endoscopic ultrasound (EUS) is a very useful modality for the diagnosis and staging of pancreatic masses. With the advent of EUS-guided fine-needle aspiration technology, this modality has made a tremendous leap from imaging modality to histologic diagnosis and therapeutic intervention. EUS offers high-resolution images of and unparalleled access to the pancreas. After locating the tip of the echoendoscope in the duodenum or stomach, several drugs or local treatment modalities can be delivered directly into the pancreas. EUS-guided ethanol lavage with/without paclitaxel injection has been tested for the treatment of cystic tumors of the pancreas, with complete resolution of cystic tumor being observed in up to 70-80% of patients. Ethanol injection is also performed for the management of solid neuroendocrine tumors of the pancreas. Various type of EUS-guided injection have also been investigated for the treatment of pancreatic cancer. An activated allogenic mixed lymphocyte culture (Cytoimplant) was injected in patients with advanced pancreatic cancer. A replication-deficient adenovirus vector carrying the tumor necrosis factor-alpha gene was also delivered intratumorally by EUS. ONYX-015 is an oncolytic attenuated adenovirus that exhibits replication preferentially in malignant cells, causing cell death, and this has also been injected into pancreatic cancers under EUS guidance. EUS-guided local ablation therapies such as radiofrequency ablation, photodynamic therapy, and brachytherapy are also under investigation. EUS-guided fine-needle injection for various solid or cystic lesions is a rapidly expanding field. This article reviews the various applications of EUS for the treatment of pancreatic tumors.

Yang D.S.,University of Ulsan
American Journal of Physical Medicine and Rehabilitation | Year: 2015

ABSTRACT: The thalamocingulate tract between the anterior thalamic nuclei and the cingulate gyrus is a part of the Papez circuit. Using diffusion tensor tractography, injury of the thalamocingulate tract was investigated in patients with mild traumatic brain injury. Two patients (patient 1: a 58-yr-old woman and patient 2: a 49-yr-old man) with head trauma resulting from a car accident were enrolled. They were classified as mild traumatic brain injury and no specific lesion was observed on brain magnetic resonance imaging. These patients complained of memory impairment after head trauma. The entire Papez circuits, including thalamocingulate tract, fornix, mammillothalamic tract, and cingulum, were reconstructed in both hemispheres except for the left thalamocingulate tract: patient 1, it was thinner and discontinued compared with the right thalamocingulate tract; and patient 2, it was not reconstructed. The injury of the left thalamocingulate tract appeared to be related to the memory impairment in these patients. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.

Kang J.-W.,Asan Heart Institute | Song H.G.,Asan Heart Institute | Yang D.H.,Asan Heart Institute | Baek S.,University of Ulsan | And 5 more authors.
JACC: Cardiovascular Imaging | Year: 2013

OBJECTIVES We sought to define the clinical importance of an integrated classification of bicuspid aortic valve (BAV) phenotypes and aortopathy using multidetector computed tomography (MDCT). BACKGROUND An association between BAV phenotypes and the pattern of valvular dysfunction or bicuspid aortopathy has yet to be definitely established. METHODS The study cohort included 167 subjects (116 men, age 54.6 ± 14.4 years) who underwent both MDCT and transthoracic echocardiography from 2003 to 2010. Two BAV phenotypes - fusion of the right and left coronary cusps (BAV-AP) and fusion of the right or left coronary cusp and noncoronary cusp (BAV-RL) - were identified. Forty-five patients showed normal aortic dimensions and were classified as type 0. In the remaining patients, hierarchic cluster analysis showed 3 different types of bicuspid aortopathy according to the pattern of aortic dilation: type 1 (aortic enlargement confined to the sinus of Valsalva [n = 34]), type 2 (aortic enlargement involving the tubular portion of the ascending aorta [n = 49]), and type 3 (aortic enlargement extending to the transverse aortic arch [n = 39]). RESULTS The prevalence of BAV-AP and BAV-RL was 55.7% and 44.3%, respectively. Comparing BAV-AP and BAV-RL, no differences in age or in the prevalence of male sex were determined. However, significant differences in the valvular dysfunction pattern were noted, with moderate-to-severe aortic stenosis predominating in patients with BAV-RL (66.2% vs. 46.2% in BAV-AP; p = 0.01), and moderate-to-severe aortic regurgitation in BAV-AP (32.3% vs. 6.8% in BAV-RL; p < 0.0001). A normal aorta was the most common phenotype in BAV-AP patients (33.3% vs. 18.9% in BAV-RL; p = 0.037), and type 3 aortopathy was the most common phenotype in BAV-RL patients (40.5% vs. 9.7% in BAV-AP; p < 0.0001). CONCLUSIONS The patterns of valvular dysfunction and bicuspid aortopathy differed significantly between the 2 BAV phenotypes, suggesting the possibility of etiologically different entities. © 2013 by the American College of Cardiology Foundation.

Di Cesare M.,Imperial College London | Khang Y.-H.,University of Ulsan | Asaria P.,Imperial College London | Blakely T.,University of Otago | And 11 more authors.
The Lancet | Year: 2013

In most countries, people who have a low socioeconomic status and those who live in poor or marginalised communities have a higher risk of dying from non-communicable diseases (NCDs) than do more advantaged groups and communities. Smoking rates, blood pressure, and several other NCD risk factors are often higher in groups with low socioeconomic status than in those with high socioeconomic status; the social gradient also depends on the country's stage of economic development, cultural factors, and social and health policies. Social inequalities in risk factors account for more than half of inequalities in major NCDs, especially for cardiovascular diseases and lung cancer. People in low-income countries and those with low socioeconomic status also have worse access to health care for timely diagnosis and treatment of NCDs than do those in high-income countries or those with higher socioeconomic status. Reduction of NCDs in disadvantaged groups is necessary to achieve substantial decreases in the total NCD burden, making them mutually reinforcing priorities. Effective actions to reduce NCD inequalities include equitable early childhood development programmes and education; removal of barriers to secure employment in disadvantaged groups; comprehensive strategies for tobacco and alcohol control and for dietary salt reduction that target low socioeconomic status groups; universal, financially and physically accessible, high-quality primary care for delivery of preventive interventions and for early detection and treatment of NCDs; and universal insurance and other mechanisms to remove financial barriers to health care.

Kim Y.,Korea University | Kim J.,Korea University | Jang S.-W.,University of Ulsan | Ko J.,Korea University
Oncogene | Year: 2015

Androgen and the androgen receptor (AR) have important roles in prostate cancer (PCa) development, and androgen ablation has been the main therapeutic option for the treatment of PCa. However, the transition mechanism from androgen-dependent to -independent PCa after androgen depletion remains unclear. We investigated the distinct roles of small leucine zipper protein (sLZIP) in proliferation of androgen-dependent and -independent PCa cells. Cyclin D3 is known to interact with AR and attenuates the ligand-dependent function of AR in PCa cells. sLZIP regulates the transcription of cyclin D3 by binding directly to the AP-1 region in the cyclin D3 promoter. sLZIP represses AR transcriptional activity by interaction with AR that is phosphorylated by cyclin D3/cyclin-dependent kinase11(p58), leading to the suppression of androgen-dependent proliferation of PCa cells. The expression level of sLZIP is elevated in androgen-independent PCa cells and advanced human prostate tumors. Knockdown of endogenous sLZIP suppresses proliferation of androgen-independent PCa cells. LNCaP cells transformed to androgen-independent PCa cells exhibit increased expressions of sLZIP and cyclin D3. Tumor formation is inhibited in nude mouse xenografts from two androgen-independent PCa cells that are stably transfected with sh-sLZIP. Our findings indicate that sLZIP negatively regulates AR transactivation in androgen-dependent PCa cells and functions as a positive regulator in tumor progression of androgen-independent PCa. sLZIP contributes to the malignant phenotype of PCa and constitutes a novel therapeutic target for human PCa.

Chung Y.-S.,University of Ulsan
Journal of the Korean Medical Association | Year: 2015

While errors in surgical site or patient identification should not occur, they are some of the most common sentinel events. These events affect not only the patient but also the surgeon and hospital. The exact incidence of surgical errors cannot be measured because measurement depends on voluntary reporting. There have been many efforts to reduce these surgical errors. For example, Universal protocol and time-out just before surgery begins have been introduced. It is also essential to mark the surgical site in a uniform manner. Despite these processes,surgical errors still happen for many reasons. One of most common root causes is communication error. It is essential to use precise communication and to speak up if something is wrong. Hospitals and surgeons should use leadership to involve their teams in a patient safety culture. Not only the system but also this patient safety culture can reduce the incidence of surgical error. © Korean Medical Association

Goo H.W.,University of Ulsan
Korean Journal of Radiology | Year: 2015

Coronary artery problems in children usually have a significant impact on both short-term and long-term outcomes. Early and accurate diagnosis, therefore, is crucial but technically challenging due to the small size of the coronary artery, high heart rates, and limited cooperation of children. Coronary artery visibility on CT and MRI in children is considerably improved with recent technical advancements. Consequently, CT and MRI are increasingly used for evaluating various congenital and acquired coronary artery abnormalities in children, such as coronary artery anomalies, aberrant coronary artery anatomy specific to congenital heart disease, Kawasaki disease, Williams syndrome, and cardiac allograft vasculopathy. © 2015 The Korean Society of Radiology.

Kim S.H.,University of Ulsan
International Journal of Systems Science | Year: 2015

This paper proposes a reliable piecewise control (RPC) law for input-saturated systems with norm-bounded external disturbances and faults, whose feature is that the following three goals can be simultaneously achieved: improving the disturbance attenuation performance, maximising the region of attraction, and totally removing the influence of the actuator fault. Here, the RPC law is developed to be dependent on several switching sets with the set invariance property, where the size of the most inner switching set is minimised and the size of the outer switching sets is maximised to fulfil the first two goals, respectively. Moreover, for the third goal, this paper introduces a norm-bounded representation method for the actuator fault and incorporates a variable structure control scheme into the RPC law. © 2013 Taylor and Francis.

Kong H.Y.,University of Ulsan
Wireless Personal Communications | Year: 2015

Cognitive radio (CR) allows unlicensed users to dynamically access the underutilized frequency bands of licensed primary users, to improve the spectrum utilization. Because of the scarcity of the radio spectrum, improving utilization of the spectrum is the primary design goal of CR systems. In this paper, we employ cooperative relaying to improve the spectrum utilization. Conventionally, cooperative relaying is used to achieve a diversity gain at the cost of spectral efficiency. In the proposed scheme, the relay node uses the spectrum that is not available for the source-to-destination direct link. Hence, it improves spectrum utilization in addition to diversity gain. To achieve diversity gain along with coding gain, we use a coded diversity that transmits incremental redundancy through relay. Tight upper bounds for bit error rate and frame error rate of the proposed scheme are also derived. Analysis and simulation results show that the proposed scheme achieves full diversity, along with improved utilization of the spectrum. © 2015, Springer Science+Business Media New York.

Lee Y.M.,University of Ulsan | Lee J.B.,Korea University
Journal of International Medical Research | Year: 2013

Objective: The aim of this study was to determine the protein expression and prognostic value of epidermal growth factor receptor (EGFR), p53 and galectin-3 in papillary thyroid carcinoma (PTC). Methods: A retrospective analysis was performed using tumour specimens from patients with PTC who underwent thyroidectomy between July 2007 and December 2008. The percentages of tumour cells staining positively for EGFR, galectin-3 and p53 were determined by immunohistochemistry. Associations between protein expression and age, sex, extrathyroidal extension and lymph node metastasis were assessed, together with the total Metastasis, Age, Completeness of resection, Invasion, Size (MACIS) score (a marker of prognosis). MACIS prognostic scores were categorized into four groups. Results: Data from 168 patients with PTC (mean follow-up, 35 months) were included. EGFR expression was significantly associated with male sex and lymph node metastasis; p53 expression was higher in males than in females; galectin-3 expression was not significantly associated with age, sex, extrathyroidal extension, lymph node metastasis or total MACIS score category, however.Conclusion: Immunohistochemical evaluation of EGFR and p53 expression in patients with PTC may be useful for determining prognosis, in PTC patients. © The Author(s) 2013.

Lee J.H.,University of Ulsan | Hwang J.,Kyung Hee University | Mustapha A.,University of Missouri
Comprehensive Reviews in Food Science and Food Safety | Year: 2014

In recent years, a dramatic increase in the demand for ethnic foods in the United States has been observed. Interestingly, with their rise in popularity, more foodborne illness outbreaks associated with ethnic foods have also been reported. Despite a more than 200-y history of ethnic foods in the United States, there is a paucity of information about them. Furthermore, there is also a lack of research on food safety issues involving ethnic foods. Therefore, this paper provides a comprehensive overview of ethnic foods, including the history, types, popularity, characteristics, ingredients, and consumer attitudes toward them. Importantly, this review provides an analysis of the statistics of foodborne illness outbreaks associated with ethnic foods based on data from the Centers for Disease Control and Prevention (CDC). The breakdown of etiology of ethnic foods identified the number of total outbreaks, the causative microorganisms, the food vectors, and the locations where foodborne disease outbreaks have occurred. Also covered is a review of the Hazard Analysis Critical Control Point (HACCP) system implementation, food safety training, and inspection score systems related to ethnic foods and how these can serve as effective tools for the prevention of foodborne illness outbreaks. This study contributes to the body of food safety literature by providing helpful information about ethnic foods in the United States. © 2013 Institute of Food Technologists®.

Seo J.H.,Dong - A University | Kim H.,Institute for Solar and Sustainable Energies | Cho S.,University of Ulsan
Physical Chemistry Chemical Physics | Year: 2012

The importance of symmetry breaking was investigated in bulk heterojunction solar cells with a conventional device structure. Artificial symmetry breaking was built up by introducing a titanium suboxide. With sufficient symmetry breaking, the influence of the cathode work-function can be diminished, thereby extracting the same level of open circuit voltage regardless of metal work-function. This journal is © the Owner Societies 2012.

Goo H.W.,University of Ulsan
Pediatric Radiology | Year: 2011

In patients with congenital heart disease, haemodynamic findings demonstrated on cardiac CT might provide useful hints for understanding the haemodynamics of cardiac defects. In contrast to morphological features depicted on cardiac CT, such haemodynamic findings on cardiac CT have not been comprehensively reviewed in patients with congenital heart disease. This article describes normal haemodynamic phenomena of cardiovascular structures and various abnormal haemodynamic findings with their mechanisms and clinical significance on cardiac CT in patients with congenital heart disease. © Springer-Verlag 2010.

Ismael G.,Hospital Amaral Carvalho | Hegg R.,University of Sao Paulo | Muehlbauer S.,Hoffmann-La Roche | Heinzmann D.,Hoffmann-La Roche | And 7 more authors.
The Lancet Oncology | Year: 2012

Background: A subcutaneous formulation of trastuzumab has been developed, offering potential improvements in patient convenience and resource use compared with the standard intravenous infusion of the drug. We compared the pharmacokinetic profile, efficacy, and safety of the subcutaneous and intravenous formulations in patients with HER2-positive early breast cancer. Methods: The HannaH study was a phase 3, randomised, international, open-label, trial in the (neo)adjuvant setting. Patients with HER2-positive, operable, locally advanced or inflammatory breast cancer were randomly assigned to eight cycles of neoadjuvant chemotherapy administered concurrently with trastuzumab every 3 weeks either intravenously (8 mg/kg loading dose, 6 mg/kg maintenance dose) or subcutaneously (fixed dose of 600 mg); 1:1 ratio. Chemotherapy consisted of four cycles of docetaxel (75 mg/m 2) followed by four cycles of fluorouracil (500 mg/m 2), epirubicin (75 mg/m 2), and cyclophosphamide (500 mg/m 2), every 3 weeks. After surgery, patients continued trastuzumab to complete 1 year of treatment. Coprimary endpoints were serum trough concentration (C trough) at pre-dose cycle 8 before surgery (non-inferiority margin for the ratio between groups of 0·80) and pathological complete response (pCR; non-inferiority margin for the difference between groups of -12·5%), analysed in the per-protocol population. This study is registered with ClinicalTrials.gov, number NCT00950300. Findings: 299 patients were randomly assigned to receive intravenous trastuzumab and 297 to receive subcutaneous trastuzumab. The geometric mean presurgery C trough was 51·8 μg/mL (coefficient of variation 52·5%) in the intravenous group and 69·0 μg/mL (55·8%) in the subcutaneous group. The geometric mean ratio of C trough subcutaneous to C trough intravenous was 1·33 (90% CI 1·24-1·44). 107 (40·7%) of 263 patients in the intravenous group and 118 (45·4%) of 260 in the subcutaneous group achieved a pCR. The difference between groups in pCR was 4·7% (95% CI -4·0 to 13·4). Thus subcutaneous trastuzumab was non-inferior to intravenous trastuzumab for both coprimary endpoints. The incidence of grade 3-5 adverse events was similar between groups. The most common of these adverse events were neutropenia (99 [33·2%] of 298 patients in the intravenous group vs 86 [29·0%] of 297 in the subcutaneous group), leucopenia (17 [5·7%] vs 12 [4·0%]), and febrile neutropenia (10 [3·4%] vs 17 [5·7%]). However, more patients had serious adverse events in the subcutaneous group (62 [21%] of 297 patients) than in the intravenous group (37 [12%] of 298); the difference was mainly attributable to infections and infestations (24 [8·1%] in the subcutaneous group vs 13 [4·4%] in the intravenous group). Four adverse events led to death (one in the intravenous group and three in the subcutaneous group), all of which occurred during the neoadjuvant phase. Of these, two-both in the subcutaneous group-were deemed to be treatment related. Interpretation: Subcutaneous trastuzumab, administered over about 5 min, has a pharmacokinetic profile and efficacy non-inferior to standard intravenous administration, with a similar safety profile to intravenous trastuzumab, and therefore offers a valid treatment alternative. © 2012 Elsevier Ltd.

Zheng T.,Johns Hopkins University | Yu J.,University of Ulsan | Oh M.H.,Johns Hopkins University | Zhu Z.,Johns Hopkins University
Allergy, Asthma and Immunology Research | Year: 2011

Atopic dermatitis (AD) is an inflammatory disease characterized by pruritic skin lesions. The pathogenesis of AD may include disrupted epidermal barrier function, immunodysregulation, and IgE-mediated sensitization to food and environmental allergens. AD is also part of a process called the atopic march, a progression from AD to allergic rhinitis and asthma. This has been supported by multiple cross-sectional and longitudinal studies and experimental data. Research on the mechanisms of AD has been centered on the adaptive immune system with an emphasis on the T-helper 1 (Th1)-Th2 paradigm. Recently, the conceptual focus has largely shifted to include a primary defect in the epithelial barrier as an initial event in AD providing a significant insight into the disease initiation and pointing to a complex secondary interplay of environmental and immunological sequelae with barrier disruption. Further understanding of AD will help the development of more effective treatment for AD and ultimately, preventative algorithms for the atopic march. In this review we highlight recent advances in our understanding of the pathogenesis of AD and the atopic march. © The Korean Academy of Asthma, Allergy and Clinical Immunology.

Jeon I.-H.,University of Ulsan | Morrey B.F.,Mayo Medical School | Sanchez-Sotelo J.,Mayo Medical School
Journal of Shoulder and Elbow Surgery | Year: 2012

Background: Controversy remains regarding the mechanisms leading to ulnar loosening after elbow replacement. We therefore assessed the loosening rate of the ulnar component as a function of the surface finish of a commonly used implant design. Materials and methods: This study included 3 groups who received implants with 3 different surface finishes: sintered beads (278 components), polymethylmethacrylate precoating (219 components), and plasma-sprayed beads (205 components). Results: The 3 groups who received the implants did not differ statistically in age, sex, or underlying diagnosis. The rates of mechanical failure for the sintered, precoated, and plasma-sprayed ulnar components were 6.8%, 12.8%, and 0%, respectively. The 7-year Kaplan-Meier survival rates free of mechanical failure were 93.1% for the sintered-beads group, 83.1% for the precoated group, and 100% for the plasma-sprayed group. Failed precoated ulnar components often failed early and exhibited typical features, including proximal debonding and severe focal or global osteolysis, sometimes leading to periprosthetic insufficiency fractures. Conclusion: Precoating the ulnar component with polymethylmethacrylate can lead to an increased rate of loosening and severe osteolysis. A plasma-sprayed ulnar component is associated with a very low mechanical failure rate with surveillance of less than 10 years. © 2012 Journal of Shoulder and Elbow Surgery Board of Trustees.

Le D.-H.,Water Resources University | Kwon Y.-K.,University of Ulsan
Computational Biology and Chemistry | Year: 2012

Finding genes associated with a disease is an important issue in the biomedical area and many gene prioritization methods have been proposed for this goal. Among these, network-based approaches are recently proposed and outperformed functional annotation-based ones. Here, we introduce a novel Cytoscape plug-in, GPEC, to help identify putative genes likely to be associated with specific diseases or pathways. In the plug-in, gene prioritization is performed through a random walk with restart algorithm, a state-of-the art network-based method, along with a gene/protein relationship network. The plug-in also allows users efficiently collect biomedical evidence for highly ranked candidate genes. A set of known genes, candidate genes and a gene/protein relationship network can be provided in a flexible way. © 2012 Elsevier Ltd.

Wu X.,Massachusetts General Hospital | Nguyen B.-C.,Massachusetts General Hospital | Dziunycz P.,University of Zurich | Chang S.,Massachusetts General Hospital | And 6 more authors.
Nature | Year: 2010

Calcineurin inhibitors such as cyclosporin A (CsA) are the mainstay of immunosuppressive treatment for organ transplant recipients. Squamous cell carcinoma (SCC) of the skin is a major complication of treatment with these drugs, with a 65 to 100-fold higher risk than in the normal population. By contrast, the incidence of basal cell carcinoma (BCC), the other major keratinocyte-derived tumour of the skin, of melanoma and of internal malignancies increases to a significantly lesser extent. Here we report that genetic and pharmacological suppression of calcineurin/nuclear factor of activated T cells (NFAT) function promotes tumour formation in mouse skin and in xenografts, in immune compromised mice, of H-ras V12 (also known as Hras1)-expressing primary human keratinocytes or keratinocyte-derived SCC cells. Calcineurin/NFAT inhibition counteracts p53 (also known as TRP53)-dependent cancer cell senescence, thereby increasing tumorigenic potential. ATF3, a member of the enlarged AP-1 family, is selectively induced by calcineurin/NFAT inhibition, both under experimental conditions and in clinically occurring tumours, and increased ATF3 expression accounts for suppression of p53-dependent senescence and enhanced tumorigenic potential. Thus, intact calcineurin/NFAT signalling is critically required for p53 and senescence-associated mechanisms that protect against skin squamous cancer development. © 2010 Macmillan Publishers Limited. All rights reserved.

Joo S.,University of Ulsan | Kim K.H.,Interdisciplinary Program | Kim H.C.,Institute of Medical and Biological Engineering | Chung T.D.,Seoul National University
Biosensors and Bioelectronics | Year: 2010

A portable microfluidic flow cytometer with dual detection ability of impedance and fluorescence was developed for cell analysis and particle-based assays. In the proposed system, fluorescence from microparticles and cells is measured through excitation by a light emitting diode (LED) and detection by a solid-stated photomultiplier (SSPM). Simultaneous impedometric detection provides information on the existence and size of microparticles and cells through polyelectrolyte gel electrodes (PGEs) operated by custom designed circuits for signal detection, amplification, and conversion. Fluorescence and impedance signals were sampled at 1 kHz with 12 bit resolution. The resulting microfluidic cytometer is 15 × 10 × 10 cm3 in width, depth, and height, with a weight of about 800 g. Such a miniaturized and battery powered system yielded a portable microfluidic cytometer with high performance. Various microbeads and human embryonic kidney 293 (HEK-293) cells were employed to evaluate the system. Impedance and fluorescence signals from each bead or cell made classification of micro particles or cells easy and fast. © 2009 Elsevier B.V. All rights reserved.

Jeon I.-H.,University of Ulsan | Morrey B.F.,Rochester College | Anakwenze O.A.,University of Pennsylvania | Tran N.V.,Rochester College
Journal of Shoulder and Elbow Surgery | Year: 2011

Hypothesis: Other than an awareness, there is little detailed information regarding wound problems after total elbow arthroplasty. The purpose of this study was to (1) determine the incidence of wound complications after elbow arthroplasty, (2) document the long-term implications, (3) characterize risk factors, and (4) discuss a management strategy. We hypothesize that the incidence of this complication can be reduced with careful preoperative planning. Materials and methods: We reviewed 1749 total elbow arthroplasties. The average patient age was 61.5 years (range; 30-91 years). Wound complications were diagnosed according to the criteria of the Centers for Disease Control and Prevention. Results: We identified and studied 97 patients (5.5%) from the 1749 procedures. The most common problems were delayed healing and drainage in 34 and wound hematoma in 33, of which 9 (27%) progressed to secondary deep infection. Of the 97 patients, 86 (88.7%) healed with the retention of the implant, 24 (∼25%) progressed to a septic elbow, and 11 (∼50%) required resection. Patients with rheumatoid arthritis represented 33% of the entire sample, but represented 45.8% of those with septic complications. Posttraumatic arthritis patients represented 58% of the entire sample and only 33% of those with septic problems (P < .05). Conclusions: The overall incidence of serious wound complications was slightly less than anticipated; however, the significance was considerable. Patients with rheumatoid arthritis are most vulnerable. Persistent wound drainage showed a high correlation for deep infection and subsequent implant removal. Anticipation of potential problems and appropriate prophylactic management may avoid wound complications. © 2011 Journal of Shoulder and Elbow Surgery Board of Trustees.

Lee S.-I.,University of Ulsan
Journal of Preventive Medicine and Public Health | Year: 2015

Since the Middle East respiratory syndrome (MERS) outbreak in the Republic of Korea (hereafter Korea) began on May 11, 2015, a total of 186 persons have been infected by the MERS coronavirus, 38 of whom have died. With this number, Korea becomes second only to the Kingdom of Saudi Arabia in the ranking of cumulative MERS cases. In this paper Korea's unique experience of an outbreak of MERS will be summarized and discussed briefly. Copyright © 2015 The Korean Society for Preventive Medicine.

Kim Y.,University of Ulsan | Lee B.-K.,Soonchunhyang University
International Archives of Occupational and Environmental Health | Year: 2013

Objectives: We present data from the Korean National Health and Nutrition Examination Survey 2008-2009 regarding the association between blood lead and mercury levels and periodontitis in a representative sample of the adult South Korean population. Methods: The analysis was restricted to participants ≥20 years of age who completed the health examination survey, including blood lead, cadmium, and mercury measurements (n = 3,966). Odds ratios (ORs) for periodontitis were calculated for log-transformed blood metal levels and quartiles thereof after covariate adjustment. Results: In a logistic regression analysis using log-transformed blood lead and mercury levels as independent variables after covariate adjustment, including blood lead, mercury, and cadmium, the ORs and 95 % CI values in men for having periodontitis with doubling of blood lead and mercury were 1.699 (1.154-2.503) and 1.394 (1.057-1.838), respectively. Furthermore, in a logistic regression analysis using tertiles of blood lead and mercury as independent variables after covariate adjustment, the ORs and 95 % CIs of men for having periodontitis in the highest tertile were 1.756 (1.184-2.604) and 1.575 (1.507-2.347), respectively. ORs in the logistic regression analysis for men using log-transformed blood cadmium or the tertile of blood cadmium as independent variables after covariate adjustments were not statistically significant in either model. Unlike men, ORs in the logistic regression analyses for women using the same independent variables after covariate adjustment were not statistically significant in any blood metal analysis. Conclusions: The association between blood lead and mercury levels and periodontitis was significant regardless of the type of variable (continuous or categorical) in the Korean male population. © 2012 Springer-Verlag.

Li S.,Hangzhou Normal University | Li S.,University of Utah | Huang J.,University of Utah | Huang J.,Zhejiang GongShang University | And 5 more authors.
Journal of the American Chemical Society | Year: 2013

We describe the formation of a suite of [3]catenanes via multicomponent coordination-driven self-assembly and host-guest complexation of a rectangular scaffold comprising a 90 Pt-based acceptor building block with a pseudorotaxane bis(pyridinium)ethane/dibenzo-24-crown-8 linear dipyridyl ligand and three dicarboxylate donors. The doubly threaded [3]catenanes are formed from a total of 10 molecular components from four unique species. Furthermore, the dynamic catenation process is reversible and can be switched off and on in a controllable manner by successive addition of KPF6 and 18-crown-6, as monitored by 1H and 31P NMR spectroscopy. © 2013 American Chemical Society.

Goo H.W.,University of Ulsan
Korean Journal of Radiology | Year: 2010

CT is increasingly being used for evaluating the cardiovascular structures and airways in the patients with congenital heart disease. Multi-slice CT has traditionally been used for the evaluation of the extracardiac vascular and airway abnormalities because of its inherent high spatial resolution and excellent air-tissue contrast. Recent developments in CT technology primarily by reducing the cardiac motion and the radiation dose usage in congenital heart disease evaluation have helped expand the indications for CT usage. Tracheobronchomalacia associated with congenital heart disease can be evaluated with cine CT. Intravenous contrast injection should be tailored to unequivocally demonstrate cardiovascular abnormalities. Knowledge of the state-of-the-art CT imaging techniques that are used for evaluating congenital heart disease is helpful not only for planning and performing CT examinations, but also for interpreting and presenting the CT image findings that consequently guide the proper medical and surgical management.

Shin H.,University of Ulsan | Santamarina J.C.,Georgia Institute of Technology
Earth and Planetary Science Letters | Year: 2010

Granular materials subjected to fluid flow may experience fracture formation and fluid flow localization. Current explanations for hydraulic fracture in soils fail to satisfy the inherent characteristics of granular materials: effective stress-dependent cohesionless-frictional strength. We apply complementary experimental and numerical techniques to identify the underlying particle-scale mechanisms. First, we show that the miscibility of the invading fluid with the host fluid leads to distinct localization processes that depend on the balance between particle-level skeletal forces (effective stress-dependent), capillary forces (the invasion of the interfacial membrane when immiscible fluids are involved), and seepage drag forces (associated with fluid flow velocity). Then, we identify the positive feedback mechanisms at surface defects and fracture tips that promote fracture initiation and sustain fracture propagation. These include increased porosity at the tip due to strains preferentially normal to the fracture alignment, either eased membrane invasion (immiscible fluids) or higher hydraulic conductivity (miscible fluids), and the emergence of particle-level forces that promote opening-mode particle displacement. This effective stress compatible sequence of events helps identify the parameters that govern fluid-driven fracture formation in uncemented sediments, and explain experimental observations. © 2010 Elsevier B.V.

Yi J.S.,CHA Medical University | Jang Y.J.,University of Ulsan
Annals of Otology, Rhinology and Laryngology | Year: 2015

Objective: This study aimed to determine frequency of external nasal deformities in patients with deviated septa and the effect of endonasalseptoplasty with batten grafting on the external nasal appearance. Methods: The 52 patients who underwent endonasalseptoplasty with a batten graft for the correction of caudal septal deviations were included in the study. The preoperative and postoperative photographs of 52 patients were reviewed retrospectively. Gross changes (nasal deviation, dorsal middle vault height, tip height change, and nostril asymmetry) were assessed. Anthropometric measurements (dorsal height, nasal tip projection, nasolabial angle, nasofrontal angle, and deviation angle) were performed. Results: Preoperative assessment showed that 71% of the 52 patients had deformities, including nasal deviation (n = 28), hump nose (n = 19), saddle nose (n = 3), and nostril asymmetry (n = 15). On postoperative analysis, favorable changes in dorsal deviations were seen in 61% of patients. There were no aesthetic changes for hump or saddle nose deformities, whereas nostril asymmetry was corrected in 20% of patients. Anthropometric measurements also showed that dorsal deviation angles were corrected after surgery (P <.05), whereas other parameters showed no significant changes. Conclusion: In selected cases, deviated noses can be corrected to some extent by septoplasty with caudal septal batten grafting. © The Author(s) 2014.

Lee J.Y.,Duke University | Lee J.Y.,University of Ulsan | Folgar F.A.,Duke University | Maguire M.G.,University of Pennsylvania | And 4 more authors.
Ophthalmology | Year: 2014

Purpose: To determine the prevalence of, risk factors for, and visual acuity (VA) correlations with outer retinal tubulation (ORT) seen on spectral-domain optical coherence tomography (SD OCT) in eyes with neovascular age-related macular degeneration (AMD) after anti-vascular endothelial growth factor (VEGF) therapy. Design: Prospective cohort study within a randomized clinical trial. Participants: Patients with SD OCT images at weeks 56 and 104 in the Comparison of AMD Treatments Trials (CATT). Methods: Participants in the CATT were assigned randomly to ranibizumab (0.5 mg) or bevacizumab (1.25 mg) treatment and to a monthly or pro re nata (PRN) injection-dosing regimen. A subset of eyes was imaged with SD OCT beginning at week 56. Cirrus 512×128 or Spectralis 20°×20° volume cube scan protocols were used to acquire SD OCT images. Two independent readers at the CATT OCT reading center graded scans, and a senior reader arbitrated discrepant grades. The prevalence of ORT, identified as tubular structures seen on at least 3 consecutive Cirrus B scans or 2 consecutive Spectralis B scans, was determined. The associations of patient-specific and ocular features at baseline and follow-up with ORT were evaluated by univariate and multivariate analyses. Main Outcome Measures: Outer retinal tubulations. Results: Seven of 69 eyes (10.1%) at 56 weeks and 64 of 368 eyes (17.4%) at week 104 had ORTs. Absence of diabetes, poor VA, blocked fluorescence, geographic atrophy, greater lesion size, and presence of subretinal hyperreflective material at baseline were associated independently with greater risk of ORT at 104 weeks (P < 0.05). Neither drug nor dosing regimen were associated significantly with ORT. The mean VA of eyes with ORT at week 104 (58.5 Early Treatment Diabetic Retinopathy Study letters) was worse than the mean VA of eyes without ORT (68.8 letters; P < 0.0001). Conclusion: At 2 years after initiation of anti-VEGF therapy for neovascular AMD, ORTs are present in a substantial proportion of eyes. We identified baseline features that independently predict ORTs. It is important to identify ORTs because eyes with ORTs have worse VA outcomes than those without this finding. © 2014 American Academy of Ophthalmology.

Son J.Y.,Pohang University of Science and Technology | Kim C.H.,Pusan National University | Cho J.H.,Pusan National University | Shin Y.-H.,University of Ulsan | Jang H.M.,Pohang University of Science and Technology
ACS Nano | Year: 2010

We report on the ferromagnetism of conducting filaments formed in a NiO thin film, which exhibited a typical bistable resistive switching characteristic. The NiO thin film showed an antiferromagnetic hysteresis loop for a high resistive state (ROFF). However, for a low resistive state (RON), the conducting filaments exhibited a ferromagnetic hysteresis loop for the field cooling. The ferromagnetic hysteresis behavior of the R ON state reveals switchable exchange coupling between the ferromagnetic Ni conducting filaments and the antiferromagnetic NiO layer. © 2010 American Chemical Society.

Son J.Y.,Pohang University of Science and Technology | Ryu S.,Pohang University of Science and Technology | Park Y.-C.,Pohang University of Science and Technology | Shin Y.-S.,Pohang University of Science and Technology | And 2 more authors.
ACS Nano | Year: 2010

We demonstrate a field-effect nonvolatile memory device made of a ferroelectric copolymer gate nanodot and a single-walled carbon nanotube (SW-CNT). A position-controlled dip-pen nanolithography was performed to deposit a poly(vinylidene fluoride-ran-trifluoroethylene) (PVDF-TrFE) nanodot onto the SW-CNT channel with both a source and drain for field-effect transistor (FET) function. PVDF-TrFE was chosen as a gate dielectric nanodot in order to efficiently exploit its bipolar chemical nature. A piezoelectric force microscopy study confirmed the canonical ferroelectric responses of the PVDF-TrFE nanodot fabricated at the center of the SW-CNT channel. The two distinct ferroelectric polarization states with the stable current retention and fatigue-resistant characteristics make the present PVDF-TrFE-based FET suitable for nonvolatile memory applications. © 2010 American Chemical Society.

Sohn I.,Samsung | Sung C.O.,University of Ulsan
PLoS ONE | Year: 2013

Purpose: Recent high-throughput sequencing technology has identified numerous somatic mutations across the whole exome in a variety of cancers. In this study, we generate a predictive model employing the whole exome somatic mutational profile of ovarian high-grade serous carcinomas (Ov-HGSCs) obtained from The Cancer Genome Atlas data portal. Methods: A total of 311 patients were included for modeling overall survival (OS) and 259 patients were included for modeling progression free survival (PFS) in an analysis of 509 genes. The model was validated with complete leave-one-out cross-validation involving re-selecting genes for each iteration of the cross-validation procedure. Cross-validated Kaplan-Meier curves were generated. Cross-validated time dependent receiver operating characteristic (ROC) curves were computed and the area under the curve (AUC) values were calculated from the ROC curves to estimate the predictive accuracy of the survival risk models. Results: There was a significant difference in OS between the high-risk group (median, 28.1 months) and the low-risk group (median, 61.5 months) (permutated p-value <0.001). For PFS, there was also a significant difference in PFS between the high-risk group (10.9 months) and the low-risk group (22.3 months) (permutated p-value <0.001). Cross-validated AUC values were 0.807 for the OS and 0.747 for the PFS based on a defined landmark time t = 36 months. In comparisons between a predictive model containing only gene variables and a combined model containing both gene variables and clinical covariates, the predictive model containing gene variables without clinical covariates were effective and high AUC values for both OS and PFS were observed. Conclusions: We designed a predictive model using a somatic mutation profile obtained from high-throughput genomic sequencing data in Ov-HGSC samples that may represent a new strategy for applying high-throughput sequencing data to clinical practice. © 2013 Sohn, Sung.

The microstructural characteristics of the CaO-SiO2-B 2O3-10 mass.% MgO-30 mass.% Al2O3 systems solidified during slow cooling from 1600 °C were investigated using SEM-EDS and a thermochemical computation package. The effect of boron oxide on the crystallization behavior of the spinel in the aluminosilicate system was observed because boron oxide is believed to become a potential flux to reduce the melting point of the liquid oxides. The primary crystalline phase was spinel, mainly MgAl2O4, irrespective of the boron content. The liquidus temperature TL continuously decreased as the boron oxide content increased, indicating that the boron oxide decreased the activity of the MgAl2O4 spinel phase in liquid melts at high temperatures. The size of the spinel crystals increased as the temperature range for the solid + liquid coexisting region, viz. the mushy zone, increased. In the present systems, because the TL continuously decreased with the increase in the boron oxide content, the viscosity of the liquid oxide may have affected the crystallization behavior of the spinel during cooling. Based on these results, an injection of a small amount of B2O3 flux into molten steel containing liquid aluminosilicate inclusions is not recommended because large spinel crystals can originate from the changes in the thermophysical properties of the liquid inclusions due to the incorporation of boron oxide into the aluminosilicate networks. © KIM and Springer.

Choi H.A.,University of Houston | Jeon S.-B.,University of Ulsan | Samuel S.,Memorial Hermann Hospital Texas Medical Center | Allison T.,Memorial Hermann Hospital Texas Medical Center | Lee K.,University of Houston
Current Neurology and Neuroscience Reports | Year: 2013

Paroxysmal sympathetic hyperactivity is a syndrome associated with brain trauma, stroke, encephalitis, and other forms of brain injury. It is characterized by uncontrolled episodes of unbalanced sympathetic surges causing hyperthermia, diaphoresis, tachycardia, hypertension, tachypnea, and dystonic posturing. Patients who develop paroxysmal sympathetic hyperactivity have worse neurologic outcomes, longer hospital stays, and more complications. Despite the clear negative impact on outcome, consensus regarding diagnostic criteria, risk factors, pathophysiology, and treatment approaches is lacking. Recently, the importance of consensus regarding diagnostic criteria has been emphasized, and new theories of pathophysiology have been proposed. Many treatment options are available, but only a few systemic studies of the efficacy of treatment algorithms exist. Treatments should focus on decreasing the frequency and intensity of episodes with regularly scheduled doses of medications, such as long-acting benzodiazepines, nonselective β-blockers, α2- agonists, morphine, baclofen, and gabapentin, usually in combination. Treatment of acute breakthrough episodes should focus on doses of as-needed morphine and short-acting benzodiazepines. A balance between control of symptoms without oversedation is the goal. © 2013 Springer Science+Business Media New York.

Kim Y.,University of Ulsan | Lee B.-K.,Soonchunhyang University
International Archives of Occupational and Environmental Health | Year: 2013

Introduction: We present data from the Korean National Health and Nutrition Examination Survey 2008-2010 on the association between blood lead and hemoglobin levels in a representative sample of the adult South Korean population. Methods: The analysis was restricted to participants ≥20 years of age who completed the health examination survey, including blood lead measurements (n = 5,951). Multivariate linear regression analyses were performed to estimate adjusted mean differences in hemoglobin level associated with doubling of whole blood and erythrocyte lead or quartiles of the metal after covariate adjustment. Odds ratios (ORs) for having borderline anemia or clinical anemia were calculated for log-transformed whole blood and erythrocyte lead or quartiles of the metal after covariate adjustment. Results: A twofold increase in whole blood lead or erythrocyte lead was associated with a 0.285 g/dL increase or 0.088 g/dL decrease in hemoglobin level, respectively. There was a 0.416 g/dL increase or 0.143 g/dL decrease in hemoglobin, respectively, in the highest, compared with the lowest tertile of whole blood lead and erythrocyte lead, respectively. Based on ORs, doubling of whole blood lead or erythrocyte lead resulted in a 36.3 % decrease or 36.2 % increase, respectively, in the risk of borderline anemia. Conclusion: The association of whole blood lead versus erythrocyte lead with hemoglobin level was opposite. In the case of anemia, which is frequently caused by iron deficiency, the effect on the whole blood lead concentration may be very significant, leading to a considerable underestimation of the person's lead status. Therefore, hematocrit-adjusted blood lead level (i.e., erythrocyte lead) should be applied to the general population. To our knowledge, this is the first study to show that erythrocyte lead levels showed a significant inverse relationship with hemoglobin level at lead levels <10 μg/dL in the general Korean population. In conclusion, increased erythrocyte lead levels may be associated with mildly decreased hemoglobin levels, after adjusting for covariates, in a representative sample of the adult Korean population. © 2012 Springer-Verlag.

Yang S.-K.,University of Ulsan
Nature Genetics | Year: 2014

Thiopurine therapy, commonly used in autoimmune conditions, can be complicated by life-threatening leukopenia. This leukopenia is associated with genetic variation in TPMT (encoding thiopurine S-methyltransferase). Despite a lower frequency of TPMT mutations in Asians, the incidence of thiopurine-induced leukopenia is higher in Asians than in individuals of European descent. Here we performed an Immunochip-based 2-stage association study in 978 Korean subjects with Crohn's disease treated with thiopurines. We identified a nonsynonymous SNP in NUDT15 (encoding p.Arg139Cys) that was strongly associated with thiopurine-induced early leukopenia (odds ratio (OR) = 35.6; Pcombined = 4.88 × 10-94). In Koreans, this variant demonstrated sensitivity and specificity of 89.4% and 93.2%, respectively, for thiopurine-induced early leukopenia (in comparison to 12.1% and 97.6% for TPMT variants). Although rare, this SNP was also strongly associated with thiopurine-induced leukopenia in subjects with inflammatory bowel disease of European descent (OR = 9.50; P = 4.64 × 10-4). Thus, NUDT15 is a pharmacogenetic determinant for thiopurine-induced leukopenia in diverse populations.

Kim D.,University of Ulsan
Materials Letters | Year: 2010

Sandwich structures of TiON/Au/TiON (TAT) films were deposited on glass substrates via RF magnetron sputtering of TiON and DC magnetron sputtering of Au. The optoelectronic properties of the films were strongly influenced by the Au intermediate layer. The Au insert caused a deteriorated optical transmittance, while electrical conductivity was improved with an increased carrier density. The intermediate Au film was crystallized in TAT films, but this may not have affected the crystallinity of the TiON films. In this study, new transparent and conducting TAT films with a sheet resistance of 29 Ω/□ and 78% of optical transmittance at 550 nm wavelength were obtained without intentional substrate heating. © 2009 Elsevier B.V. All rights reserved.

Son J.Y.,Pohang University of Science and Technology | Shin Y.-H.,University of Ulsan | Kim H.,Yonsei University | Jang H.M.,Pohang University of Science and Technology
ACS Nano | Year: 2010

In this study, a NiO RRAM nanocapacitor array was fabricated on a graphene sheet, which was on a Nb-doped SrTiO3 substrate containing terraces with a regular interval of about 100 nm and an atomically smooth surface. For the formation of the NiO RRAM nanocapacitor (Pt/NiO/graphene capacitor) array, an anodic aluminum oxide (AAO) nanotemplate with a pore diameter of about 30 nm and an interpore distance of about 100 nm was used. NiO and Pt were subsequently deposited on the graphene sheet. The NiO RRAM nanocapacitor had a diameter of about 30 ± 2 nm and a thickness of about 33 ± 3 nm. Typical unipolar switching characteristics of the NiO RRAM nanocapacitor array were confirmed. The NiO RRAM nanocapacitor array on graphene exhibited lower SET and RESET voltages than that on a bare surface of Nb-doped SrTiO3. © 2010 American Chemical Society.

Kim Y.,University of Ulsan | Lee B.-K.,Soonchunhyang University
Science of the Total Environment | Year: 2011

Introduction: We present data from the Korean National Health and Nutrition Examination Survey (KNHANES) 2008 on the associations between urinary arsenic and diabetes mellitus in a representative sample of the adult Korean population. Methods: This study was based on data obtained in KNHANES 2008, which was conducted for three years (2007-2009) using a rolling sampling design involving a complex, stratified, multistage, probability-cluster survey of a representative sample of the noninstitutionalized civilian population of South Korea. Results: Geometric means of total urinary arsenic concentration in females and total participants with diabetes mellitus were significantly higher than in participants without diabetes mellitus after adjustment for covariates, including age, seafood consumption, body mass index (BMI), hypertension, area of residence, regional area, education level, and smoking and drinking status. Multiple regression analysis after similar adjustment showed that total urinary arsenic concentration was associated with diabetes status in the females and total participants. In addition, after similar adjustment, the odds ratios (ORs) for diabetes mellitus in female participants and all participants were 1.502 (95% CI, 1.038-2.171) and 1.312 (95% CI, 1.040-1.655), respectively, for doubling of the level of urinary total arsenic concentration. Conclusion: This study showed an association between total urinary arsenic concentration and the prevalence of diabetes mellitus in a representative sample of the adult population, especially women, with environmental arsenic exposure after adjustment for seafood intake and relevant diabetes risk factors. © 2011 Elsevier B.V.

Although tumor size is a prognostic factor in cervical cancer patients, its role in the diagnosis of lymph node metastasis is unclear. We therefore evaluated the diagnostic value of tumor and lymph node size compared with lymph node size alone in the detection of metastatic lymph nodes in patients with early-stage cervical cancer.We retrospectively evaluated 699 patients with International Federation of Obstetrics and Gynecology stage IB1-IIA cervical carcinoma who underwent magnetic resonance imaging before lymphadenectomy involving all visible lymph nodes in the surgical fields. Seven nodal groups were evaluated: para-aortic, both common iliac, both external iliac, and both internal/obturator areas. Pathologic evaluation was the diagnostic standard. The largest short-axis diameter of lymph nodes in each region and the largest tumor diameters were measured in magnetic resonance images. The value of additional information from magnetic resonance images was evaluated by receiver operating characteristic curve analysis.Of the 699 patients, 108 (15.8%) had lymph node metastases. The areas under the curve for measurements of lymph node size, tumor size, and both were (A) 0.635, (B) 0.706, and (C) 0.742, respectively (A vs B, P = 0.006; A vs C P < 0.001; B vs C, P = 0.002).This study illustrates that magnetic resonance imaging measurements of tumor size and tumor size plus lymph node size showed a higher diagnostic performance than lymph node size alone in predicting lymph node metastasis in patients with early-stage cervical cancer.

Yang S.-K.,University of Ulsan
Digestive Diseases | Year: 2016

Background: All patients with inflammatory bowel disease (IBD) share common therapeutic goals, such as complete mucosal healing and improved long-term outcomes (e.g., reduction in hospitalization, surgery and mortality). However, because IBD patients have diverse features in terms of severity, phenotypes, clinical courses and responses to therapy, therapeutic options for achieving these goals differ among patients, from no therapy to early introduction of combination therapy with anti-TNF and immunosuppressive agents. Key Messages: By personalizing IBD therapy, we may be able to maximize management efficacy, minimize the risk of adverse events and ultimately decrease costs. The initial steps of personalized therapy involve the selection of the right patients by predicting the clinical course of IBD and the subsequent selection of the right therapy by predicting the response to therapy. The next step of personalized therapy involves the adjustment of therapy through therapeutic response evaluation and therapeutic drug monitoring. Notably, current recommendations on personalized IBD therapy are mainly based on results derived from Western populations. However, Asian patients with IBD are different from Western patients in many respects, including clinical characteristics, therapeutic response and prognosis, probably due to differences in environmental and genetic backgrounds. In addition, the healthcare systems and sociocultural backgrounds of Asian countries are not the same as those of Western countries. Therefore, personalized IBD therapy for Asians may differ from that for Westerners in some aspects. Conclusions: This review discusses the current progress of personalized IBD therapy and its application from the Asian perspective. © 2016 S. Karger AG, Basel.

An J.,University of Ulsan
The Korean journal of hepatology | Year: 2012

Hepatitis A virus (HAV) infections occur predominantly in children, and are usually self-limiting. However, 75-95% of the infections in adults are symptomatic (mostly with jaundice), with the illness symptoms usually persisting for a few weeks. Atypical manifestations include relapsing hepatitis, prolonged cholestasis, and complications involving renal injury. Drug rash with eosinophilia and systemic symptoms (DRESS) syndrome is a severe, drug-induced hypersensitivity reaction characterized by skin rash, fever, lymph-node enlargement, and internal organ involvement. We describe a 22-year-old male who presented with acute kidney injury and was diagnosed with prolonged cholestatic hepatitis A. The patient also developed DRESS syndrome due to antibiotic and/or antiviral treatment. To our knowledge, this is the first report of histopathologically confirmed DRESS syndrome due to antibiotic and/or antiviral treatment following HAV infection with cholestatic features and renal injury.

Brant J.A.,Duquesne University | Clark D.J.,Binghamton University State University of New York | Kim Y.S.,Binghamton University State University of New York | Kim Y.S.,University of Ulsan | And 3 more authors.
Chemistry of Materials | Year: 2014

A study was conducted to demonstrate the formation of Li 2CdGeS4, a diamond-like semiconductor (DLS) having strong second-order optical nonlinearity in the infrared and exceptional laser damage threshold. Tetrahedral building blocks were employed to conduct the investigations, which were predisposed to assemble diamond-like structures by aligning along a single crystallographic direction, rendering the structures non-centrosymmetric. The readily accessible diamond structure was accompanied by minimal centrosymmetric contenders when design principles were involved. It was also observed that the lack of two-photon absorption (TPA) effects and the non-phase-matching behavior at this low wavelength implied Li 2CdGeS4 did not undergo any fundamental depletion by TPA or phase-matched second harmonic generation (SHG) conversion into 532 nm, ensuring ideal, 100%, input for difference frequency generation (DFG) mixing with another beam source.

Cha J.-H.,Seoul National University | Roh M.-I.,University of Ulsan | Lee K.-Y.,Seoul National University
Ocean Engineering | Year: 2010

In this paper, the dynamic response simulation of heavy cargo suspended by a floating crane is performed. The dynamic equations of the motions of the floating crane and the heavy cargo must be considered by the coupled equations because the floating crane and the heavy cargo are connected by wire ropes and provide force and a moment for each other. Hence, the dynamic equations of motion are set up for considering the 6-degrees-of-freedom floating crane and the 6-degrees-of-freedom cargo based on multibody system dynamics. The nonlinear terms in the equations of motion are considered. In addition, the nonlinear hydrostatic force, the linear hydrodynamic force, the wire rope force, and the mooring force are considered as the external forces. Finally, we estimate the motion of the loating crane and the heavy cargo and also calculate the tension of the wire rope between the two. © 2010 Elsevier Ltd. All rights reserved.

Roh J.-L.,University of Ulsan | Kim J.-M.,Chungnam National University | Park C.I.,Chungnam National University
Annals of Surgical Oncology | Year: 2011

Background: Although subclinical cervical lymph node (LN) metastases in papillary thyroid carcinoma (PTC) are common, the efficacy of prophylactic central LN dissection (CLND) is unclear. Few prospective studies have assessed the relationships between complete pathologic information regarding tumors and metastatic nodes in the central compartment. We therefore investigated the pattern and predictive indicators of central LN metastasis, morbidity, and recurrence in patients who underwent total thyroidectomy and prophylactic CLND for unilateral PTC and clinically node-negative neck (cN0) disease. Methods: This prospective study involved 184 patients with previously untreated unilateral PTC and cN0 who underwent total thyroidectomy and bilateral CLND. Nodal samples were divided into the prelaryngeal/pretracheal and ipsilateral and contralateral paratracheal regions, with each assessed for clinicopathologic predictors of central metastases. Postoperative morbidity and recurrence were assessed. Results: Rates of metastasis to ipsilateral and contralateral central compartments were 42.9 and 9.8%, respectively. Multivariate analysis showed that tumor size >1 cm and extrathyroidal extension were independent predictors of ipsilateral metastasis, and ipsilateral metastases independently predicted contralateral metastases (P < 0.05 each). Permanent hypoparathyroidism and incidental recurrent nerve paralysis were found in 1.6 and 0% of patients, respectively. After a mean follow-up of 46 months, none of these patients had recurrence in the central compartment. Conclusions: Subclinical metastases are highly prevalent in the ipsilateral central neck of patients with PTC >1 cm. Contralateral central metastases, although uncommon, are associated with ipsilateral central metastases. These findings may guide the necessity and extent of prophylactic bilateral or unilateral CLND. © 2011 Society of Surgical Oncology.

Shin H.,University of Ulsan | Santamarina J.C.,Georgia Institute of Technology | Cartwright J.A.,University of Cardiff
Journal of Geophysical Research: Solid Earth | Year: 2010

We investigate the distribution of strain and deformation in the host sediment that arises once a contraction-driven shear fault has localized and propagated under a zero-lateral strain condition. Numerical modeling of displacement distributions compares well with those measured using 3D seismic data. The parameters that determine the displacement field for a single normal fault embedded in sediments are fault height, overburden effective stress, stiffness, and residual friction angle (or post-peak strength). Proximity to the free boundary biases the displacement pattern, which becomes asymmetric. Although the measured displacements and numerical predictions are similar, the measured magnitude requires pronounced low stiffness of the sediment as well as low post peak shear strength. This requirement suggests that sediments hosting contraction-driven shear faults most likely have high porosity and high clay fraction and have undergone diagenetic reactions involving significant mineral dissolution. The diagenetic evolution of the sediment and its current composition may explain the global scaling relationship between the measured displacement and fault height for polygonal fault systems.Copyright 2010 by the American Geophysical Union.

Choi D.H.,University of Ulsan
Journal of Craniofacial Surgery | Year: 2014

ABSTRACT: Distant free flaps have become a routine option for reconstruction of large, complicated facial soft tissue defects. The challenge is to find a flap that is pliable to provide good contour and function. The purpose of this paper was to evaluate the use of superficial circumflex iliac artery perforator (SCIP) flaps for facial defects.From November 2010 to June 2013, facial reconstruction was performed on 6 patients (age range, 15–79 years). The harvesting technique was modified to elevate above the deep fat, and the pedicles were taken above or just below the deep fascia. The mean size of the flap was 75.6 cm, with a thickness of 7 mm; the mean pedicle length was 4.9 cm; and the mean artery caliber was 0.7 mm. The supermicrosurgery technique was used successfully in all 6 cases. Donor sites were all closed primarily. The mean follow-up was 16.7 months.All flaps survived without flap loss, and the donor sites healed without complications including lymphorrhea. The patients were satisfied with contour and function after reconstruction.The result of these 6 cases suggested that the SCIP flap can be a reliable flap for moderate-sized to large defects in the face. The use of new instrumentation and supermicrosurgical techniques allows use of the SCIP flap reliably while providing patients with a good contour, function, and minimal donor site morbidity. © 2014 by Mutaz B. Habal, MD.

Kim D.S.,University of Ulsan
Clinics in Chest Medicine | Year: 2012

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive and ultimately fatal disease, the clinical course of which in individual patients is highly variable. Sudden deterioration of a patient's respiratory condition during a stable course is not uncommon. Many cases of uncertain etiology have been called acute exacerbation (AEx) of IPF, under the assumption of sudden acceleration of the underlying disease process. In recent years, several studies have reported the clinical significance of AEx-IPF. In 2007 Collard and colleagues created a Consensus Perspective, which proposed consensus definition and standard diagnostic criteria. This review primarily discusses studies performed after this Consensus Perspective. © 2012 Elsevier Inc.

Kim H.,Gwangju Institute of Science and Technology | Hwa Seo J.,Dong - A University | Cho S.,University of Ulsan
Applied Physics Letters | Year: 2011

Solution processable titanium suboxide (TiOx) was introduced as an artificial symmetry breaking layer in bulk-heterojunction (BHJ) solar cells comprising a low band gap conjugated polymer, poly[(4,4′-bis(2-ethylhexyl) dithiene[3,2-b:2′,3′-d]silole)-2,6-diyl-alt-(4,7-bis(2-thienyl)-2,1, 3-benzothiadiazole)-5,5′-diyl] (Si-PCPDTBT), and a soluble fullerene, [6,6]-phenyl-C71-butyric methyl ester (PC71BM). The inserted TiOx layer obviously extracted the same level of open circuit voltage (Voc) regardless of metal work function. Ultraviolet photoelectron spectroscopy (UPS) results indicated that the formation of the interface dipole between the TiOx symmetry breaking layer and metal electrode successfully modifies the effective work function of the cathode electrode, thereby leading to symmetry breaking in BHJ solar cells. © 2011 American Institute of Physics.

Jeon N.,Korea Advanced Institute of Science and Technology | Rout D.,Korea Advanced Institute of Science and Technology | Kim I.W.,University of Ulsan | Kang S.-J.L.,Korea Advanced Institute of Science and Technology
Applied Physics Letters | Year: 2011

Dense single-phase BiFeO3 and Bi0.9 Ho0.1 FeO3 ceramics were prepared by the solid-state reaction method. With Ho doping, the remnant polarization of BiFeO3 was enhanced and the switching characteristics improved at low electric fields. Ho doping increased the breakdown voltage with a reduction of the leakage current while mitigating the remnant polarization at high electric fields. These results can explain conflicting findings regarding the effects of rare-earth doping on remnant polarization. Bi0.9 Ho0.1 FeO3 exhibited peculiar double hysteresis looplike magnetization-magnetic field curves with a much enhanced remnant magnetization. These improved properties obtained by Ho doping demonstrate the possibility of enhancing the multiferroic applicability of BiFeO3. © 2011 American Institute of Physics.

Hyun S.-J.,Seoul National University | Riew K.D.,University of Washington | Rhim S.-C.,University of Ulsan
Spine Journal | Year: 2013

Background context: Although numerous studies have reported on the loss of flexion-extension range of motion (ROM) associated with laminoplasty, few have reported on the time course of this loss of motion for a long-term follow-up period. Purpose: We previously reported our early data on postlaminoplasty cervical ROM. In this article, we describe our minimum 5-year follow-up data to identify the time-dependent change in ROM after cervical laminoplasty. Study design: A prospective cohort study. Patient sample: The procedure was performed in 23 patients. Eighteen patients with a minimum 5-year follow-up were included in the study. Outcome measures: The time-dependent neck ROM changes observed in the neutral, flexion, and extension radiographs were used to measure the radiological outcome. The Japanese Orthopaedic Association classification and a numerical rating scale of axial neck pain and arm pain were used to evaluate clinical outcome. Methods: Twenty-three patients who received unilateral open-door laminoplasties, including miniplate fixation over three levels, were serially evaluated at regular set intervals postoperatively. Eighteen patients with a minimum 5-year follow-up were included in the study. The mean follow-up period was 68.1 months (range, 60-78 months). Nine patients had ossification of posterior longitudinal ligament (OPLL) and nine patients had cervical spondylotic myelopathy (CSM). Enrolled patients were divided into subgroups (OPLL vs. CSM; autofusion vs. nonautofusion) to compare the ROM between the groups. We evaluated the time-dependent neck ROM changes by taking neutral, flexion, and extension radiographs preoperatively and at 1, 3, 6, 9, 12, 18, and 24 months postoperatively. Follow-up radiographs were taken annually after a 2-year follow-up. Results: The preoperative and 1-, 3-, 6-, 12-, 24-, 36-, 48-, and 60-month postoperative ROM figures were 39.9±11.2°, 35.0±9.2°, 33.0±11.0°, 30.1±10.4°, 25.8±13.1°, 24.7±10.0°, 23.8±6.5°, 24.6±8.3°, and 23.6±9.4°, respectively, and at the most recent follow-up, ROM was 24.5±10.1°. Thus, the mean ROM decreased by 15.4±8.4°(38.5%) by the last follow-up (p<.0001). In the OPLL group, we observed a more limited cervical ROM than in the CSM group (47.2% vs. 72.7%). As expected, in the laminar autofusion group, the ROM decreased significantly (55.6% decrease), whereas in the nonautofusion group, the ROM decreased less significantly (13.4% decrease) at the last follow-up. Postoperative axial pain did not correlate with the cervical ROM. Conclusions: These results suggest that the loss of cervical ROM after laminoplasty is time-dependent, and patients with OPLL and laminar autofusion had less ROM. Postlaminoplasty ROM reduction can recover after several years, unless laminar autofusion occurs. © 2013 Elsevier Inc. All rights reserved.

Kim M.J.,Yeungnam University | Gu M.J.,Yeungnam University | Chang H.-K.,Kosin University | Yu E.,University of Ulsan
Histopathology | Year: 2015

Aims: To investigate AT-rich interactive domain-containing protein 1A (ARID1A) and p53 expression in small intestinal carcinoma (SIC) and to determine its prognostic significance. Methods and results: Immunohistochemical staining for ARID1A and p53 was performed in 178 SICs using a tissue microarray (TMA). Loss of or low ARID1A expression was observed in 36 (20.2%) and 60 (33.7%) of cases, respectively. Aberrant p53 expression was observed in 99 (55.6%) cases. Loss of or low ARID1A expression was found to be associated with signet ring cell carcinoma and undifferentiated carcinoma, a high-grade tumour, and a higher T stage. No relationship was found between aberrant p53 expression and clinicopathological factors or overall survival. Patients with loss of ARID1A expression, irrespective of p53 expressional status, showed significantly poorer overall survival than those expressing ARID1A. Multiple regression analysis revealed that grade and pT stage were associated significantly with ARID1A loss, and multivariate analysis showed that patients with high ARID1A expression had a lower risk of death than those with loss of ARID1A expression. Conclusions: Low or loss of ARID1A expression is correlated significantly with a high-grade tumour, higher T stage, and poorer overall survival. These findings suggest that ARID1A expression could be used as a prognostic marker in SIC. © 2014 John Wiley & Sons Ltd.

Sung C.O.,University of Ulsan | Sohn I.,Samsung
Scientific Reports | Year: 2014

Cancer diagnosis and classification have traditionally been based on the assessment of morphology by microscopy. However, the histological classification system is challenging and demand for genetic information is increasing in the era of targeted and personalized molecular therapy. Recently accumulated comprehensive genomic data could be used to provide a molecular cancer classification alongside the histological classification. This study identified a 19 gene signature able to classify endometrial cancers into the two major histological subtypes, endometrioid and serous. In addition, when the genomic classifier was applied to endometrioid adenocarcinoma of high grade (EM-HG), a subset (23.6%, 25/106) was predicted to be similar to serous tumors at the molecular level. In analyses of multiple cancers, the classification model may also be applicable to ovarian cancers.

Huh J.-W.,Southwestern Medical Center | Huh J.-W.,University of Ulsan | Wu J.,Southwestern Medical Center | Lee C.-H.,Southwestern Medical Center | And 4 more authors.
EMBO Journal | Year: 2012

The Rpd3S histone deacetylase complex represses cryptic transcription initiation within coding regions by maintaining the hypo-acetylated state of transcribed chromatin. Rpd3S recognizes methylation of histone H3 at lysine 36 (H3K36me), which is required for its deacetylation activity. Rpd3S is able to function over a wide range of H3K36me levels, making this a unique system to examine how chromatin regulators tolerate the reduction of their recognition signal. Here, we demonstrated that Rpd3S makes histone modification-independent contacts with nucleosomes, and that Rpd3S prefers di-nucleosome templates since two binding surfaces can be readily accessed simultaneously. Importantly, this multivalent mode of interaction across two linked nucleosomes allows Rpd3S to tolerate a two-fold intramolecular reduction of H3K36me. Our data suggest that chromatin regulators utilize an intrinsic di-nucleosome-recognition mechanism to prevent compromised function when their primary recognition modifications are diluted. © 2012 European Molecular Biology Organization | All Rights Reserved.

Goo H.W.,University of Ulsan
Journal of the Korean Medical Association | Year: 2010

Thanks to the benefits of 3 tesla (T) magnetic resonance imaging (MRI), its clinical use is increasing in pediatric patients. However, technical considerations and clinical applications of 3T MRI have not been comprehensively reviewed. Potential advantages of 3T imaging over 1.5T imaging include a higher signal-to-noise ratio, higher contrast-to-noise ratio, higher spatial resolution, and shorter scan time. These merits are easily achieved in neuroimaging, musculoskeletal imaging, and pelvic imaging, while body imaging is substantially limited by dielectric shading and an increased specific absorption rate (SAR) owing to B 1 inhomogeneity and increased susceptibility artifacts. T1 and T2 relaxation times as well as chemical shifts are influenced by the higher magnetic field strength. SAR issues and dielectric shading of 3T body MRI are less problematic in pediatric patients having a smaller body size. Improved image quality can be achieved by using parallel imaging, the shortest echo time or echo train length, the highest receiver bandwidth, and improved local shimming. Potential reduction of scan time at 3T should be emphasized for pediatric patients. Three-dimensional MRI with post-processing can improve the image quality in a short acquisition time and, therefore, has become a clinical reality at 3T. A dualsource parallel radiofrequency excitation system can reduce dielectric shading, SAR, and scan time by increasing B1 homogeneity, which eventually improves the image quality of 3T body MRI. The usefulness of 3T MRI in pediatric patients can be maximized by further technical developments and optimization. © Korean Medical Association.

Bar A.K.,Indian Institute of Science | Shanmugaraju S.,Indian Institute of Science | Chi K.-W.,University of Ulsan | Mukherjee P.S.,Indian Institute of Science
Dalton Transactions | Year: 2011

Design and synthesis of three novel [2 + 2] self-assembled molecular rectangles 1-3via coordination driven self-assembly of predesigned Pd(ii) ligands is reported. 1,8-Diethynylanthracene was assembled with trans-Pd(PEt 3) 2Cl 2 in the presence of CuCl catalyst to yield a neutral rectangle 1via Pd-C bond formation. Complex 1 represents the first example of a neutral molecular rectangle obtained via C-Pd coordination driven self-assembly. A new Pd 2 II organometallic building block with 180° bite-angle 1,4-bis[trans-(ethynyl) Pd(PEt 3) 2(NO 3)]benzene (M 2) containing ethynyl functionality was synthesized in reasonable yield by employing Sonagashira coupling reaction. Self-assembly of M 2 with two organic clip-type donors (L 2-L 3) afforded [2 + 2] self-assembled molecular rectangles 2 and 3, respectively [L 2 = 1,8-bis(4-pyridylethynyl)anthracene; L 3 = 1,3-bis(3-pyridyl) isophthalamide]. The macrocycles 1-3 were fully characterized by multinuclear NMR and ESI-MS spectroscopic techniques, and in case of 1 the structure was unambiguously determined by single crystal X-ray diffraction analysis. Incorporation of Pd-ethynyl bonds helped to make the assemblies π-electron rich and fluorescent in nature. Complexes 1-2 showed quenching of fluorescence intensity in solution in presence of nitroaromatics, which are the chemical signatures of many commercially available explosives. © 2011 The Royal Society of Chemistry.

Ahn J.Y.,University of Ulsan
The Korean journal of gastroenterology = Taehan Sohwagi Hakhoe chi | Year: 2012

Accessory spleen can be mistaken as a gastric subepithelial mass, and may not be differentiated in CT or endoscopic ultrasonography (EUS). A gastric subepithelial mass was detected on routine endoscopy in a 39-year old woman with history of splenectomy. In subsequent CT and EUS, the subepithelial mass was located on the fourth layer of the stomach. To make a definite diagnosis, EUS-guided fine needle aspiration (FNA) was performed, and a splenic tissue was demonstrated in histologic examination. EUS-guided FNA can be beneficial in the diagnosis of accessory spleen which mimics a gastric subepithelial mass.

Jung-Choi K.,Ewha Womans University | Khang Y.H.,University of Ulsan
Journal of Epidemiology and Community Health | Year: 2011

Objectives: To determine the contribution of different causes of death to absolute socioeconomic inequalities in mortality for the whole population of children of South Korea aged 1-4 years and 5-9 years. Methods: A cohort study based on the national birth and death registers of Korea was performed for 3 724 347 children born in 1995-2000 and 657 209 children born in 1995 to analyse mortality among children aged 1-4 and 5-9 years old, respectively. Adjusted mortality, risk difference (RD), slope index of inequality (SII), RR and relative index of inequality were calculated. The contributions of different causes of death to absolute mortality inequalities were calculated as percentages based on RD and SII. Results: Injuries other than from transport accidents contributed the most to total SIIs for male deaths at ages 1-4 (30.0% for father's education). The second largest contribution was from transport accident injuries (19.6% for father's education). For male deaths at ages 5-9, transport accident injuries and other injuries also accounted for most of the educational and occupational differentials in absolute mortality (63.5-90.5%). Patterns in cause-specific contribution to total inequalities in mortality among girls were generally similar to those among boys. Conclusions: The major contributing causes to absolute socioeconomic inequality in all-cause mortality for children aged 1-9 were external. To reduce the absolute magnitude of socioeconomic inequalities in childhood mortality, policy efforts should be directed towards injury prevention and treatment in South Korea.

Suh M.,Inha University | Choi-Kwon S.,Seoul National University | Kim J.S.,University of Ulsan
Journal of Stroke and Cerebrovascular Diseases | Year: 2014

Background Poststroke sleep disturbances (PSSDs) are frequent and reported to be associated with unfavorable clinical outcomes. PSSDs appear to be related to a multitude of factors including lesion location and environmental causes. Moreover, depression and fatigue, which frequently develop in stroke patients may also contribute to PSSD development. The purpose of this study was to evaluate the prevalence and characteristics of PSSDs and factors related to PSSDs including depression and fatigue in hospitalized stroke patients. Methods Patients who were hospitalized with acute stroke at the Asan Medical Center were evaluated. The quality (Verran-Snyder-Halpern [VSH] Sleep Scale score), duration and latency of night-time sleep, the frequency of waking after sleep onset, and daytime sleepiness were evaluated during the hospitalization period. To validate the self-reported night-time sleep, an actigraphy was performed in a subset of patients. The location, circulation, and laterality of each lesion were determined from brain magnetic resonance images obtained within 7 days of stroke onset. Depression and fatigue were assessed using the Beck Depression Inventory and the Fatigue Severity Scale, respectively. For environmental factors, the duration of hospitalization and the number of other patients in the same room were recorded. Univariate, multiple regression, and multiple logistic regression analyses were used to evaluate predictors of PSSD development. Results A total of 282 patients completed the study. The mean age of the patients was 62.3 (±12.76) years and 58.9% of them were male. Sixty patients (21.3%) reported sleep duration less than 6 hours/night and 110 (39.0%) reported more daytime sleepiness than before the stroke. In 54 patients who agreed to wear an actigraph, self-reported sleep duration was significantly correlated with time in bed measured with an actigraph (r =.407, P =.002) and, VSH Sleep Scale score and sleep efficiency in actigraphy were also significantly correlated (r =.305, P =.026). Quality of night-time sleep was independently related to cortical lesion location (P =.002), diabetes mellitus (P =.020), and depression (P <.001), whereas increased daytime sleepiness was independently associated with subcortical lesion location (P =.031), fatigue (P =.001), and quality of night-time sleep (P =.001). Conclusions PSSDs are common in hospitalized stroke patients. The most powerful factor predicting night-time sleep disturbances in stroke patients was depression. Cortical brain lesion and diabetes mellitus were also associated with night-time sleep disturbances. On the other hand, although poststroke daytime sleepiness is in part caused by night-time sleep disturbance, it is more closely associated with fatigue and subcortical lesion location. © 2014 by National Stroke Association.

Khang Y.-H.,University of Ulsan | Kim H.R.,Korea Institute for Health and Social Affairs
International Journal of Public Health | Year: 2010

Objectives: This study explored gender- and age-specific contributions of explanatory factors to the relationship between self-rated health (SRH) and all-cause mortality. Methods: We used mortality follow-up data from 1998 and 2001 National Health and Nutrition Examination Surveys of South Korea (n = 9,663). Explanatory factors included baseline health status, socioeconomic status, health behaviors, clinical risk factors, psychosocial factors, and family medical history. Results: The ability of explanatory factors to explain the SRH-mortality relationship differed with age. For those aged 30-64, most excess hazards were explained by all explanatory factors. However, a large part of the mortality differentials by SRH remained unexplained among elderly samples. Conclusions: A wide range of health-related factors could explain the SRH-mortality association in younger population but not in older population. Factors to explain a large part of mortality differentials by SRH among older population should be identified. © 2010 Swiss School of Public Health.

Shanmugaraju S.,Indian Institute of Science | Bar A.K.,Indian Institute of Science | Chi K.-W.,University of Ulsan | Mukherjee P.S.,Indian Institute of Science
Organometallics | Year: 2010

A new PtII 2 organometallic building block with 90° geometry, 3,6-bis[trans-platinum(triethylphosphine)2(nitrate) (ethynyl)]carbazole (5), containing an ethynyl functionality is synthesized in reasonable yield by employing a Sonagashira coupling reaction. Multinuclear NMR and electrospray ionization mass spectrometry (ESI-MS) including a single-crystal X-ray diffraction study characterized this 90° building unit. The self-assembly of 5 with three flexible ditopic donors (La-L c) afforded [2 + 2] metallamacrocycles (6a-c) [where La = 1,3-bis(4-pyridyl)isophthalamide; Lb = 1,3-bis(3-pyridyl) isophthalamide, and Lc = 1,2-di(4-pyridyl)ethane]. All three [2 + 2] self-assembled macrocycles were characterized by various spectroscopic techniques, and the molecular structure of 6a was determined by the single-crystal X-ray diffraction method. The square-type macrocycle 6a was designed using amide-based ligand La to make it a suitable system composed of a fluorophorereceptor combination. The amide functional group is the receptor site for the anions, which can bind through hydrogen-bonding interaction, whereas the carbazole-based 90° building unit is the fluorophore unit. Macrocycle 6a was found to be fluorescent in nature and showed dramatic fluorescence enhancement in a DMF/H2O solvent mixture upon titration with P2O7 4-, which plays important roles in various biological functions such as energy transduction in organisms and controls metabolic processes by participating in various enzymatic reactions. Interestingly, the nonresponsive nature of the fluorescence intensity of 6a upon addition of the anions F-, ClO4 -, and H2PO4 - makes it a suitable fluorescent sensor for pyrophosphate anion (P2O7 4-). © 2010 American Chemical Society.

Park J.,University of Ulsan
American journal of physical medicine & rehabilitation / Association of Academic Physiatrists | Year: 2011

A couple of the most common complications after anterior cervical spine surgery are dysphagia and hoarseness. This is often related to recurrent laryngeal nerve palsy and it can also be caused by injury to the branches of the lower cranial nerves. In general, Tapia syndrome is combined injuries of the recurrent laryngeal nerve of the vagus and the hypoglossal nerves. There has been no reported case until now of Tapia syndrome after a patient underwent anterior cervical spine surgery. We present here the case of a 42-yr-old man who complained of hoarseness, dysphagia, and right deviation of the tongue with an atrophic change for 2 mos after he underwent C3-4 discectomy and anterior fusion body. We found that he has a diagnosis of a variant of Tapia syndrome, although recurrent laryngeal nerve injury did not seem to be involved according to a videofluoroscopic swallowing study and electromyography. Our case report demonstrates that the combined diagnostic tools of videofluoroscopic swallowing study, electromyography, and laryngoscopy can be very useful in localizing and evaluating the level of lesions in patients with Tapia syndrome.

Won C.H.,University of Ulsan
Dermatologic surgery : official publication for American Society for Dermatologic Surgery [et al.] | Year: 2013

A new botulinum toxin type A (NBoNT) produced from the same strain of Clostridium botulinum as onabotulinumtoxinA (OBoNT) is widely used in Asia. To compare the efficacy and safety of NBoNT and OBoNT for moderate to severe glabellar wrinkles. A double-blind, randomized, active-controlled, phase III study was performed. Three hundred fourteen patients were randomized at a 1:1 ratio to receive 20 U of toxin. The primary end point was the responder rate according to investigator live assessment at maximum frown at week 4. Secondary end points were responder rates according to investigator live assessment with frowning and at rest at weeks 8, 12, and 16, with additional photographic assessment by a panel of blinded raters 4 weeks after injection. Subjective satisfaction scores were also evaluated. Four weeks after treatment, responder rates for maximum frown were 93.7% (133/142) in the NBoNT group and 94.5% (138/146) in the OBoNT group. For secondary end points, there was no significant difference between the two groups for any variable at any time point. Noninferiority of NBoNT was confirmed. There were no serious adverse effects with either toxin. NBoNT is equally as effective as OBoNT for the treatment of glabellar frown lines. Both toxins were well tolerated. © 2012 by the American Society for Dermatologic Surgery, Inc. Published by Wiley Periodicals, Inc.

Heo L.,Seoul National University | Shin W.-H.,Seoul National University | Lee M.S.,University of Ulsan | Seok C.,Seoul National University
Nucleic Acids Research | Year: 2014

Knowledge of ligand-binding sites of proteins provides invaluable information for functional studies, drug design and protein design. Recent progress in ligand-binding-site prediction methods has demonstrated that using information from similar proteins of known structures can improve predictions. The GalaxySite web server, freely accessible at http://galaxy.seoklab.org/site, combines such information with molecular docking for more precise binding-site prediction for non-metal ligands. According to the recent critical assessments of structure prediction methods held in 2010 and 2012, this server was found to be superior or comparable to other state-of-the-art programs in the category of ligand-binding-site prediction. A strong merit of the GalaxySite program is that it provides additional predictions on binding ligands and their binding poses in terms of the optimized 3D coordinates of the protein-ligand complexes, whereas other methods predict only identities of binding-site residues or copy binding geometry from similar proteins. The additional information on the specific binding geometry would be very useful for applications in functional studies and computer-aided drug discovery. © 2014 The Author(s).

Kim Y.S.,University of Ulsan
Otolaryngology - Head and Neck Surgery (United States) | Year: 2012

Objective. To determine the incidence and patterns of and to evaluate the predictive factors for lateral cervical lymph node metastasis (LNM) in papillary thyroid microcarcinoma (PTMC). Study Design. Case series with chart review. Setting. Academic university hospital Subjects and Methods. From March 2007 to September 2010, a retrospective review was performed of 490 patients with PTMC who underwent total thyroidectomy and central lymph node dissection with or without lateral cervical lymph node dissection. The clinicopathologic results were reviewed, and the incidence and patterns of lateral cervical lymph node metastasis were analyzed. Results. The overall frequency of central and lateral LNM was 39.6% and 3.0%, respectively. The incidence of lateral lymph node metastasis in level IIa, III, IV, Vb, IIb, and Va was 46.7%, 53.3%, 73.3%, 6.7%, 6.7%, and 20.0%, respectively. Lateral LNM without central LNM was observed in 3 (0.6%) cases of PTMC. A multivariate analysis revealed that the predictive factors for the presence of lateral lymph node metastasis are male sex, increased tumor size, T4 stage, and pathologic central lymph node metastasis. Conclusion. Although lateral LNM was rare, the surgeon should perform thorough preoperative studies to look for lateral LNM in cases of PTMC if the patient is male, has a relatively larger tumor size, and has aggressive mass and also to look for the possibility of skip metastasis. Lymph node metastasis involving the spinal accessory chain (IIb) was not that rare, and careful level IIb lymph node dissection should be considered for patients who will undergo a modified radical neck dissection for lateral LNM. © 2012 American Academy of Otolaryngology - Head and Neck Surgery Foundation.

Shin H.,University of Ulsan | Santamarina J.C.,Georgia Institute of Technology
Journal of Geotechnical and Geoenvironmental Engineering | Year: 2013

Particle shape affects the mechanical behavior of soils, including packing density, stiffness, volume change during shear, and strength. Laboratory experiments conducted to study the mechanical response of sand mixtures made of round and angular grains show an increase in void ratio, small strain shear modulus Gmax (constant fabric), oedometric compressibility CC (fabric changes), and friction angle but a decrease in lateral stress coefficient k0 as the mass fraction of angular particles increases. These results reflect variations in particle mobility and highlight the relative role of contact stiffness versus fabric changes. © 2013 American Society of Civil Engineers.

Kwon J.H.,University of Ulsan
Pancreas | Year: 2015

OBJECTIVES: Glucose homeostasis changes after pancreatic resection are not well understood. We aimed to identify the incidence of, and risk factors for, a change in glucose homeostasis in patients who underwent pancreatectomy for benign pancreatic tumors. METHODS: Clinical and pathological data from 229 patients were collected prospectively and analyzed retrospectively. The pancreas resection volume was calculated by computed tomography volumetry. RESULTS: After pancreatectomy, newly diagnosed diabetes mellitus (DM) occurred in 52 patients (22.7%) and impaired fasting glucose and impaired glucose tolerance occurred in 74 patients (32.3%). The incidence of DM was highest for patients who underwent distal pancreatectomy (DP) (30.5%). Patients in the DP group had a significantly increased rate of DM as the pancreatic resection volume (in milliliters) and resected volume ratio (in percent) increased. A high body mass index and older age were significant risk factors for the development of DM by multivariate analysis. CONCLUSIONS: The resection volume of the pancreas is associated with a change in glucose homeostasis after pancreatectomy. Therefore, preservation of the pancreatic parenchyma is important to minimize the onset of DM in patients with a high pancreatic resected volume ratio (>35.6%) in DP, a high body mass index, or in old age. © 2015 Wolters Kluwer Health, Inc. All rights reserved.

Ahn J.H.,University of Ulsan
Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology | Year: 2012

Cultures obtained from preoperative middle ear swabs from patients with chronic suppurative otitis media (CSOM) have traditionally been used to guide antibiotic selection. However, little is known about changes in the bacterial flora during surgery. To analyze preoperative, intraoperative, and postoperative bacterial cultures of CSOM patients who underwent tympanomastoidectomy. We retrospectively reviewed the medical records of 244 patients (113 male and 131 female subjects; 252 ears) diagnosed with CSOM between January 2006 and December 2008. Middle ear swabs and mastoid granulation tissue were collected preoperatively and intraoperatively, respectively. We also cultured middle ear swabs from patients with postoperative otorrhea. The most commonly identified preoperative pathogenic bacterial species was methicillin-resistant Staphylococcus aureus (MRSA). There were no statistical differences in prevalence of preoperative bacterial pathogens between patients with and without cholesteatoma. No bacteria were observed in 34.1% of preoperative or 76.6% of intraoperative cultures. Patients preoperatively positive for coagulase-negative Staphylococcus, S. aureus, or Pseudomonas aeruginosa remained positive intraoperatively. Of the patients preoperatively negative for bacteria and those positive for fungi, 6.9% and 20.0%, respectively, were positive for bacteria, including MRSA, intraoperatively. Of the patients that were preoperatively positive for bacteria, 16.7% to 50.0% was intraoperatively positive for different pathogens from previous results. Patients with postoperative otorrhea yielded the highest culture rates of MRSA, preoperatively, intraoperatively, and postoperatively. Although the similarities between preoperative and intraoperative culture results were relatively high, remaining or different pathogens also may have been present from intraoperative mastoid granulation tissue culture. Patients with preoperative MRSA were at high risk of postoperative otorrhea.

Kim D.,University of Ulsan
Transactions on Electrical and Electronic Materials | Year: 2013

Sn-doped In2O3 (ITO) thin films were prepared by radio frequency magnetron sputtering without intentional substrate heating on bare glass and TiO2-deposited glass substrates to investigate the effect of a TiO2 buffer layer on the electrical and optical properties of ITO films. The thicknesses of TiO2 and ITO films were kept constant at 5 and 100 nm, respectively. As-deposited ITO single layer films show an optical transmittance of 75.9%, while ITO/TiO2 bi layered films show a lower transmittance of 76.1%. However, as-deposited ITO/TiO2 films show a lower resistivity (9.87×10-4 Ωcm) than that of ITO single layer films. In addition, the work function of the ITO film is affected by the TiO2 buffer layer, with the ITO/TiO2 films having a higher work-function (5.0 eV) than that of the ITO single layer films. The experimental results indicate that a 5-nm-thick TiO2 buffer layer on the ITO/TiO2 films results in better performance than conventional ITO single layer films. © 2013 KIEEME. All rights reserved.

Kim K.,Ulsan National Institute of Science and Technology | Shin M.,Ulsan National Institute of Science and Technology | Cha S.,University of Ulsan
Construction and Building Materials | Year: 2013

The recycling of demolished concrete has been emerging as a sustainable solution to warrant the reduction of construction wastes, as well as to prevent the depletion of natural resources from growing construction demand. Nevertheless, some key factors that would affect the properties of recycled aggregate concrete have not been thoroughly investigated, such as the proportion of recycled aggregates, the moisture state of recycled aggregates, and the design compressive strength of concrete. In particular, little research was done on the combined effects of recycled aggregates and fly ash, popularly used as a partial substitution of cement. Given the concerns, this study investigates the effects of such factors on the mechanical and durability properties of recycled aggregate concrete. Eleven cases of concrete mixtures were tested for the rheological properties of fresh concrete, compressive strength, tensile strength, and chloride diffusion coefficient. In general, the higher ratio of recycled aggregates resulted in the better flowability of concrete. Also, the use of fly ash improved the flowability of recycled aggregate concrete. The strength test results showed that the higher ratio of recycled aggregates generally caused the lower compressive and tensile strengths of concrete. However, the cases with 30% recycled aggregates showed only slight compressive strength reductions. Similarly, the use of fly ash caused only small reductions in the compressive strength of recycled aggregate concrete. In contrast, the negative effects of recycled aggregates and fly ash were greater in the tensile strength than in the compressive strength. Lastly, the cases containing fly ash exhibited much higher resistance to chloride penetration, even in the cases with recycled aggregates. © 2013 Elsevier Ltd. All rights reserved.

Koo W.,University of Ulsan | Kim M.-H.,Texas A&M University
Journal of Waterway, Port, Coastal and Ocean Engineering | Year: 2010

A two-dimensional time domain, fully nonlinear numerical wave tank (NWT) based on potential theory, the mixed Eulerian-Lagrangian approach, and the boundary element method was developed and applied to land-based oscillating water columns (OWCs) with compressed air inside the chamber. The nonlinear free-surface condition inside the chamber was specially devised to represent both the viscous effect of the water column motion and the pneumatic effect of the time-varying pressure. The latter not only influenced the water column motions, but also generated radiated waves to interfere with incident and reflected wave fields. Both linear and quadratic models are used for the viscous and pneumatic effects. The regular-wave cases are also compared with irregular-wave cases. The developed NWT was verified through comparison with viscous-flow-based numerical and experimental results for both narrow-gap and wide-gap chambers at two different skirt depths, with and without air ducts. All of the NWT simulations correlated well with experimental values for a variety of wave and chamber conditions, so that the developed numerical tool can be practically used for the optimal design of land-based OWCs. The fully nonlinear simulations were also compared with linear simulations. In case that had the same skirt depth and air duct area, the efficiency of the wide-gap chamber was generally higher than that of the narrow-gap chamber over a wider range of wavelengths, due to the larger amount of compressed air and the corresponding higher flow velocities. © 2010 ASCE.

Song K.-J.,University of Ulsan
Ocean and Coastal Management | Year: 2014

Although marine mammals, particularly cetaceans, have been protected in Korea for more than 24 years after a commercial whaling moratorium in 1986, relatively little effort has been focused on assessing their current status of marine mammals in this area after this protection and the efficacy of this protection. Thus, for the first time, the status of marine mammals in Korea was investigated using potential biological removal (PBR) and mortality data. A total of 5 stocks of marine mammals were investigated and 4 stocks experienced anthropogenic mortalities that exceeded their estimated PBR level. Therefore, these 4 stocks were considered strategic. These mortalities were mainly associated with commercial fishing activities. To conserve and manage marine mammals in this area effectively, it urgently needs to investigate the efficiency of various bycatch mitigation measures and to apply these measures in field actually for reducing bycatch. This study has advanced our understanding of the current status of marine mammals in Korea, but quantitative data on abundance are not available for most small cetaceans such as common dolphin, harbor porpoise. Thus, further study needs to examine abundance of small cetaceans for investigating of the current status of these stocks in Korea. © 2014 Elsevier Ltd.

Byeon J.-S.,University of Ulsan
Clinical Endoscopy | Year: 2013

Colonic perforation occurs in a variety of clinical scenarios and colonoscopy-associated perforation is one of the important reasons for colonic perforation. Colonoscopy-associated perforation may be diagnosed during colonoscopy procedure by the visualization of evident colonic wall defect or, after the completion of colonoscopy, by the visualization of leaked air in the peritoneal or retroperitoneal space. Recently, the incidence of colonoscopy-associated perforation increased because of the introduction of colorectal endoscopic submucosal dissection. Traditionally, colonoscopy-associated perforation was managed surgically. However, medical management has been introduced widely and endoscopic clipping is the most important component for the medical management of colonoscopy-associated perforation. Timely administration of antibiotics is also important. Large perforations, diagnostic colonoscopy-associated perforations, large amount of pneumoperitoneum, and severe abdominal pain have been reported to be predictive of the necessity of surgery after endoscopic clipping. Surgery should be performed if patients show clinical deterioration even after the initiation of medical management. © 2013 Korean Society of Gastrointestinal Endoscopy.

Nam G.-B.,University of Ulsan
Journal of Arrhythmia | Year: 2013

Brugada syndrome (BS) and early repolarization syndrome (ERS) are newly introduced electrical disorders responsible for ventricular fibrillation (VF) and sudden cardiac death in patients with structurally normal hearts. The electrocardiographic J wave, a hallmark of these two syndromes, plays a critical role in the pathophysiology of malignant ventricular tachyarrhythmias. BS and ERS share many clinical characteristics, including male preponderance, circadian distribution of VF episodes, prevalence of concomitant atrial tachyarrhythmias, dynamic behavior of J waves, and response to therapeutic managements. In this review, we compare the key clinical manifestations of BS and ERS with their underlying cellular electrophysiologic mechanisms. © 2013 Japanese Heart Rhythm Society. Published by Elsevier B.V. All rights reserved.

Shin J.H.,University of Ulsan
Clinical Endoscopy | Year: 2013

Although endoscopic hemostasis remains initial treatment modality for nonvariceal gastrointestinal (GI) bleeding, severe bleeding despite endoscopic management occurs in 5% to 10% of the patients, requiring surgery or transcatheter arterial embolization (TAE). TAE is now considered the first-line therapy for massive GI bleeding refractory to endoscopic management. GI endoscopists need to be familiar with indications, principles, outcomes, and complications of TAE, as well as embolic materials available. © 2013 Korean Society of Gastrointestinal Endoscopy.

Kim S.,U.S. National Center for Biotechnology Information | Kwon D.,Myongji University | Shin S.,University of Ulsan | Wilbur W.J.,U.S. National Center for Biotechnology Information
Bioinformatics | Year: 2012

Motivation: Finding protein-protein interaction (PPI) information from literature is challenging but an important issue. However, keyword search in PubMed® is often time consuming because it requires a series of actions that refine keywords and browse search results until it reaches a goal. Due to the rapid growth of biomedical literature, it has become more difficult for biologists and curators to locate PPI information quickly. Therefore, a tool for prioritizing PPI informative articles can be a useful assistant for finding this PPI-relevant information. Results: PIE (Protein Interaction information Extraction) the search is a web service implementing a competition-winning approach utilizing word and syntactic analyses by machine learning techniques. For easy user access, PIE the search provides a PubMed-like search environment, but the output is the list of articles prioritized by PPI confidence scores. By obtaining PPI-related articles at high rank, researchers can more easily find the up-to-date PPI information, which cannot be found in manually curated PPI databases. © The Author(s) 2012. Published by Oxford University Press.

Human papillomavirus (HPV) infection is a major cause of cervical cancer. Here, we investigate whether concurrent therapy using HPV E7 DNA vaccines (pE7) plus IL-2 vs. IL-15 cDNA and anti-4-1BB Abs might augment antitumor activity against established tumors. IL-2 cDNA was slightly better than IL-15 cDNA as a pE7 adjuvant. Co-delivery of pE7+IL-2 cDNA increased tumor cure rates from 7% to 27%, whereas co-delivery of pE7+IL-2 cDNA with anti-4-1BB Abs increased tumor cure rates from 27% to 67% and elicited long-term memory responses. This increased activity was concomitant with increased induction of Ag-specific CTL activity and IFN-c responses, but not with Ag-specific IgG production. Moreover, the combined stimulation of IL-2 and 4-1BB receptors with rIL-2 and anti-4-1BB Abs resulted in enhanced production of IFN-γ from Ag-specific CD8+ T cells. However, this effect was abolished by treatment with anti-IL-2 Abs and 4-1BB-Fc, suggesting that the observed effect was IL-2- and anti-4-1BB Ab-specific. A similar result was also obtained for Ag-specific CTL activity. Thus, these studies demonstrate that combined stimulation through the IL-2 and 4-1BB receptors augments the Ag-specific CD8+ CTL responses induced by pE7, increasing tumor cure rates and long-term antitumor immune memory. These findings may have implications for the design of DNA-based therapeutic vaccines against cancer. © 2013 Kim et al.

Kim G.H.,Pusan National University | Bang S.J.,University of Ulsan | Hwang J.H.,University of Washington
World Journal of Gastroenterology | Year: 2015

Endoscopic ultrasonography (EUS) has become a useful diagnostic and therapeutic modality in gastrointestinal endoscopy. However, EUS requires additional training since it requires simultaneous endoscopic manipulation and ultrasonographic interpretation. Obtaining adequate EUS training can be challenging since EUS is highly operator-dependent and training on actual patients can be associated with an increased risk of complications including inaccurate diagnosis. Therefore, several models have been developed to help facilitate training of EUS. The models currently available for EUS training include computer-based simulators, phantoms, ex vivo models, and live animal models. Although each model has its own merits and limitations, the value of these different models is rather complementary than competitive. However, there is a lack of objective data regarding the efficacy of each model with recommendations on the use of various training models based on expert opinion only. Therefore, objective studies evaluating the efficacy of various EUS training models on technical and clinical outcomes are still needed. © 2015 Baishideng Publishing Group Inc. All rights reserved. © 2015 The Author(s).

Kim Y.,University of Ulsan
IEEE transactions on image processing : a publication of the IEEE Signal Processing Society | Year: 2013

Image segmentation plays a crucial role in numerous biomedical imaging applications, assisting clinicians or health care professionals with diagnosis of various diseases using scientific data. However, its high computational complexities require substantial amount of time and have limited their applicability. Research has thus focused on parallel processing models that support biomedical image segmentation. In this paper, we present analytical results of the design space exploration of many-core processors for efficient fuzzy c-means (FCM) clustering, which is widely used in many medical image segmentations. We quantitatively evaluate the impact of varying a number of processing elements (PEs) and an amount of local memory for a fixed image size on system performance and efficiency using architectural and workload simulations. Experimental results indicate that PEs=4,096 provides the most efficient operation for the FCM algorithm with four clusters, while PEs=1,024 and PEs=4,096 yield the highest area efficiency and energy efficiency, respectively, for three clusters.

Jung K.-H.,Pohang University of Science and Technology | Lee D.,University of Ulsan | Lee J.,Pohang University of Science and Technology
Pattern Recognition | Year: 2010

In many support vector-based clustering algorithms, a key computational bottleneck is the cluster labeling time of each data point which restricts the scalability of the method. In this paper, we review a general framework of support vector-based clustering using dynamical system and propose a novel method to speed up labeling time which is log-linear to the size of data. We also give theoretical background of the proposed method. Various large-scale benchmark results are provided to show the effectiveness and efficiency of the proposed method. © 2009 Elsevier Ltd. All rights reserved.

Lee S.-A.,Asan Medical Center | Lee S.-M.,Asan Medical Center | No Y.-J.,University of Ulsan
Epilepsia | Year: 2010

We investigated factors contributing to depression in patients with epilepsy. Data were collected from 150 adult patients. Beck Depression Inventory (BDI), Beck Anxiety Inventory, Daily Hassles Scale, Epilepsy Self-Efficacy Scale, Social Support Scale, Stress Coping Style Checklist, and Quality of Life in Epilepsy Inventory 31 (QOLIE-31) were used. The mean BDI score was 13.4 [standard deviation (SD) 9.0]. Abnormal BDI scores were recorded in 93 patients. Six significant predictors of BDI were identified in a stepwise linear regression analysis: level of stress (p < 0.001), social support (p = 0.037), anxiety (p = 0.001), self-efficacy (p < 0.001), employment status (p = 0.021), and age (p = 0.042). Stress accounted for 38.8% of the variance in BDI score, social support accounted for 6.8%, anxiety accounted for 3.9%, and the remaining three variables accounted for an additional 5.2% of the variance (total explained variance = 54.7%). © 2009 International League Against Epilepsy.

Ye B.D.,University of Ulsan
The Korean journal of gastroenterology = Taehan Sohwagi Hakhoe chi | Year: 2012

Crohn's disease (CD) is a chronic inflammatory bowel disease (IBD) with uncertain etiopathogenesis. CD can involve any site of gastrointestinal tract from the mouth to anus and is associated with serious complications such as bowel strictures, perforations, and fistula formation. The incidence and prevalence rates of CD in Korea are still lower than those of Western countries, but have been rapidly increasing during the past decades. Although there are no definitive curative modalities for CD, various medical and surgical therapies are currently applied for diverse clinical situations of CD. However, a lot of decisions on the management of CD are made depending on the personal experiences and choices of physicians. To suggest preferable approaches to diverse problems of CD and to minimize the variations according to physicians, guidelines for the management of CD are needed. Therefore, IBD Study Group of the Korean Association for the Study of the Intestinal Diseases has set out to develop the guidelines for the management of CD in Korea. These guidelines were developed using the adaptation methods and encompass the treatment of inflammatory disease, stricturing disease, and penetrating disease. The guidelines also cover the indication of surgery, prevention of recurrence after surgery, and CD in pregnancy and lactation. These are the first Korean guidelines for the management of CD and the update with further scientific data and evidences is needed.

Alzheimer's disease (AD) and Parkinson's disease (PD) have overlapping clinical and pathological features, suggesting a common pathway for these 2 neurodegenerative disorders. Here we investigated the association of both AD and PD GWAS top hits with PD susceptibility. We selected 25 single nucleotide polymorphisms (SNPs) in 9 genes (ABCA7, APOE, BST1, CLU, CR1, LRRK2, PARK16, PICALM, and SNCA) that were genotyped in 1036 PD case patients and 1208 controls. Case patients and controls were all ethnic Koreans. Logistic regression analysis was performed to calculate age- and sex-adjusted odds ratios. None of the AD-susceptibility loci (ABCA7, APOE, CLU, CR1, and PICALM) showed statistically significant association with PD susceptibility. In contrast, we replicated associations of SNCA, LRRK2, BST1, and PARK16 with PD susceptibility in Koreans. Of those, the SNCA SNP rs11931074 showed the most significant association with PD susceptibility (adjusted odds ratio = 1.48; 95% confidence interval = 1.31-1.67; p = 2.20E-10). In a logistic regression analysis with SNPs coded under an additive model, there was no significant genetic interaction between the LRRK2 and the PARK16 locus gene RAB7L1 in PD risk. Our results confirm the associations of SNCA, LRRK2, BST1, and PARK16 with PD susceptibility and fail to show significant associations of AD genome-wide association study (GWAS) top hits with PD susceptibility in a Korean population. Copyright © 2013 Elsevier Inc. All rights reserved.

Nguyen-Thanh N.,Orange S.A. | Koo I.,University of Ulsan
IEEE Sensors Journal | Year: 2013

The cost for increasing the accuracy of cooperative spectrum sensing in cognitive radio requires a long time for collecting sensing data. Sequential fusion, in which the sensing data reports are sequentially collected, combined, and tested with two thresholds for deciding to wait for the next data report or concluding the presence or absence of the primary signal, is considered to reduce the collecting time. A further reduction in the average sequential report number (ASN) can be achieved by arranging the reports in descending order of data quality where the better sensing data is reported earlier. In this paper, the ASN and the error probability of the ordered sequential fusion are analytically calculated based on the direct method. The results are then adopted to design an optimal method for obtaining the optimal sequential thresholds and truncated point. The optimal truncated point enables one to minimize the ASN by discarding the sensing data with low quality, while the optimal sequential thresholds ensure the maintaining of the sensing performance of sequential fusion be the same level to that of the conventional parallel fusion. © 2013 IEEE.

Song G.W.,University of Ulsan
The Korean journal of gastroenterology = Taehan Sohwagi Hakhoe chi | Year: 2010

Hepatocellular carcinoma (HCC) is the third most common malignancy, with a new incidence of more than 11,000 cases per year and the second most common cause of malignancy-related death in Korean males. In Korea, more than 80% of all HCCs have developed from hepatitis B virus (HBV)-related cirrhotic livers. Liver transplantation (LT) is the only treatment that offers a chance of cure for HCC and the underlying liver cirrhosis simultaneously, but the availability of liver grafts and the aggressiveness of tumor recurrence are critical limiting factors of LT for HCC patients. The serious shortage of deceased-donors on strong demand for LT leads to the development of living-donor LT (LDLT) as a practical alternative replacing deceased-donor LT. Considering that HCC recurrence is the most common cause of posttransplant patient death, recipient candidates should be prudently selected through objectively established criteria. Uniquely, some Asian major LDLT centers challenged the Milan criteria, accepting a much higher number of HCC nodules instead of tumor size expansion. The eligibility criteria of LDLT for HCC are likely to be expanded more than before, but it still requires further qualified risk-benefit analyses. The development of new effective treatment modalities for HCC recurrence will reasonably expand the selection criteria further wide without the expense of recurrence rate. This article is mainly focused on the role of LT for HCC and discussed on the validity of currently available indication criteria.

Park K.-M.,Konkuk University | Park K.-M.,University of Pennsylvania | Kim Y.-H.,University of Ulsan | Marchlinski F.E.,University of Pennsylvania
PACE - Pacing and Clinical Electrophysiology | Year: 2012

The surface electrocardiogram (ECG) is a useful tool to help identify the sites of origin of ventricular tachycardia (VT). Despite such limitations as chest wall deformity and metabolic and drug effects, the analysis of the QRS morphologic patterns and vectors can discern the site of activation of myocardium. There have been described numerous reports about ECG features of idiopathic left-and right-ventricular VT. In this review, we summarized typical ECG characteristics according to the VT sites of origin based on previous reports, with anatomical considerations of the left and right ventricles, including the outflow tracts and epicardium. (PACE 2012;35:1516-1527) ©2012, The Authors. Journal compilation ©2012 Wiley Periodicals, Inc.

Lee D.,University of Ulsan | Lee J.,Pohang University of Science and Technology
IEEE Transactions on Knowledge and Data Engineering | Year: 2010

Clustering methods utilizing support estimates of a data distribution have recently attracted much attention because of their ability to generate cluster boundaries of arbitrary shape and to deal with outliers efficiently. In this paper, we propose a novel dissimilarity measure based on a dynamical system associated with support estimating functions. Theoretical foundations of the proposed measure are developed and applied to construct a clustering method that can effectively partition the whole data space. Simulation results demonstrate that clustering based on the proposed dissimilarity measure is robust to the choice of kernel parameters and able to control the number of clusters efficiently. © 2006 IEEE.

Kim S.,University of Ulsan
Journal of the Electrochemical Society | Year: 2012

Ni substrates were electrochemically deposited on p-GaN side of vertical structure GaN-based light emitting diodes (LEDs). The Ni substrate functions as a part of p-electrode, a heat sink, and a mechanical supporter of vertical structure LED devices. Using a proper Ni electrodeposition bath, the residual stress of 50-m thick Ni substrates was lower than 10 MPa, which is very low to be regarded as stress-free. Stress-free Ni substrate with better mechanical strength than Cu substrate was effective in minimizing mechanical damage possibly generated during LED chip fabrication. Vertical structure LED devices comprised in a 2-inch Ni-supported wafer had forward voltage on average as low as 3.35 V at 20 mA compared with 3.54 V of Cu-supported LED devices. Ni-supported LED devices showed comparable optical performance to Cu-supported LED devices in output power and operation reliability at constant forward currents. Electrical and optical performances of vertical structure LEDs with WO 3-added Cu substrate, which was previously considered to enhance the mechanical property of pure Cu substrate, were also presented for reference. In conclusion, Ni substrate affects the efficiency of vertical structure LEDs positively more than Cu and WO 3-added Cu substrates as long as those substrates are electrodeposited equally in stress-free conditions. © 2012 The Electrochemical Society.

Suh Y.S.,University of Ulsan
IEEE Transactions on Instrumentation and Measurement | Year: 2010

This paper is concerned with orientation estimation using inertial and magnetic sensors. A quaternion-based indirect Kalman filter structure is used. The magnetic sensor output is only used for yaw angle estimation using two-step measurement updates. External acceleration is estimated from the residual of the filter and compensated by increasing the measurement noise covariance. Using the direction information of external information, the proposed method prevents unnecessarily increasing the measurement noise covariance corresponding to the accelerometer output, which is not affected by external acceleration. Through numerical examples, the proposed method is verified. © 2006 IEEE.

Thirunavukkarasu K.,Indian Institute of Technology Madras | Jothiramalingam R.,University of Ulsan
Powder Technology | Year: 2013

Synthesis and characterization of Ga-doped ZnO nanodisk and the formation of nanodisk/nanorod hybrid morphologies on AlN/Si substrate by polymer assisted one-pot hydrothermal process have been studied. The low concentration of Ga-ZnO sol (0.2. M) and optimized concentration (0.5. M) of Zinc sol is used to vary the morphology and physico-chemical properties. Varying amounts of Ga (1%-3%) doped ZnO nanodisks have also been synthesized and characterized. The morphology and structural properties were determined by field emission scanning electron microscopy (FESEM) and X-ray diffraction techniques. Ga-ZnO nanodisk shows major intense X-ray diffraction peak at ZnO (101). X-ray photoelectron spectroscopy (XPS) confirms the effect of gallium doping and variation in their surface property after Ga doping in ZnO. FESEM images clearly confirm the pure nanodisk formation for Ga-ZnO (0.5) at optimized ZnO concentration and hybrid nanodisk/nanorod formation obtained for Ga-ZnO (0.2) at lower ZnO concentration. The pure Ga-ZnO (0.5) nanodisk on AlN/Si thin film substrate showed effective response and fast recovery time towards UV light sensing in dark condition compared to low concentration route prepared Ga-ZnO (0.2)/AlN/Si sample. © 2013 Elsevier B.V.

Ratajczak M.Z.,University of Louisville | Ratajczak M.Z.,Pomeranian Medical University | Shin D.-M.,University of Ulsan | Schneider G.,University of Louisville | And 4 more authors.
Leukemia | Year: 2013

In recent years, solid evidence has accumulated that insulin-like growth factor-1 (IGF-1) and 2 (IGF-2) regulate many biological processes in normal and malignant cells. Recently, more light has been shed on the epigenetic mechanisms regulating expression of genes involved in IGF signaling (IFS) and it has become evident that these mechanisms are crucial for initiation of embryogenesis, maintaining the quiescence of pluripotent stem cells deposited in adult tissues (for example, very-small embryonic-like stem cells), the aging process, and the malignant transformation of cells. The expression of several genes involved in IFS is regulated at the epigenetic level by imprinting/methylation within differentially methylated regions (DMRs), which regulate their expression from paternal or maternal chromosomes. The most important role in the regulation of IFS gene expression is played by the Igf-2-H19 locus, which encodes the autocrine/paracrine mitogen IGF-2 and the H19 gene, which gives rise to a non-coding RNA precursor of several microRNAs that negatively affect cell proliferation. Among these, miR-675 has recently been demonstrated to downregulate expression of the IGF-1 receptor. The proper imprinting of DMRs at the Igf-2-H19 locus, with methylation of the paternal chromosome and a lack of methylation on the maternal chromosome, regulates expression of these genes so that Igf-2 is transcribed only from the paternal chromosome and H19 (including miR-675) only from the maternal chromosome. In this review, we will discuss the relevance of (i) proper somatic imprinting, (ii) erasure of imprinting and (iii) loss of imprinting within the DMRs at the Igf-2-H19 locus to the expression of genes involved in IFS, and the consequences of these alternative patterns of imprinting for stem cell biology. © 2013 Macmillan Publishers Limited All rights reserved.

Tran T.D.,University of Ulsan
Journal of the Royal Society, Interface / the Royal Society | Year: 2013

Many biological networks tend to have a high modularity structural property and the dynamic characteristic of high robustness against perturbations. However, the relationship between modularity and robustness is not well understood. To investigate this relationship, we examined real signalling networks and conducted simulations using a random Boolean network model. As a result, we first observed that the network robustness is negatively correlated with the network modularity. In particular, this negative correlation becomes more apparent as the network density becomes sparser. Even more interesting is that, the negative relationship between the network robustness and the network modularity occurs mainly because nodes in the same module with the perturbed node tend to be more sensitive to the perturbation than those in other modules. This result implies that dynamically similar nodes tend to be located in the same module of a network. To support this, we show that a pair of genes associated with the same disease or a pair of functionally similar genes is likely to belong to the same module in a human signalling network.

Cha J.-H.,Seoul National University | Roh M.-I.,University of Ulsan
Advances in Engineering Software | Year: 2010

In this study, a simulation framework which can support to develop various simulation systems for process planning in shipbuilding is proposed. In addition, a simulation kernel which is a key component of the proposed simulation framework is implemented according to the concept of the combined discrete event and discrete time simulation. To evaluate the efficiency and applicability of the simulation framework proposed in this study, it is applied to the block erection process in shipbuilding. The result shows that the proposed simulation framework can provide the consistent, integrated development environment for a simulation system. © 2009 Elsevier Ltd. All rights reserved.

OBJECTIVES:: To evaluate the safety, feasibility, and oncologic outcomes of laparoscopic pylorus-preserving pancreaticoduodenectomy (L-PPPD) to treat periampullary tumors. The clinical outcomes of L-PPPD were compared with open pylorus-preserving pancreaticoduodenectomy (O-PPPD).BACKGROUND:: Despite recent advances in laparoscopic pancreatic surgery, few studies have compared L-PPPD with O-PPPD. The safety, short-term clinical benefits, and oncologic outcomes of L-PPPD remain controversial.METHODS:: Between January 2007 and December 2012, a total of 2192 patients diagnosed with periampullary tumors were treated with curative resection at our institution. Of these patients, 137 underwent a laparoscopic approach and 2055 an open technique. A retrospective study was performed to evaluate the safety, feasibility, and oncologic outcomes of L-PPPD compared with O-PPPD.RESULTS:: The mean operation time for the L-PPPD group was longer than for the O-PPPD group (P < 0.001). Estimated blood loss was similar, as was the incidence of complications, such as pancreatic fistula and delayed gastric empting (P > 0.05). The mean number of analgesic injections administered was lower in the L-PPPD group than in the O-PPPD group (P < 0.001), and the mean duration of the postoperative hospital stays was shorter (P < 0.001). The surgical resection margins and the number of lymph nodes in the resected specimens did not differ between the 2 groups, and there was no significant difference in overall survival curves.CONCLUSIONS:: L-PPPD had the typical advantages of minimally invasive abdominal procedures, such as less pain, shorter hospital stay, and quicker recovery. It is technically safe and feasible, and has favorable oncologic outcomes in comparison with O-PPPD in patients with periampullary tumors. © 2015 by Lippincott Williams & Wilkins.

Kim S.H.,University of Ulsan
IET Control Theory and Applications | Year: 2013

This study is devoted to controlling a class of non-linear systems in the presence of packet transmission delays, packet losses and sampling-related phenomena over a communication network. To increase the applicability of the Takagi-Sugeno (T-S) fuzzy approach for non-linear networked control systems, this study sets the premise variables in T-S fuzzy plant and control to be asynchronous and then introduces a useful relaxation technique in a better position to handle the asynchronous problem. Moreover, this study provides a method capable of exploiting fully the induced delay term d(t) from the derivation of robust stabilisation condition. © 2013 The Institution of Engineering and Technology.

Transparent and conductive ZnO/CuSn/ZnO (ZCSZ) multilayer films were deposited on glass substrates by magnetron sputtering without intentional substrate heating. The thicknesses of CuSn layer was varied from 5 to 20 nm. In the XRD patterns, ZCSZ films with a 5 nm thick CuSn layer had a ZnO (0 0 2) peak, while the 20 nm thick CuSn intermediate films had ZnO (0 0 2) and CuSn (6 6 0) peaks. As the CuSn thickness increased, the sheet resistance decreased from 44 to 16 Ω/□ and the optical transmittance deteriorated due to increased optical absorption. The ZCSZ films with the 5 nm thick CuSn interlayer had the best figure of merit of 4.5 × 10 -3 Ω -1. The work function of the films with a 5 nm thick CuSn interlayer was 4.55 eV. These results indicate that the film with a 5 nm thick CuSn interlayer is an alternative candidate for use as a transparent electrode in OLEDs and various displays. © 2010 Elsevier B.V. All rights reserved.

Choi B.M.,University of Ulsan
Korean Journal of Anesthesiology | Year: 2016

Fentanyl is the most commonly used opioid analgesic in intravenous patient-controlled analgesia (IV PCA) in Korea. IV oxycodone was approved for postoperative IV PCA by the Ministry of Food and Drug Safety of Korea in 2013. The approved dosage regimen for postoperative pain relief with IV oxycodone is IV bolus loading of 2 mg followed by PCA composed of demand boluses of 1 mg and no background infusion with an oxycodone concentration of 1 mg/ml. However, a simulation study indicated that the minimum effective analgesic concentration (MEAC, as indicated by relief of pain by administering rescue analgesics) of oxycodone was reached most quickly with a higher loading dose of 0.1 mg/kg and IV PCA with background infusion. Oxycodone is a therapeutic option as an analgesic for postoperative pain management. It is necessary to reduce the analgesic dose of oxycodone in elderly patients because metabolic clearance decreases with age. © The Korean Society of Anesthesiologists, 2016.

Park H.,Kangwon National University | Kim C.-S.,University of Ulsan
Korean Journal of Urology | Year: 2015

Purpose: To carry out long-term follow-up of patients diagnosed with asymptomatic simple renal cysts (SRCs). Materials and Methods: One hundred fifty-eight adult patients in whom SRCs were incidentally diagnosed by abdominal ultrasonography or abdominopelvic computed tomography between August 1994 and June 2004 were followed up for over 10 years. The retrospective analysis investigated sequential changes in the size, shape, and Bosniak classification of the renal cyst and analyzed risk factors for increased size and growth rate of the cysts. Results: The median follow-up period was 13.9 years (range, 10.0–19.8 years). Median patient age was 54.1 years (range, 22–86 years). Mean maximal cyst size was 33 mm (range, 2–90 mm). Among all patients, 120 (76%) showed a mean increase in maximum renal cyst diameter of 1.4 mm (6.4%) per year. Age at initial diagnosis was a risk factor for increased renal cyst maximum diameter. The probability of an increase in maximum diameter of an SRC was 7.1 times greater in patients aged 50 years or older at diagnosis than in those aged less than 50 years. However, among patients with an increased maximum diameter, the mean growth rate was lower in patients aged ≥50 years than in those aged <50 years. Conclusions: About three-quarters of adult patients with accidentally diagnosed SRCs presented with an increased maximum diameter. The only risk factor for an increase in maximum diameter was age. In patients with an increase in the maximum diameter, the growth rate of the maximum diameter was 6.4% per year during 10 years and decreased with age. © The Korean Urological Association, 2015.

Kim I.K.,University of Ulsan
Free radical research | Year: 2013

Oxidative stress triggered by amyloid beta (Aβ) accumulation contributes substantially to the pathogenesis of Alzheimer's disease (AD). In the present study, we examined the involvement of the antioxidant activity of peroxiredoxin 6 (Prdx 6) in protecting against Aβ25-35-induced neurotoxicity in rat PC12 cells. Treatment of PC12 cells with Aβ25-35 resulted in a dose- and time-dependent cytotoxicity that was associated with increased accumulation of intracellular reactive oxygen species (ROS) and mitochondria-mediated apoptotic cell death, including activation of Caspase 3 and 9, inactivation of poly ADP-ribosyl polymerse (PARP), and dysregulation of Bcl-2 and Bax. This apoptotic signaling machinery was markedly attenuated in PC12 cells that overexpress wild-type Prdx 6, but not in cells that overexpress the C47S catalytic mutant of Prdx 6. This indicates that the peroxidase activity of Prdx 6 protects PC12 cells from Aβ25-35-induced neurotoxicity. The neuroprotective role of the antioxidant Prdx 6 suggests its therapeutic and/or prophylactic potential to slow the progression of AD and limit the extent of neuronal cell death caused by AD.

Kim S.H.,University of Ulsan
IET Control Theory and Applications | Year: 2013

This study establishes a multi-stage control strategy that can systematically reduce the effect of quantisation errors without resort to any prescribed control gains applicable to the stabilisation of quantisation-free systems. First of all, a twostage control strategy is built under a fixed quantisation sensitivity, and then a multi-stage control strategy is established on the possibility of adjusting on-line the quantisation sensitivity. In the derivation, the overall control law is constructed with linear and non-linear feedback controls, where non-linear feedback control plays an important role of eliminating the effect of control input quantisation errors. © The Institution of Engineering and Technology 2013.

Based on the fuzzy weighting-dependent Lyapunov function, this paper proposes a method to drive the relaxed stabilization condition for continuous-time Takagi-Sugeno (T-S) fuzzy control systems without resorting to elimination and bounding techniques. Here, to achieve an improved robust H performance while enhancing the interactions among the fuzzy subsystems, this paper proposes a valuable relaxation technique that is capable of incorporating the derivatives of fuzzy weighting functions to the relaxation process. Finally, three examples are given to verify the effectiveness of the proposed method. © 1993-2012 IEEE.

Lim O.T.,University of Ulsan | Iida N.,Keio University
Experimental Thermal and Fluid Science | Year: 2012

The HCCI combustion mode poses its own set of narrow engine operating by knocking. In order to solve this, inhomogeneity method of mixture and temperature is suggested. The purpose of this research is to get fundamental knowledge about the effect of thermal stratification on HCCI combustion of DME/. n-Butane-air mixture. The temperature stratification is made by buoyancy effect in combustion chamber of RCM. The analysis items are pressure, temperature of in-cylinder gas and combustion duration. In addition, the structure of flames using the two dimensional chemiluminescence's images by a framing camera are analyzed. Under stratification, the LTR starting time and the HTR starting time are advanced than that of homogeneous. Further, the LTR period of homogeneous conditions became shorter than that of the stratified conditions. With the case of homogeneous condition, the luminosity duration becomes shorter than the case of stratified condition. Additionally, under stratified condition, the brightest luminosity intensity is delayed longer than at homogeneous condition. © 2012.

Suhas D.P.,Poornaprajna Institute of Scientific Research | Raghu A.V.,Poornaprajna Institute of Scientific Research | Jeong H.M.,University of Ulsan | Aminabhavi T.M.,Poornaprajna Institute of Scientific Research
RSC Advances | Year: 2013

Graphene-loaded sodium alginate (NaAlg) nanocomposite membranes have been prepared to enhance the pervaporation (PV) dehydration of isopropanol. The effect of graphene loading on the physico-chemical properties, micro-morphology and barrier performance of the derived nanocomposite membranes was investigated as a function of temperature and feed water composition of the isopropanol mixture. The interaction of graphene with the NaAlg matrix as well as water and isopropanol seems to influence the thermal, kinetic and Arrhenius activation energy parameters. At the lowest concentration of graphene, the membrane performance was optimum with a permeance value of 3122 GPU and a selectivity of 4623 for a 10 wt.% water containing feed mixture at 30 °C. Flory-Huggins theory could explain the polymer-solvent interaction as well as equilibrium swelling; both of these affected the membrane performance. © 2013 The Royal Society of Chemistry.

Shin J.H.,University of Ulsan | Park J.H.,Hanyang University
ISIJ International | Year: 2013

The distribution ratio of phosphorous between the CaO-CaF2 (-SiO2) flux and SiMn alloy melts at 1 823 K was measured under strongly reducing atmosphere. Furthermore, thermodynamic and kinetics analyses were carried out for the environmental stability of reducing refining slags containing Ca3P2 under wet cooling conditions from the effect of slag composition on the evolution of PH3 (phosphine) gas. The distribution ratio of phosphorous between the CaO-CaF2 (-SiO 2) flux and SiMn metal phases increased with increasing CaO concentration in the flux, followed by a constant value. The composition for the saturating distribution ratio of phosphorous was in good accordance to the saturation content of CaO in the CaO-CaF2 flux at 1 823 K. When the Vee ratio (= CaO/SiO2) of the dephosphorization slag was greater than about 1.35, the lime and dicalcium silicate phases precipitated during solidification, resulting in an increase in the evolution rate of PH3 gas under wet and dry conditions due to an increase in the reaction area. However, when the Vee ratio of the slag was lower than about 1.35, fluorite, cuspidine, and wollastonite phases precipitated from the phase diagram, resulting in less amount of PH3 evolution during cooling because the reaction between Ca3P2 and H2O was restricted to the surface of bulk slag. © 2013 ISIJ.

Cho W.,University of Ulsan
Knee Joint Arthroplasty | Year: 2014

This book presents up-to-date knowledge on all aspects of total knee joint arthroplasty (TKA). It opens by considering indications for TKA and implant selection, covering basic science, design, and prosthetic materials. The basic and advanced operative procedures, along with theoretical background, are then described in detail for both primary and revision surgery. The operative techniques for TKA in specific and complex conditions are included. Complications of TKA and their treatment are also discussed, and clear guidance is provided on postoperative management and patient education. The author introduces his personal surgical tips and opinions on controversial issues based on his experience of TKA in some 6,000 cases. Numerous helpful illustrations and radiographs from the author’s caseload are presented to assist readers in carrying out the described procedures. © Springer-Verlag Berlin Heidelberg 2014.

Yoo D.J.,University of Ulsan
The Korean journal of hepatology | Year: 2010

Hepatocellular carcinoma (HCC) is a major health problem worldwide, and it has a poor prognosis. Extrahepatic metastasis from HCC is not unusual, with direct invasion representing the main spreading mode. Sites that are frequently involved are the lung, bone, and lymph nodes. There are few reports of HCC invading the distant gastrointestinal tract, especially hematogenously. Herein we report a case of sigmoid colon metastasis from HCC. The patient was diagnosed with HCC and treated with transcatheter arterial chemoembolization (TACE). Eighteen months after TACE the patient presented with abdominal pain on the left lower quadrant, and a CT scan showed an enhanced mass on the sigmoid colon. Immunohistochemical staining revealed that a tumor cell was positive for polyclonal carcinoembryonic antigen and weakly positive for hepatocyte antigen, supporting the diagnosis of HCC metastasis. The patient underwent anterior resection for the metastatic HCC.

Hong G.S.,University of Ulsan
The international journal of cardiovascular imaging | Year: 2012

To investigate the prevalence of ligamentum arteriosum calcification (LAC) on multi-section spiral CT and digital radiography. Five hundred and eight children and 232 adults who performed multi-section chest CT were included in this study and were divided into nine age groups: A (0-5 years), B (6-10 years), C (11-15 years), D (16-20 years), E (21-30 years), F (31-40 years), G (41-50 years), H (51-60 years), and I (61-70 years). Two radiologists assessed the presence of LAC on axial and coronal CT images, defined as focal calcific density on both or on one plane with attenuation >100 Hounsfield unit. The prevalence of LAC on CT was compared between children and adults, and between unenhanced and enhanced CT in children. The prevalence of LAC on digital radiography was evaluated in 476 children. The prevalence of definite LAC on unenhanced multi-section CT was significantly higher in children (37.8 %) than in adults (11.2 %) (P < 0.001), with prevalences in groups: A through I of 35.8, 48.7, 35.1, 28.6, 25.0, 10.2, 15.5, 7.8, and 5.6 %, respectively. The prevalences of indeterminate LAC in age groups A-I on unenhanced multi-section CT were 4.5, 12.8, 8.1, 19.0, 0.0, 0.0, 0.0, 2.0, and 1.9 %. In children, the prevalence of LAC was significantly higher on unenhanced than on enhanced CT (37.8 vs. 16.4 %, P < 0.001). The prevalence of LAC on digital radiography was 3.6 % in children. LAC is frequently observed in children and adults on multi-section spiral CT, more frequently than previously reported. Compared with that on multi-section spiral CT, the prevalence of LAC on digital radiography is substantially low.

The Barcelona Clinic Liver Cancer (BCLC) staging system is logical for the staging and treatment of hepatocellular carcinoma (HCC) because it was based on survival data. This study evaluated the applicability of the BCLC staging system and reasons for divergence from BCLC-recommended treatments in Korean HCC patients. One hundred and sixty consecutive HCC patients were prospectively enrolled. Treatments were generally recommended according to the guideline of the American Association for the Study of Liver Diseases, but patients were also informed about alternative treatments. The final decision was made with patient agreement, and was based on the doctor's preferences when a patient was unable to reach a decision. There were 2 (1%), 101 (64%), 20 (12.5%), 34 (21.5%), and 3 (1%) patients with very early-, early-, intermediate-, advanced-, and terminal-stage disease, respectively. Only 64 patients (40%) were treated according to BCLC recommendations. The treatment deviated from BCLC recommendations in 68% (69/101) and 79% (27/34) of patients with early and advanced stage, respectively. The main causes of deviation were refusal to undergo surgery, the presence of an indeterminate malignancy nodule, the absence of a suitable donor, or financial problems. Donor shortage, financial problems, the relatively limited efficacy of molecular targeting agents, and the presence of an indeterminate nodule were the main causes of deviation from BCLC recommendations. Even after excluding cases in which decisions were made by patient preference, only 66% of the HCC patients were treated according to BCLC recommendations. Treatment guidelines that reflect the Korean situation are mandatory for HCC patients.

Hwang C.H.,University of Ulsan
American Journal of Physical Medicine and Rehabilitation | Year: 2016

ABSTRACT: Phenytoin induces lymphoid proliferation, resulting in complications that can range from tissue hyperplasia to lymphoma. Some of the complications resolve spontaneously after drug discontinuation. This report describes for the first time a case of dysphagia with lack of velopharyngeal coordination and nasopharyngeal reflux combined with massive palatine tonsillar hypertrophy. The condition did not develop before phenytoin administration, was induced by phenytoin, and spontaneously resolved upon drug discontinuation. The patient was referred for a video-fluoroscopic swallowing study owing to a recurring nasal reflux of foods that had developed since phenytoin administration. The video-fluoroscopic swallowing study revealed incidentally that the large bilateral elongated masses extended downward into the larynx and disturbed velar elevation. This finding was confirmed by computed tomography of the neck, which showed that palatine tonsillar hypertrophy disturbed the laryngopharynx on both sides. The symptoms (sleep apnea and nasal reflux) and the abnormal imaging findings disappeared without surgery approximately 1 month after drug discontinuation. This case suggests that dysphagia related to phenytoin-induced lymphoid hypertrophy may be treated by phenytoin discontinuation followed by a sufficient amount of time to allow symptom resolution rather than by prompt surgery. Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.

Roh M.-I.,University of Ulsan | Ha S.,Seoul National University
Computers in Industry | Year: 2013

Advanced ship evacuation analysis is one of stochastic methods in which the total evacuation time is calculated via computer-based simulations, by considering each passenger's characteristics (e.g., age, gender, etc.) and the detailed layout of the ship. In this study, simulations for advanced evacuation analysis using a cell-based simulation model are performed. The cell-based simulation model divides the space in a uniform grid, "cell". Each passenger in the ship is located in a cell and moves to another cell according to a set of local rules that are supposed to be associated with the individual, crowd, and counterflow-avoiding behavior of the passengers. These behavior patterns are implemented as the local rules and are assigned to each cell. Each cell was implemented using a combined discrete event and a discrete time simulation model that represents different variables of the local rules. To verify the applicability of the advanced ship evacuation analysis, it was applied to 11 tests specified in the IMO/MSC/Circ. 1238, and the result shows that all the requirements of such tests had been met. Finally, the analysis was applied to a car ferry having 2487 persons. © 2012 Elsevier B.V.

Cho S.K.,Mount Sinai School of Medicine | Lu Y.,Mount Sinai School of Medicine | Lee D.-H.,Mount Sinai Medical Center | Lee D.-H.,University of Ulsan
Bone and Joint Journal | Year: 2013

Dysphagia is a common complication of anterior surgery of the cervical spine. The incidence of post-operative dysphagia may be as high as 71% within the first two weeks after surgery, but gradually decreases during the following months. However, 12% to 14% of patients may have some persistent dysphagia one year after the procedure. It has been shown that female gender, advanced age, multilevel surgery, longer operating time and severe pre-operative neck pain may be risk factors. Although the aetiology remains unclear and is probably multifactorial, proposed causes include oesophageal retraction, prominence of the cervical plate and prevertebral swelling. Recently, pre-operative tracheal traction exercises and the use of retropharyngeal steroids have been proposed as methods of reducing post-operative dysphagia. We performed a systematic review to assess the incidence, aetiology, risk factors, methods of assessment and management of dysphagia following anterior cervical spinal surgery. itorial Society of Bone & Joint Surgery.

Kim S.-Y.,University of Ulsan | Park S.-P.,Kyungpook National University
Journal of Clinical Neuroscience | Year: 2014

Population-based studies have reported an increased risk of suicidal ideation in patients with migraine. However, there is some controversy as to whether migraine itself is a risk factor for suicidal ideation after adjusting for psychiatric comorbidities. We calculated the frequency of suicidal ideation among patients with migraine visiting a tertiary care hospital and determined its risk factors. Patients with migraine and healthy controls completed self-report questionnaires to assess depression, anxiety, and suicidal ideation, and the frequency of suicidal ideation. Risk factors for suicidal ideation were investigated in terms of demographic, clinical, and psychiatric variables. One hundred eighty-five patients with migraine (156 females and 29 males; mean age 39.1 years) and 53 age and education-matched healthy controls participated in the study. The frequency of suicidal ideation was significantly greater in patients with migraine than healthy controls (odds ratio [OR] = 5.09, 95% confidence interval [CI] 1.17-22.10, p = 0.003), but this significance was not sustained after adjusting for comorbid depression and anxiety. The risk of suicidal ideation in patients with migraine was associated with lower education levels, higher frequency of migraine attacks, stronger intensity of headaches, and presence of phonophobia, chronic migraine, depression, and anxiety. The strongest predictor was depression (OR = 15.36, 95% CI 5.39-43.78, p < 0.001), followed by the intensity of headache while completing the questionnaire (OR = 1.293, 95% CI 1.077-1.553; p = 0.006). The contribution of migraine-specific variables to suicidal ideation is trivial compared to that of depression and headache intensity. © 2014 Elsevier Ltd. All rights reserved.

Choi S.,University of Ulsan
Journal of Institute of Control, Robotics and Systems | Year: 2013

By performing interval analysis on the system transfer function, we propose an improved method of control loop design for a DC/DC converter. In conventional design methods, the effect of system parameter change due to the specified range of operating conditions and production tolerances in power components should be checked a posteriori, because this may result in a transfer function shift and performance degradation. In the proposed method, a possible parameter change is considered a priori in the design step in order that the desired crossover frequency and sufficient phase margin can be achieved even in the worst case condition. As an illustrative example, a buck dc/dc converter is designed by two different methods and performance comparisons are performed to verify the feasibility of the proposed scheme. © ICROS 2013.

Park S.K.,University of Ulsan
Sensors (Basel, Switzerland) | Year: 2010

In pedestrian navigation systems, the position of a pedestrian is computed using an inertial navigation algorithm. In the algorithm, the zero velocity updating plays an important role, where zero velocity intervals are detected and the velocity error is reset. To use the zero velocity updating, it is necessary to detect zero velocity intervals reliably. A new zero detection algorithm is proposed in the paper, where only one gyroscope value is used. A Markov model is constructed using segmentation of gyroscope outputs instead of using gyroscope outputs directly, which makes the zero velocity detection more reliable.

Nam J.-H.,University of Ulsan
Current Opinion in Obstetrics and Gynecology | Year: 2010

Purpose of review Borderline ovarian tumors (BOTs) are a distinct diagnostic category of epithelial ovarian tumors, distinguished from both benign and invasive epithelial ovarian tumors. Because they affect young women of childbearing age, are diagnosed at an early stage, and are associated with excellent prognosis, fertility-sparing options are often used. In this review, we discuss recent findings on the outcomes of fertility-sparing treatments in patients with BOTs. Recent findings Reports on the use of fertility-sparing surgery in patients with advanced-stage BOTs and on the application of laparoscopy in fertility-sparing surgery are increasing. As potential alternative, experiences on ovarian tissue cryopreservation have been reported. Summary Fertility-sparing surgery is the best option to preserve childbearing capacity in young patients with BOTs. Fertility-sparing surgery is well tolerated not only in patients with early-stage BOTs but also in patients with advanced-stage BOTs with noninvasive extraovarian implants, if these implants can be resected completely. After fertility-sparing surgery, pregnancy outcomes are promising and most pregnancies are achieved spontaneously. There are few complications associated with pregnancy, and subsequent pregnancy seems to have little impact on disease course. Fertility drugs are well tolerated in patients with infertility after fertility-sparing surgery for early-stage BOTs, but caution should be exercised when using these drugs after surgery in patients with advanced-stage BOTs. If fertility-sparing surgery is technically not feasible owing to extensive tumor involvement of both ovaries, recent artificial reproductive technologies can be considered, including embryo, oocyte, and ovarian tissue freezing; use of donor oocytes; and surrogacy, but more experience with these options is required. © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins.

The real-time tracking of rotational motions of biological molecules in live cells is of great importance for fundamental and mechanistic studies in biological systems. Recently, plasmonic anisotropic gold nanorods (AuNRs) have attracted a great deal of attention as optical orientation probes in live-cell imaging due to their unique size- and shape-induced optical properties, photostability, large scattering and absorption cross-sections, biocompatibility, and easy surface modi-fication. Furthermore, single particle rotational tracking techniques have seen rapid development in the past 10 years. In this article, we provide a brief introduction to various far-field optical imaging and spectroscopic techniques that can be used for visualizing plasmonic Au nanoparticles. We further discuss recent developments of single particle rotational tracking techniques in combination with the AuNR probes under far-field optical microscopy. © 2016 Taylor & Francis Group, LLC.

Shin H.,University of Ulsan
Proceedings of the International Offshore and Polar Engineering Conference | Year: 2011

A large number of offshore wind farms with fixed foundations have been installed in Europe with relatively state-of-the-art techniques. However the installation of floating wind farms in deeper water is encouraged by the stronger and steadier winds, the lower visibility, the absence of ship lanes restrictions and the economic potential. Compared to a fixed foundation, a floating offshore wind turbine (FOWT) may sustain more complicated environmental conditions including stochastic winds and waves. One of the FOWT concepts was designed and analyzed. It consists of a three bladed 5-MW up wind turbine, which is the basic model under the IEA Annex 23 Subtask 2 Offshore Code Comparison Collaboration (OC3) project, and supported by an OC3-Hywind spar buoy platform. The platform is connected by three mooring lines to the sea bed. To study motion characteristics of the OC3-Hywind platform, a model was built with a 1/128 scale ratio. The model test was carried out in various sea states, including rotating rotor effect with wind in the Ocean Engineering Wide Tank of the University Of Ulsan (UOU). The characteristic motions of the OC3-Hywind platform were captured and the RAO and significant motion were obtained. Copyright © 2011 by the International Society of Offshore and Polar Engineers (ISOPE).

Yu J.J.,University of Ulsan
Korean Journal of Pediatrics | Year: 2012

Several authors suggested that the clinical characteristics of incomplete presentation of Kawasaki disease are similar to those of complete presentation and that the 2 forms of presentation are not separate entities. Based on this suggestion, a diagnosis of incomplete Kawasaki disease in analogy to the findings of complete presentation is reasonable. Currently, the diagnosis of incomplete Kawasaki disease might be made in cases with fewer classical diagnostic criteria and with several compatible clinical, laboratory or echocardiographic findings on the exclusion of other febrile illness. Definition of incomplete presentation in which coronary artery abnormalities are included as a necessary condition, is restrictive and specific. The validity of the diagnostic criteria of incomplete presentation by the American Heart Association should be thoroughly tested in the immediate future. © 2012 by The Korean Pediatric Society.

Goo H.W.,University of Ulsan
Pediatric Radiology | Year: 2010

Initial experience of dual-source dual-energy (DE) lung perfusion CT in children is described. In addition to traditional identification of pulmonary emboli, the assessment of lung perfusion is technically feasible with dual-source DE CT in children with acceptable radiation dose. This article describes how to perform dual-source DE lung perfusion CT in children, including the optimization of intravenous injection method and CT dose parameters. How to produce weighted-average CT images for the assessment of pulmonary emboli and colour-coded perfusion maps for the assessment of regional lung perfusion is also detailed. Lung perfusion status can then be evaluated on perfusion maps by means of either qualitative or quantitative analysis. Potential advantages and disadvantages of this emerging CT technique compared to lung perfusion scintigraphy and cardiac MRI are discussed. © 2010 Springer-Verlag.

ABSTRACT: The aim of this study was to determine the strongest suture technique that retains the most muscle thickness to obtain functional outcome for Sprague–Dawley rat rectus abdominis muscle repair. We exposed the paired rectus abdominis muscle of 32 Sprague–Dawley rats on both sides (n = 64) and cut transversely. Immediate closure of the muscle was performed using one of 4 different suture methods (group A: interrupted suture, group B: horizontal mattress suture, group C: vertical mattress suture, group D: overlapping suture). After 8 weeks, the sutured muscle was dissected and cut for evaluation of tensile strength and muscle thickness. Histologic findings were evaluated using automatic quantitative component image analysis software (i-Solution) and immunohistochemical staining using CD31. P values were based on the Mann–Whitney test and Bonferroni correction. Group A showed the strongest tensile strength (P < 0.001). This group also demonstrated the greatest muscle thickness in comparison to the other groups. Differences between group A and the other groups were statistically significant (P < 0.001). Group A showed the highest ratio of muscle fibers and demonstrated the highest expression of CD31 (P < 0.05). The interrupted suture method used for muscle closure shows the greatest tensile strength and muscle thickness and is therefore a good option for suturing skeletal muscle. This finding has clinical applicability for suturing in the repair of skeletal muscle, especially for congenitally dehisced muscle repair. Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.

Na J.H.,University of Ulsan
Korean journal of ophthalmology : KJO | Year: 2010

To characterize the features of peripapillary atrophy (PPA), as imaged by spectral-domain optical coherence tomography (SD-OCT). SD-OCT imaging of the optic disc was performed on healthy eyes, eyes suspected of having glaucoma, and eyes diagnosed with glaucoma. From the peripheral β-zone, the retinal nerve fiber layer (RNFL), the junction of the inner and outer segments (IS/OS) of the photoreceptor layer, and the Bruch's membrane/retinal pigment epithelium complex layer (BRL) were visualized. Nineteen consecutive eyes of 10 subjects were imaged. The RNFL was observed in the PPA β-zone of all eyes, and no eye showed an IS/OS complex in the β-zone. The BRL was absent in the β-zone of two eyes. The BRL was incomplete or showed posterior bowing in the β-zone of five eyes. The common findings in the PPA β-zone were that the RNFL was present, but the photoreceptor layer was absent. Presence of the BRL was variable in the β-zone areas.

Youm Y.S.,University of Ulsan
Clinics in orthopedic surgery | Year: 2010

Osteonecrosis of the femoral head is classified into idiopathic and secondary forms. A number of etiological factors in the development of osteonecrosis have been suggested but the biological mechanisms are still unclear. Recently, some reports suggested that the apoptosis is closely related to osteonecrosis of the femoral head. Therefore, this study examined the expression of apoptosis in osteonecrosis of the femoral head. Of the patients diagnosed preoperatively with osteonecrosis and underwent total hip replacement arthroplasty between August 2004 and July 2005, 58 patients (58 hips) were available for this study. Their diagnoses were confirmed by the postoperative pathology findings. Tissue samples of the femoral head sections were terminal deoxynucleotydyl transferase mediated dUTP nick-end labeling (TUNEL) stained using an in situ cell death detection POD kit. The number of total and TUNEL-positive osteocytes, and the average ratio of TUNEL-positive cells were calculated and analyzed according to the cause. Osteonecrosis was steroid-induced in 8 cases (13.8%), alcohol-induced in 29 cases (50%), post-traumatic in 6 cases (10.3%) and idiopathic in 15 cases (25.9%). The percentage of TUNEL-positive osteocytes was high in patients with steroid- and alcohol-induced osteonecrosis of the femoral head but low in patients with post-traumatic and idiopathic osteonecrosis. The difference in the percentage of TUNEL-positive osteocytes between these groups was significant (p < 0.05). Apoptosis might play an important role in the pathogenesis of osteonecrosis of the femoral head induced by steroid and alcohol. These findings highlight a need for further research into the role of apoptosis in the development of osteonecrosis of the femoral head.

Park S.W.,University of Ulsan
Annals of Plastic Surgery | Year: 2016

BACKGROUND: Persistent velopharyngeal insufficiency occurrence after double-opposing Z-plasty has been treated with either posterior pharyngeal flap or sphincteroplasty. Both these methods can be accompanied by mild discomfort, such as mouth breathing and hyponasal resonance, and can lead to severe complications, such as sleep apnea and upper airway compromise. The purpose of this study was to review the efficacy of repeat double-opposing Z-plasty for the management of persistent velopharyngeal insufficiency in patients who received a prior surgical intervention by double-opposing Z-plasty. METHODS: All patients who were treated by repeat double-opposing Z-plasty between January 2000 and December 2014 were reviewed. Patient demographics, cleft type, surgical technique, and complications, such as wound dehiscence, infection, fistula, and upper airway obstruction, were evaluated. Preoperative and postoperative speech evaluations were reviewed for comparison. RESULTS: Fourteen patients underwent repeat double-opposing Z-plasty, with an average follow-up of 34 months. There was no complication including wound dehiscence, flap necrosis, fistula, or upper airway compromise. Velopharyngeal competence (resonance, nasal emission, intraoral pressure, social/personal problems) was significantly improved postoperatively (P < 0.05). Only 1 patient required posterior pharyngeal flap for persistent velopharyngeal insufficiency. CONCLUSIONS: Repeat double-opposing Z-plasty is an effective and safe surgical strategy for the management of persistent velopharyngeal insufficiency, in patients who received a prior surgical intervention by double-opposing Z-plasty. This strategy allows speech improvement and reduces the risk of postoperative upper airway compromise. Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.

Kim C.-H.,University of Ulsan
Minerva Ginecologica | Year: 2013

The desired objective of controlled ovarian stimulation (COS) is to allow the growth of a cohort of follicles and to facilitate the recovery of a large number of fertilizable oocytes. However, poor responders with diminished ovarian reserve often fail to respond adequately despite the maximal dose of gonadotropins administered, with the results that the number as well as quality of oocytes harvested may be very low, thereby decreasing the pregnancy rate in IVF cycles. Therefore, successful COS for poor responders remains to be a major challenge in IVF program. One of promising strategies for augmenting follicular recruitment in poor responders is androgen supplementation. However, there are limited data on androgen treatment for poor responders undergoing IVF. Therefore, well-designed larger studies with standardized methods are required.

Jeon M.J.,University of Ulsan
European journal of endocrinology / European Federation of Endocrine Societies | Year: 2013

The presence of central neck lymph node (LN) metastases (defined as pN1a according to Tumor Node Metastasis classification) in papillary thyroid cancer (PTC) is known as an independent risk factor for recurrence. Extent of LN metastasis and the completeness of removal of metastatic LN must have an impact on prognosis but they are not easy to measure. Moreover, the significance of the size of metastatic tumors in LNs has not been clarified. This study was to evaluate the impact of the extent of LN metastasis and size of metastatic tumors on the recurrence in pathological N1a PTC. This retrospective observational cohort study enrolled 292 PTC patients who underwent total thyroidectomy with central neck dissection from 1999 to 2005. LN ratio was defined as the number of metastatic LNs divided by the number of removed LNs, which was regarded as variable reflecting both extent of LN metastasis and completeness of resection, and LN size as the maximal diameter of tumor in metastatic LN. The significant risk factors for recurrence in univariate analysis were large primary tumor size (defined as larger than 2 cm), high LN ratio (defined as higher than 0.4), and presence of macrometastasis (defined as larger than 0.2 cm). Age, sex, clinical node status, and microscopic perithyroidal extension had no effect on recurrence. In multivariate analysis, high LN ratio and presence of macrometastasis were independent risk factors for recurrence. LN ratio and size of metastatic nodes had a significant prognostic value in pathological N1a PTC. We suggest that risk stratification of pathological N1a PTC according to the pattern of LN metastasis such as LN ratio and size would give valuable information to clinicians.

Lee S.W.,University of Ulsan
Catheterization and cardiovascular interventions : official journal of the Society for Cardiac Angiography & Interventions | Year: 2011

The aims of this study were to investigate the long-term clinical outcomes of patients with successful versus unsuccessful revascularization with drug-eluting stents (DES) for chronic total occlusion (CTO). The benefits of successful revascularization of CTO remain unclear. Consecutive patients (n = 333) with "true" CTO, defined as Thrombolysis In Myocardial Infarction (TIMI) flow grade 0 on angiography and duration ≥3 months, were divided into two groups, those with successful (CTO success group, n = 251) and unsuccessful (CTO failure group, n = 82) revascularization with DES for CTO lesions. The primary endpoint was defined as major adverse cardiac events (MACE) the composite of death, Q-wave myocardial infarction (MI), or target vessel revascularization (TVR). The CTO success group was significantly younger, with a higher involvement of LAD, and lower incidences of renal failure, previous myocardial infarction, and previous coronary intervention than the CTO failure group. After a median follow up of 1,317 days (interquartile range, 1,059-1,590 days), there were no significant between-group differences in rate of MACE, both after crude analysis (9.4% vs. 11.8%, log-rank P = 0.16) and after adjustment (HR 1.17; 95% CI 0.47-2.88, P = 0.53). On multivariate analysis, major predictors of MACE were left ventricle ejection fraction (LVEF) <40% (HR 3.14; 95% CI 1.39-7.09, P = 0.005) and multiple CTO (HR 2.38; 95% CI 1.01-5.71, P = 0.049). Long-term clinical outcomes were similar in the CTO success and failure groups. Multiple CTOs and LVEF <40% in CTO patients were independent predictors of MACE. Copyright © 2011 Wiley-Liss, Inc.

Lee B.-S.,Incheon Catholic University | Kim J.-M.,Kosin University | Kim K.-A.,Chungbuk National University | Bin S.-I.,University of Ulsan
Arthroscopy : the journal of arthroscopic & related surgery : official publication of the Arthroscopy Association of North America and the International Arthroscopy Association | Year: 2015

RESULTS: The mean lateral subluxation in the coronal plane was 2.6 ± 1.6 mm. Among our patients, 23 transplants (32.4%) showed extrusion. The intraoperative cartilage status of the femoral condyle and tibial plateau showed significant differences between the nonextruded (≤3 mm) and extruded (>3 mm) groups (P = .010 and P = .001, respectively). There were no differences in other factors between these 2 groups. Binary logistic regression analysis showed that tibial-side cartilage wear of International Cartilage Repair Society grade 3 or more was a significant risk factor for meniscal extrusion.PURPOSE: The objective of this study was to identify the patient-related risk factors for lateral meniscal extrusion after lateral meniscal allograft transplantation (MAT) regarding demographic characteristics, alignment, and pre-existing arthrosis.METHODS: Seventy-one patients who underwent arthroscopic lateral MAT with bone bridge fixation between 2008 and 2011 were assessed. Lateral meniscal subluxation was measured on mid-coronal sections of magnetic resonance images 1 year postoperatively. Subluxation of more than 3 mm was considered to be extrusion. Age, gender, body mass index, time from previous meniscectomy, mechanical axis deviation, Kellgren-Lawrence grade on preoperative radiographs, and intraoperative International Cartilage Repair Society grade were assessed as possible patient-related factors.CONCLUSIONS: Lateral meniscal extrusion 1 year after lateral MAT is affected by the degree of intraoperative cartilage wear, most notably on the tibial side. Patient demographic characteristics, alignment, and radiographic arthritic changes did not differ between nonextruded and extruded MAT cases.LEVEL OF EVIDENCE: Level IV, therapeutic case series. Copyright © 2015 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Factor X (FX) deficiency is a rare, autosomal-recessive coagulation disorder. Diagnosis can be confirmed by a factor X assay. Although fresh frozen plasma and prothrombin complex concentrates have been used as a temporary treatment of bleeding symptoms and preparation for surgery, frequent transfusion has its risk and prothrombin complex is not available in Korea. We report the first pediatric case of successful liver transplantation for the correction of a severe congenital FX deficiency in a child with recurrent life-threatening hemorrhagic episodes.

Goo H.W.,University of Ulsan
Acta Radiologica | Year: 2013

Cardiac CT is increasingly utilized in children thanks to advanced scan techniques reducing cardiac and respiratory motion artifacts. Consequently, clinical indications of cardiac CT are not confined to the extracardiac evaluation and extended further to the assessment of intracardiac structures, coronary arteries, ventricular volumetry, and ventricular function. In addition, dual-energy CT allows the assessment of regional lung perfusion and ventilation. Four-dimensional airway evaluation is also useful and may be added to cardiac CT protocols. At the same time, a favorable risk-benefit ratio of cardiac CT can be achieved by means of various dose-saving techniques. Therefore, flexible scan techniques with minimal motion artifacts, low dose techniques without compromising excellent image quality, and extended clinical applications towards truly cardiac assessments constitute current trends in cardiac CT in children.

Son Y.-J.,Soonchunhyang University | Song E.K.,University of Ulsan
European Journal of Cardiovascular Nursing | Year: 2012

Background: Anxiety or depressive symptoms are known to be predictors of impaired health-related quality of life (HRQoL). However, little research has focused on the impact of Type D personality as chronic psychological distress on HRQoL in atrial fibrillation (AF) patients. Increased high-sensitivity C-reactive protein (hsCRP) is likely to be associated with anxiety or depressive symptoms, whereas the relation of hsCRP to Type D personality was unexplored, and the impact of hsCRP on HRQoL was undetermined in AF patients. Aim: To determine whether Type D personality and hsCRP are independently associated with impaired HRQoL. Methods: A cross-sectional study design was used among a total of 114 patients with chronic AF. Patients underwent measurements of serum levels of hsCRP. Type D personality, anxiety and depressive symptoms, and HRQoL were assessed by the Type D Scale, the Hospital Anxiety and Depression Scale, and the Short-Form Medical Outcomes Survey, respectively. Hierarchical linear regression was used to determine the impact of Type D personality and hsCRP on HRQoL. Results: Thirty-two percent of patients had Type D personality. Patients with Type D personality had higher hsCRP than those with non-Type D personality (1.4 ± 1.9 vs. 0.6 ± 2.2, p = 0.046). In hierarchical linear regression, Type D personality (β = - 0.28; p = 0.005) and hsCRP (β = - 0.21; p = 0.034) were independently associated with HRQoL controlling for clinical risk factors, anxiety, and depression symptoms. Conclusions: Type D personality and hsCRP are independent predictors of impaired HRQoL. Clinicians need to pay attention to patients with Type D personality and monitor serum levels of hsCRP to prevent impaired HRQoL in AF patient. © The European Society of Cardiology 2012.

Hur S.H.,University of Ulsan | Park J.-N.,Kyungil University
Asia-Pacific Journal of Chemical Engineering | Year: 2013

Graphene is considered a promising material for fuel cell vehicles because of its excellent chemical, mechanical, and electrical properties. Recent studies have revealed that using graphene or modified graphene as the catalyst support or as a metal-free catalyst results in significant improvement in the electrocatalytic activity, long term durability, and CO tolerance. This article summarizes both the recent progress of graphene-based fuel cell research and current developments in graphene fabrication processes such as mechanical exfoliation, chemical vapor deposition, and chemical exfoliation. The roles of graphene are also discussed by introducing mechanisms on the basis of theoretical calculations as well as experimental analysis. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.

Hong K.-S.,Inje University | Choi Y.J.,Asan Medical Center | Kwon S.U.,University of Ulsan
International Journal of Stroke | Year: 2015

Rationale: Patients with atrial fibrillation (AF) in the acute stage of ischemic stroke or transient ischemic attack (TIA) are at high risk of recurrent stroke, but the optimal anticoagulation strategy remains unclear due to the concern of intracranial bleeding. Novel oral anticoagulants compared to warfarin might be more safe and efficacious in patients suitable for early anticoagulation. Aims: This trial is to evaluate the feasibility of early anticoagulation with rivaroxaban in acute ischemic stroke or TIA patients with nonvalvular AF. Design: This is a randomized, open-label, blinded endpoint evaluation trial. Inclusion criteria are (1) nonvalvular AF, (2) presumed cardioembolic stroke or transient ischemic attack (TIA) confirmed by MRI within five-days from onset, and (3) mild to moderate stroke severity. We will randomize 196 patients to either rivaroxaban (10mg once daily for five-days followed by 15mg or 20mg once daily) or dose-adjusted warfarin (coadministration of aspirin 100mg per day until achieving international normalized ratio of 1·7). The study is registered in ClinicalTrials.gov (NCT02042534). © 2014 The Authors. International Journal of Stroke published by John Wiley & Sons Ltd on behalf of World Stroke Organization.

Sim J.-Y.,University of Ulsan
Korean Journal of Anesthesiology | Year: 2010

Pulmonary hypertension is a serious complication of a number of lung and heart diseases that is characterized by peripheral vascular structural remodeling and loss of vascular tone. Nitric oxide can modulate vascular injury and interrupt elevation of pulmonary vascular resistance selectively; however, it can also produce cytotoxic oxygen radicals and exert cytotoxic and antiplatelet effects. The balance between the protective and adverse effects of nitric oxide is determined by the relative amount of nitric oxide and reactive radicals. Nitric oxide has been shown to be clinically effective in the treatment of congenital heart disease, mitrial valvular disease combined with pulmonary hypertension and in orthotropic cardiac transplantation patients. Additionally, new therapeutic modalities for the treatment of pulmonary hypertension, phosphodiesterase inhibitors, natriuretic peptides and aqueous nitric oxide are also effective for treatment of elevated pulmonary vascular resistance. Copyright © Korean Society of Anesthesiologists, 2010.

Nam G.-B.,University of Ulsan
Korean Circulation Journal | Year: 2011

Regular physical activity provides a variety of health benefits, including improvement in cardiopulmonary or metabolic status, reduction of the risk of coronary artery disease or stroke, prevention of cancer, and decrease in total mortality. Exerciserelated cardiac events are occasionally reported during highly competitive sports activity or vigorous exercises. However, the risk of sudden death is extremely low during vigorous exercise, and habitual vigorous exercise actually decreases the risk of sudden death during exercise. The cause of sudden death is ischemic in older subjects (≥35 years old), while cardiomyopathies or genetic ion channel diseases are important underlying pathology in younger (<35 years old) victims. The subgroup of patients who are particularly at higher risk of exercise-related sudden death may be identified in different ways, such as pre-participation history taking, physical examination and/or supplementary cardiac evaluation. Limitations exist because current diagnostic tools are not sufficient to predict a coronary artery plaque with potential risk of disruption and/or an acute thrombotic occlusion. Proper and cost-effective methods for identification of younger subjects with cardiac structural problems or genetic ion channel diseases are still controversial. Copyright © 2011 The Korean Society of Cardiology.

Swietach P.,Oxford Genetics | Leem C.-H.,University of Ulsan | Spitzer K.W.,Nora Eccles Harrison Cardiovascular Research and Training Institute | Vaughan-Jones R.D.,Oxford Genetics
Journal of Physiology | Year: 2014

Cellular processes are exquisitely sensitive to H+ and Ca2+ ions because of powerful ionic interactions with proteins. By regulating the spatial and temporal distribution of intracellular [Ca2+] and [H+], cells such as cardiac myocytes can exercise control over their biological function. A well-established paradigm in cellular physiology is that ion concentrations are regulated by specialized, membrane-embedded transporter proteins. Many of these couple the movement of two or more ionic species per transport cycle, thereby linking ion concentrations among neighbouring compartments. Here, we compare and contrast canonical membrane transport with a novel type of Ca2+-H+ coupling within cytoplasm, which produces uphill Ca2+ transport energized by spatial H+ ion gradients, and can result in the cytoplasmic compartmentalization of Ca2+ without requiring a partitioning membrane. The mechanism, demonstrated in mammalian myocytes, relies on diffusible cytoplasmic buffers, such as carnosine, homocarnosine and ATP, to which Ca2+ and H+ ions bind in an apparently competitive manner. These buffer molecules can actively recruit Ca2+ to acidic microdomains, in exchange for the movement of H+ ions. The resulting Ca2+ microdomains thus have the potential to regulate function locally. Spatial cytoplasmic Ca2+-H+ exchange (cCHX) acts like a 'pump' without a membrane and may be operational in many cell types. © 2014 The Physiological Society.

Kim S.-W.,University of Ulsan
International Journal of Production Economics | Year: 2015

Abstract When airlines sell the same or similar seats on an air flight at different fares, the demand for any given fare class depends on the demand for the other fare classes. Demand is affected by customer buying behaviors e.g. diversion, strategic customer behavior. Diversion is denoted for situations when customers buy other fare class tickets if the originally requested fare is unavailable. Strategic customer behavior is used for situations when customers delay a purchase until some point in the future and wait in anticipation of reopening of lower fare. Customer buying behaviors have a considerable profit implication, which was ignored in many earlier studies. We develop an extension of the approach taken by Wilson et al. (2006) to multi-period, multi-fare airline seat inventory allocation decisions and heuristic models with efficient computer algorithms to reduce computation time. Our numerical results are compared with those from the expected marginal seat revenue (EMSR) approach, an exhaustive search, a simulation approach and the approach outlined by Wilson et al. (2006). © 2015 Elsevier B.V. All rights reserved.

Jung C.H.,University of Ulsan
Diabetic medicine : a journal of the British Diabetic Association | Year: 2013

Fatty liver disease, especially non-alcoholic fatty liver disease, is considered to be the hepatic manifestation of the metabolic syndrome, both closely associated with insulin resistance. Furthermore, fatty liver disease assessed by ultrasonography is known to be a predictor of the development of Type 2 diabetes mellitus. However, it remains unclear whether fatty liver disease plays a role in the pathogenesis of Type 2 diabetes independently of insulin resistance. In this study, we investigated whether fatty liver disease assessed by the fatty liver index can predict the development of Type 2 diabetes independently of systemic insulin resistance. We examined the clinical and laboratory data of 7860 subjects without diabetes who underwent general routine health evaluations at the Asan Medical Center in 2007 and had returned for follow-up examinations in 2011. Fatty liver index was calculated using an equation that considers serum triglyceride levels, γ-glutamyltransferase, waist circumference and BMI. During a 4-year period, 457 incident diabetes cases (5.8%) were identified. The odds ratios for the development of Type 2 diabetes were significantly higher in the group with a fatty liver index ≥ 60 (fatty liver index-positive) than in the group with a fatty liver index < 20 (fatty liver index-negative) after adjusting for various confounding variables including homeostasis model assessment of insulin resistance. Odds ratios were significant regardless of the insulin resistance status at baseline. Our results suggest that fatty liver index as a simple surrogate indicator of hepatic steatosis is valuable in identifying subjects at high risk for Type 2 diabetes. In addition, fatty liver disease itself contributes to the development of Type 2 diabetes independently of systemic insulin resistance. © 2012 The Authors. Diabetic Medicine © 2012 Diabetes UK.

Anderson K.G.,University of Minnesota | Mayer-Barber K.,National Institute of Allergy and Infectious Diseases | Sung H.,University of Minnesota | Sung H.,University of Ulsan | And 8 more authors.
Nature Protocols | Year: 2014

Characterization of the cellular participants in tissue immune responses is crucial to understanding infection, cancer, autoimmunity, allergy, graft rejection and other immunological processes. Previous reports indicate that leukocytes in lung vasculature fail to be completely removed by perfusion. Several studies suggest that intravascular staining may discriminate between tissue-localized and blood-borne cells in the mouse lung. Here we outline a protocol for the validation and use of intravascular staining to define innate and adaptive immune cells in mice. We demonstrate application of this protocol to leukocyte analyses in many tissues and we describe its use in the contexts of lymphocytic choriomeningitis virus and Mycobacterium tuberculosis infections or solid tumors. Intravascular staining and organ isolation usually takes 5-30 min per mouse, with additional time required for any subsequent leukocyte isolation, staining and analysis. In summary, this simple protocol should help enable interpretable analyses of tissue immune responses. © 2013 Nature America, Inc. All rights reserved.

Do K.-H.,University of Ulsan
Journal of the Korean Medical Association | Year: 2011

Low dose radiation has been defined as doses in the range under 100 mSv of low linear energy transfer (low-LET) radiation. There are two sources of ionizing radiation: natural and artificial radiation. Medical radiation exposure is the most common artificial radiation exposure. The frequency and volume of medical radiation exposure has markedly increased because of recent developments in medical technology. Radiation protection is now a concern due to the increasing use of computed tomography (CT) scans and diagnostic X-rays. This article introduced several models and hypotheses regarding the possible carcinogenic risks associated with low-LET radiation. Although opinions vary on the health effects of low level radiation exposure, current studies of medical radiation rely on exposure information collected prospectively, including cohort studies such as atomic bomb survivor studies. Although there are differences in perspective, the majority of studies have supported 'linear-no-threshold model without threshold' between low-LET radiation and the incidence of cancer risk. There is a need for further studies on medical radiation exposure including CT and positron emission tomography in order to understand the health effects of low-LET radiation, including the cancer incidence. © Korean Medical Association.

Koh Y.,University of Ulsan
Journal of Intensive Care | Year: 2014

Acute respiratory distress syndrome (ARDS) is characterized by permeability pulmonary edema and refractory hypoxemia. Recently, the new definition of ARDS has been published, and this definition suggested severity-oriented respiratory treatment by introducing three levels of severity according to PaO2/FiO2 and positive end-expiratory pressure. Lung-protective ventilation is still the key of better outcome in ARDS. Through randomized trials, short-term use of neuromuscular blockade at initial stage of mechanical ventilation, prone ventilation in severe ARDS, and extracorporeal membrane oxygenation in ARDS with influenza pneumonia showed beneficial efficacy. However, ARDS mortality still remains high. Therefore, early recognition of ARDS modified risk factors and the avoidance of aggravating factors during the patient's hospital stay can help decrease its development. In addition, efficient antifibrotic strategies in late-stage ARDS should be developed to improve the outcome. © 2014 Koh.

This study considers an air-filled heavy geomembrane tube section on a rigid horizontal foundation. All quantities are normalized to obtain similarity solutions. Integral terms of the semianalytic solutions are evaluated analytically, resulting in closed-form solutions. The closed-form solutions are expressed as simple functions of the pressure parameter. The validity of these solutions is confirmed, and some results are shown for characteristic values and shapes. © 2012 American Society of Civil Engineers.

Phan V.-T.,Nanyang Technological University | Lee H.-H.,University of Ulsan
IEEE Transactions on Industry Applications | Year: 2012

In this paper, the control of a stand-alone doubly fed induction generator (DFIG)-based wind power conversion system with unbalanced and nonlinear loads is investigated. Under these load conditions, the quality of stator voltage and current waveforms of the DFIG is strongly affected due to the negative and distorted components, reducing the performance of other normal loads connected to the DFIG. To tackle this problem, the control strategy is comprehensively developed in both rotor-side converter (RSC) and load-side converter (LSC) of the DFIG. The LSC is used as an active power filter to compensate for unbalanced and distorted stator currents whereas the RSC is developed to fully eliminate unbalanced and harmonic voltages at the point of common coupling. The proposed compensation method is based on current controllers in either the RSC or the LSC, which employ a proportional integral plus a resonant controller. These current controllers are controlled in the positive synchronous reference frame so that the rotor current and stator current are directly regulated without decomposing sequential components. Analytical issues on how to eliminate unbalanced and distorted components in the stator voltage and current are also described in this paper. To verify the effectiveness of the proposed control strategy, experimental results with 2.2-kW DFIG topology are presented and discussed in the paper. © 2006 IEEE.

Lee K.,Ulsan College | Yoo H.,University of Ulsan | Levermore G.J.,University of Manchester
Renewable Energy | Year: 2013

The measured data of global solar irradiation on a horizontal surface, the number of bright sunshine hours, and the amount of cloud cover for major cities of South Korea, during the period (1986-2005) are analyzed. Quality controls tests were carried out to eliminate spurious data and inaccurate measurements resulting from the cosine response error of the pyranometers. Accordingly, in six locations of South Korea where hourly global solar irradiation is currently measured, the hourly global solar irradiation was calculated using two Sunshine Fraction Radiation Model (SFRM) and a Cloud Cover Radiation Model (CRM), were compared and analyzed. Data for Ulsan, where hourly global solar irradiation is not currently measured, can be calculated from the data of the six other locations. The total solar irradiation on horizontal surfaces is separated into the beam and diffuses components. Empirical correlations for estimating the diffuse solar irradiation incident on horizontal surfaces have been proposed. The purpose of our work consists of predicting the solar irradiation on inclined surfaces based on horizontal measurements. To reach this goal, two studies were performed. They consisted of quantifying the accuracy of various well-known models. The first type of models calculated diffuse horizontal irradiations from global ones and the second type computed global irradiations on inclined planes from diffuse and global components on a horizontal surface. The proposed model can provide an alternative to building designers in estimating the solar irradiation on inclined surfaces where only the horizontal measurements are available. © 2013.

Intra-aneurysmal hemodynamics such as wall shear stress and complex flow structures have been implicated as one of the important factors on the growth and risk of rupture of an aneurysm. In this study, the sensitivity of intra-aneurysmal blood flow dynamics to the shear-thinning rheological model is investigated by using the idealized geometries of a basilar tip aneurysm with two representative anterior-posterior (AP) tilting angles (2° and 30°). By choice of different rheological models, time-averaged hemodynamic factors such as wall shear stress, oscillatory shear index and relative residence time exhibited only minor effects. However, highly unstable flow present in idealized aneurysm model with 2° AP tilting angle facilitated an evident change in the instantaneous local flow dynamics with a considerable increase in effective viscosity. Nevertheless, the distinct hemodynamic phenotype, which characterizes the gross intraaneurysmal flow pattern, was independent of the choice of rheological model. This result suggests that the shear thinning viscous effect is of secondary importance in the gross hemodynamics in a basilar tip aneurysm but is appreciably enhanced on the instantaneous hemodynamics with unstable complex flow structures. © 2012 The Korean Society of Mechanical Engineers and Springer-Verlag Berlin Heidelberg.

Park S.Y.,University of Ulsan
The international journal of cardiovascular imaging | Year: 2011

Migration of orthopedic wires to a solid organ or body cavity is a rare complication that can cause various symptoms and may lead to death. We report a patient with Kirschner wire (K-wire) migration from the right pelvic cavity, a previous fracture site, into the right ventricle of the heart. K-wire migration was initially detected by simple chest radiography. The origin of the foreign body was initially unclear. Cardiac CT angiography with volume-rendered imaging helped to locate the migrating K-wire in the heart; a pelvic scan showed another K-wire in the right pelvic bone.

Lee D.H.,University of Ulsan
Journal of the Korean Medical Association | Year: 2016

Multidisciplinary care service has started on August 1, 2014 after Korean health authority's decision of its approval and reimbursement. However, despite its early success, it raises some issues caused by less flexibility of the model, which might limit further expansion and development of the model or even establishment of a new model. It has only two types of 4-expert and 5 or more-expert services. It is also reimbursed only when given in outpatient clinic, and much worse, as of face-to-face service. Then, I will review the issues raised so far and try to suggest possible solutions, for example, sort of multidisciplinary consultation service for in-patient multidisciplinary care service. The issues and solutions will engender a lot of controversy, but to discuss about them might be the first step to further develop the service. In addition, I will briefly touch on expected effects of the service, including improvement of cancer care, such as shortening the time from the first visit to diagnosis and treatment or speed-up of diagnosis process, enhancement of cancer patients' satisfaction and so on, which might be helpful to guide future direction of the multidisciplinary care service. The commencement of multidisciplinary care service is an important milestone in cancer care as well as medical system of Korea. However, it is not the best and perfect one but was just chosen as one of champion models. It has much room for improvement or there is still more work to be done to make it better. © Korean Medical Association.

An exchange living donor program for liver transplantation, similar to the exchange living donor kidney program, was proposed to avoid ABO-incompatible adult living donor liver transplantation (LDLT). The objective of this study was to present updated changes in exchange adult LDLT program at our institution. Between January 2003 and December 2011, approximately 2,182 adult LDLT cases were included in this study. During this period, 26 paired-exchange donor LDLT cases were performed (1.2%). Of the 26 paired-exchange donor LDLT cases, 22 pairs were matched due to ABO-incompatibility, and 4 pairs were matched because of cascade allocation of unrelated donors or relatively small graft volume to the recipients. A total of 28 living donors were included in the 26 paired-exchange donor LDLT cases because of inclusion of two dual-graft transplants. Elective surgery was performed in 22 cases, and urgent operation was performed in 4 cases. The overall 1-year and 5-year patient and graft survivals were both 96.2% and 90.1%, respectively. Our experience suggests that the paired-exchange donor program for adult LDLT seems to be a feasible modality to overcome donor ABO incompatibility. Reasonably acceptable indications for donor exchange LDLT will be proposed in near future.

Jung D.H.,Pusan National University | Jeong H.M.,University of Ulsan | Kim B.K.,Pusan National University
Journal of Materials Chemistry | Year: 2010

Vinyltrimethoxysilane (VTMS)-modified silica particles were incorporated into the chain of amorphous polyurethane (PU) by covalent bonds, to synthesize an organic-inorganic hybrid material with an extremely long relaxation time. At 1% silica, the PU-silica chemical hybrids gave over 99% shape fixity and shape recovery with <2% hysteresis during the four thermomechanical cycles. As silica content increases (2, 3%) shape memory performance slightly decreased with repeated cycles. Results were favorably compared with PUs cross-linked by hydroxyl ethylacrylate (HEA) and VTMS, and physical blends with silica particles. The results were interpreted based on the triple effects of silica particles as multifunctional cross-linkers, reinforcing fillers, and relaxation retarders of the polymer chains during loading and unloading. © The Royal Society of Chemistry 2010.

Au-intermediate TiO2/Au/TiO2 (TAT) multilayer films were deposited by RF magnetron sputtering onto glass substrates. Changes in the optical and electrical properties of the films were investigated with respect to the thickness of the Au interlayer. The observed optical and electrical properties were dependent on the thickness of the Au interlayer. The resistivity decreased to 3.3 × 10-4 Ω cm for TiO2 films with a 20 nm-thick Au interlayer and the optical transmittance was also influenced by the Au interlayer. Although optical transmittance deteriorated as Au thickness increased, TiO2 films with a 5 nm-thick Au interlayer showed a relatively high optical transmittance of 80% at a wavelength of 550 nm. In addition, since a TAT film with a 5 nm-thick Au interlayer showed a relatively high work function value, it is an alternative candidate for use as a transparent anode in OLEDs and flat panel displays. © 2010 Elsevier B.V. All rights reserved.

Son Y.,Wonkwang University | Kim S.,Wonkwang University | Chung H.-T.,University of Ulsan | Pae H.-O.,Wonkwang University
Methods in Enzymology | Year: 2013

There are three well-defined subgroups of mitogen-activated protein kinases (MAPKs): the extracellular signal-regulated kinases (ERKs), the c-Jun N-terminal kinases (JNKs), and the p38 MAPKs. Three subgroups of MAPKs are involved in both cell growth and cell death, and the tight regulation of these pathways, therefore, is paramount in determining cell fate. MAPK pathways have been shown to be activated not only by receptor ligand interactions but also by different stressors placed on the cell. MAPK phosphatases (MKPs) dephosphorylate and deactivate MAPKs. Reactive oxygen species (ROS), such as hydrogen peroxide, have been reported to activate ERKs, JNKs, and p38 MAPKs, but the mechanisms by which ROS can activate these kinases are unclear. Oxidative modifications of MAPK signaling proteins and inactivation and/or degradation of MKPs may provide the plausible mechanisms for activation of MAPK pathways by ROS, which will be reviewed in this chapter. © 2013 Elsevier Inc.

This paper is concerned with attitude and position estimation of movement, which is between two zero velocity intervals. The proposed method is suitable for analysis of movement for a short moving interval. Using two boundary information (zero velocity interval), attitude is estimated by an attitude smoother. Using the smoothed attitude, velocity is estimated by a velocity smoother. The position is computed by integrating the velocity estimate. Through numerical examples, the proposed method is shown to be less sensitive to the uncalibrated sensor parameters and sensor noises, which are main sources of estimation errors. © 2011 IEEE.

Park S.H.,University of Ulsan
American Journal of Roentgenology | Year: 2016

OBJECTIVE. The purpose of this article is to provide a comprehensive review regarding DWI enterography used for evaluating Crohn disease and to summarize the relevant evidence. CONCLUSION. Active bowel inflammation in Crohn disease causes restricted diffusion on MR enterography with DWI. Enterographic DWI to evaluate Crohn disease is increasingly drawing attention for both academic research and clinical practice and has shown potential as a quantitative tool for assessing bowel inflammation. DWI enterography also has multiple unresolved issues and limitations. © American Roentgen Ray Society.

Kim H.Y.,University of Ulsan
Clinical nuclear medicine | Year: 2012

As a healthy volunteer for amyloid imaging study, a 83-year-old woman with no history of neurologic or psychiatric illness underwent carbon 11-labeled Pittsburgh compound-B (PIB) PET, which showed focal increased PIB binding in the right anterior temporal region. This focal PIB uptake turned out to be a mass lesion on MRI, which was consistent with a benign meningioma. This is the first case report on the incidentally found intracranial meningioma by PIB PET scan, highlighting the excellent sensitivity of PIB radiotracer in detecting brain amyloid deposition.

Transparent and conducting TiO2/Au/TiO2 (TAuT) films were deposited by reactive magnetron sputtering on polycarbonate substrates to investigate the effect of the Au interlayer on the optical, electrical, and structural properties of the films. In TAuT films, the Au interlayer thickness was kept at 5 nm. Although total thickness was maintained at 100 nm, the stack structure was varied as 50/5/45, 70/5/25, and 90/5/5 nm. In XRD pattern, the intermediate Au films were crystallized, while all TAuT films did not show any diffraction peaks for TiO2 films with regardless of stack structure. The optical and electrical properties were dependent on the stack structure of the films. The lowest sheet resistance of 23 Ω/□ and highest optical transmittance of 76% at 550 nm were obtained from TiO2 90 nm/Au 5 nm/TiO2 5 nm films. The work function was dependent on the film stack. The highest work function (4.8 eV) was observed with the TiO2 90 nm/Au 5 nm/TiO2 5 nm film stack. The TAuT film stack of TiO 2 90 nm/Au 5 nm/TiO2 5 nm films is an optimized stack that may be an alternative candidate for transparent electrodes in flat panel displays. © 2010 Elsevier B.V. All rights reserved.

Choi Y.-R.,University of Ulsan
Quarterly Journal of Mechanics and Applied Mathematics | Year: 2012

Membrane structures are widely used as storage containers. The accurate estimation of shape, structural tension and internal pressure are essential for the effective and safe use of such structures. This study evaluates the statics of a fluid-filled membrane section submerged in ambient fluid. Mathematical modelling is used to formalize the problem via simultaneous non-linear ordinary differential equations with undetermined boundary conditions. A close examination of the problem confirms that the shapes of membrane sections fall into one of three types depending on cross-sectional volume. Analytic integration of the curvature results in a solution of the universal shape, which is expressed in terms of elliptic integrals. Using the methods described in this study, it is possible to estimate the characteristic parameters, shapes, pressures and tensions of membrane container sections of arbitrary sizes. © The author 2011.

Jo M.W.,University of Ulsan
Health and quality of life outcomes | Year: 2014

There are few publications on quality measurement of COPD health state according to the severity level using EQ-5D in Korea. The present study aimed to evaluate the health-related quality of life (HRQoL) in patients with chronic obstructive pulmonary disease (COPD) in terms of disease severity in Korea. Totally two hundred patients with COPD were consecutively recruited in one tertiary hospital of Korea. Each respondent was asked to fill out the questionnaire through a face-to-face interview after providing informed consent. The questionnaire included general and clinical characteristics as well as the EQ-5D and Clinical COPD Questionnaire (CCQ). HRQoL was evaluated according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria and severity of breathlessness. The adjusted mean EQ-5D index scores were 0.83, 0.88, 0.81 and 0.60 in stage I, II, III and IV, respectively. The EQ-5D index tended to decrease with GOLD criteria. The adjusted mean EQ-Visual Analog Scale (VAS) scores ranged from 65.1 in stage IV to 73.9 in stage I. The CCQ total scores deteriorated with an increasing GOLD stage and severity of breathlessness (all P < 0.001). The correlation between CCQ total score and EQ-5D index was -0.69. Our study shows that HRQoL in COPD measured by EQ-5D and CCQ worsens with the GOLD stage and severity of breathlessness. EQ-5D and CCQ could be useful instruments for an evaluation of HRQoL in COPD patients in Korea.

Kim C.-H.,University of Ulsan | Howles C.M.,Merck Serono International | Lee H.-A.,Kangwon National University
Fertility and Sterility | Year: 2011

Objective: To investigate the effectiveness of treatment with transdermal testosterone gel (TTG) before controlled ovarian stimulation (COS) using GnRH antagonist multiple-dose protocol (MDP) in low responders undergoing IVF/intracytoplasmic sperm injection (ICSI). Design: Prospective randomized controlled trial. Setting: University-affiliated infertility clinic. Patient(s): A total of 110 low responders, who were defined as patients who failed to produce ≤3 follicles with a mean diameter of ≥16 mm with the result that ≤3 oocytes were retrieved despite the use of a high gonadotropin dose (>2,500 IU) in a previous failed IVF/ICSI cycle. Intervention(s): Patients were randomized into TTG pretreatment group or control group. For TTG pretreatment group, 12.5 mg TTG were applied daily for 21 days in the cycle preceding COS for IVF. Main Outcome Measure(s): COS results and IVF outcome. Result(s): There were no differences in patients' characteristics between the two groups. Total dose and days of rhFSH used were significantly fewer in the TTG pretreatment group than in the control group. The numbers of oocytes retrieved, mature oocytes, fertilized oocytes, and good-quality embryos were significantly higher in the TTG pretreatment group. Embryo implantation rate and clinical pregnancy rate per cycle initiated also were significantly higher in the women pretreated with TTG. No patient reported adverse effects attributed to TTG use. Conclusion(s): TTG pretreatment might be beneficial in improving both response to COS and IVF outcome in low responders undergoing IVF/ICSI. © 2011 American Society for Reproductive Medicine, Published by Elsevier Inc.

Interfacial adhesion between an indium tin oxide (ITO)/Ni/Ag/Ni/Au p-electrode, and Au and Ni/Au seeds in vertical GaN-based light emitting diodes (LEDs) was enhanced by O2 plasma cleaning treatment of the Au surface in the p-electrode. However, AES and REELS analyses of the Au surface in the p-electrode detected surface damage to the p-electrode and photoresist (PR) passivation structure from O2 plasma cleaning. W/Ni and Al/Ni adhesion layers were introduced in the Au seed to increase interfacial adhesion between Au seed and untreated PR passivation. Forward leakage current as low as 0.91 nA at 2 V was observed for the vertical LED with the Al/Ni/Au seed, for which adhesion strength to O2 plasma-cleaned Au and untreated PR was 141.2 MPa and 62.8 MPa, respectively. © 2010 Elsevier B.V. All rights reserved.

Sung K.R.,University of Ulsan
Korean journal of ophthalmology : KJO | Year: 2013

To evaluate the clinical characteristics of newly diagnosed glaucomatous subjects who had a history of refractive corneal ablation surgery (RCAS). Sixty-eight glaucomatous subjects who had a history of RCAS and 68 age- and visual field (VF) mean deviation-matched glaucomatous subjects with no history of RCAS were included. Intraocular pressure (IOP), central corneal thickness (CCT), VF, and retinal nerve fiber layer thickness determined by optical coherence tomography were assessed. Parameters were compared between patients with and without a history of RCAS. Between-eye comparisons in the same participant (more advanced vs. less-advanced eye, in terms of glaucoma severity) were performed in the RCAS group. With similar levels of glaucoma severity, those with a history of RCAS showed significantly lower baseline IOP and a thinner CCT than the eyes of individuals without a RCAS history (13.6 vs. 18.7 mmHg, 490.5 vs. 551.7 μm, all p < 0.001). However, the extent of IOP reduction after anti-glaucoma medication did not significantly differ between the two groups (17% vs. 24.3%, p = 0.144). In the between-eye comparisons of individual participants in the RCAS group, the more advanced eyes were more myopic than the less-advanced eyes (-1.84 vs. -0.58 diopter, p = 0.003). Eyes with a history of RCAS showed a similar level of IOP reduction as eyes without such a history after anti-glaucoma medication. Our finding that the more advanced eyes were more myopic than the less-advanced eyes in the same participant may suggest an association between glaucoma severity and myopic regression.

Kim D.,University of Ulsan
Journal of Alloys and Compounds | Year: 2010

Transparent Sn-doped In 2O 3 (ITO) single-layer and ITO/Au/ITO multilayer films were deposited on glass substrate by reactive magnetron sputtering to compare morphology, optical and electrical properties of the films and were then annealed in a vacuum of 1 × 10 -2 Pa at various temperatures from 150 to 450 °C to determine the influence of annealing temperature on the properties of the films. As-deposited 100 nm thick ITO films exhibit a sheet resistance of 130 Ω/□ and optical transmittance of 77% at 550 nm-wavelength. By inserting a 5 nm-thick Au layer in ITO/metal/ITO films, the sheet resistance decreased to as low as 21 Ω/□ and optical transmittance also decreased to as little as 73% at 550 nm-wavelength. Post-deposition annealing of ITO/Au/ITO films lead to considerably lower electrical resistivity, higher optical transparency, and crystallization of the films. A sheet resistance of 8 Ω/□ and an optical transmittance of 82% at 550 nm wavelength were obtained from the ITO/Au/ITO films annealed at 450 °C. In the X-ray diffraction pattern, as-deposited ITO films did not show any diffraction peak, while as-deposited ITO/Au/ITO films have Au (1 1 1) and In 2O 3 (2 2 2) crystal planes. When the annealing temperature reached the 150-450 °C range, both diffraction peak intensities increased significantly. © 2009 Elsevier B.V. All rights reserved.

Gamma knife surgery (GKS) is the prevailing method for treatment of medically intractable trigeminal neuralgia (TN), although there are some technical differences among radiosurgical centers. We assessed the long-term outcomes of GKS using retrogasserian petrous bone targeting and evaluated factors associated with the clinical outcomes. Between December 2003 and June 2009, a total of 91 GKS treatments were performed in 90 patients with classic TN. The surgical target was defined at the anterior portion of the trigeminal nerve, just above the retrogasserian petrous bone. A single 4-mm collimator was used to deliver a median 88.0 Gy (range 75-90 Gy) dose of radiation. During follow-up, which ranged from 24 to 90 months, 89 patients (97.8 %) reported initial pain relief, 75 (82.4 %) experienced pain control, and 47 (51.6 %) achieved a pain-free state without medications at the last follow-up. Barrow Neurological Institute (BNI) scores of I-III at 2, 3, 4, 5, and 7 years were observed in 84 of 91, 68 of 77, 46 of 53, 33 of 36, 17 of 19, and 7 of 7 patients, respectively. Trigeminal nerve dysfunction was experienced by 34 patients, with 12 having BNI facial numbness scores of III-IV (13.2 %). In all, 14 patients (15.4 %) experienced pain recurrence at a mean 32 months (range 10-62 months) after treatment. The actuarial rates of pain control at 2, 4, and 6 years were 93 %, 88 %, and 79 %, respectively. Gamma Knife radiosurgery is an efficient option for intractable TN. Our results can help medical practitioners to counsel their patients on the likelihood of achieving successful pain control.

Choi S.T.,University of Ulsan | Kwon J.O.,Samsung
Sensors and Actuators, A: Physical | Year: 2013

We designed and fabricated multilayered relaxor ferroelectric poly(vinylidene fluoride-trifluoroethylene-clorotrifluoroethylene) [P(VDF-TrFE-CTFE)] actuators in this study. To minimize the driving voltage of the P(VDF-TrFE-CTFE) actuator, which produces bending deformation, we designed a multilayered structure and analyzed the structure using composite beam theory. We developed a new adhesion-mediated film transfer technique to fabricate 1.5 μm-thick P(VDF-TrFE-CTFE) films and laminate them onto a micromachined silicon substrate. Metal electrodes were deposited on top of each P(VDF-TrFE-CTFE) film to obtain a multilayer structure with alternating electrodes. We show that with an applied voltage of only 40 V, the multilayered P(VDF-TrFE-CTFE) actuators fabricated in this study produced deflections of about 9 μm, and their transient behavior faded out within 10 ms. When the actuators were integrated onto a varifocal liquid-filled microlens, an optical power change of more than 50 diopters was obtained. This is the first report of a method to fabricate and stack 1-2 μm-thick PVDF-based films. © 2013 Elsevier B.V. All rights reserved.

Lee I.,University of Ulsan
World Journal of Gastroenterology | Year: 2014

Helicobacter pylori (H. pylori) gastritis may progress to high risk gastropathy and cancer. However, the pathological progression has not been characterized in detail. H. pylori induce persistent inflammatory infiltration. Neutrophils are unique in that they directly infiltrate into foveolar epithelium aiming the proliferative zone specifically. Neutrophilic proliferative zone foveolitis is a critical pathogenic step in H. pylori gastritis inducing intensive epithelial damage. Epithelial cells carrying accumulated genomic damage and mutations show the Malgun (clear) cell change, characterized by large clear nucleus and prominent nucleolus. Malgun cells further undergo atypical changes, showing nuclear folding, coarse chromatin, and multiple nucleoli. The atypical Malgun cell (AMC) change is a novel premalignant condition in high risk gastropathy, which may progress and undergo malignant transformation directly. The pathobiological significance of AMC in gastric carcinogenesis is reviewed. A new diagnosis system of gastritis is proposed based on the critical pathologic steps classifying low and high risk gastritis for separate treatment modality. It is suggested that the regulation of H. pylori - induced neutrophilic foveolitis might be a future therapeutic goal replacing bactericidal antibiotics approach. © 2014 Baishideng Publishing Group Inc. All rights reserved.

Lee S.-G.,University of Ulsan
British Medical Bulletin | Year: 2010

IntroductionThe technique of paediatric living-donor liver transplantation (LDLT) has become standardized. In adults, however, there is scope for innovation. Unlike cadaveric whole-size liver transplantation and paediatric LDLT, size matching between the liver graft and the recipient by body weight has been a major challenge in adult LDLT because it is important to provide an adequate graft mass to the recipient while leaving a sufficient mass of remnant liver in the donor to ensure donor safety.Growing pointsIn adult LDLT, liver grafts have been selected to meet graft-recipient size-matching requirements. In 1996, the Hong Kong group pioneered the use of the right-lobe grafts vein to overcome the volume insufficiency often encountered with the left-lobe liver grafts. Subsequently, the Asan group introduced modified right-lobe grafting with interposition vein grafts to drain the venous outflow of the anterior sector, thus increasing the functioning hepatocyte mass, and this group initiated dual left-lobe liver grafts to overcome both donor risk and volume insufficiency.Areas of agreement and controversyAlthough the surgical procedures for both donors and recipients are more complex for adult LDLT than for whole-organ deceased donor transplantation, the outcomes in large-volume centers are now similar. Accordingly, the indications for adult LDLT are continually being expanded.Areas timely for developing researchIn performing these procedures, it is crucial to minimize the risks of morbidity and mortality to the healthy live donor. This review focuses on the current technical development and discusses the ethical issues of adult LDLT. © The Author 2010. Published by Oxford University Press. All rights reserved.

Kim S.H.,University of Ulsan
Archives of Gerontology and Geriatrics | Year: 2016

Introduction: This study was performed to examine the characteristics of indoor and outdoor falls in older patients and the factors related to severe injury in the emergency department (ED). Methods: In total, 26,515 patients fell indoors and 19,581 outdoors. The general and clinical characteristics were compared between the two groups and factors associated with severe injury following the falls were evaluated. Results: Younger males fell more frequently outdoors than indoors. The common activities during outdoor falls were sports and leisure activities. Environmental hazards lead to more outdoor falls than indoor falls. Factors associated with severe injury after indoor falls were transport to the ED by public ambulance or from another medical facility rather than individual transportation, fall from stairs rather than fell over, and a head and neck injury rather than a lower extremity injury. Factors related to severe injury after outdoor falls were male sex, transport to the ED by public ambulance or from another medical facility or by another method rather than individual transportation, state employed, fall from stairs rather than fell over, head and neck or thorax or abdomen injury rather than a lower extremity injury. Conclusion: Transport to the ED by public ambulance or from another medical facility, and head and neck injury were risks for severe injury following indoor and outdoor falls in elderly subjects. Efforts to identify the risk factors for severe injury and for falling itself are important to prevent and reduce fall injuries in elderly subjects. © 2015 Elsevier Ireland Ltd.

Tak Lim Y.,Pohang University of Science and Technology | Yeog Son J.,Kyung Hee University | Shin Y.-H.,University of Ulsan
Applied Physics Letters | Year: 2014

We investigate the domain wall speed of a ferroelectric PbZr 0.48Ti0.52O3 (PZT) thin film using an atomic force microscope incorporated with a mercury-probe system to control the degree of electrical fatigue. The depolarization field in the PZT thin film decreases with increasing the degree of electrical fatigue. We find that the wide-range activation field previously reported in ferroelectric domains result from the change of the depolarization field caused by the electrical fatigue. Domain wall speed exhibits universal behavior to the effective electric field (defined by an applied electric field minus the depolarization field), regardless of the degree of the electrical fatigue. © 2014 AIP Publishing LLC.

Kwon S.,KAIST | Ko J.-H.,KAIST | Jeon K.-J.,University of Ulsan | Kim Y.-H.,KAIST | Park J.Y.,KAIST
Nano Letters | Year: 2012

Atomically thin graphene is an ideal model system for studying nanoscale friction due to its intrinsic two-dimensional (2D) anisotropy. Furthermore, modulating its tribological properties could be an important milestone for graphene-based micro- and nanomechanical devices. Here, we report unexpectedly enhanced nanoscale friction on chemically modified graphene and a relevant theoretical analysis associated with flexural phonons. Ultrahigh vacuum friction force microscopy measurements show that nanoscale friction on the graphene surface increases by a factor of 6 after fluorination of the surface, while the adhesion force is slightly reduced. Density functional theory calculations show that the out-of-plane bending stiffness of graphene increases up to 4-fold after fluorination. Thus, the less compliant F-graphene exhibits more friction. This indicates that the mechanics of tip-to-graphene nanoscale friction would be characteristically different from that of conventional solid-on-solid contact and would be dominated by the out-of-plane bending stiffness of the chemically modified graphene. We propose that damping via flexural phonons could be a main source for frictional energy dissipation in 2D systems such as graphene. © 2012 American Chemical Society.

Although endoscopic treatment has become the first choice to treat biliary complications, percutaneous transhepatic treatment still has important roles to treat biliary stricture or leak after living donor liver transplantation. This study reviewed a total of 527 recipients who had undergone percutaneous transhepatic treatment to treat biliary stricture (n=498) and leaks (n=29). Percutaneous transhepatic treatment included percutaneous transhepatic biliary drainage, perihepatic biloma drainage, balloon dilation of biliary stricture, and drainage catheter interposition or retrievable covered stent placement across a stricture or leak segment. Clinical success was achieved in 440 (88.4%) recipients with biliary stricture and 19 (65.5%) recipients with bile leaks. Percutaneous transhepatic treatment seems to be an effective alternative for treating biliary complications resistant to or inaccessible by endoscopic treatment.

Kim D.,Rochester College | Kim D.,Seoul National University | Kim W.R.,Rochester College | Kim H.J.,University of Ulsan | Therneau T.M.,Rochester College
Hepatology | Year: 2013

The clinical and public health significance of nonalcoholic fatty liver disease (NAFLD) is not well established. We investigated the long-term effect of NAFLD on mortality. This analysis utilized the National Health and Nutrition Examination Survey conducted in 1988-1994 and subsequent follow-up data for mortality through December 31, 2006. NAFLD was defined by ultrasonographic detection of hepatic steatosis in the absence of other known liver diseases. The presence and severity of hepatic fibrosis in subjects with NAFLD was determined by the NAFLD fibrosis score (NFS), the aspartate aminotransferase to platelet ratio index (APRI), and FIB-4 score. Of 11,154 participants, 34.0% had NAFLD-the majority (71.7%) had NFS consistent with lack of significant fibrosis (NFS <-1.455), whereas 3.2% had a score indicative of advanced fibrosis (NFS >0.676). After a median follow-up of 14.5 years, NAFLD was not associated with higher mortality (age- and sex-adjusted hazard ratio [HR]: 1.05; 95% confidence interval [CI]: 0.93-1.19). In contrast, there was a progressive increase in mortality with advancing fibrosis scores. Compared to subjects without fibrosis, those with a high probability of advanced fibrosis had a 69% increase in mortality (for NFS: HR, 1.69, 95% CI: 1.09-2.63; for APRI: HR, 1.85, 95% CI: 1.02-3.37; for FIB-4: HR, 1.66, 95% CI: 0.98-2.82) after adjustment for other known predictors of mortality. These increases in mortality were almost entirely from cardiovascular causes (for NFS: HR, 3.46, 95% CI: 1.91-6.25; for APRI: HR, 2.53, 95% CI: 1.33-4.83; for FIB-4: HR, 2.68, 95% CI: 1.44-4.99). Conclusions: Ultrasonography-diagnosed NAFLD is not associated with increased mortality. However, advanced fibrosis, as determined by noninvasive fibrosis marker panels, is a significant predictor of mortality, mainly from cardiovascular causes, independent of other known factors. © 2012 American Association for the Study of Liver Diseases.

Clark S.M.,Macquarie University | Jeon K.-J.,University of Ulsan | Chen J.-Y.,Washington State University | Yoo C.-S.,Washington State University
Solid State Communications | Year: 2013

The effect of pressure on the structure of few-layer graphene has been investigated to 50 GPa in both quasi-hydrostatic and non-hydrostatic conditions, using X-ray diffraction and Raman spectroscopy. The results indicate that few-layer graphene loses its long-range order at the critical interlayer distance of ∼2.8 Å (or above ∼18 GPa), while maintaining the local sp2 hybridization in the layer to 50 GPa. This suggests that graphene not only has the highest stability of all graphitic layer structures, but also becomes one of the most healable structures under large stress.

Lee S.-O.,Rochester College | Lee S.-O.,University of Ulsan | Brown R.A.,Rochester College | Razonable R.R.,Rochester College
Transplant Infectious Disease | Year: 2013

Background: Toll-like receptor 3 (TLR3) is implicated in the pathogenesis of viral diseases owing to its ability to recognize viral double-stranded RNA. We hypothesized that single nucleotide polymorphism (SNP) in TLR3 gene that impairs the function of the protein-receptor influences the outcome of hepatitis C virus (HCV) infection after liver transplantation. Methods: The clinical characteristics of 611 liver recipients (HCV-infected: n = 153, non-HCV-infected: n = 458) were assessed to investigate the impact of TLR3 L412F SNP on transplant outcomes. Results: TLR3 L412F is common, and it was significantly more prevalent among the HCV-infected cohort (57.5% vs. 45.2%, P = 0.008). In a multivariate analysis, TLR3 L412F was significantly associated with chronic hepatitis C (odds ratio: 1.73, 95% confidence interval [CI]: 1.13-2.65, P = 0.01). In an analysis that compared HCV-infected patients with wild-type versus TLR3 L412F, a marginally higher rate of allograft failure and mortality was observed in the TLR3 L412F group (44.3% vs. 30.8%, P = 0.09). However, in a multivariate analysis, only donor age was significantly associated with allograft failure and mortality (relative risk: 1.04, 95% CI: 1.007-1.06, P = 0.02). Conclusion: TLR3 L412F is significantly common in HCV-infected liver recipients, and may be associated with worse outcomes. However, larger studies are needed to determine its significant association with allograft failure and mortality after liver transplantation for chronic hepatitis C. © 2012 John Wiley & Sons A/S.

Khang Y.-H.,University of Ulsan
Journal of Preventive Medicine and Public Health | Year: 2013

Noncommunicable diseases (NCDs) are the most important causes of premature mortality and disability-adjusted life years in Korea NCDs are also the main contributor to socioeconomic inequalities in mortality and life expectancy. Reduction of NCDs and NCD inequalities would result in significant improvement in healthy life expectancy and health equity in Korea. Major NCD risk factors such as dietary risks (including salt intake), alcohol consumption, cigarette smoking, and high blood pressure were found to be the leading modifiable risk factors of disability-adjusted life years in Korea, based on the 2010 Global Burden of Disease Study. Several Korean studies have shown that these risk factors play an important role in creating socioeconomic inequalities in NCD mortality and total mortality.Current international discussions on NCD policies in the United Nations and the World Health Organization would provide better opportunities for developing aggressive population-wide policy measures in Korea. Considering the paucity of population-wide policies to control major NCD risk factors in Korea, rigorous population approaches such as taxation and regulation of unhealthy commodities as well as public education and mass campaigns should be further developed in Korea. Copyright © 2013 The Korean Society for Preventive Medicine.

Park D.H.,University of Ulsan
Journal of Hepato-Biliary-Pancreatic Sciences | Year: 2015

Only 20-30% of patients with hilar cholangiocarcinoma (CC) are candidates for potentially curative resection. However, even after curative (R0) resection, these patients have a disease recurrence rate of up to 76%. The prognosis of hilar cholangiocarcinoma (CC) is limited by tumor spread along the biliary tree leading to obstructive jaundice, cholangitis, and liver failure. Therefore, palliative biliary drainage may be a major goal for patients with hilar CC. Endoscopic retrograde cholangiopancreatography (ERCP) with stent placement is an established method for palliation of patients with malignant biliary obstruction. However, there are patients for whom endoscopic stent placement is not possible because of failed biliary cannulation or tumor infiltration that limits transpapillary access. In this situation, percutaneous transhepatic biliary drainage (PTBD) is an alternative method. However, PTBD has a relatively high rate of complications and is frequently associated with patient discomfort related to external drainage. Endoscopic ultrasound-guided biliary drainage has therefore been introduced as an alternative to PTBD in cases of biliary obstruction when ERCP is unsuccessful. In this review, the indications, technical tips, outcomes, and the future role of EUS-guided intrahepatic biliary drainage, such as hepaticogastrostomy or hepaticoduodenostomy, for hilar biliary obstruction will be summarized. © 2015 Japanese Society of Hepato-Biliary-Pancreatic Surgery.

Kim A.Y.,University of Ulsan
Clinical Endoscopy | Year: 2012

Today, cross-sectional imaging modalities, such as computed tomography enterography (CTE) and magnetic resonance enterography (MRE), are particularly suited to evaluate small bowel diseases, especially Crohn's disease (CD). It is well known that CTE/MRE can provide excellent assessment of disease activity as well as the macroscopic features, extramural abnormalities, and complications of the small intestine in patients with CD. In general, CTE is considered as the first-line modality for the evaluation of suspected inflammatory bowel disease and for long-term assessment or follow-up of these patients. Because of the advantage of lack of radiation, MRE is being used more frequently, especially in children or young patients with CD. © 2012 Korean Society of Gastrointestinal Endoscopy.

Park Y.S.,University of Ulsan
Korean Journal of Pediatrics | Year: 2012

Urinary tract infection (UTI) is a common bacterial illness in children.Acute pyelonephritis in children may lead to renal scarring with the risk of later hypertension, preeclampsia during pregnancy, proteinuria, and renal insufficiency. Until now, vesicoureteral reflux (VUR) has been considered the most important risk factor for post-UTI renal scar formation in children. VUR predisposes children with UTI to pyelonephritis, and both are associated with renal scarring. However,reflux nephropathy is not always acquired; rather, it reflects refluxassociated congenital dysplastic kidneys. The viewpoint that chronic kidney disease results from renal maldevelopment-associated VUR has led to questioning the utility of any regimen directed at identifying or treating VUR. Despite the recognition that underlying renal anomalies may be the cause of renal scarring that was previously attributed to infection, the prevention of renal scarring remains the goal of all therapies for childhood UTI. Therefore, children at high risk of renal scar formation after UTI should be treated and investigated until a large clinical study and basic research give us more information. © 2012 by The Korean Pediatric Society.

Kim S.H.,University of Ulsan
Nonlinear Dynamics | Year: 2013

This paper is devoted to controlling a class of nonlinear systems over a communication network in the presence of packet transmission delays, packet losses, quantization errors, and sampling-related phenomena. Specifically, based on the Takagi-Sugeno (T-S) fuzzy approach, this paper presents a way of designing a quantized controller that allows all the states of nonlinear NCSs to converge exponentially to a bounded ellipsoid. In particular, this paper provides a method capable of exploiting fully the time-varying delay term d(t), induced by Jensen inequality, for nonlinear NCSs. © 2013 Springer Science+Business Media Dordrecht.

Lee S.-O.,Rochester College | Lee S.-O.,University of Ulsan | Brown R.A.,Rochester College | Razonable R.R.,Rochester College
Transplantation | Year: 2011

Background. The clinical relevance of chromosomally integrated human herpesvirus-6 (CIHHV-6) after transplantation is not known. This study was aimed to determine the potential role of CIHHV-6 on the occurrence of other infections, allograft rejection, and outcomes after liver transplantation. Methods. A real-time quantitative human herpesvirus-6 (HHV-6) polymerase chain reaction assay was performed on whole blood samples of 548 liver transplant recipients. Clinical characteristics and outcomes of the patients with CIHHV-6 (defined as HHV-6 levels >1×10 genomes/mL) were compared with those of patients with low-level or no HHV-6 DNAemia. Results. Seven had CIHHV-6, 35 had low-level HHV-6 DNAemia, and 506 had no HHV-6 DNAemia before liver transplantation. Bacterial infection was significantly more common in the CIHHV-6 group compared with the group without HHV-6 (71.4% vs. 31.4%; P=0.04). A higher rate of allograft rejection was observed in the CIHHV-6 group compared with the group with low-level HHV-6 DNAemia (71.4% vs. 37.1%; P=0.12) and those without HHV-6 DNAemia (71.4% vs. 42.9%; P=0.25), although these differences did not reach statistical significance. Other opportunistic infections and outcomes were not significantly different between the CIHHV-6 group and the non-CIHHV-6 groups. Conclusion. Patients with CIHHV-6 may be at increased risk of indirect HHV6 effects after transplantation. This clinically relevant observation warrants confirmation using a larger cohort of transplant recipients. © 2011 Lippincott Williams & Wilkins.

Seo J.H.,Dong - A University | Nam S.Y.,Hannam University | Lee K.-S.,Hannam University | Kim T.-D.,Hannam University | Cho S.,University of Ulsan
Organic Electronics: physics, materials, applications | Year: 2012

The effects of processing additive on fullerene aggregation in polymer BHJ solar cells were investigated using new fullerene derivatives bearing a thiophene moiety and alkyl groups. Although new fullerene derivatives showed quite similar electronic transport properties in field-effect transistors, the photovoltaic performances were significantly limited by their aggregative nature. Processing with 1% CN additive, however, changed the aggregated morphology of BHJ films to a smoother and homogeneous morphology, improving photovoltaic performance. The result indicates that processing additive not only influences on polymer side, but also significantly affects fullerene acceptor component. © 2012 Elsevier B.V. All rights reserved.

Transparent and conductive ZnO/Au/ZnO (ZAZ) multilayer films were deposited on glass substrates by magnetron sputtering without intentional substrate heating. The thickness of Au interlayer was set at 1, 2 and 3 nm. The observed structural, optical and electrical properties were dependent on the thickness of the Au interlayer. For all of the ZAZ films, the diffraction peaks in the XRD pattern were identified as the (002) and (103) planes of a ZnO films and the (111) plane of an Au interlayer. The ZAZ films with a 2 nm thick Au interlayer showed a higher figure of merit than the other ZAZ films prepared in this study, and they also demonstrated the relatively high work function of 5.13 eV. From these results, we concluded that a ZAZ film with a 2 nm thick Au interlayer is an alternative candidate for use as a transparent electrode in OLEDs and various flat panel displays. © 2011 Elsevier B.V. All rights reserved.