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Hanyang University is a private research university in South Korea. The main campus is in Seoul, and the second one, the Education Research Industry Cluster at Ansan, or ERICA campus, is located in Ansan. Hanyang derives from the former name of the capital Seoul which was used during the Chosun Dynasty. Its motto and educational philosophy is Love in Truth and Deed.The university established the nation's first engineering institute in 1939 which became the founding facility of Hanyang University. It also established the first school of architecture and civil engineering in Korea.Hanyang University has an alumni network of 230,000 that is not only limited to the field of engineering but also to other fields. In 2009 the university was ranked 4th for the number of alumni serving as CEOs and executives at Korea’s top 100 companies. In the same year the École des Mines de Paris ranked Hanyang University 89th for the number of alumni CEOs in the world’s top 500 companies.The university enrolls over 1,500 foreign students each year and more than 1,700 students study abroad annually. HYU counts the Massachusetts Institute of Technology, University of Cambridge, and Tsinghua University among its 339 sister institutions in 42 countries. Wikipedia.

Yu Y.H.,Hanyang University
World journal of gastroenterology : WJG | Year: 2012

Hepatic artery pseudoaneurysm (HAP) is a very rare disease but in cases of complication, there is a very high mortality. The most common cause of HAP is iatrogenic trauma such as liver biopsy, transhepatic biliary drainage, cholecystectomy and hepatectomy. HAP may also occur with complications such as infections or inflammation associated with septic emboli. HAP has been reported rarely in patients with acute pancreatitis. As far as we are aware, there is no report of a case caused by acute idiopathic pancreatitis, particularly. We report a case of HAP caused by acute idiopathic pancreatitis which developed in a 61-year-old woman. The woman initially presented with acute pancreatitis due to unknown cause. After conservative management, her symptoms seemed to have improved. But eight days after admission, abdominal pain abruptly became worse again. Abdominal computed tomography (CT) was rechecked and it detected a new HAP that was not seen in a previous abdominal CT. Endoscopic retrograde cholangiopancreatography (ERCP) was performed because of a suspicion of hemobilia as a cause of aggravated abdominal pain. ERCP confirmed hemobilia by observing fresh blood clots at the opening of the ampulla and several filling defects in the distal common bile duct on cholangiogram. Without any particular treatment such as embolization or surgical ligation, HAP thrombosed spontaneously. Three months after discharge, abdominal CT demonstrated that HAP in the left lateral segment had disappeared.

Lee K.-G.,Hanyang University
Journal of the Korean Physical Society | Year: 2014

Single photons from single emitters are good candidates for a high-quality single-photon source which is essential in current quantum optical experiments and applications. Because the statistics of emitted photons is mainly determined by the energy level structure of the system, knowing the correct level scheme and the transition rates between levels is of primary importance. In this work, the energy level scheme and the photon-emission statistics of a single terrylene molecule are studied by measuring the second-order correlation function and the time trace of the emitted photons. The details in the measurement and analysis are discussed, and a more advanced energy-level structure of the terrylene molecule is suggested. © 2014 The Korean Physical Society.

Ha K.,LG Corp | Kim R.-Y.,Hanyang University | Ramu R.,Virginia Polytechnic Institute and State University
IEEE Transactions on Industrial Electronics | Year: 2011

Position estimation using only active phase voltage and current is presented to perform high-accuracy position sensorless control of a switched reluctance motor (SRM) drive. By extracting the amplitude of the first switching harmonic terms of phase voltage and current for a pulsewidth modulation period through the Fourier series, flux linkage and position are estimated without external hardware circuitry, such as a modulator and a demodulator, resulting in increasing cost, as well as large position estimation error produced when the motional back electromotive force is ignored near zero speed. Hence, the proposed position estimation scheme covers the entire speed range, including the standstill under various loads, and it has high-resolution information depending on switching frequency. A two-phase SRM drive system, consisting of an asymmetrical converter and a conventional closed-loop proportional-integral current controller, is utilized to validate the performance of the proposed position estimation scheme in comprehensive operating conditions. The estimated values very closely track the actual values in dynamic simulations and experiments. It is shown that the proposed position estimation scheme using the Fourier series is sufficiently accurate and works satisfactorily at various operating points. © 2011 IEEE.

Zalnezhad E.,Hanyang University
Applied Surface Science | Year: 2016

Zirconia (ZrO2) nanotube arrays were fabricated by anodizing pure zirconium (Zr) coated Ti-6Al-7Nb in fluoride/glycerol electrolyte at a constant potential of 60 V for different times. Zr was deposited atop Ti-6Al-7Nb via a physical vapor deposition magnetron sputtering (PVDMS) technique. Structural investigations of coating were performed utilizing X-ray diffraction (XRD) analysis. Field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) were used to characterize the morphology and microstructure of coatings. Unannealed ZrO2 nanotube arrays were amorphous. Monoclinic and tetragonal ZrO2 appeared when the coated substrates were heat treated at 450 °C and 650 °C, while monoclinic ZrO2 was found at 850 °C and 900 °C. Mechanical properties, including nanohardness and modulus of elasticity, were evaluated at different annealing temperatures using a nanoindentation test. The nanoindentation results show that the nanohardness and modulus of elasticity for Ti-6AL-7Nb increased by annealing ZrO2 coated substrate at 450 °C. The nanohardness and modulus of elasticity for coated substrate decreased with annealing temperatures of 650, 850, and 900 °C. At an annealing temperature of 900 °C, cracks in the ZrO2 thin film coating occurred. The highest nanohardness and elastic modulus values of 6.34 and 218 GPa were achieved at an annealing temperature of 450 °C. © 2016 Elsevier B.V. All rights reserved.

Yoon S.H.,Michigan Technological University | Lee C.S.,Hanyang University
Fuel | Year: 2012

This paper investigates the effects of neat bioethanol combustion on the performance and emission reduction characteristics of a spark ignition (SI) engine at various air temperature conditions. The experiments were carried out for different intake air temperatures and various operating conditions, and the results were compared to those for conventional gasoline fuel. The investigated results show that as intake ambient air temperatures is decreased, the intake flow rates is increased by the increased density of the intake air. The ethanol fuel has a higher volumetric efficiency than gasoline for all engine speeds and ambient temperature conditions. The cylinder pressures are increased with the improvement of volumetric efficiency due to the decrease of intake temperature. In addition, ethanol combustion creates higher combustion pressures than that of gasoline due to the high latent heat evaporation rate and low boiling point. The coefficients of variation of maximum pressure show slightly decreasing trends as the ambient air temperature increases. The concentration of NO x emissions tends to increase proportionally with the increase of ambient air temperature and engine speed for all test conditions. However, the HC, and CO emissions from ethanol combustion are improved than those of gasoline combustion. © 2012 Elsevier Ltd. All rights reserved.

Yoon S.H.,University of Michigan | Lee C.S.,Hanyang University
Energy and Fuels | Year: 2011

Lean combustion and exhaust emission characteristics in a spark ignition engine (SI engine) with variation of the ethanol-gasoline blending ratio and the excess air ratio were investigated in this research. To investigate the influence of the excess air ratio and ethanol blends, the lean combustion characteristics such as brake torque, cylinder pressure, and the rate of heat release (ROHR) were analyzed under the various excess-air ratios. In addition, the reduction effects of exhaust emissions such as carbon monoxide (CO), unburned hydrocarbon (HC), oxides of nitrogen (NOx), and carbon dioxide (CO2) were compared with those of gasoline fuel. The results showed that the peak combustion pressures and the ROHR of all test fuels linearly decreased as the excess air ratio (λ > 1.0) increased. As compared with gasoline fuel (G100) at each given excess air ratio, there were slight improvements in combustion pressure for ethanol blended fuels (E20-E100). The power output and brake mean effective pressure (BMEP) slightly increased at each air fuel ratio condition compared to G100 as the increase of ethanol fraction. The difference in the power and BMEP between E100 and G100 were maximized with the increases in the air-fuel ratio up to λ = 1.5. Ethanol blends have higher BSFCs compared to G100 and also achieved fairly stable combustion features at all excess air ratios compared to gasoline. NO x emissions tended to decrease proportionally with increases in the excess air ratio for all test conditions, and all of the ethanol blends emitted slightly less NOx compared to G100. © 2011 American Chemical Society.

Lee S.,Hanyang University
International Journal of Human-Computer Interaction | Year: 2013

The concept of user experience emphasizes the importance of understanding users for applications that have various contextual features. To address this issue, this study examines the changes in the relationships among user satisfaction and users' perceptions of usability and aesthetics according to use situations. For data, an experiment was conducted using 15 existing websites with similar levels of usability and aesthetics. Forty-five engineering students participated in the experiment. The results indicated that the relationships among perceived usability, perceived aesthetics, and user satisfaction could be dependent on how users perceived the use purposes and interaction types of the websites. Specifically, the relationship between perceived usability and user satisfaction was stronger for websites requiring users' goal-directed activities, whereas the relationship between perceived aesthetics and user satisfaction was stronger for the websites mainly providing useful information, regardless of the existence of a specific use goal. Also, the strong relationship between perceived usability and perceived aesthetics was more obvious for websites where users mainly wanted to obtain information than for those where users primarily wanted to use the leisure and relaxation content. The findings can be utilized in the design of websites with different contextual features, especially related to use purposes and interaction types. © 2013 Taylor and Francis Group, LLC.

Song G.G.,Korea University | Bae S.-C.,Hanyang University | Lee Y.H.,Korea University
Clinical Rheumatology | Year: 2012

The aim of this study was to summarize published results on the association between vitamin D intake and the development of rheumatoid arthritis (RA) and between serum vitamin D levels and RA activity. Evidence of a relationship between vitamin D intake and the development of RA and between serum vitamin D levels and RA activity was studied by summarizing published results using a meta-analysis approach. Three cohort studies including 215,757 participants and 874 incident cases of RA were considered in this meta-analysis, and eight studies on the association between serum vitamin D levels and RA activity involving 2,885 RA patients and 1,084 controls were included. Meta-analysis showed an association between total vitamin D intake and RA incidence (relative risk (RR) of the highest vs. the lowest group=0.758, 95 % confidence interval (CI) 0.577-0.937, p=0.047), without between-study heterogeneity (I2=0 %, p=0.595). Individuals in the highest group for total vitamin D intake were found to have a 24.2 % lower risk of developing RA than those in the lowest group. Subgroup meta-analysis also showed a significant association between vitamin D supplement intake and RA incidence (RR 0.764, 95 % CI 0.628-0.930, p=0.007), without between-study heterogeneity. All studies, except for one, found that vitamin D levels are inversely associated with RA activity. One study found no correlation between vitamin D levels and disease activity among 85 RA patients, but these patients had a high incidence of vitamin D deficiency, which might have influenced the study outcome. Meta-analysis of 215,757 participants suggests that low vitamin D intake is associated with an elevated risk of RA development. Furthermore, available evidence indicates that vitamin D level is associated with RA activity. © Clinical Rheumatology 2012.

Choi W.,Florida International University | Lahiri I.,Florida International University | Seelaboyina R.,Florida International University | Kang Y.S.,Hanyang University
Critical Reviews in Solid State and Materials Sciences | Year: 2010

Graphene, one-atom-thick planar sheet of carbon atoms densely packed in a honeycomb crystal lattice, has grabbed appreciable attention due to its exceptional electronic and optoelectronic properties. The reported properties and applications of this two-dimensional form of carbon structure have opened up new opportunities for the future devices and systems. Although graphene is known as one of the best electronic materials, synthesizing single sheet of graphene has been less explored. This review article aims to present an overview of the advancement of research in graphene, in the area of synthesis, properties and applications, such as field emission, sensors, electronics, and energy. Wherever applicable, the limitations of present knowledgebase and future research directions have also been highlighted.

In this study a potential magnetic resonance (MR) T2 contrast agent was developed systematically based on heparin-coated superparamagnetic iron oxide (SPIO) nanoparticles. Dextran-coated SPIO, which is commercially available as Feridex®, was prepared for the control group. The size of the crystalline core was adjusted to provide suitable relaxometric properties. Compared to the uncoated SPIO, the heparin or dextran coating provided a better dispersion of SPIO nanoparticles in solution. The zeta potential of the SPIO surface was detected to confirm the polymer coating. The Zeta potential of non-coated SPIO was approximatelt -44 mV, whereas dextran-coated or heparin-coated SPIO was -6.4 and -33.5 mV, respectively. The zeta potential of heparin-coated SPIO was caused by the rich sulfonate group of heparin. In addition, the heparin-coated SPIO showed higher hyponegativity than dextran- coated SPIO. The reason was that the heparin-coated had a lower r 2/r1 ratio (18.2) at 1.5-T magnetic resonance imaging (MRI) compared to dextran-coated SPIO (r2/r1 ratio 32.9). Both SPIO nanoparticles can be still suitable for T2-weighted MRI because r2/r1 ratio was >10. From the results of in vitro cellular labeling, heparin-coated SPIO was more advantageous for cellular labeling because it could powerfully visualize the cells after a short incubation time (2 h). From these findings, it is possible that heparin-coated SPIO can be used as a good negative contrast agent in clinical MRI.

Jung H.,Hyundai Steel Company | Kim J.,Hanyang University
Journal of Magnetism and Magnetic Materials | Year: 2014

The influence of cooling rate on iron loss behaviors has been investigated in 6.5 wt% grain-oriented silicon steels. To fabricate 6.5 wt% grain-oriented silicon steels and control the microstructure, 3.0 wt% grain-oriented silicon steels covered with SiO2 materials were annealed at 1200 C and then cooled to room temperature using oil quenching, air cooling, or furnace cooling. The magnetic loss of furnace-cooled samples was reduced by 25% compared with oil-quenched samples due to lower anomalous and hysteresis losses. Microstructural analysis showed that these loss behaviors were strongly related to the formation and growth of ordered phases, i.e., B2 and D03. These correlations could be ascribed to the formation of antiphase boundaries, which acted as pinning sites of the magnetic domain walls. © 2013 Published by Elsevier B.V.

Recently, based on a quadratic complex rational function, an attractive finite-difference time-domain algorithm was suggested for dispersive modeling of complex media because it is accurate and easy to implement. To fully utilize the quadratic complex rational function finite-difference time-domain, it is essential to investigate its numerical errors based on an exact mathematical approach. Toward this purpose, the exact expression of the numerical permittivity is first derived. From this numerical permittivity, the numerical dispersion, numerical dissipation, and numerical anisotropy inherent to the quadratic complex rational function finite-difference time-domain are examined. Numerical examples illustrate that the numerical errors of the quadratic complex rational function finite-difference time-domain is almost same as those of the nondispersive finite-difference time-domain. © Copyright Taylor & Francis.

Jun D.W.,Hanyang University
The Korean journal of hepatology | Year: 2012

Pegylated interferon and ribavirin combination therapy is accepted as the standard antiviral treatment for chronic hepatitis C regardless of HCV genotype. This combination therapy achieves higher response rates than previous therapy, but, nevertheless, a large proportion of patients suffer from treatment failure or adverse events. Recent clinical studies of viral kinetics during antiviral treatment have led to the introduction of response-guided therapy, the concept of 'customized therapy depending on viral response', which focuses on modulation of the treatment period depending on the viral response to create a sustained viral response without unnecessary medication and costs. New upcoming direct-acting antivirals (DAAs) maximize response rate, and triple therapy including DAAs along with pegylated interferon and ribavirin combination therapy could soon be the standard therapy. In this article, we reviewed the factors affecting treatment, response guided treatment, retreatment after failure of standard treatment, management of adverse events during treatment, and new treatment options.

Song T.L.,Hanyang University
Journal of Institute of Control, Robotics and Systems | Year: 2014

This paper is to survey and put in perspective the working methods of multi-target tracking in clutter. This paper includes theories and practices for data association and related filter structures and is motivated by increasing interest in the area of target tracking, security, surveillance, and multi-sensor data fusion. It is hoped that it will be useful in view of taking into consideration a full understanding of existing techniques before using them in practice. © ICROS 2014.

Yoon Y.J.,Hanyang University
International Journal of Precision Engineering and Manufacturing | Year: 2013

The mechanical compatibility between the dentin and any restorative dental material plays is an important factor in selecting dental restorative materials. In this work we characterize the elastic constants of dentin by developing effective composite moduli estimates, based on either the assumption of a periodic distribution or the assumption of a dilute distribution. The estimated dentin elastic constants obtained are close to the experimentally measured dentin elastic constants determined by ultrasonic speed of sound (SOS) measurements and resonant ultrasound spectroscopy (RUS). The estimated dentin elastic constants obtained provide a database to be used in evaluating potential dental restorative materials and for computational models evaluation other situations involving dentin. © 2013 Korean Society for Precision Engineering and Springer-Verlag Berlin Heidelberg.

Hur J.,Chung - Ang University | Kang K.,Hanyang University
IEEE/ACM Transactions on Networking | Year: 2014

Mobile nodes in military environments such as a battlefield or a hostile region are likely to suffer from intermittent network connectivity and frequent partitions. Disruption-tolerant network (DTN) technologies are becoming successful solutions that allow wireless devices carried by soldiers to communicate with each other and access the confidential information or command reliably by exploiting external storage nodes. Some of the most challenging issues in this scenario are the enforcement of authorization policies and the policies update for secure data retrieval. Ciphertext-policy attribute-based encryption (CP-ABE) is a promising cryptographic solution to the access control issues. However, the problem of applying CP-ABE in decentralized DTNs introduces several security and privacy challenges with regard to the attribute revocation, key escrow, and coordination of attributes issued from different authorities. In this paper, we propose a secure data retrieval scheme using CP-ABE for decentralized DTNs where multiple key authorities manage their attributes independently. We demonstrate how to apply the proposed mechanism to securely and efficiently manage the confidential data distributed in the disruption-tolerant military network. © 2012 IEEE.

Woon Kim Y.,Pusan National University | Kim S.,Pusan National University | Geun Kim C.,Hanyang University | Kim A.,Pusan National University
Nucleic Acids Research | Year: 2011

GATA-1 and NF-E2 are erythroid specific activators that bind to the β-globin locus. To explore the roles of these activators in transcription of the human fetal stage specific γ-globin genes, we reduced GATA-1 and p45/NF-E2 using shRNA in erythroid K562 cells. GATA-1 or p45/NF-E2 knockdown inhibited the transcription of the γ-globin genes, hypersensitive site (HS) formation in the LCR and chromatin loop formation of the β-globin locus, but histone acetylation across the locus was decreased only in the case of GATA-1 knockdown. In p45/NF-E2 knockdown cells, GATA-1 binding was maintained at the LCR HSs and γ-globin promoter, but NF-E2 binding at the LCR HSs was reduced by GATA-1 knockdown regardless of the amount of p45/NF-E2 in K562 cells. These results indicate that histone acetylation is dependent on GATA-1 binding, but the binding of GATA-1 is not sufficient for the γ-globin transcription, HS formation and chromatin loop formation and NF-E2 is required. This idea is supported by the distinctive binding pattern of CBP and Brg1 in the β-globin locus. Furthermore GATA-1-dependent loop formation between HS5 and 3′HS1 suggests correlation between histone modifications and chromatin looping. © 2011 The Author(s).

Sohn J.W.,Hanyang University
Tuberculosis and Respiratory Diseases | Year: 2013

Acute eosinophilic pneumonia is a severe and rapidly progressive lung disease that can cause fatal respiratory failure. Since this disease exhibits totally different clinical features to other eosinophilic lung diseases (ELD), it is not difficult to distinguish it among other ELDs. However, this can be similar to other diseases causing acute respiratory distress syndrome or severe community-acquired pneumonia, so the diagnosis can be delayed. The cause of this disease in the majority of patients is unknown, even though some cases may be caused by smoke, other patients inhaled dust or drugs. The diagnosis is established by bronchoalveolar lavage. Treatment with corticosteroids shows a rapid and dramatic positive response without recurrence. Copyright©2013. The Korean Academy of Tuberculosis and Respiratory Diseases. All rights reserved.

Lee H.,Hanyang University | Kwon S.J.,Daegu University
Expert Systems with Applications | Year: 2014

Cognitive map is a well-known approach to model the dynamics of qualitative systems, and has been studied and used in various fields, such as psychology, education, engineering, and management. Although the validity and usefulness of cognitive maps has been proven in many fields, and a considerable number of cognitive maps have been built during the last decade, cognitive map construction and use was just one-off event. In addition, the high degree of cognitive complexities in large cognitive maps makes it difficult for others to understand and exploit the pre-defined cognitive map in another similar domain problem. In this paper, an ontological semantic inference method, which combines the cognitive map and semantic influence, is proposed. This approach reuses a pre-defined cognitive map and provides an ontological semantic inference mechanism in decision making environments by reducing the degree of cognitive complexities in a large cognitive map. © 2013 Elsevier Ltd. All rights reserved.

Kim J.W.,Hanyang University
Journal of the Korean Physical Society | Year: 2012

High-power operation of an Nd:YAG laser with a first-order Laguerre-Gaussian (LG 01) mode output by using a simple pump-beam-shaping technique in an end-pumped solid-state laser configuration is reported. An analytical expression for threshold pump power for determining the ring-shape pump beam dimension to allow direct excitation of the first-order LG 01 mode is derived. This approach has been applied to a diode-laser-pumped Nd:YAG laser, yielding a 10. 4 W LG01 mode output at 1064 nm in a beam with M 2 ≈ 2. 15 for a 21. 7 W incident pump power. The experimental results for the threshold pump power and the beam quality under three different pump beam conditions are in very good agreement with the calculated values. The prospects for power scaling and improved laser performance will be discussed. © 2012 The Korean Physical Society.

Kim T.Y.,Hanyang University | Kim D.J.,Hallym University
Clinical and molecular hepatology | Year: 2013

Acute-on-chronic liver failure (ACLF) is an increasingly recognized distinct disease entity encompassing an acute deterioration of liver function in patients with chronic liver disease. Although there are no widely accepted diagnostic criteria for ACLF, the Asia.Pacific Association for the Study of the Liver (APASL) and the American Association for the Study of Liver Disease and the European Association for the Study of the Liver (AASLD/EASL) consensus definitions are commonly used. It is obvious that the APASL and the AASLD/EASL definitions are based on fundamentally different features. Two different definitions in two different parts of the world hamper the comparability of studies. Recently, the EASL-Chronic Liver Failure Consortium proposed new diagnostic criteria for ACLF based on analyses of patients with organ failure. There are areas of uncertainty in defining ACLF, such as heterogeneity of ACLF, ambiguity in qualifying underlying liver disease, argument for infection or sepsis as a precipitating event, etc. Although the exact pathogenesis of ACLF remains to be elucidated, alteration of host response to injury, infection, and unregulated inflammation play important roles. The predisposition, infection/inflammation, response, organ failure (PIRO) concept used for sepsis might be useful in describing the pathophysiology and clinical categories for ACLF. Treatment strategies are limited to organ support but better understanding of the pathophysiology is likely to lead to discovery of novel biomarkers and therapeutic strategies in the future.

Greiner T.,Hanyang University
Nutrition Research and Practice | Year: 2011

Women's nutrition has received little attention in nutrition programming, even though clinical trials and intervention trials have suggested thatdietary improvement or supplementation with several nutrients may improve their health, especially in low-income settings, the main focus of this paper. Most attention so far has focused on how improvements in maternal nutrition can improve health outcomes for infants and young children. Adequate vitamin D and calcium nutrition throughout life may reduce the risk of osteoporosis, and calcium supplementation during pregnancy may reduce preeclampsia and low birth weight. To reduce neural tube defects, additional folic acid and possibly vitamin B12 need to be provided to non-deficient women before they know they are pregnant. This is best achieved by fortifying a staple food. It is unclear whether maternal vitamin A supplementation will lead to improved health outcomes for mother or child. Iron, iodine and zinc supplementation are widely needed for deficient women. Multimicronutrient supplementation (MMS) in place of the more common iron-folate supplements given in pregnancy in low-income countries may slightly increase birth weight, but its impact on neonatal mortality and other outcomes is unclear. More sustainable alternative approaches deserve greater research attention. ©2011 The Korean Nutrition Society and the Korean Society of Community Nutrition.

The three-zone simulated moving bed (SMB) chromatographic process for separation of succinic acid and lactic acid, which has been developed previously, was based on a classical port-location arrangement (desorbent. →. extract. →. feed. →. raffinate) and a classical feeding mode (full-feeding). To improve the performance of the three-zone SMB process, it is worth utilizing the strategy of either a port-location rearrangement (desorbent. →. feed. →. raffinate. →. extract) or a partial-feeding. To investigate which of the two strategies is more effective, the three-zone SMBs based on the port-location rearrangement (PR) and the partial-feeding (PF) were optimized each under equal conditions and then the two strategies were compared in terms of product purities or throughput. The result showed that the PR strategy led to higher purities or higher throughput than the PF strategy in regard to the previously reported three-zone SMB system. To check whether such trend is still valid in other separation systems, the above optimization works were repeated while varying only the selectivity between two feed components. It was confirmed that the PR strategy is definitely superior to the PF strategy. However, such superiority of the PR over the PF strategy is lessened as the selectivity becomes lower. If the selectivity is significantly low, the PR strategy is rather outperformed by the PF strategy. © 2014 Elsevier B.V.

Kim S.-G.,Hanyang University
Korean Circulation Journal | Year: 2010

Because blood pressure (BP) is an ever changing hemodynamic phenomenon, a BP value, once measured at a physician's office (Office BP), is often unrepresentative of an individual's true BP status. Both ambulatory blood pressure monitoring (ABPM) and home blood pressure monitoring (HBPM) provide more accurate and reproducible estimate of BP, and produce stronger predictive ability for cardiovascular outcome than conventional office BP. Two BP measuring techniques, ABPM and HBPM have been widely in clinical use for the detection and management of hypertension. However, they have different advantages and limitations in practice. At present, it has become crucial to understand the characteristics and clinical implications of these BP measuring techniques for those responsible for the care of hypertensive patients. Copyright © 2010 The Korean Society of Cardiology.

Wu Y.,Nanjing University of Information Science and Technology | Lim J.,Hanyang University | Yang M.-H.,University of California at Merced
IEEE Transactions on Pattern Analysis and Machine Intelligence | Year: 2015

Object tracking has been one of the most important and active research areas in the field of computer vision. A large number of tracking algorithms have been proposed in recent years with demonstrated success. However, the set of sequences used for evaluation is often not sufficient or is sometimes biased for certain types of algorithms. Many datasets do not have common ground-truth object positions or extents, and this makes comparisons among the reported quantitative results difficult. In addition, the initial conditions or parameters of the evaluated tracking algorithms are not the same, and thus, the quantitative results reported in literature are incomparable or sometimes contradictory. To address these issues, we carry out an extensive evaluation of the state-of-the-art online object-tracking algorithms with various evaluation criteria to understand how these methods perform within the same framework. In this work, we first construct a large dataset with ground-truth object positions and extents for tracking and introduce the sequence attributes for the performance analysis. Second, we integrate most of the publicly available trackers into one code library with uniform input and output formats to facilitate large-scale performance evaluation. Third, we extensively evaluate the performance of 31 algorithms on 100 sequences with different initialization settings. By analyzing the quantitative results, we identify effective approaches for robust tracking and provide potential future research directions in this field. © 1979-2012 IEEE.

Kim J.-K.,Hanyang University
Chemical Engineering Journal | Year: 2012

System-wide analysis of water systems to minimize water use in process industries has been carried out when charges for effluents from the process are simultaneously considered with cost of freshwater intake and in-house water treatment in the design of water and effluent systems. It has been demonstrated that the degree of wastewater regeneration and recycling is heavily dependent on the charges associated wastewater effluent. The reusability of water and its techno-economic impacts are examined with both a graphic-based manual technique and an automated design method using mathematical optimization, with which conceptual insights are sought in a systematic manner to evaluate different integrated options including water reuse, regeneration and recycling. For the optimization model, new solution strategy has been proposed for solving the MINLP problem of total water systems which carries out rigorous economic trade-offs existed in an integrated water network, together with wastewater charges. © 2012 Elsevier B.V.

Park D.W.,Hanyang University
Journal of the Korean Medical Association | Year: 2015

The development of advanced magnetic resonance (MR) imaging techniques for tumors has not only lead to improved diagnostic accuracy, but has also assisted with tumor staging, surgical planning, and postoperative follow-up study. Recently introduced and/or clinically used MR imaging techniques for tumors, including chemical exchange saturation transfer imaging, molecular imaging, magnetic resonance spectroscopy, perfusion, and blood flow suppression techniques, could improve diagnostic accuracy and provide useful information to guide the management of tumors. It is essential to properly obtain and evaluate advanced MR images for tumors, depending on the specific characteristics of each tumor. © Korean Medical Association.

Park Y.,Dong - A University | Moon H.-J.,Dong - A University | Kim S.-H.,Hanyang University
Journal of Nutritional Biochemistry | Year: 2012

Epidemiological data and clinical trials suggest that n-3 polyunsaturated fatty acids (PUFA) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have preventive and therapeutic effects on depression; however, the underlying mechanism remains elusive. The present study aimed to examine the behavioral effects and antidepressant mechanism of n-3 PUFA using a forced swimming test. Eleven-week-old male Sprague-Dawley rats were fed an American Institute of Nutrition-93M diet containing 0%, 0.5% or 1% EPA and DHA relative to the total energy intake in their diet for 12 weeks (n=8 per group). Total dietary intake, body weight and hippocampus weights were not significantly different among groups. The groups administered 0.5% and 1% EPA+DHA diets had significantly higher levels of n-3 PUFA in their brain phospholipids compared to those in the control group. The immobility time was significantly decreased and the climbing time was significantly increased in the 0.5% and 1% EPA+DHA groups compared with those in the 0% EPA+DHA group. Plasma serotonin concentration and hippocampus c-AMP response element binding protein (CREB) expression were significantly increased in the 0.5% and 1% EPA+DHA groups compared with those in the 0% EPA+DHA group. Conversely, interleukin (IL)-6 expression was significantly reduced in the 0.5% and 1% EPA+DHA groups compared with that in the 0% EPA+DHA group. However, there were no dose-dependent effects of n-3 PUFA and no significant differences in expressions of IL-1β, tumor necrosis factor-α, brain-derived neurotrophic factor or phosphorylated CREB. In conclusion, long-term intake of EPA+DHA induced antidepressant-like effects in rats and overexpression of CREB via decreased IL-6 expression. © 2012 Elsevier Inc.

A tandem simulated moving bed (SMB) process, which consists of two four-zone SMB units (Ring I and Ring II) in series, has been developed previously for complete separation of a ternary bioproduct mixture. In all of previous studies on the optimization of such a tandem SMB process, the adsorbent particle sizes in Ring I and Ring II have been kept the same. To make a further improvement in the performance of a tandem SMB, one can adopt the strategy of making a difference between the adsorbent particle sizes of Ring I and Ring II, which was studied in this paper using the ternary paclitaxel-related mixture as an example separation system. The results showed that the proposed strategy led the adsorbent particle sizes in Ring I and Ring II to be selected in favor of reducing the product dilution of Ring I and reducing the pressure drop of Ring II, respectively. Such pattern of particle-size selection resulted in a marked improvement in the productivity of the tandem SMB of interest, which was confirmed for both the low-pressure and the high-pressure systems. Furthermore, such advantage of the proposed strategy became more pronounced as the selectivity related to the ternary separation was reduced. © 2011 Elsevier Ltd. All rights reserved.

Yoo D.H.,Hanyang University
Expert Review of Clinical Immunology | Year: 2014

Although biologic agents are effective in the treatment of rheumatoid arthritis, the high price of drugs and restricted health care budgets have restricted easy access to biologics. Eventually, the use of biologic disease-modifying antirheumatic drugs might be inversely associated with disease activity in countries with low gross domestic product. The EMA approved an infliximab biosimilar for the first time in September 2013. The first approval of a biosimilar monoclonal antibody by a major regulatory authority provided a global standard for subsequent biosimilars and for biopharmaceutical companies developing biosimilars. Biosimilars with a highly similar quality and efficacy profile at an acceptable lower cost would significantly increase affordability of biologic disease-modifying antirheumatic drugs in the treatment of rheumatoid arthritis. Here, we will review the current status of first biosimilar antibody agent and the potential discussion points raised against biosimilars. In addition, the importance of awareness on biosimilars for stakeholders is discussed. © 2014 Informa UK, Ltd.

Excessive activation of platelets is a causative factor for thrombotic diseases such as acute coronary syndrome or stroke, and various anti-platelet drugs were developed. Aspirin and clopidogrel have been used as gold standards for anti-platelet therapies, however, their clinical limitations including bleeding problem have increased the demand driving development of novel anti-platelet drugs with new targets. Among several activating pathways leading to platelet aggregation, the interaction between von Willebrand factor (vWF) and glycoprotein Ib, which mainly occurs under high shear stress in arterioles, is recently suggested to be a new promising target. The anti-thrombotic efficacy of anti-vWF agents, such as ARC1779, has been proved in several preclinical and clinical studies. Here, we will discuss the potential benefits of targeting vWF as a novel antiplatelet therapy, providing an insight into the role of vWF in increased thrombotic risk.

Zhang L.,Myongji University | Lee Y.-W.,Hanyang University | Jahng D.,Myongji University
Bioresource Technology | Year: 2011

The objective of this study was to evaluate the feasibility of anaerobic co-digestion of food waste and piggery wastewater, and to identify the key factors governing the co-digestion performance. The analytical results indicated that the food waste contained higher energy potential and lower concentrations of trace elements than the piggery wastewater. Anaerobic co-digestion showed a significantly improved biogas productivity and process stability. The results of co-digestion of the food waste with the different fractions of the piggery wastewater suggested that trace element might be the reason for enhancing the co-digestion performance. By supplementing the trace elements, a long-term anaerobic digestion of the food waste only resulted in a high methane yield of 0.396m3/kg VSadded and 75.6% of VS destruction with no significant volatile fatty acid accumulation. These results suggested that the typical Korean food waste was deficient with some trace elements required for anaerobic digestion. © 2011 Elsevier Ltd.

Cho E.C.,Washington University in St. Louis | Cho E.C.,Hanyang University | Zhang Q.,Washington University in St. Louis | Xia Y.,Washington University in St. Louis
Nature Nanotechnology | Year: 2011

In vitro experiments typically measure the uptake of nanoparticles by exposing cells at the bottom of a culture plate to a suspension of nanoparticles, and it is generally assumed that this suspension is well-dispersed. However, nanoparticles can sediment, which means that the concentration of nanoparticles on the cell surface may be higher than the initial bulk concentration, and this could lead to increased uptake by cells. Here, we use upright and inverted cell culture configurations to show that cellular uptake of gold nanoparticles depends on the sedimentation and diffusion velocities of the nanoparticles and is independent of size, shape, density, surface coating and initial concentration of the nanoparticles. Generally, more nanoparticles are taken up in the upright configuration than in the inverted one, and nanoparticles with faster sedimentation rates showed greater differences in uptake between the two configurations. Our results suggest that sedimentation needs to be considered when performing in vitro studies for large and/or heavy nanoparticles.

Mesenchymal stromal cells (MSCs) are emerging as candidate cells for the treatment of neurological diseases because of their neural replacement, neuroprotective, and neurotrophic effects. However, the majority of MSCs transplanted by various routes fail to reach the site of injury, and they have demonstrated only minimal therapeutic benefit in clinical trials. Therefore, enhancing the migration of MSCs to target sites is essential for this therapeutic strategy to be effective. In this study, we assessed whether inhibition of glycogen synthase kinase-3β (GSK-3β) increases the migration capacity of MSCs during ex vivo expansion. Human bone marrow MSCs (hBM-MSCs) were cultured with various GSK-3β inhibitors (LiCl, SB-415286, and AR-A014418). Using a migration assay kit, we found that the motility of hBM-MSCs was significantly enhanced by GSK-3β inhibition. Western blot analysis revealed increased levels of migration-related signaling proteins such as phospho-GSK-3β, β-catenin, phospho-c-Raf, phospho-extracellular signal-regulated kinase (ERK), phospho-β-PAK-interacting exchange factor (PIX), and CXC chemokine receptor 4 (CXCR4). In addition, real-time polymerase chain reaction demonstrated increased expression of matrix metalloproteinase-2 (MMP-2), membrane-type MMP-1 (MT1-MMP), and β-PIX. In the reverse approach, treatment with β-PIX shRNA or CXCR4 inhibitor (AMD 3100) reduced hBM-MSC migration. These findings suggest that inhibition of GSK-3β during ex vivo expansion of hBM-MSCs may enhance their migration capacity by increasing expression of β-catenin, phospho-c-Raf, phospho-ERK, and β-PIX and the subsequent up-regulation of CXCR4. Enhancing the migration capacity of hBM-MSCs by treating these cells with GSK-3β inhibitors may increase their therapeutic potential.

Chang S.-H.,Chung - Ang University | Kim H.-S.,Hanyang University
Polymer | Year: 2011

Moisture-induced package failures such as interfacial delamination and pop-corn cracking are common failure phenomena that occur during the solder reflow process in the semiconductor industry. Therefore, the hygroscopic properties of the package materials are crucial factors in the reliability of electronic packaging products. In this work, molecular dynamics (MD) simulation was performed to study the hygroscopic properties, including diffusivity and swelling strain, of epoxy materials with respect to temperature and moisture concentration. Hygroscopic material properties predicted by MD are discussed and compared with the experimental data. © 2011 Elsevier Ltd. All rights reserved.

Mohamed R.M.,Central Metallurgical Research and Development Institute | Mohamed R.M.,King Abdulaziz University | McKinney D.L.,MM Virtuoso Inc. | Sigmund W.M.,University of Florida | Sigmund W.M.,Hanyang University
Materials Science and Engineering R: Reports | Year: 2012

Rapid development of nanofabrication techniques has created many different types of advanced nanosized semiconductors. Photocatalytic materials used to degrade organic and inorganic pollutants now include, in addition to TiO 2, ZnO, Fe 2O 3, WO 3, MoS 2, and CdS. Nanoparticles' unique properties, e.g. surface to volume ratio and quantum effects, continue to improve and expand photocatalysis' role in areas like environmental remediation, odor control, sterilization, and renewable energy. Controlling semiconductor size, shape, composition, and microstructure promises to benefit future research and applications in these fields. This review examines recent advances at the interface of nanoscience and photocatalysis, especially pertaining to nanocatalyst enhancements, for current and future environmental applications. © 2011 Elsevier B.V.

Kim K.H.,Hanyang University | Haberl J.S.,Texas A&M University
Energy and Buildings | Year: 2015

This study developed a methodology for a calibrated simulation of single-family residential buildings using a three-parameter change-point regression model. This new method provides a reproducible systematic and consistent calibration procedure. The procedure consists of two parts: a sensitivity analysis that can analyze the characteristics of the building; and a calibration procedure that uses the results of the sensitivity analysis. In the first part, the characteristics of the case-study house were analyzed using a detailed sensitivity analysis with a three-parameter change-point regression model. In this procedure, the most to least influential parameters for each three-parameter coefficient for the house were identified. Next, the identified parameters for each three-parameter coefficient were adjusted to closely match the actual building energy use of the house. Using the procedure, the 36.9% global CV (RMSE) of the initial simulation was improved to 8.8% after calibrated simulation, which is within the accuracy criterion according to the ASHRAE Guideline 14-2014. This study was conducted using a case-study house in a hot and humid climate. However, the procedure developed should be useful for other climates as well. In addition, the results of calibrated simulation can help determining energy efficient measures that are appropriate for the house in the future. © 2015 Elsevier B.V. All rights reserved.

Holt J.W.,University of Washington | Rho M.,Hanyang University | Rho M.,CEA Saclay Nuclear Research Center | Weise W.,TU Munich
Physics Reports | Year: 2016

Chiral symmetry, first entering in nuclear physics in the 1970s for which Gerry Brown played a seminal role, has led to a stunningly successful framework for describing strongly-correlated nuclear dynamics both in finite and infinite systems. We review how the early, germinal idea conceived with the soft-pion theorems in the pre-QCD era has evolved into a highly predictive theoretical framework for nuclear physics, aptly assessed by Steven Weinberg: "it (chiral effective field theory) allows one to show in a fairly convincing way that what they (nuclear physicists) have been doing all along... is the correct first step in a consistent approximation scheme". Our review recounts both how the theory presently fares in confronting Nature and how one can understand its extremely intricate workings in terms of the multifaceted aspects of chiral symmetry, namely, chiral perturbation theory, skyrmions, Landau Fermi-liquid theory, the Cheshire cat phenomenon, and hidden local and mended symmetries. © 2015 Elsevier B.V.

Park S.-H.,Catholic University of Daegu | Shim J.-I.,Hanyang University
Applied Physics Letters | Year: 2013

The carrier density dependence of the polarization switching characteristics of the light emission in deep-ultraviolet AlGaN/AlN quantum well structures was investigated using the multiband effective-mass theory and non-Markovian model. The critical Al composition from transverse electric (TE) to transverse-magnetic (TM) polarization decreases gradually with increasing carrier density. This can be explained by the fact that matrix elements for TM-polarization above the band-edge (k | | = 0) is much larger than those for TE-polarization. That is, the light emission for TM-polarization becomes larger than that for TE-polarization at higher carrier density because carriers will occupy higher states above k | | = 0 in the conduction and valence bands. As a result, the critical Al composition is reduced with increasing carrier density. Also, the critical Al composition is observed to decrease with increasing well width. © 2013 AIP Publishing LLC.

Kim W.D.,Seoul National University | Kim Y.W.,Seoul National University | Cho I.J.,Seoul National University | Lee C.H.,Hanyang University | Kim S.G.,Seoul National University
Journal of Cell Science | Year: 2012

Nrf2 has an anti-carcinogenic effect. However, an increase in Nrf2 activity is also implicated in cancer chemoresistance. A switch from E-cadherin to N-cadherin affects the transdifferentiation and metastasis of cancer cells. In view of the key role of this switch in cancer malignancy, we investigated the regulatory effect of E-cadherin on Nrf2. In HEK293 cells, overexpression of E-cadherin inhibited the nuclear accumulation of Nrf2, and prevented Nrf2-dependent gene induction. GST pull-down and immunocytochemical assays verified the interaction between E-cadherin and Nrf2: E-cadherin bound the C-terminus of Nrf2, but not its N-terminus, which comprises the Neh2 domain responsible for phosphorylation of Ser40. Our finding that the mutation of Ser40 to alanine in Nrf2 did not affect the ability of E-cadherin to bind Nrf2 and repress target gene transactivation suggests that E-cadherin might not disturb the phosphorylation. Studies using mutant constructs of E-cadherin suggested that the b-catenin-binding domain contributes to the inhibitory effect of Ecadherin on Nrf2. Consistently, knockdown of β-catenin attenuated not only the effect of E-cadherin binding to Nrf2, but also Keap1-dependent ubiquitylation of Nrf2, and thereby increased Nrf2 activity, supporting the involvement of b-catenin in the interactions. Collectively, E-cadherin recruits Nrf2 through b-catenin, and assists the function of Keap1 for the inhibition of nuclear localization and transcriptional activity of Nrf2. In HepG2 cells, the loss of E-cadherin by either siRNA knockdown or treatment with TGFb1 enhanced the constitutive or inducible activity of Nrf2, implying that chemoresistance of cancer cells upon the loss of E-cadherin might be associated with Nrf2. © 2012.

Park C.,Hanyang University
International Journal of Geometric Methods in Modern Physics | Year: 2014

Ebadian et al. [Stability of bi-θ-derivations on JB*-triples, Int. J. Geom. Meth. Mod. Phys. 9(7) (2012) 1250051, 12 pp.] proved the Hyers-Ulam stability of bi-θ-derivations on JB*-triples. Under the conditions of the definition of bi-θ-derivation given in the above paper, the bi-θ-derivation must be zero. So the results given in the above paper must be trivial. Under the conditions in the main theorem, we can show that the related mapping must be zero. In this paper, we correct the statements of the results and prove the corrected theorems and corollaries. © World Scientific Publishing Company.

STUDY DESIGN.: Retrospective case-control study. OBJECTIVE.: A cost-effectiveness analysis was performed by comparing patients who received extension revision operations for adjacent segment disease (ASD) reusing the pedicle screws extracted from fused segments with patients who received conventional surgery. SUMMARY OF BACKGROUND DATA.: ASD often required extension revision surgery, and during extension surgery, pedicle screws maybe reused by extracting from the fused segments of primary surgery. METHODS.: Study examined 37 patients who received extension revision surgery for ASD from January 2003 to December 2013. For the fixation of extended segments during revision operation, in 16 cases the pedicle screws extracted from fused segments were reused (group R), and in 21 cases new pedicle screws were used (group?C) as a conventional method. Clinical outcomes were evaluated by means of Visual Analogue Scale (VAS) scores for lumbago and leg pain, and the Korean Oswestry disability index (K-ODI). Radiologic outcomes were evaluated from the extent of bone union. The total operating costs in the two groups were compared. RESULTS.: VAS scores for lumbago and leg pain, and the K-ODI measured at final follow up averaged 3.6 and 3.8, and 19.9 in group R, and 3.8 and 3.1, and 21.1 in group C, respectively (p?=?0.280, p?=?0.387, p?=?0.751). For radiologic outcomes, there was 1 case of nonunion in each group. The cost of surgery was 5,332 US dollars (USD) in group R, and 6,109 USD in group C, respectively (p?=?0.036). CONCLUSION.: Reusing pedicle screws extracted from the fused segments during extension revision operation for ASD can reduce the cost of surgery, and achieves clinical and radiological results similar to those of the conventional operation.Level of Evidence: 4. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.

Maiti U.N.,KAIST | Lee W.J.,KAIST | Lee J.M.,KAIST | Oh Y.,KAIST | And 5 more authors.
Advanced Materials | Year: 2014

Outstanding pristine properties of carbon nanotubes and graphene have limited the scope for real-life applications without precise controllability of the material structures and properties. This invited article to celebrate the 25th anniversary of Advanced Materials reviews the current research status in the chemical modification/doping of carbon nanotubes and graphene and their relevant applications with optimized structures and properties. A broad aspect of specific correlations between chemical modification/doping schemes of the graphitic carbons with their novel tunable material properties is summarized. An overview of the practical benefits from chemical modification/doping, including the controllability of electronic energy level, charge carrier density, surface energy and surface reactivity for diverse advanced applications is presented, namely flexible electronics/optoelectronics, energy conversion/storage, nanocomposites, and environmental remediation, with a particular emphasis on their optimized interfacial structures and properties. Future research direction is also proposed to surpass existing technological bottlenecks and realize idealized graphitic carbon applications. The current research status in the chemical modification/doping of carbon nanotubes and graphene is reviewed and their relevant applications in diverse areas, such as flexible electronics/optoelectronics, energy conversion/storage, nanocomposites and environmental remediation are discussed. An overview of specific correlations between chemical modification/doping of the graphitic carbons with their tunable material properties is presented, which offers research direction to realize idealized graphitic carbon nanostructures in future advanced applications. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Yoon Y.,Hanyang University
Nuclear Physics B | Year: 2014

We have discussed a particular class of exact cosmological solutions of the 4-dimensional low energy string gravity in the string frame. In the vacuum without matter and the 2-form fields, the exact cosmological solutions always give monotonically shrinking universes if the dilaton field is not a constant. However, in the presence of the 2-form fields and/or the radiation-like fluid in the string frame, the exact cosmological solutions show a minimum size of the universe in the evolution, but with an initial cosmological curvature singularity in the string frame. © 2014.

Yeh S.-W.,Hanyang University | Kug J.-S.,Korea Advanced Institute of Science and Technology | An S.-I.,Yonsei University
Asia-Pacific Journal of Atmospheric Sciences | Year: 2014

The climate community has made significant progress in observing, understanding and predicting El Niño and Southern Oscillation (ENSO) over the last 30 years. In spite of that, unresolved questions still remain, including ENSO diversity and extreme events, decadal modulation, predictability, teleconnection, and the interaction of ENSO with other climate phenomena. In particular, the existence of a different type of El Niño from the conventional El Niño has been proposed. This type of El Niño has occurred more frequently during the recent decades and received a great attention in the climate community. This review provides recent progresses on dynamics, decadal variability and future projection of El Niño, with a focus on the two types of El Niño. © The Korean Meteorological Society and Springer 2014.

Park S.H.,Chonnam National University | Lee C.S.,Hanyang University
Energy Conversion and Management | Year: 2014

From the perspectives of environmental conservation and energy security, dimethyl-ether (DME) is an attractive alternative to conventional diesel fuel for compression ignition (CI) engines. This review article deals with the application characteristics of DME in CI engines, including its fuel properties, spray and atomization characteristics, combustion performance, and exhaust emission characteristics. We also discuss the various technological problems associated with its application in actual engine systems and describe the field test results of developed DME-fueled vehicles. Combustion of DME fuel is associated with low NOx, HC, and CO emissions. In addition, PM emission of DME combustion is very low due to its molecular structure. Moreover, DME has superior atomization and vaporization characteristics than conventional diesel. A high exhaust gas recirculation (EGR) rate can be used in a DME engine to reduce NOx emission without any increase in soot emission, because DME combustion is essentially soot-free. To decrease NOx emission, engine after-treatment devices, such as lean NOx traps (LNTs), urea-selective catalytic reduction, and the combination of EGR and catalyst have been applied. To use DME fuel in automotive vehicles, injector design, fuel feed pump, and the high-pressure injection pump have to be modified, combustion system components, including sealing materials, have to be rigorously designed. To use DME fuel in the diesel vehicles, more research is required to enhance its calorific value and engine durability due to the low lubricity of DME, and methods to reduce NOx emission are also required. © 2014 Elsevier Ltd. All rights reserved.

Lee S.-H.,Hanyang University
Journal of Dynamic Systems, Measurement and Control, Transactions of the ASME | Year: 2010

This paper presents a discrete-time design of a dual-stage actuator control system with sliding mode for computer disk drives. A state estimator based discrete-time boundary layer sliding mode control scheme is developed for a dual-stage actuator, which consists of a voice coil motor and a microactuator. Considering dominant microactuator flexible mode dynamics and the interaction between the two actuators, an optimal sliding hyperplane is designed to maximize their cooperation so as to attain desired responses. An application example demonstrates the utility of the proposed sliding mode dual-stage actuator control scheme for track-seek in the microactuator range, settle, and track-follow. © 2010 by ASME.

Jun D.W.,Hanyang University
The Korean journal of hepatology | Year: 2011

Chronic liver disease is closely associated with lifestyle, and public enlightenment of the lifestyle factors is important in reducing prevalence of chronic liver disease. The KASL (Korean Association for the Study of the Liver) conducted a survey of basic information and epidemiological data regarding chronic liver diseases. A survey of chronic liver disease involving a total of 2,794 respondents was conducted. The respondents included patients and their guardians, visitors for health check-ups, and online pollees who completed a questionnaire on the awareness of fatty liver or chronic liver disease. Of the entire cohort, 854 (39.7%) said they have had or still have fatty liver or an elevated transaminase level (>40 IU/L), but only 23.4% of the respondents had visited a hospital. It was found that 35% of healthy subjects and 45% of patients and their guardians misunderstood hepatitis B as the hereditary disesase. Furthermore, 26% of the subjects responded that patients with inactive hepatitis B do not require regular follow-up. While 17.9% answered that it is not too late to test for liver cancer when symptoms arise, 38.8% believed that liver transplant in liver cancer patients has a low success rate and is thus not recommended. Despite the inundation of information and widespread media advertising, the awareness of chronic liver disease is unsatisfactory among Korean adults. Systematic nationwide studies are needed to obtain data and information regarding the prevalence of chronic liver disease and patterns of use of the health-care system.

Xu B.,Columbia University | Chen X.,Columbia University | Chen X.,Xian Jiaotong University | Chen X.,Hanyang University
Physical Review Letters | Year: 2013

Encapsulating a single water molecule inside an endohedral fullerene provides an opportunity for manipulating the H2O@C60 through the encapsulated polar H2O molecule. Using molecular dynamic simulations, we propose a strategy of electrical-driven transport of H 2O@C60 inside a channel, underpinned by the unique behavior of a water molecule free from a hydrogen-bonding environment. When an external electrical field is applied along the channel's axial direction, steady-state transport of H2O@C60 can be reached. The transport direction and rate depend on the applied electrical intensity as well as the polar orientation of the encapsulated H2O molecule. © 2013 American Physical Society.

Cho E.,Hanyang University | Choi M.,Sungkyunkwan University
Journal of Hydrology | Year: 2014

An understanding soil moisture spatio-temporal variability is essential for hydrological and meteorological research. This work aims at evaluating the spatio-temporal variability of near surface soil moisture and assessing dominant meteorological factors that influence spatial variability over the Korean peninsula from May 1 to September 29, 2011. The results of Kolmogorov-Smirnov tests for goodness of fit showed that all applied distributions (normal, log-normal and generalized extreme value: GEV) were appropriate for the datasets and the GEV distribution described best spatial soil moisture patterns. The relationship between the standard deviation and coefficient of variation (CV) of soil moisture with mean soil moisture contents showed an upper convex shape and an exponentially negative pattern, respectively. Skewness exhibited a decreasing pattern with increasing mean soil moisture contents and kurtosis exhibited the U-shaped relationship. In this regional scale (99,720 km2), we found that precipitation indicated temporally stable features through an ANOVA test considering the meteorological (i.e. precipitation, insolation, air temperature, ground temperature and wind speed) and physical (i.e. soil texture, elevation, topography, and land use) factors. Spatial variability of soil moisture affected by the meteorological forcing is shown as result of the relationship between the meteorological factors (precipitation, insolation, air temperature and ground temperature) and the standard deviation of relative difference of soil moisture contents (SDRDt ) which implied the spatial variability of soil moisture. The SDRDt showed a positive relationship with the daily mean precipitation, while a negative relationship with insolation, air temperature and ground temperature. The variation of spatial soil moisture pattern is more sensitive to change in ground temperature rather than air temperature changes. Therefore, spatial variability of soil moisture is greatly affected by meteorological factors and each of the meteorological factors has certain duration of effect on soil moisture spatial variability in regional scale. The results provide an insight into the soil moisture spatio-temporal patterns affected by meteorological and physical factors simultaneously, as well as the design criteria of regional soil moisture monitoring network at regional scale. © 2014 Elsevier B.V. All rights reserved.

Ryu S.E.,Hanyang University
Journal of Biochemistry | Year: 2012

The oxidation of cysteine sulphydryl in proteins produces sulphenic acid that can form a reversible disulphide bond with another cysteine. The disulphide bond formation often triggers switches in protein structure and activity, especially when the distance between the two cysteine sulphur atoms is longer than the resulting disulphide bond distance. As an early example for the reversible disulphide bond-mediated functional switches, the reduced and oxidized forms of the bacterial transcription factor OxyR were characterized by X-ray crystallography. Recently, the Drosophila vision signalling protein, the association of inactivation-no-afterpotential D (INAD) was analysed by structural and functional methods. The two conserved cysteines of INAD were found to cycle between reduced and oxidized states during the light signal processing in Drosophila eyes, which was achieved by conformation dependent modulation of the disulphide bond redox potential. The production of the hypertension control peptide angiotensins was also shown to be controlled by the reversible disulphide bond in the precursor protein angiotensinogen. The crystal structure of the complex of angiotensiongen with its processing enzyme renin elucidated the role of the disulphide bond in stabilizing the precursor-enzyme complex facilitating the production of angiotensins. The increasing importance of the disulphide bond-mediated redox switches in normal and diseased states has implications in the development of novel antioxidant-based therapeutic approaches. © 2012 The Authors. Published by Oxford University Press on behalf of the Japanese Biochemical Society. All rights reserved.

Lahiri I.,University of North Texas | Choi W.,University of North Texas | Choi W.,Hanyang University
Critical Reviews in Solid State and Materials Sciences | Year: 2013

Advent of nanotechnology has generated huge interest in application of carbon-based nanomaterials as a possible replacement for conventionally used graphite as anode of Li-ion batteries. Future Li-ion batteries demand high capacity, energy, power, and better safety, while graphite falls short of fulfilling all these necessities. Inspired by high conductivity, flexibility, surface area, and Li-ion insertion ability, a number of nano carbon materials, individually or as a composite, have been studied in detail to identify the best suitable material for next-generation energy storage devices. Many of these nano-C-based structures hold good promise, although issues like density of nanomaterials and scalability are yet to be addressed with confidence. This article aims to summarize the major research directions of nano-C materials in anodic application of Li-ion batteries and proposes possible future research directions in this widely studied field. Copyright © Taylor and Francis Group, LLC.

This study illustrates that consumers' GM food purchase decision is determined by a set of correlated variables. The interrelationship among the GM food purchase decision determinants is examined conceptually and empirically with a multi-attribute model, describing this interrelationship. Consumers' attitudes toward subjects such as innovation, science & technology as well as their trust towards the government's regulatory system of food safety and GM food are strong indicators of the consumers' GM food purchase decision. Given the limited availability of foods in the market which leads to a lack of understanding and experience of GM foods, consumers' knowledge and their search for information on food label appear to be weaker determinants of the GM food purchase decision for consumers.

Kim M.G.,Hanyang University
Surgical Laparoscopy, Endoscopy and Percutaneous Techniques | Year: 2015

Background: In the surgical treatment of perforated duodenal ulcer disease, laparoscopic surgery has become a key technique. However, difficult cases are not eligible for laparoscopic surgery. The purpose of this study was to evaluate the risk factors for postoperative complications and to examine the safety and effectiveness of laparoscopic surgery. Materials and Methods: Seventy duodenal ulcer perforation patients who underwent laparoscopic surgery between July 2010 and March 2014 were reviewed. The type of surgery was chosen on the basis of the size of the perforation. All patients were classified into 2 groups according to the surgical treatment method: primary repair with omentopexy (PR group, n=56) and distal gastrectomy with truncal vagotomy (DG group, n=14). Results: No conversions to open surgery occurred. Three deaths (mortality rate, 4.1%) occurred within 90 postoperative days. Postoperative complications, including 5 severe complications, occurred in 9 patients. There were no differences between the PR and DG groups, except in the mean operation time. In univariate analysis, history of nonsteroidal anti-inflammatory drug use, American Society of Anesthesiologist score (over 3), presence of shock, and time to surgery from symptom onset until surgery (over 48 h) were prognostic factors for postoperative complications. Of particular note, the different perforation sizes were not significantly different. Multivariate analysis showed that history of nonsteroidal anti-inflammatory drug use and treatment delay (48 h) were independent risk factors for overall postoperative complications. The presence of shock on admission was a risk factor for severe postoperative complications. Conclusions: Our results suggest that laparoscopic surgery may be applied to all duodenal ulcer perforations. However, because of the learning period, we believe that laparoscopic surgery may not be suited to every surgeon. However, when performed by laparoscopic experts, laparoscopic surgery can be a valuable approach for treating difficult duodenal ulcer perforations. © 2015 Wolters Kluwer Health, Inc. All rights reserved.

Weber J.,Max Planck Institute of Colloids and Interfaces | Du N.,NRC Institute for Chemical Process and Environmental Technology | Guiver M.D.,NRC Institute for Chemical Process and Environmental Technology | Guiver M.D.,Hanyang University
Macromolecules | Year: 2011

The intrinsic microporosity of hydrolyzed polymeric films was studied by means of gas sorption using nitrogen and carbon dioxide as probe molecules. X-ray scattering was used to get a better insight into the polymer microstructure. The results show that the polymer chain stiffness is not affected by the degree of hydrolysis, it can be assumed that the reduction of the size of the free-volume elements is due to chain deformations. The presence of this hysteresis points to a much denser structure compared to the initial samples. The unmodified PIM-1 exhibit microporosity as determined by nitrogen sorption at 77 K, and PIM1s modified with carboxylic acid groups did not take up nitrogen, except they were precipitated from solution. Temperature-dependent SAXS measurements show that microstructure of the carboxylated polymer films is changed upon heating.

Yun K.-S.,Pusan National University | Yeh S.-W.,Hanyang University | Ha K.-J.,Pusan National University
Journal of Geophysical Research: Atmospheres | Year: 2013

The distinct impact of tropical Indian Ocean (IO) and western Pacific (WP) sea surface temperatures (SSTs) after the El Niño winter has been investigated in relation to the summer North Pacific high (NPH) and western North Pacific subtropical high (WNPSH). After the El Niño winter, warming of the IO leads to a summer eastern Pacific (EP) SST anomaly distinct from the cooling of WP; EP cooling occurs in the extreme IO warming case and EP warming in the WP cooling case. Both the warming of the IO and cooling of the WP are responsible for the development of the WNPSH, whereas the summer EP cooling induces an enhanced NPH, especially if it coexists with IO warming. The IO warming triggers an abrupt termination of the El Niño event by causing the easterly anomaly in the WP, which leads to the coexistence of IO warming and EP cooling during the boreal summer. The tropical EP cooling may change the North Pacific SST anomalies via the atmospheric bridge and consequently strengthen the extratropical NPH. The experimental results, which have been obtained from the use of atmospheric general circulation model, support the distinct roles of EP cooling on the NPH and of IO warming and WP cooling on the WNPSH. This finding suggests that the combined effect of IO warming and EP cooling generates a coupled pattern of NPH and WNPSH. Key PointsIO warming and WP cooling induce the development of the WNPSHIO warming-related summer EP cooling induces an enhanced NPHIO warming and EP cooling generate a coupled pattern of NPH and WNPSH ©2013. American Geophysical Union. All Rights Reserved.

Cheng L.,Shanghai University | Ge X.-H.,Shanghai University | Sin S.-J.,Hanyang University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2014

Generically, the black brane solution with planar horizons is thermodynamically stable. We find a counter-example to this statement by demonstrating that an anisotropic black brane is unstable. We present a charged black brane solution dual to a spatially anisotropic finite temperature N=4 super Yang-Mills plasma at finite U(1) chemical potential. This static and regular solution is obtained both numerically and analytically. We uncover rich thermodynamic phase structures for this system by considering the cases when the anisotropy constant "a" takes real and imaginary values, respectively. In the case a2 > 0, the phase structure of this anisotropic black brane is similar to that of Schwarzschild-AdS black hole with S3 horizon topology, yielding a thermodynamical instability at smaller horizon radii. For the condition a2 ≤ 0, the thermodynamics is dominated by the black brane phase for all temperatures. © 2014 The Authors.

Chemoresistive carbon black-polyvinylpyrrolidone (CB-PVP) composite sensors were prepared with different physical properties in CB dispersion, CB content and film thickness by using the fabrication method of a drop casting or a spin coating. To verify the influences of the physical properties, their vapor detection characteristics were measured and evaluated in terms of the magnitude in sensor responses. From these evaluations, the highest response was observed around at the optimized CB contents of 12.5 wt.% for the drop casting and 17.5 wt.% for the spin coating. Furthermore, homogeneous CB dispersion and careful thickness regulation were found to be necessary to achieve a sensor with good performance. © 2009 Elsevier B.V. All rights reserved.

Kwon S.J.,Hanyang University
Journal of Gastric Cancer | Year: 2011

Since January of 2010, the seventh edition of UICC tumor node metastasis (TNM) Classification, which has recently been revised, has been applied to almost all cases of malignant tumors. Compared to previous editions, the merits and demerits of the current revisions were analyzed. Many revisions have been made for criteria for the classification of lymph nodes. In particular, all the cases in whom the number of lymph nodes is more than 7 were classified as N3 without being differentiated. Therefore, the coverage of the N3 was broad. Owing to this, there was no consistency in predicting the prognosis of the N3 group. By determining the positive cases to a distant metastasis as TNM stage IV, the discrepancy in the TNM stage IV compared to the sixth edition was resolved. In regard to the classification system for an esophagogastric (EG) junction carcinoma, it was declared that cases of an invasion to the EG junction should follow the classification system for esophageal cancer. A review of clinical cases reported from Asian patients suggests that it would be more appropriate to follow the previous editions of the classification system for gastric cancer. In addition, in the classification of the TNM stages in the overall cases, the discrepancy in the prognosis between the different stages and the consistency in the prognosis between the same TNM stages were achieved to a lesser extent as compared to that previously. Accordingly, further revisions are needed to develop a purposive classification method where the prognosis can be predicted specifically to each variable and the mode of the overall classification can be simplified. © 2011 by The Korean Gastric Cancer Association.

Chung J.H.,Hanyang University | Ryu J.H.,Korea National University of Transportation
Ceramics International | Year: 2012

We successfully prepared β-SiAlON:Eu 2+ phosphors with composition of Eu xSi 6-zAl zO yN 8-y (y = z - 2x, x = 0.018, z = 0.23) by gas-pressured synthesis for application to LED. The crystal phase, microstructure, PL emission and thermal quenching properties were investigated in detail. The β-SiAlON:Eu 2+ phosphors absorbed broad UV-vis spectral region, and showed a single intense broadband emission near 538 nm. The Stokes shift and zero-phonon line were calculated mathematically, and also estimated from the spectral data. The β-SiAlON:Eu 2+ green phosphor showed superior thermal quenching properties compared to commercial silicate (SrBaSiO 4:Eu 2+) green phosphor. The white light-emitting diode (LED) using the prepared β-SiAlON:Eu 2+ green phosphor exhibited high color gamut, and good optical stability in high working temperature. © 2012 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

Kim J.-A.,University of Seoul | Shin D.-U.,Hanyang University
Journal of Combinatorial Theory. Series A | Year: 2013

We introduce new combinatorial models, called zigzag strip bundles, over quantum affine algebras Uq(Bn (1)), Uq(Dn (1)) and Uq(Dn+1 (2)), and show that the sets of all zigzag strip bundles for Uq(Bn (1)), Uq(Dn (1)) and Uq(Dn+1 (2)) realize the crystal bases B( ∞ ) of Uq -(Bn (1)), Uq -(Dn (1)) and Uq -(Dn+1 (2)), respectively. Further, we discuss the connection between zigzag strip bundle realization, Nakajima monomial realization, and polyhedral realization of the crystal B( ∞ ). © 2013 Elsevier Inc.

Kim H.O.,Yonsei University | Baek E.J.,Hanyang University
Tissue Engineering - Part A | Year: 2012

In vitro generation of artificial red blood cells (RBCs) is very important to overcome insufficient and unsafe blood supply. Despite recent progresses in RBCs engineering from several stem cell sources, none of them could succeed in generation of functional RBCs in the absence of serum/plasma and feeder cells. Without the elimination of serum and plasma, human RBC engineering in a large scale is impossible, especially for the future bioreactor system. Using an appropriate combination of cost-effective and safe reagents, the present study demonstrated the terminal maturation of hematopoietic stem cells into enucleated RBCs, which were functional comparable to donated human RBCs. Surprisingly, the viability of erythroid cells was higher in our serum-and feeder-free culture condition than in the previous serum-added condition. This was possible by supplementation with vitamin C in media and hypothermic conditions. Also, our report firstly presents the storability of artificial RBCs, which possibility is essential for clinical application. In summary, our report demonstrates engineering of human applicable RBCs with a dramatically enhanced viability and shelf-life in both serum-and stroma-free conditions. This innovative culture technology could contribute to the realization of the large-scale pharming of human RBCs using bioreactor systems. © 2012 Mary Ann Liebert, Inc.

Kim J.K.,Korea University | Choi K.-J.,CHA Medical University | Lee M.,Hanyang University | Jo M.-H.,CHA Medical University | Kim S.,CHA Medical University
Biomaterials | Year: 2012

MicroRNAs (miRNA, miR) have been reported as cancer biomarkers that regulate tumor suppressor genes. Hence, simultaneous detecting and inhibiting of miRNA function will be useful as a cancer theragnostics probe to minimize side effects and invasiveness. In this study, we developed a cancer-targeting therangostics probe in a single system using an AS1411 aptamer - and miRNA-221 molecular beacon (miR-221 MB)-conjugated magnetic fluorescence (MF) nanoparticle (MFAS miR-221 MB) to simultaneously target to cancer tissue, image intracellularly expressed miRNA-221 and treat miRNA-221-involved carcinogenesis. AS1411 aptamer-conjugated MF (MFAS) nanoparticles displayed a great selectivity and delivery into various cancer cell lines. The miR-221 MB detached from the MFAS miR-221 MB in the cytoplasm of C6 cells clearly imaged miRNA-221 biogenesis and simultaneously resulted in antitumor therapeutic effects by inhibiting miRNA function, indicating a successful astrocytoma-targeting theragnostics. MFAS miRNA MB can be easily applied to other cancers by simply changing a targeted miRNA highly expressed in cancers. © 2011 Elsevier Ltd.

Ryu H.-Y.,Inha University | Shim J.-I.,Hanyang University
IEEE Journal of Quantum Electronics | Year: 2010

Light extraction efficiency (LEE) in thin-film InGaN vertical light-emitting diode (LED) structures with photonic crystal patterns is studied using the three-dimensional finite-difference time-domain simulation. We systematically investigate the dependence of LEE on various structural parameters of photonic crystal vertical LEDs such as the thickness of the p-GaN and n-GaN layers, and air-hole depth and size. It is found that high LEE of >80% is obtainable from unencapsulated photonic crystal LEDs for a wide range of structural parameters. In particular, higher LEE is observed for the structures with relatively long-period photonic crystal patterns and possible mechanisms for the large enhancement of LEE are discussed. © 2009 IEEE.

Kang B.J.,Hanyang University
Machine Vision and Applications | Year: 2010

Although iris recognition technology has been reported to be more stable and reliable than other biometric systems, performance can be degraded due to many factors such as small eyes, camera defocusing, eyelash occlusions and specular reflections on the surface of glasses. In this paper, we propose a new multi-unit iris authentication method that uses score level fusion based on a support vector machine (SVM) and a quality assessment method for mobile phones. Compared to previous research, this paper presents the following two contributions. First, we reduced the false rejection rate and improved iris recognition accuracy by using iris quality assessment. Second, if even two iris images were determined to be of bad quality, we captured the iris images again without using a recognition process. If only one iris image among the left and right irises was regarded as a good one, it was used for recognition. However, if both the left and right iris images were good, we performed multi-unit iris recognition using score level fusion based on a SVM. Experimental results showed that the accuracy of the proposed method was superior to previous methods that used only one good iris image or those methods that used conventional fusion methods. © Springer-Verlag 2009.

Heo E.,Seoul National University | Kim J.,Hanyang University | Cho S.,Economy Energy
International Journal of Hydrogen Energy | Year: 2012

In this study, we evaluated six hydrogen-producing methods using a fuzzy analytic hierarchy process (AHP) under benefits, opportunities, costs, and risks concepts. Twelve factors were set up, and the weights of each factor were appraised using the fuzzy AHP method. We conclude that steam methane reforming is the optimal method for hydrogen production in Korea; equipment investment cost and market size are the most important factors, while the indirect benefits such as spillover effect, human resource development, and environmental contribution are less important. The results show that achieving economic feasibility and lowering risks are very important. Therefore, considering stable natural gas prices and unconventional gas production, steam methane reforming is a promising option for hydrogen production. Copyright © 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

Lee K.S.,Hanyang University
International Journal of Green Energy | Year: 2011

Coupled hydrogeological-thermal simulation of the standing column well (SCW) system is essential to provide an optimized configuration and operation schedule for boreholes on the site. This paper presents numerical investigations and thermohydraulic evaluation of SCW system operating under continuous flow regime. A three-dimensional numerical model for groundwater flow and heat transport is used to analyze the heat exchange in the ground. The model includes the effects of convection and conduction heat transfer, heat loss to the adjacent confining strata, and hydraulic anisotropy. The operation scenario consists of continuous injection and recovery, and four periods per year to simulate the seasonal temperature conditions. For different parameters of the system, performances have been evaluated in terms of variations in the recovery temperature. The calculated temperatures at the producing pipe were relatively constant within a certain range through the year and fluctuating quarterly a year. Pipe-to-pipe distance, injection/production rate, ground thickness, and permeability considered in the model are shown to impact the predicted temperature profiles at each stage and the recovery water temperature. The influence of pressure gradient, which determines the direction and velocity of regional groundwater flow, is also substantial. © Taylor & Francis Group, LLC.

Dewitte B.,CNRS Geophysical Research and Oceanographic Laboratory | Yeh S.-W.,Hanyang University | Thual S.,CNRS Geophysical Research and Oceanographic Laboratory
Climate Dynamics | Year: 2013

Vertical stratification changes at low frequency over the last decades are the largest in the western-central Pacific and have the potential to modify the balance between ENSO feedback processes. Here we show evidence of an increase in thermocline feedback in the western-central equatorial Pacific over the last 50 years, and in particular after the climate shift of 1976. It is demonstrated that the thermocline feedback becomes more effective due to the increased stratification in the vicinity of the mean thermocline. This leads to an increase in vertical advection variability twice as large as the increase resulting from the stronger ENSO amplitude (positive asymmetry) in the eastern Pacific that connects to the thermocline in the western-central Pacific through the basin-scale 'tilt' mode. Although the zonal advective feedback is dominant over the western-central equatorial Pacific, the more effective thermocline feedback allows for counteracting its warming (cooling) effect during warm (cold) events, leading to the reduced covariability between SST and thermocline depth anomalies in the NINO4 (160°E-150°W; 5°S-5°N) region after the 1976 climate shift. This counter-intuitive relationship between thermocline feedback strength as derived from the linear relationship between SST and thermocline fluctuations and stratification changes is also investigated in a long-term general circulation coupled model simulation. It is suggested that an increase in ENSO amplitude may lead to the decoupling between eastern and central equatorial Pacific sea surface temperature anomalies through its effect on stratification and thermocline feedback in the central-western Pacific. © 2012 Springer-Verlag.

Moon H.,Hanyang University
IEEE Journal on Selected Areas in Communications | Year: 2016

Channel-adaptive random access is proposed to reduce the required transmission power for random access in TDD-based wireless systems. With channel-adaptive random access, a remote station measures the channel state of the downlink, estimates the channel state of the corresponding uplink based on the downlink measurement, and transmits a random access packet only when the channel satisfies a predetermined transmission condition. Thus, transmission is delayed until the channel satisfies the transmission condition. With conventional channel-adaptive random access, a remote station continuously measures the channel state to check if the channel satisfies the transmission condition, which consumes a large amount of power. In this paper, we propose a discontinuous channel measurement scheme for channel-adaptive random access to reduce the power consumption. The performance of the proposed method is investigated in terms of the detection performance of a random access packet, transmission delay, and the power consumption of the receiver. © 1983-2012 IEEE.

Li N.,National Research Council Canada | Li N.,Georgia Institute of Technology | Guiver M.D.,National Research Council Canada | Guiver M.D.,Hanyang University
Macromolecules | Year: 2014

The search for the next generation of highly ion-conducting polymer electrolyte membranes has been a subject of intense research because of their potential applications in energy storage and transformation devices, such as fuel cells, vanadium flow batteries, membrane-based artificial photosynthesis, water electrolysis, or water treatment processes such as electrodialysis desalination. Nanochannels that contain ionic groups, through which "hydrated" ions can pass, are believed to be of key importance for efficient ion transport in polymer electrolytes membranes. In this Perspective, we present an overview of the approaches to induce ion-conducting nanochannel formation by self-assembly, using polymer architecture such as block or comb-shaped copolymers. The transport properties of ion-containing aromatic copolymers are examined to obtain an insight into the fundamental behavior of these materials, which are targeted toward applications in fuel cells and other electrochemical devices. Challenges in obtaining well-defined nanochannel morphologies, and possible strategies to improve transport properties in aromatic copolymers having structures with the potential to withstand operation in electrochemical/chemical devices, are discussed. Opportunities for the application of ion-containing aromatic copolymer membranes in fuel cells, vanadium flow batteries, membrane-based artificial photosynthesis, electrolysis, and electrodialysis are also reviewed. Research needs for further improvements in ionic conductivity and durability, and their applications are identified. © Published 2014 by the American Chemical Society.

Shin Y.U.,Hanyang University
Korean journal of ophthalmology : KJO | Year: 2012

Chronic sclerosing sialadenitis, also known as Kuttner tumor, is a chronic inflammatory disease of the salivary glands that is reported in a few cases in medical literature. Recent reports suggest that certain aspects of sclerosing diseases, including chronic sclerosing sialadenitis or dacryoadenitis, should be classified under immunoglobulin G4 (IgG4)-related sclerosing disease based on immunohistochemical studies. This study reports an unusual case of IgG4-related sclerosing disease appearing simultaneously in the lacrimal glands, submandibular glands, and extraocular muscles. A 56-year-old male presented with complaints of bilateral eyelid swelling and proptosis that began two years ago. Computed tomography confirmed that bilateral submandibular enlargements also existed five years ago in the subject. Orbital computed tomography and magnetic resonance imaging revealed bilateral lacrimal gland enlargement and thickening of extraocular muscles. Typical findings of chronic sclerosing dacryoadenitis were revealed upon pathologic exam of the right lacrimal gland. Immunostaining revealed numerous IgG4-positive plasma cells. Through these clinical features, we make a diagnosis of IgG4-relataed sclerosing disease in the subject.

Jung S.H.,Gyeongsang National University | Jeon J.,Korea Advanced Institute of Science and Technology | Kim H.,Korea Advanced Institute of Science and Technology | Jaworski J.,Hanyang University | And 2 more authors.
Journal of the American Chemical Society | Year: 2014

Chiral materials composed of organized nanoparticle superstructures have promising applications to photonics and sensing. Reliable customization of the chiroptical properties of these materials remains an important goal; hence, we report a customizable scheme making use of modular gelator components for controlling the helicity and formation of nanofibers over long length scales resulting in hydrogel templates. Controlled growth of gold nanoparticles at spatially arranged locations along the nanofiber is achieved by UV reduction of Au(I) ions on the supramolecular templates. The resulting materials were found to have significant interparticle interactions and well-defined helicity to provide high quality, chiroptically active materials. With this novel approach, the tailored assembly of nanoparticle superstructures with predictable chiroptical properties can be realized in high yield, which we expect to allow rapid advancement of chiral nanomaterials research. © 2014 American Chemical Society.

Lee W.J.,KAIST | Maiti U.N.,KAIST | Lee J.M.,KAIST | Lim J.,KAIST | And 2 more authors.
Chemical Communications | Year: 2014

Substitutional heteroatom doping is a promising route to modulate the outstanding material properties of carbon nanotubes and graphene for customized applications. Recently, (nitrogen-) N-doping has been introduced to ensure tunable work-function, enhanced n-type carrier concentration, diminished surface energy, and manageable polarization. Along with the promising assessment of N-doping effects, research on the N-doped carbon based composite structures is emerging for the synergistic integration with various functional materials. This invited feature article reviews the current research progress, emerging trends, and opening opportunities in N-doped carbon based composite structures. Underlying basic principles are introduced for the effective modulation of material properties of graphitic carbons by N-doping. Composite structures of N-doped graphitic carbons with various functional materials, including (i) polymers, (ii) transition metals, (iii) metal oxides, nitrides, sulphides, and (iv) semiconducting quantum dots are highlighted. Practical benefits of the synergistic composite structures are investigated in energy and catalytic applications, such as organic photovoltaics, photo/electro-catalysts, lithium ion batteries and supercapacitors, with a particular emphasis on the optimized interfacial structures and properties. © the Partner Organisations 2014.

Yoon G.H.,Hanyang University
Computer Methods in Applied Mechanics and Engineering | Year: 2016

In this research, a new finite element (FE) based topology optimization (TO) for turbulent flow was developed using the Spalart-Allmaras (S-A) equation, which is one of the Reynolds-Averaged Navier-Stokes (RANS) equations. Despite many innovative works on the subject of fluidic TO, it is rare to consider the influence of turbulent flow in TO. To consider the effect of complex turbulent fluid motion, this research considered the S-A model developed mainly for aerodynamic flows. For a successful TO, one primary issue is modification of the S-A turbulent model to account for topological evolution during the optimization process. To address this issue, we proposed the addition of penalization terms to the original governing equations. To show the validity of the present approach and the effect of turbulent flow on optimal layouts, some two dimensional benchmark designs studied for laminar flow were reconsidered. By considering the effect of turbulent flow, the eddy viscosity values were increased at some local regions due to the Boussinesq hypothesis, and naturally optimal layouts affected by the spatially varying viscosity were obtained in turbulent flow. It was also found that the balance between the inertia force and the viscosity force plays an important role in topological designs. © 2016 Elsevier B.V.

Lee K.S.,Hanyang University
Petroleum Science and Technology | Year: 2011

This numerical study was undertaken to investigate and compare the performances of polymer flood processes through horizontal or vertical wells. To achieve the objective, the author performed an extensive numerical simulation for 3 different well configurations under polymer flood followed by waterflood. The potential for a horizontal well application was assessed through different scenarios in combinations of injection and production wells and reservoir geometry. Other parameters included the length and spacing of horizontal injectors and horizontal or vertical producers. For different parameters of the system, performances were compared in terms of cumulative recovery and water-oil ratio at the production well and pressure drop or injectivity at the injection well. Results demonstrate that additional oil can be recovered and injectivity was significantly improved by utilizing a combination of horizontal wells when the same volume of fluid is injected into the reservoir. The improvement of injectivity through a horizontal injection well was higher when it was combined with a horizontal producer. Parameters such as reservoir thickness, well spacing, and well length are also shown to impact the predicted injectivity. Improvement in injectivity is obtained for thicker and larger reservoirs and longer horizontal wells. Copyright © Taylor & Francis Group, LLC.

Wang G.,CAS Yantai Institute of Coastal Zone Research | Wang Y.,CAS Yantai Institute of Coastal Zone Research | Chen L.,CAS Yantai Institute of Coastal Zone Research | Choo J.,Hanyang University
Biosensors and Bioelectronics | Year: 2010

Aptamers are single-strand DNA or RNA selected in vitro that bind specifically with a broad range of targets from metal ions, organic molecules, to proteins, cells and microorganisms. As an emerging class of recognition elements, aptamers offer remarkable convenience in the design and modification of their structures, which has motivated them to generate a great variety of aptamer sensors (aptasensors) that exhibit high sensitivity as well as specificity. On the other hand, the development of nanoscience and nanotechnology has generated nanomaterials with novel properties compared with their counterparts in macroscale. By integrating their strengths of both fields, recently, versatile aptamers coupling with novel nanomaterials for designing nanomaterial-assisted aptasensors (NAAs) make the combinations universal strategies for sensitive optical sensing. NAAs have been considered as an excellent sensing platform and found wide applications in analytical community. In this review, we summarize recent advances in the development of various optical NAAs, employing various detection techniques including colorimetry, fluorometry, surface-enhanced Raman scattering (SERS), magnetic resonance imaging (MRI) and surface plasmon resonance (SPR). © 2009 Elsevier B.V. All rights reserved.

Hong S.-H.,Kangwon National University | Kim K.-S.,Hanyang University | Oh I.-H.,Catholic University of Korea
Stem Cells | Year: 2015

Hematopoiesis is governed by a multidimensional regulatory network involving both intrinsic and extrinsic factors that control self-renewal and differentiation of hematopoietic stem cells (HSCs) through the coordination of influences that affect cell fate. Increasing evidence indicates that microRNAs (miRNAs), short noncoding RNAs of approximately 22 nucleotides, play a central role in orchestrating these regulatory mechanisms to modulate the multiple entities of hematopoietic function in a cell-type specific manner, including self-renewal, lineage commitment, and survival of HSCs as well as their microenvironmental crosstalk. Here, we summarize the current understanding regarding the regulatory effects of miRNA on hematopoietic cells, thus enlightening their role in fine-tuning HSC function and hematopoietic homeostasis. Stem Cells 2015;33:1-7 © 2014 AlphaMed Press.

Lim D.-W.,Seoul National University | Lim D.-W.,Korea Atomic Energy Research Institute | Chyun S.A.,Seoul National University | Suh M.P.,Seoul National University | Suh M.P.,Hanyang University
Angewandte Chemie - International Edition | Year: 2014

To develop a metal-organic framework (MOF) for hydrogen storage, SNU-200 incorporating a 18-crown-6 ether moiety as a specific binding site for selected cations has been synthesized. SNU-200 binds K+, NH4 +, and methyl viologen(MV2+) through single-crystal to single-crystal transformations. It exhibits characteristic gas-sorption properties depending on the bound cation. SNU-200 activated with supercritical CO2 shows a higher isosteric heat (Qst) of H2 adsorption (7.70 kJ mol-1) than other zinc-based MOFs. Among the cation inclusions, K+ is the best for enhancing the isosteric heat of the H2 adsorption (9.92 kJ mol-1) as a result of the accessible open metal sites on the K+ ion. Crown ethers strut their stuff: The metal-organic framework SNU-200 incorporates 18-crown-6 moieties as a cation binding site. SNU-200 binds K+, NH4 +, and methyl viologen2+ (MV2+) and their counteranions. Its gas sorption properties depend on the bound cation. The K+/SCN - bound SNU-200 shows the highest isosteric heat (9.92 kJ mol -1) of H2 adsorption, a result of the open metal sites on the K+ ions. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Kim S.-K.,Hanyang University
Journal of the Korean Physical Society | Year: 2011

For photolithography technology, the double patterning (DP) process has been supported for resolution and cost. However, the additional DP process results in additional yield liability and increased wafer cost. In this paper, the litho-cure-litho-etch (LCLE) process is researched to reduce complexity and the disadvantage of the DP process. Advanced modeling algorithms for the spin coating and the exposure processes are introduced to explore the pattern interaction between the two lithography processes of the LCLE process. The pattern interaction of the LCLE process is discussed in terms of the fluctuation of a wet resist during spin coating and in terms of the optical properties of a resist due to the chemical effects of resist exposure to light. Based on the reasonability of simulation results, the modeling methods for the spin-coating and the exposure processes in the LCLE process are reliable.

Lee Y.H.,Korea University | Bae S.-C.,Hanyang University | Song G.G.,Korea University
Clinical and Experimental Rheumatology | Year: 2013

Objective. The aim of this study was to assess the effects of anti-tumour necrosis factor (TNF) agents on hepatitis B virus (HBV) reactivation in hepatitis B surface antigen (HBsAg)-negative and anti-hepatitis B core (HBc)-positive patients (HBV occult carriers) with rheumatic diseases. Methods. Evidence of HBV reactivation after anti-TNF therapy in HBV occult carriers with a rheumatic disease was studied by summarising results and by performing meta-analysis analysis. Results. A total of 468 HBsAg-negative and anti-HBc-positive patients with a rheumatic disease undergoing treatment with an anti-TNF agent were identified in nine studies. The anti-TNF agents used were etanercept in 269 cases, adalimumab in 95, and infliximab in 100 cases, and these were administered for rheumatoid arthritis (RA) in 327 patients, ankylosing spondylitis in 49, and psoriatic arthritis (PsA) in 73 patients. Follow-up periods ranged from 6 to 60 months. HBV reactivation in patients on an anti-TNF agent was reported in 8 cases (8/468 = 1.7%). Seven of these patients had RA and 1 had PsA. Seven patients received etanercept and one adalimumab. HBV-DNA was detectable in 7 of these 8 cases. Antiviral treatment was administered in 6 of the 8 (lamivudine in 2, entecavir in 4) and clinical outcomes were satisfactory in all 8 patients. Conclusions. HBV reactivation was found in 8 (1.7%) patients among 468 HBsAg-negative and anti-HBc-positive patients with rheumatic diseases treated with anti-TNF agents. Our data suggest that HBsAg-negative and anti-HBc-positive patients undergoing anti-TNF therapy need to be carefully monitored during anti-TNF therapy. © Clinical and Experimental Rheumatology 2012.

Yoo D.-H.,Hanyang University
Lupus | Year: 2010

Systemic lupus erythematosus is a prototype of heterogeneous autoimmune disease. There have been few newly approved therapeutic agents in lupus treatment for many reasons. Several animal studies and human data have shown that many potential cytokines are related to the pathogenesis and disease activity of systemic lupus erythematosus. Cytokines are produced by many immune cell types and have variable functions in the immune system. Following the success of biological agents in the treatment of inflammatory arthritis, inflammatory bowel disease, and psoriasis, biological targeting to specific cytokines or receptor molecules is now promising in the treatment of systemic lupus erythematosus. In addition to B-cell deleting modalities, clinical trials targeting potential cytokines associated with disease pathogenesis are underway at various clinical stages. Among potential cytokines, targeting agents against B-cell activating factor and interferon-alpha are in the most advanced stage, and belimumab (anti-B-cell activating factor antibody) could be the first biological agent approved in the treatment of systemic lupus erythematosus. Anti-tumor necrosis factor was tried with some success, but with a potential risk of infection in a small number of patients. In this review, we discuss the rationale for anticytokine therapies and review agents currently in clinical trials, and those that could be developed in the near future for systemic lupus erythematosus. We present the results mostly from published trials and data from http://clinicaltrials.gov/ct2/ © 2010 The Author(s).

Kim S.,Hongik University | Cho T.,Hanyang University
Journal of the Acoustical Society of America | Year: 2013

Categorical perception experiments were performed on an English /b-p/ voice onset time (VOT) continuum with native (American English) and non-native (Korean) listeners to examine whether and how phonetic categorization is modulated by prosodic boundary and language experience. Results demonstrated perceptual shifting according to prosodic boundary strength: A longer VOT was required to identify a sound as /p/ after an intonational phrase than a word boundary, regardless of the listeners' language experience. This suggests that segmental perception is modulated by the listeners' computation of an abstract prosodic structure reflected in phonetic cues of phrase-final lengthening and domain-initial strengthening, which are common across languages. © 2013 Acoustical Society of America.

Justo J.J.,Dongguk University | Mwasilu F.,Dongguk University | Lee J.,Hanyang University | Jung J.-W.,Dongguk University
Renewable and Sustainable Energy Reviews | Year: 2013

This paper presents the latest comprehensive literature review of AC and DC microgrid (MG) systems in connection with distributed generation (DG) units using renewable energy sources (RESs), energy storage systems (ESS) and loads. A survey on the alternative DG units' configurations in the low voltage AC (LVAC) and DC (LVDC) distribution networks with several applications of microgrid systems in the viewpoint of the current and the future consumer equipments energy market is extensively discussed. Based on the economical, technical and environmental benefits of the renewable energy related DG units, a thorough comparison between the two types of microgrid systems is provided. The paper also investigates the feasibility, control and energy management strategies of the two microgrid systems relying on the most current research works. Finally, the generalized relay tripping currents are derived and the protection strategies in microgrid systems are addressed in detail. From this literature survey, it can be revealed that the AC and DC microgrid systems with multiconverter devices are intrinsically potential for the future energy systems to achieve reliability, efficiency and quality power supply. © 2013 Elsevier Ltd.

Kochanska G.,University of Iowa | Kim S.,Hanyang University | Boldt L.J.,University of Iowa | Yoon J.E.,University of Iowa
Journal of Child Psychology and Psychiatry and Allied Disciplines | Year: 2013

Background Growing research on children's traits as moderators of links between parenting and developmental outcomes has shown that variations in positivity, warmth, or responsiveness in parent-child relationships are particularly consequential for temperamentally difficult or biologically vulnerable children. But very few studies have addressed the moderating role of children's callous-unemotional (CU) traits, a known serious risk factor for antisocial cascades. We examined children's CU traits as moderators of links between parent-child Mutually Responsive Orientation (MRO) and shared positive affect and future externalizing behavior problems. Methods Participants included 100 two-parent community families of normally developing children, followed longitudinally. MRO and shared positive affect in mother-child and father-child dyads were observed in lengthy, diverse naturalistic contexts when children were 38 and 52 months. Both parents rated children's CU traits at 67 months and their externalizing behavior problems (Oppositional Defiant Disorder and Conduct Disorder) at 67, 80, and 100 months. Results Children's CU traits moderated links between early positive parent-child relationships and children's future externalizing behavior problems, even after controlling for strong continuity of those problems. For children with elevated CU traits, higher mother-child MRO and father-child shared positive affect predicted a decrease in mother-reported future behavior problems. There were no significant associations for children with relatively lower CU scores. Conclusions Positive qualities for early relationships, potentially different for mother-child and father-child dyads, can serve as potent factors that decrease probability of antisocial developmental cascades for children who are at risk due to elevated CU traits. © 2013 The Authors Journal of Child Psychology and Psychiatry © 2013 Association for Child and Adolescent Mental Health.

Choi Y.S.,Hanyang University
Knowledge-Based Systems | Year: 2011

Recently, due to the widespread on-line availability of syntactically annotated text corpora, some automated tools for searching in such text corpora have gained great attention. Generally, those conventional corpus search tools use a decomposition-matching-merging method based on relational predicates for matching a tree pattern query to the desired parts of text corpora. Thus, their query formulation and expressivity are often complicated due to poorly understood query formalisms, and their searching tasks may require a big computational overhead due to a large number of repeated trials of matching tree patterns. To overcome these difficulties, we present TPEMatcher, a tool for searching in parsed text corpora. TPEMatcher provides not only an efficient way of query formulation and searching but also a good query expressivity based on concise syntax and semantics of tree pattern query. We also demonstrate that TPEMatcher can be effectively used for a text mining in practice with its useful interface providing in-depth details of search results. © 2011 Elsevier B.V. All rights reserved.

In the past few decades, there have been great developments in remotely sensed soil moisture, with validation efforts using land surface models (LSMs) and ground-based measurements, because soil moisture information is essential to understanding complex land surface-atmosphere interactions. However, the validation of remotely sensed soil moisture has been very limited because of the scarcity of the ground measurements in Korea. This study validated Advanced Microwave Scanning Radiometer E (AMSR-E) soil moisture data with the Common Land Model (CLM), one of the most widely used LSMs, and ground-based measurements at two Korean regional flux monitoring network sites. There was reasonable agreement regarding the different soil moisture products for monitoring temporal trends except National Snow and Ice Data Centre (NSIDC) AMSR-E soil moisture, albeit there were essential comparison limitations by different spatial scales and soil depths. The AMSR-E soil moisture data published by the National Aeronautics and Space Administration and Vrije Universiteit Amsterdam (VUA) showed potential to replicate temporal variability patterns (root-mean-square errors = 0·10-0·14 m 3 m -3 and wet BIAS = 0·09 - 0·04 m 3 m -3) with the CLM and ground-based measurements. However, the NSIDC AMSR-E soil moisture was problematic because of the extremely low temporal variability and the VUA AMSR-E soil moisture was relatively inaccurate in Gwangneung site characterized by complex geophysical conditions. Additional evaluations should be required to facilitate the use of recent and forthcoming remotely sensed soil moisture data from Soil Moisture and Ocean Salinity and Soil Moisture Active and Passive missions at representative future validation sites. © 2011 John Wiley & Sons, Ltd.

Ko K.Y.,University of Ulsan | Park J.H.,Hanyang University
ISIJ International | Year: 2013

The viscosity of the CaO-SiO2-MnO(-CaF2) slags (CaO/SiO2 = 1.0, MnO = 10, 40 mass%) was measured to clarify the effect of CaF2 on the viscous flow of molten slags at high temperatures. Furthermore, the Raman spectra of the quenched glass samples were quantitatively analyzed to investigate the structural role of CaF2 in a depolymerization of silicate networks. The critical temperature of the slags abruptly increased at 15 mass% CaF2, which was confirmed to originate from a crystallization of cuspidine using XRD analysis. The viscosity of the slags continuously decreased by CaF2 addition in the 10 mass% MnO system, whereas the viscosity of the 40 mass% MnO system was not significantly affected by CaF2 addition. The activation energy for the viscous flow of silicate melts decreased by CaF2 addition and its tendency became less significant in the more basic composition, i.e. in the 40 mass% MnO system. The effect of CaF2 on the viscosity of the slags was quantitatively analyzed using micro-Raman spectra of quenched glass samples accompanying with a concept of silicate polymerization index, Q 3/Q2 ratio. A polymerization index continuously decreased with increasing content of CaF2 in the 10 mass% MnO system, whereas it was not affected by CaF2 in the 40 mass% MnO system. Consequently, the bulk thermophysical property of the CaO-SiO2-MnO-CaF2 slags was quantitatively correlated to the structural information. © 2013 ISIJ.

Noh H.-C.,Sejong University | Park T.,Hanyang University
Computer Methods in Applied Mechanics and Engineering | Year: 2011

Young's modulus is at the center of attention in the stochastic finite element analysis since the parameter plays an important role in determining structural behavior. However, the other material parameter of Poisson's ratio is another independent material parameter that governs the behavior of structural systems. Accordingly, the independent estimation of the influence of this parameter on the uncertain response of a system is of importance from the perspective of stochastic analysis. To this end, we propose a formulation to determine the response variability in laminated composite plates due to the spatial randomness of Poisson's ratio. To filter out the independent contribution of random Poisson's ratio, a decomposition of the constitutive matrix into several sub-matrices by using the Taylor's expansion is needed, which makes the random Poisson's ratio simple enough to be included in the formulation. To validate the adequacy of the proposed formulation, several examples are chosen and the results are compared with those given by Monte Carlo analysis. By means of the formulation suggested here, it is expected that an extension of the formulation to include the effect of correlations between random Poisson's ratio and other structural and/or geometrical parameters will be achieved with ease, resulting in a more practical estimation of the response variability of laminated composite plates. © 2011.

The absorber of a collector receives solar energy which is delivered to the transport medium to be carried away as useful energy. During this process, temperature of the absorber plate increases and therefore, thermophysical parameters engaged to determine the thermal performance of an absorber plate varies with temperature of the plate. The present study demonstrates analytically to determine the performance of an absorber plate fin with temperature dependent both thermal conductivity and overall heat loss coefficient. The decomposition method is proposed for the solution methodology. An optimum design analysis has also been carried out. A comparative study has been executed among the present results and that of existed in the published work, and a notable difference in results has been found. Finally, unlike published work, dependency parameters on the performances and optimum design have been highlighted. © 2010 Elsevier Ltd. All rights reserved.

Binas B.,Hanyang University | Verfaillie C.M.,Catholic University of Leuven
Stem Cells | Year: 2013

This article discusses the implications of the recent discovery that rat bonemarrow-derivedmultipotent adult progenitor cells (rMAPCs), a cell type with broad somatic differentiation potential but of uncertain lineage identity, are similar to rat blastocystderived extraembryonic endoderm precursor (rXENP) cells, which appear to represent the committed extraembryonic endoderm precursor of the blastocyst. It was found that under rMAPC culture conditions, rXENP cells can be homogeneously cultured and similar cells, named rat hypoblast stem cells (rHypoSCs), can be derived from rat blastocysts more rapidly and directly. The detailed comparison of rHypoSCs, rXENP cells, and rMAPCs revealed highly similar gene expression profiles and developmental potentials. The significance of these findings for embryology, stem cell biology, and medicine is discussed. Specifically, the results assign a lineage identity to rMAPCs, indicate thatrMAPCs originated by environmental reprogramming, and imply that HypoSCs, XENP cells, and MAPCs possess lineage plasticity. The MAPC-HypoSC relation also strengthens the consistency of rat and mouse embryology and consequently the idea that HypoSCs represent the committed extraembryonic endoderm precursor of the blastocyst. On this basis, it is argued that the direct comparison of HypoSCs (now available in pure form) with embryonic stem cells will be highly useful for the understanding of pluripotency and plasticity. Finally, the new findings suggest an explanation for an obscure observation on stem cell-induced transplantation tolerance. Thus, the HypoSC/ XENP/MAPC phenotype provides a unique but broadly instructive model with which to study stem cell plasticity, reprogramming, and transplantation tolerance, all central themes in regenerative medicine. © AlphaMed Press.

Kim H.-S.,Hanyang University | Yoo S.-H.,Chung - Ang University | Chang S.-H.,Chung - Ang University
Composites Part B: Engineering | Year: 2013

Generally, a large, thermal residual stress is generated during the curing process for composite laminates due to differences in the coefficients of thermal expansion of the respective layers. The thermal residual stress during fabrication greatly decreases the fatigue life and dimensional accuracy of the composite structures. In the present study, through a fiber bragg grating (FBG) sensor and dielectrometry in an autoclave, the strain evolution and curing reaction in composite laminates with a stacking sequence of [0 5/90 5] S were monitored simultaneously during a conventional cure cycle and a modified cure cycle to reduce the thermal residual stress. From the study, it was verified that about 50% of the thermal residual stress during fabrication could be reduced in a composite laminate by adjusting the cure cycle; this improved the static strength and fatigue life by 16% and up to 614%, respectively, for a peak ratio of 0.9. © 2012 Published by Elsevier Ltd.

Noh D.K.,Daejeon University | Kang K.,Hanyang University
Journal of Computer and System Sciences | Year: 2011

Solar power can extend the lifetime of wireless sensor networks (WSNs), but it is a very variable energy source. In many applications for WSNs, however, it is often preferred to operate at a constant quality level rather than to change application behavior frequently. Therefore, a solar-powered node is required adaptation to a highly varying energy supply. Reconciling a varying supply with a fixed demand requires a good prediction of that supply, so that demand can be regulated accordingly. We describe two energy allocation schemes, based on time-slots, which aim at optimum use of the periodically harvested solar energy, while minimizing the variability in energy allocation. The simpler scheme is designed for resource-constrained sensors; and a more accurate approach is designed for sensors with a larger energy budget. Each of these schemes uses a probabilistic model based on previous observation of harvested solar energy. This model takes account of long-term trends as well as temporary fluctuations of right levels. Finally, this node-level energy optimization naturally leads to the improvement of the network-wide performance such as latency and throughput. The experimental results on our testbeds and simulations show it clearly. © 2010 Elsevier Inc.

OBJECTIVES:Although various endoscopic therapies have been suggested for preventing bleeding after colorectal polypectomy, the optimal therapy has yet to be fully clarified. We assessed the comparative efficacy of prophylactic therapies for postpolypectomy bleeding through a network meta-analysis combining direct and indirect comparisons.METHODS:We searched for all relevant randomized controlled trials published up until January 2016 examining the effects of prophylactic therapy for bleeding after colorectal polypectomy. The types of prophylactic therapy were classified as mechanical therapy, epinephrine-saline injection therapy, coagulation therapy, combined therapy, or no prophylactic therapy. Combined therapy was defined as a combination of two or more types of therapy including mechanical therapy, epinephrine-saline injection therapy, and coagulation therapy. We performed a Bayesian network meta-analysis for all prophylactic therapies.RESULTS:Fifteen studies with 3,462 patients were included in the meta-analysis. Compared with no prophylactic therapy, both epinephrine-saline injection and mechanical therapy showed superiority for preventing early postpolypectomy bleeding with a moderate quality of evidence (injection therapy, risk ratio (RR; 95% credible interval (CrI))=0.32 (0.11–0.67); mechanical therapy, RR (95% CrI)=0.13 (0.03–0.37)). Combined therapy did not show a statistically significant difference for decreasing the risk of early bleeding compared with injection or mechanical therapies, respectively (combined vs. injection therapy: RR (95% CrI)=0.35 (0.10–1.00); combined vs. mechanical therapy: RR (95% CrI)=0.88 (0.23–3.00)). In cases of delayed bleeding, no type of prophylactic therapy decreased the risk of bleeding compared with no prophylactic therapy.CONCLUSIONS:Either mechanical therapy or injection therapy reduced the risk of early postpolypectomy bleeding. As for delayed bleeding, none of the prophylactic therapies was associated with a lower risk of bleeding compared with no prophylactic therapy.Am J Gastroenterol advance online publication, 12 July 2016; doi:10.1038/ajg.2016.287. © 2016 American College of Gastroenterology

Park S.,KEPCO E&C | Jeun G.,Hanyang University
Computer Methods in Applied Mechanics and Engineering | Year: 2011

The moving particle semi-implicit (MPS) method does not require grids for simulating fluid motions. Therefore, the MPS method can easily handle a large deformation of fluid. However, the MPS method has some difficulties in simulating transfer of momentum caused by a physical collision between different fluids because fluid particles have no mass or volume and only have weights for interacting with other particles. To overcome this inherent defect of the MPS method, rigid body dynamics is explicitly coupled with the MPS method in this study. In the first step, the MPS calculation is performed with particles which are considered to have no mass or volume. In the second step, rigid body dynamics comes into the calculation and considers the particles to have a slightly lesser diameter than the initial distance between particles. Then, physical contacts between particles are simulated with the dynamic energy conserved while the incompressibility of fluids is effectively maintained. In the single fluid region, the coupled method deals with the behavior of the particles. For the interface of the different fluids, only rigid body dynamics is used to simulate the transfer of the momentum caused by physical collisions of fluids. Through this coupling of rigid body dynamics and the MPS method, the overall stability related with the incompressibility of a fluid is comparatively increased in the single-phase fluid simulation. For the calculation of the multi-phase fluids behavior, fluids interactions can be easily treated with improving stability of the MPS calculation. In this study, collapse of water column and the isothermal fuel-coolant interaction (FCI), in which a water jet is directed into a denser fluid pool, were simulated to validate the coupling method of the MPS method and rigid body dynamics. © 2010 Elsevier B.V.

Moon H.,Hanyang University
IEEE Transactions on Wireless Communications | Year: 2013

Channel-adaptive random access can reduce the power required for successful random access transmission in a TDD-based wireless system. With channel-adaptive random access, transmission of a random access packet is delayed until a predefined channel condition is satisfied. The performance of channel-adaptive random access has been investigated with suboptimal power allocations including constant and channel inversion power allocations. However, the optimal power allocation has not been studied for channel-adaptive random access. In this paper, the optimum power allocation is derived for channel-adaptive random access, especially considering the detection performance of a random access preamble. Some important properties are investigated for the optimum power allocation. Numerical results compare the performances of the optimum and the suboptimal power allocations. © 2013 IEEE.

Lahiri I.,Florida International University | Verma V.P.,Florida International University | Choi W.,Florida International University | Choi W.,Hanyang University
Carbon | Year: 2011

All-graphene based cathode and anode structures were fabricated and their application as a flexible and transparent field emission device is presented. The graphene film was grown on a Cu foil by thermal chemical vapor deposition and later transferred to a polymer substrate through a hot press lamination technique. Multiwall carbon nanotubes (MWCNTs) were spin-coated onto a graphene film on a transparent, flexible substrate to form the cathode of the field emission device. A green-phosphor coated graphene-PET film was used as the anode. The device showed good transparency and flexibility as well as giving an appreciable emission current. The simple processing techniques used can easily be upgraded to a larger scale and be tailored for any transparent and flexible substrate. The device offers exciting applications of carbon nanostructures in foldable electronics. © 2010 Elsevier Ltd. All rights reserved.

Jin X.,Dongguk University | No J.-S.,Seoul National University | Shin D.-J.,Hanyang University
IEEE Transactions on Signal Processing | Year: 2013

Abstract-Transmit antenna selection (TAS) is usually applied to multiple- input multiple-output (MIMO) systems because it does not require additional radio frequency (RF) chains which are quite expensive. In MIMO decode-and-forward (DF) relay networks, both source-destination and source-relay-destination paths should be simultaneously considered to find an effective source TAS (STAS). In this paper, a new STAS is proposed based on both channel state information and transmission scheme for the MIMO DF relay networks. It is also shown that the proposed STAS which selects antennas among transmit antennas at the source can achieve full diversity regardless of the value of . Simulation results show that the proposed STAS has better average bit error probability (BEP) performance than other STASs. Also, the proposed STAS with has lower cost, complexity, overhead, and BEP than the STAS with using full-rate full-diversity space-time block codes with the same total transmit power. © 2012 IEEE.

Jang J.-I.,Hanyang University
Journal of Alloys and Compounds | Year: 2014

Alloy 690 has been widely used as steam generator tubing material in nuclear power plants owing to its excellent properties such as stress corrosion cracking resistance. In the present study, a series of nanoindentation experiments were conducted to explore the nanomechanical characteristics of the grain boundaries (GBs) and grain interior (GI) in the alloy 690 that were isothermally aged for four different times (for simulating the 20-80 years operation under power plant condition). While the accelerated aging induced no pronounced degradation, the GB and GI show remarkable and reproducible differences in nanohardness (plastic flow), pop-in stress (yielding), and strain-rate sensitivity. The results are discussed in terms of dislocation activities in the various mechanisms of deformation behavior. © 2013 Elsevier B.V. All rights reserved.

Chang J.-H.,Hanyang University
Digital Signal Processing: A Review Journal | Year: 2013

In this paper, we propose a novel speech enhancement technique based on an improved minimum statistics (MS) approach incorporating acoustic environmental noise awareness. A relevant noise estimation approach, known as MS, tracks the minimal values if a smoothed power estimate of the noisy signal is within a finite search window. From an investigation of previous MS-based methods, it is discovered that a fixed size of the minimum search window is assumed regardless of the environmental conditions. To overcome this limitation, we initially determine the optimal window sizes in terms of the perceived speech quality according to a variety of noise types. We then assign a different search window size according to the determined noise type, for which we use a real-time noise classification algorithm based on the Gaussian mixture model (GMM). The performance of the proposed approach is evaluated by a quantitative comparison method and by objective tests under various noise environments. It was found to yield better results compared to the previous MS method. © 2013 Elsevier Inc. All rights reserved.

Park J.-S.,Hanyang University
Information Display | Year: 2013

AMOLED TVs using promising oxide semiconductor and thin-film transistors (TFTs) have been unveiled. This article will present the issues, challenges, and concerns of oxide TFTs for AMOLED TVs. © SID 2013.

Oh J.H.,Sangmyung University | Kang Y.S.,Hanyang University | Kang S.W.,Sangmyung University
Chemical Communications | Year: 2013

In this study, we show for the first time that potassium fluoride (KF) can be utilized as a carrier for facilitated CO2 transport. A polymer electrolyte membrane was prepared by incorporating KF through coordinate covalent bonding with the amide groups of poly(vinylpyrrolidone) (PVP). The resulting PVP/KF electrolyte membrane showed enhanced CO2 separation performance compared with neat PVP. The selectivity ratio CO2/N 2 increased to 4.1 with a CO2 permeance of 28 GPU. This enhanced separation performance was attributable to the reversible interaction of KF with CO2 molecules, resulting in the increase of CO2 transport. The interaction between KF and the amide groups of PVP was confirmed by FT-IR spectroscopy and X-ray photoelectron spectroscopy (XPS). The coordination of potassium ions with the amide groups caused the free ions in KF to be increased, resulting in the favorable interaction with CO2 molecules. © The Royal Society of Chemistry 2013.

Kim J.-B.,Ajou University | Kim D.,Hanyang University
IEEE Transactions on Wireless Communications | Year: 2010

In this letter, we study outage performance of opportunistic single relay selection (OSRS) in decode-and-forward (DF) relaying with unequal-power co-channel interferers under Rayleigh fading channels. With the interferers, signal-to-interference-plus-noise ratio (SINR) may not be so great when the interferers also transmit signals at a power level similar to the source. In this case, high signal-to-noise ratio (SNR) approximation often used in outage analysis is not suitable for giving an adequate outage expression. We provide an exact and closed-form outage expression. And using asymptotic analysis, we show that OSRS still achieves full diversity gain in the presence of a finite number of interferers whose transmission powers are finite. When a finite number of interferers also transmit signals at the power level proportional to the source, we show that the asymptotic outage decreases log-linearly as the density of nodes increases. Finally, we show that when the number of interferers is proportional to the node density, the higher density, though creating the greater number of potential relays, does not necessarily contribute to improving the outage performance but deteriorates the performance. © 2010 IEEE.

To investigate the use and success rates of the GlideScope (GVL) by emergency physicians (EPs) during the initial two years after its introduction. We performed an observational study using registry data of five emergency departments. The success rates in adult patients were evaluated and compared with those of conventional laryngoscope (CL). The GVL was used in 345 (10.7%) of 3233 intubation attempts by EPs. The overall success rate of the GVL was not higher than a CL (79.1% vs 77.6%, p=0.538). The success rate for the patients with difficult airway was higher in the GVL than a CL (80.0% vs 50.4%, p<0.001). The GVL was not used frequently by EPs during the initial two years after its introduction. Although the GVL provides a better glottic view, the overall success rates were similar to a CL. The GVL may be useful in patients with difficult airway.

Rho M.,CEA Saclay Nuclear Research Center | Rho M.,Hanyang University
Nuclear Physics A | Year: 2014

When vector mesons are considered on the same footing as pions as suggested by hidden local symmetry, the property of the nuclear tensor forces is strongly controlled by the behavior of the vector mesons in dense medium. This led to BR scaling in 1991. When baryons as skyrmions are put on crystal, there can be a phase transition from skyrmions to half-skyrmions at a density above that of normal nuclear matter. This topology change can induce fundamental changes to the parameters in hidden local symmetric Lagrangian, hence BR scaling, and brings a drastic modification to the structure of nuclear forces, in particular, the tensor forces. This can have far-reaching consequences on the EoS of compact-star matter and the structure of neutron-rich nuclei. © 2014 Elsevier B.V.

This paper describes the optimization of combustion chamber geometry and engine operating conditions for stoichiometric diesel combustion, targeting lower gross indicated specific fuel consumption. The KIVA code, coupled with a micro genetic algorithm population of nine for each generation was used. The optimization variables were composed of ten variables related to the combustion chamber geometry and engine operating conditions. In addition, an auto mesh generator was developed for generating various kinds of combustion chambers, such as open-crater, re-entrant, deep, and shallow types. In addition, the computational models were validated against the experimental results for a stoichiometric process in terms of the combustion pressure history and emissions. Through the preset optimization, a 35% improvement in the gross indicated that specific fuel consumption was achieved. In addition, the optimization results showed that the optimum engine operating conditions employed a premixed charge compression ignition combustion regime with early injection and a narrow spray included angle. Furthermore, a higher boost pressure was used to prevent fuel film formation. © 2010 Elsevier B.V. All rights reserved.

Kim J.-K.,Hanyang University
Chemical Engineering Transactions | Year: 2015

Conventional cooling water systems are typically based on once-though usage of cooling water for each cooler. Cooling water between coolers can be re-used, which allows reducing overall cooling water flowrate at the increased cooling water return temperature (Kim and Smith, 2001). This reuse concept for cooling water can provide new debottlenecking options by effectively utilizing existing cooling tower. However, care must be taken for the implementation of cooling water reuse in retrofit scenarios, as temperature difference between process streams and reused cooling water is likely to be decreased and hence feasibility of heat transfer for coolers may not be sustained. This study investigates impacts resulted from the reconfiguration of cooling water network when cooling water reuse is introduced for debottlenecking of existing cooling water systems. Conceptual design guidelines are provided to regain driving force of heat transfer for coolers by increasing cooling water flowrate for the cooler. Case study is given to illustrate how cooling water network should be reconfigured for retrofit cases in which overall cooling water flowrate is considerably reduced without compensating performance of coolers. Copyright © 2015, AIDIC Servizi S.r.l.,.

A multiwavelength erbium-doped fiber laser based on a nonlinear amplified loop mirror with a highly-nonlinear photonic crystal fiber was proposed and experimentally investigated. The performance of the nonlinear amplified loop mirror was improved by using a single 3-dB coupler and a highly-nonlinear photonic crystal fiber with a length of 100 m. The extinction ratio of the proposed multiwavelength erbium-doped fiber laser was measured to be more than 50 dB. The output power fluctuation was measured to be less than 0.5 dB. The output power difference among multiple peaks was measured to be less than 0.3 dB. A Lyot-Sagnac filter with two segments of polarizationmaintaining photonic-crystal fibers was employed as a multichannel filter, and the wavelength spacing was controlled by changing the polarization states within the Lyot-Sagnac filter. Two different wavelength spacings, 0.6 nm and 0.8 nm, were obtained. The number of channels was also changed: 20 for Δλ = 0.6 nm and 16 for Δλ = 0.8 nm. In addition, a precisely-interleaved switching based on the proposed multiwavelength erbium-doped fiber laser was realized by changing the polarization states. © 2013 The Korean Physical Society.

Kim S.-H.,Harvard University | Kim J.W.,Hanyang University | Cho J.-C.,Amore Pacific | Weitz D.A.,Harvard University
Lab on a Chip - Miniaturisation for Chemistry and Biology | Year: 2011

We introduce an emulsification technique that creates monodisperse double-emulsion drops with a core-shell geometry having an ultra-thin wall as a middle layer. We create a biphasic flow in a microfluidic capillary device by forming a sheath flow consisting of a thin layer of a fluid with high affinity to the capillary wall flowing along the inner wall of the capillary, surrounding the innermost fluid. This creates double-emulsion drops, using a single-step emulsification, having a very thin fluid shell. If the shell is solidified, its thickness can be small as a hundred nanometres or even less. Despite the small thickness of this shell, these structures are nevertheless very stable, giving them great potential for encapsulation. We demonstrate this by creating biodegradable microcapsules of poly(lactic acid) with a shell thickness of a few tens of nanometres, which are potentially useful for encapsulation and delivery of drugs, cosmetics, and nutrients. © 2011 The Royal Society of Chemistry.

This paper describes the optimization of compression ignition engines fueled with dimethyl ether (DME), an alternative to diesel fuel. In order to calculate in-cylinder flow and combustion processes, a KIVA code, coupled with the Chemkin chemistry solver, was used. The optimization processes were performed based on a micro-genetic algorithm with a population number of five for each generation. The optimization processes were performed for one hundred generations. In addition, the computational mesh generated an auto-mesh generator, which was able to produce a computational mesh based on the given parameters, such as cup depth and Beizer curve definitions. The optimized design for the DME engine was also compared to that of conventional diesel engines for combustion and emission characteristics. The results showed that significant merit value improvements were achieved for both DME and diesel engines with the presented optimization. For the optimized design of DME engines, the combustion and emission characteristics were significantly different from those of diesel engines because of differences in fuel properties. For conventional diesel engine cases, a 136% improvement in merit value was achieved during the optimization process from the baseline to the optimized design. © 2012 Elsevier Ltd. All rights reserved.

Single-walled carbon nanotubes (SWCNTs), multiwalled carbon nanotubes (MWCNTs), and oxidized MWCNTs (O-MWCNTs) were studied for the adsorption of ibuprofen (IBU) and triclosan (TCS) as representative types of pharmaceutical and personal care products (PPCPs) under different chemical solution conditions. A good fitting of sorption isotherms was obtained using a Polanyi-Manes model (PMM). IBU and TCS sorption was stronger for SWCNTs than for MWCNTs due to higher specific surface area. The high oxygen content of O-MWCNT further depressed PPCP sorption. The sorption capacity of PPCPs was found to be pH-dependent, and more adsorption was observed at pHs below their pK a values. Ionic strength was also found to substantially affect TCS adsorption, with higher adsorption capacity observed for TCS at lower ionic strength. In the presence of a reference aquatic fulvic acid (FA), sorption of IBU and TCS was reduced due to the competitive sorption of FA on carbon nanotubes (CNTs). Sorption isotherm results with SWCNTs, MWCNTs and O-MWCNTs confirmed that the surface chemistry of CNTs, the chemical properties of PPCPs, and aqueous solution chemistry (pH, ionic strength, fulvic acid) all play an important role in PPCP adsorption onto CNTs. © 2011 American Chemical Society.

Na S.,University of California at San Diego | Paek E.,Hanyang University
Mass Spectrometry Reviews | Year: 2015

Post-translational modifications (PTMs) are critical to almost all aspects of complex processes of the cell. Identification of PTMs is one of the biggest challenges for proteomics, and there have been many computational studies for the analysis of PTMs from tandem mass spectrometry (MS/MS). Most early PTM identification studies have been performed by matching MS/MS data to protein databases, using database search tools, but they are prohibitively slow when a large number of PTMs is given as a search parameter. In this article, we present recent developments to search for more types of PTMs and to speed up the search, and discuss many computational issues and solutions in terms of identifying multiply modified peptides or searching for all possible modifications at once in unrestrictive mode. Apart from the most common type of PTMs involving covalent addition of functional groups to proteins, PTMs such as disulfide linkage require dedicated software for the analysis because they may involve cross-linking between two different parts of proteins. Finally, methods for identification of protein disulfide bonds are presented. © 2014 Wiley Periodicals, Inc.

Park G.-J.,Hanyang University
Structural and Multidisciplinary Optimization | Year: 2011

Linear static response structural optimization has been developed fairly well by using the finite element method for linear static analysis. However, development is extremely slow for structural optimization where a non linear static analysis technique is required. Optimization methods using equivalent static loads (ESLs) have been proposed to solve various structural optimization disciplines. The disciplines include linear dynamic response optimization, structural optimization for multi-body dynamic systems, structural optimization for flexible multi-body dynamic systems, nonlinear static response optimization and nonlinear dynamic response optimization. The ESL is defined as the static load that generates the same displacement field by an analysis which is not linear static. An analysis that is not linear static is carried out to evaluate the displacement field. ESLs are evaluated from the displacement field, linear static response optimization is performed by using the ESLs, and the design is updated. This process proceeds in a cyclic manner. A variety of problems have been solved by the ESLs methods. In this paper, the methods are completely overviewed. Various case studies are demonstrated and future research of the methods is discussed. © Springer-Verlag 2010.

Lee S.H.,Hanyang University
International Journal of Machine Tools and Manufacture | Year: 2012

The goal of this research is to investigate/monitor the machining characteristics and mode transitions during AFM nanoscratching of a brittle material such as Si (100) using acoustic emission (AE). By utilizing a specially designed AFM/nano stage setup, nano experiments were performed for various AFM tip engaging depths. With the aid of AFM and FE-SEM images, not only the typical features of each mode, such as pile-ups, chip formations, and crack propagations, but major mode changes including elastic/plastic and ductile brittle/transitions are observed and analyzed. To estimate mode transition depths, such as the yielding depth, the cutting initiating depth and the crack starting depth, theoretical models are employed and compared with the experimental results. Regarding in-process AE monitoring, various AE parameters such as AE RMS, AE count rate and AE frequency contents are generated from the monitoring signals and utilized to detect the mode states and transitions. Our results, which shows reasonably close theoretical estimations and appropriate sensitivity in AE monitoring, indicate that the proposed scheme can be used to characterize machining states and to differentiate various mode transitions from plastic deformation to the brittle crack generations during nano-scale machining. © 2012 Elsevier Ltd. All rights reserved.

Chen Z.,Argonne National Laboratory | Qin Y.,Argonne National Laboratory | Amine K.,Argonne National Laboratory | Sun Y.-K.,Hanyang University
Journal of Materials Chemistry | Year: 2010

Surface coating of cathode materials has been widely investigated to enhance the life and rate capability of lithium-ion batteries. The surface coating discussed here was divided into three different configurations which are rough coating, core shell structure coating and ultra thin film coating. The mechanism of surface coating in achieving improved cathode performance and strategies to carry out this surface modification is discussed. An outlook on atomic layer deposition for lithium ion battery is also presented. © 2010 The Royal Society of Chemistry.

The aim of this study was to determine whether the functional integrin-α-M (ITGAM) rs1143679 polymorphism is associated with susceptibility to systemic lupus erythematosus (SLE), lupus nephritis (LN), and rheumatoid arthritis (RA). A series of meta-analyses were conducted to test for associations between the ITGAM rs1143679 polymorphism and SLE, LN, or RA. A total of 24 comparisons involving 7,738 patients and 8,309 controls for SLE, and 2,663 patients and 2,694 controls in RA were considered. Meta-analysis showed a significant association between the ITGAM rs1143679 A allele and SLE in all subjects (OR 1.773, 95 % CI 1.656, 1.901, p < 1.0 × 10−9). After stratification by ethnicity, the A allele was found to be significantly associated with SLE in European, Latin American, and Asian. A significant association was also found between the ITGAM A allele and lupus nephritis in Europeans (OR 2.131, 95 % CI 1.565, 2.903, p = 1.6 × 10−7). However, no association was found between RA and the ITGAM rs1143679 polymorphism. Our meta-analyses confirm that the ITGAM rs1143679 polymorphism is associated with SLE susceptibility in different ethnic groups and demonstrate that the polymorphism is associated with LN in European. © 2014, Springer-Verlag Berlin Heidelberg.

Na S.,Hanyang University
Molecular & cellular proteomics : MCP | Year: 2012

With great biological interest in post-translational modifications (PTMs), various approaches have been introduced to identify PTMs using MS/MS. Recent developments for PTM identification have focused on an unrestrictive approach that searches MS/MS spectra for all known and possibly even unknown types of PTMs at once. However, the resulting expanded search space requires much longer search time and also increases the number of false positives (incorrect identifications) and false negatives (missed true identifications), thus creating a bottleneck in high throughput analysis. Here we introduce MODa, a novel "multi-blind" spectral alignment algorithm that allows for fast unrestrictive PTM searches with no limitation on the number of modifications per peptide while featuring over an order of magnitude speedup in relation to existing approaches. We demonstrate the sensitivity of MODa on human shotgun proteomics data where it reveals multiple mutations, a wide range of modifications (including glycosylation), and evidence for several putative novel modifications. Based on the reported findings, we argue that the efficiency and sensitivity of MODa make it the first unrestrictive search tool with the potential to fully replace conventional restrictive identification of proteomics mass spectrometry data.

Lee K.Y.,Harvard University | Lee K.Y.,Hanyang University | Mooney D.J.,Harvard University
Progress in Polymer Science (Oxford) | Year: 2012

Alginate is a biomaterial that has found numerous applications in biomedical science and engineering due to its favorable properties, including biocompatibility and ease of gelation. Alginate hydrogels have been particularly attractive in wound healing, drug delivery, and tissue engineering applications to date, as these gels retain structural similarity to the extracellular matrices in tissues and can be manipulated to play several critical roles. This review will provide a comprehensive overview of general properties of alginate and its hydrogels, their biomedical applications, and suggest new perspectives for future studies with these polymers. © 2011 Elsevier Ltd. All rights reserved.

Cho E.J.,Hanyang University | Kim J.S.,Ewha Womans University
Journal of Physical Chemistry B | Year: 2012

We investigate the phase separation of Lennard-Jones (LJ) particles in the presence of cosolute crowders using molecular dynamics simulations. In the absence of crowders, LJ particles phase-separate and form liquid and vapor phases only when the attraction between LJ particles is strong enough such that kBT/ε is less than 1.085, where ε is the attraction strength of the LJ potential, kB is the Boltzmann constant, and T is the temperature. On the other hand, the phase separation of LJ particles is observed even for larger kBT/ε and thus for weaker attractions when volume exclusive, repulsive crowders are present. Although the impact of crowding becomes less significant as the attraction between crowders and LJ particles is increased, the phase separation observed from simulations containing both nonattractive and attractive crowders shows that the crowding-induced phase separation by nonattractive crowders is still very significant even in the presence of other attractive crowders. This occurs because not only LJ particles but also attractive crowders are subject to the excluded volume effect of nonattractive crowders and found together in the condensed phase. This study suggests that the excluded volume effect in the crowded nuclear environment may play a crucial role in the formation and maintenance of biological structures in a cell, such as nuclear bodies including nucleoli and cajal bodies. © 2012 American Chemical Society.

Kim Y.,Hanyang University
IEEE Transactions on Consumer Electronics | Year: 2011

Motion estimation is a core process within video coding schemes, because it enables the transmission and storage of video signals, while using a lower bit rate. Various methods have been proposed for motion estimation. A full search algorithm is considered to be the optimal method, but it suffers from a high computational burden. In order to reduce the computations, this paper proposes an adaptive two-step edgebased partial distortion search algorithm. The proposed algorithm reduces computations by reducing the total search point and adjusting the search range. The proposed algorithm is 147 times faster than full search (FS), 12 times faster than normalized partial distortion search, and 1.75 times faster than a two-step edge based partial distortion search (TS-EPDS). It also shows a high video quality, in comparison with FS, in terms of PSNR. The proposed algorithm is suitable for real-time implementation of high-quality digital video applications. © 2011 IEEE.

Kim H.A.,Hanyang University
Journal of controlled release : official journal of the Controlled Release Society | Year: 2011

Dexamethasone was conjugated to low molecular weight polyethylenimine (2kDa, PEI2k). Dexamethasone conjugated PEI2k (PEI2k-Dexa) was evaluated as a combined delivery carrier of dexamethasone and plasmid DNA (pDNA) in an animal model of lipopolysaccharide (LPS) induced acute lung injury (ALI). In vitro transfection of L2 lung epithelial cells, PEI2k-Dexa exhibited higher transfection efficiency than PEI2k or a simple mixture of PEI2k and dexamethasone. In addition, the PEI2k-Dexa/pβ-Luc complexes reduced the levels of pro-inflammatory cytokines in LPS activated Raw 264.7 macrophage cells. The anti-inflammatory effect of PEI2k-Dexa was higher than that of controls. The PEI2k-Dexa/pβ-Luc complexes were administered to mice via intratracheal injection. PEI2k-Dexa had higher pDNA delivery efficiency than PEI2k in the lung and decreased TNF-α and IL-6 in the lung homogenates and bronchoalveolar lavage (BAL) fluid compared with the controls. Furthermore, total protein and immunoglobulin M (IgM) concentrations in BAL fluid were reduced by the PEI2k-Dexa/pβ-Luc complexes. The intratracheal injection of the PEI2k-Dexa/pcDNA-EGFP complexes in the ALI model showed higher EGFP expression compared with PEI2k. Hematoxylin and eosin (H&E) staining showed that PEI2k-Dexa reduced inflammatory reaction in the lung. Therefore, PEI2k-Dexa may be useful for combination gene and drug therapy for ALI. Copyright © 2011 Elsevier B.V. All rights reserved.

A long-distance remote sensing technique using a multiwavelength Raman fiber laser with fiber Bragg gratings (FBGs) embedded in a quartz tube is proposed. A Raman linear cavity for multiwavelength generation was configured by using a long length of single mode fiber and FBGs. To discriminate concurrent sensitivities, such as temperature and strain sensitivities, FBG2 was etched to reduce the cladding diameter. Then, two FBGs with different cladding diameters put in a quartz capillary tube and FBG1 with a large diameter (125 μm) was firmly attached in a quartz capillary tube with UV curable epoxy. Since the two FBGs have identical material composition, the multiwavelength Raman fiber laser outputs have the same temperature sensitivities. However, since the FBG1 with a diameter of 125 μ m was substantially fixed in a quartz capillary tube, the strain-induced wavelength shift was effectively suppressed. Since the FBG2 with a small cladding diameter of 60 μ m only responds to the external strain change, the multiwavelength Raman fiber laser outputs have different strain sensitivities. Therefore, it is possible to simultaneously measure temperature and strain over a long distance of more than 75 km by using the proposed multiwavelength Raman fiber laser without additional input sources. © 2011 IEEE.

Cho E.J.,Hanyang University
Chemistry - A European Journal | Year: 2012

Pick a pathway: Upon activation with an electrophilic transition-metal catalyst, a propargylic acetate undergoes competing [1,2]- and [1,3]-acyloxy migration depending on the reaction temperature as well as the substituent pattern around the alkyne. The nature of the catalyst also affects the reaction course. The reactions provided clear evidence for the interconversion between carbenoid and allene intermediates (see scheme). © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Thai H.-T.,Hanyang University | Vo T.P.,Glyndwr University
International Journal of Mechanical Sciences | Year: 2012

In this paper, various higher-order shear deformation beam theories for bending and free vibration of functionally graded beams are developed. The developed theories account for higher-order variation of transverse shear strain through the depth of the beam, and satisfy the stress-free boundary conditions on the top and bottom surfaces of the beam. A shear correction factor, therefore, is not required. In addition, these theories have strong similarities with Euler-Bernoulli beam theory in some aspects such as equations of motion, boundary conditions, and stress resultant expressions. The material properties of the functionally graded beam are assumed to vary according to power law distribution of the volume fraction of the constituents. Equations of motion and boundary conditions are derived from Hamilton's principle. Analytical solutions are presented, and the obtained results are compared with the existing solutions to verify the validity of the developed theories. Finally, the influences of power law index and shear deformation on the bending and free vibration responses of functionally graded beams are investigated. © 2012 Elsevier Ltd.

Purpose: Laparoendoscopic single-site (LESS) surgery was used to treat various urological operations by a single surgeon who was skilled in conventional laparoscopic surgery. The effectiveness and safety of the procedure were examined. Patients and Methods: LESS surgery was performed on 70 patients by using a homemade single port device composed of an Alexis® wound retractor and a powder-free surgical glove. There were 29 cases of varicocelectomy (including two bilateral cases), 21 cases of renal cyst marsupialization (including one bilateral case), 16 cases of ureterolithotomy, 3 cases of radical nephrectomy, and 1 case of radical nephroureterectomy. The mean patient age was 42.90 ± 17.58 years (range, 11 to 74 years), and the male-to-female ratio was 55:15. Results: In two cases (one ureterolithotomy and one radical nephrectomy), the LESS surgery was converted to conventional laparoscopic surgery. The mean operative time was 96.02 minutes (range, 30 to 285 minutes), the estimated blood loss was 60.80 mL (range, 0 to 500 mL), and the mean hospital stay was 5.10 days (range, 3 to 15 days). Only one patient had to use patient-controlled anesthesia due to pain; none of the patients developed major complications; and all patients were satisfied, with 85.7% expressing a high degree of satisfaction. Conclusion: In the urological field, LESS surgery using a homemade single-port device appears to be a feasible and safe surgical treatment option that could replace conventional laparoscopic surgery. Copyright 2011, Mary Ann Liebert, Inc.

Huang L.,Zhejiang GongShang University | Suh I.H.,Hanyang University | Abraham A.,Network Intelligence
Information Sciences | Year: 2011

Dynamic multi-objective optimization is a current hot topic. This paper discusses several issues that has not been reported in the static multi-objective optimization literature such as the loss of non-dominated solutions, the emergence of the false non-dominated solutions and the necessity for an online decision-making mechanism. Then, a dynamic multi-objective optimization algorithm is developed, which is inspired by membrane computing. A novel membrane control strategy is proposed in this article and is applied to the optimal control of a time-varying unstable plant. Experimental results clearly illustrate that the control strategy based on the dynamic multi-objective optimization algorithm is highly effective with a short rise time and a small overshoot. © 2011 Elsevier Inc. All rights reserved.

Yim H.,Hanyang University | Erikson R.L.,Harvard University
Mutation Research - Reviews in Mutation Research | Year: 2014

Despite advances in treatment, prognosis for many types of carcinoma remains poor. Polo-like kinase 1 (Plk1) has been explored as a target for the development of anticancer drugs. As a mitotic master Ser/Thr kinase, Plk1 is involved in centrosomal maturation, microtubule nucleation, chromosomal segregation, and cytokinesis. Additional functions in interphase and in response to DNA damage have been revealed. The multiple locations of Plk1 correspond to distinct functions, mediated by phosphorylation of multiple substrates. Since it is highly expressed in several carcinomas, and expression of Plk1 is inversely correlated with the survival rate of patients in non-small cell lung, head and neck, and esophageal cancer, Plk1 is recognized as a valid prognostic marker. Connections between Plk1 and p53 or KRAS in carcinoma provide a rationale and several possible routes to the development of therapies. Tumors with both p53-deficiency and high Plk1 expression may be particularly sensitive to Plk1 inhibitors, although some controversial data exist. In KRAS-mutant cancers, on the other hand, Plk1 may be essential for tumor cell survival, but detailed studies as to whether Plk1 inhibitors are more effective in KRAS-mutant cancers must be performed in order to determine whether this is the case. Here, we present evidence for Plk1 as a prognostic marker and potentially effective target for the treatment of patients with carcinoma, to demonstrate the value of Plk1 as a target for the development of cancer treatment, especially for patients with solid tumors. In addition, the effects of Plk1 inhibition in p53- or KRAS-mutated cancer are discussed with respect to clinical implications. Structural specifics of Plk1 are presented, as well as current strategies for discovering new Plk1 inhibitors by targeting the conserved ATP binding site or polo-box domain of Plk1, in order to develop Plk1-specific anticancer drugs. © 2014 Elsevier B.V.

Lee C.H.,Hanyang University | Kim J.-H.,Chonbuk National University
Journal of Ginseng Research | Year: 2014

Ginseng is widely used for its promising healing and restorative properties as well as for its possible tonic effect in traditional medicine. Nowadays, many studies focus on purified individual ginsenoside, an important constituent in ginseng, and study its specific mechanism of action instead of whole-plant extracts on cardiovascular diseases (CVDs). Of the various ginsenosides, purified ginsenosides such as Rb1, Rg1, Rg3, Rh1, Re, and Rd are the most frequently studied. Although there are many reports on the molecular mechanisms and medical applications of ginsenosides in the treatment of CVDs, many concerns exist in their application. This review discusses current works on the countless pharmacological functions and the potential benefits of ginseng in the area of CVDs. Results: Both in vitro and in vivo results indicate that ginseng has potentially positive effects on heart disease through its various properties including antioxidation, reduced platelet adhesion, vasomotor regulation, improving lipid profiles, and influencing various ion channels. To date, approximately 40 ginsenosides have been identified, and each has a different mechanism of action owing to the differences in chemical structure. This review aims to present comprehensive information on the traditional uses, phytochemistry, and pharmacology of ginseng, especially in the control of hypertension and cardiovascular function. In addition, the review also provides an insight into the opportunities for future research and development on the biological activities of ginseng. © 2014, The Korean Society of Ginseng, Published by Elsevier.

Jun Y.B.,Gyeongsang National University | Kang M.S.,Hanyang University
Computers and Mathematics with Applications | Year: 2011

On the basis of the theory of a falling shadow, the notion of a falling fuzzy positive implicative ideal of a BCK-algebra is introduced. Relations between falling fuzzy positive implicative ideals and falling fuzzy ideals are given. Relations between fuzzy positive implicative ideals and falling fuzzy positive implicative ideals are provided. © 2010 Elsevier Ltd. All rights reserved.

Park S.,Semyung University | Shin W.-S.,Hanyang University
Physiology and Behavior | Year: 2015

This study aimed to determine whether there might be differences in masticatory performance and eating behaviors by gender and obesity status. Forty eight (24 males; 24 females) non-obese and pre-obese young adults were matched for age, gender, and dental health. Eating behaviors were assessed using the Three-Factor Eating Questionnaire (TFEQ), and chewing performance while eating 152. g of boiled rice was measured using electromyography (EMG). Compared with non-obese participants, pre-obese participants had significantly higher levels of disinhibition according to the TFEQ (P < 0.05 for males; P. < 0.01 for females). Microstructures of chewing performance were significantly different by gender but not by obesity status. Males had a greater bite size (P < 0.05), greater chewing power (P < 0.001) and a faster eating rate (P < 0.05) than females. Females habitually chewed more (P < 0.05) and had a longer meal duration (P < 0.01) than males. Eating rate was positively associated with disinhibition (r=0.490, P. < 0.05) score in males. Bite size (r=- 0.449, P. < 0.05 for non-obese) and chewing power (r=- 0.581, P. < 0.01 for non-obese and r=- 0.446, P. < 0.05 for pre-obese) were negatively associated with disinhibition score. Results suggest that the effects of gender and, in part, obesity on eating responses may be explained as chewing performance. Therefore, gender-specific interventions and counseling aimed at slowing the rate of ingestion could be promising behavioral treatments for obese persons. © 2014 Elsevier Inc.

Zhang L.,Dalian University of Technology | Zhang L.,Myongji University | Lee Y.-W.,Hanyang University | Jahng D.,Myongji University
Journal of Hazardous Materials | Year: 2012

In this study, the effects of ammonia removal by air stripping as a pretreatment on the anaerobic digestion of piggery wastewater were investigated. Ammonia stripping results indicated that ammonia removal was strongly dependent on pH and aeration rate, and the ammonia removal rate followed the pseudo-first-order kinetics. A significant enhancement of biomethanization was observed for wastewaters of which ammonia was air-stripped at pH 9.5 and pH 10.0. The methane productivity increased from 0.23±0.08L CH 4/Ld of the control (raw piggery wastewater) to 0.75±0.11L CH 4/Ld (ammonia-stripped at pH 9.5) and 0.57±0.04L CH 4/Ld (ammonia-stripped at pH 10.0). However, the improvement of methane production from the piggery wastewater pretreated at pH 11.0 was negligible compared to the control, which was thought to be due to the high concentration of sodium ions supplied from sodium hydroxide for pH adjustment. From these results, it was concluded that ammonia removal through air stripping at the alkaline pH could be a viable option for preventing the failure of anaerobic digestion of the raw piggery wastewater. Additionally, it was also found that a high concentration of sodium ion originated from sodium hydroxide for pH adjustment inhibited methane production. © 2011 Elsevier B.V.

Jung H.G.,Hanyang University
Nature communications | Year: 2011

Lithium batteries are receiving considerable attention as storage devices in the renewable energy and sustainable road transport fields. However, low-cost, long-life lithium batteries with higher energy densities are required to facilitate practical application. Here we report a lithium-ion battery that can be cycled at rates as high as 10 C has a life exceeding 500 cycles and an operating temperature range extending from -20 to 55 °C. The estimated energy density is 260 W h kg(-1), which is considerably higher than densities delivered by the presently available Li-ion batteries.

Han Y.,Hanyang University
International Journal of Electronics | Year: 2014

Finite or Galois fields are used in numerous applications like error correcting codes in digital communication, pseudorandom number generation and cryptography. These applications often require computing exponentiation GF (2m) in which is a very computationally intensive operation. This article presents a high-performance computing method for performing exponentiation in GF (2m). The key contribution of this article is to extend the bit-parallel structure for multiplication and division where bits of operands are processed at the same time, each bit traveling over a different path in the circuits to perform exponentiation. In addition, we also simplify the structure of parallel modules and pipelining stages in the proposed bit-parallel structure for exponentiation by considering the properties of GF (2m) and hardwiring many constant terms. The circuit architecture for the developed structure is shown for the example case of m = 4, and compared with existing approaches with respect to latency, hardware cost, area, delay, throughput and power dissipation for m=4 to 512. The results show that the proposed system has a low latency, hardware costs, area, delay and power dissipation that do not increase rapidly with increasing m and a high throughput that does not decrease rapidly as m increases compared with existing approaches. © 2013 Taylor & Francis.

Numerical investigations and a thermohydraulic evaluation are presented for two-well models of an aquifer thermal energy storage (ATES) system operating under a continuous flow regime. A three-dimensional numerical model for groundwater flow and heat transport is used to analyze the thermal energy storage in the aquifer. This study emphasizes the influence of regional groundwater flow on the heat transfer and storage of the system under various operation scenarios. For different parameters of the system, performances were compared in terms of the temperature of recovered water and the temperature field in the aquifer. The calculated temperature at the producing well varies within a certain range throughout the year, reflecting the seasonal (quarterly) temperature variation of the injected water. The pressure gradient across the system, which determines the direction and velocity of regional groundwater flow, has a substantial influence on the convective heat transport and performance of aquifer thermal storage. Injection/production rate and geometrical size of the aquifer used in the model also impact the predicted temperature distribution at each stage and the recovery water temperature. The hydrogeological-thermal simulation is shown to play an integral part in the prediction of performance of processes as complicated as those in ATES systems. © Springer-Verlag Berlin Heidelberg 2013.

Yeh S.-W.,Hanyang University | Kim C.-H.,Korea Ocean Research and Development Institute
Continental Shelf Research | Year: 2010

We examine characteristics in the variability of sea surface temperature (SST) in the Yellow/East China Sea during the boreal winter (December-January-February) for the period 1950-2008 in observations. It is found that the mean SST in the Yellow Sea/East China Sea gradually increases during recent decades. A warming trend of a basin scale SST is significant in most of the regions in the Yellow/East Sea, which is well explained by the variability of the first empirical orthogonal function SST mode. We suggest one candidate mechanism that the North Pacific oscillation (NPO)-like sea level pressure play an important role to warm the Yellow/East China Sea. Anomalous anticyclonic circulation, which is the southern lobe of NPO-like sea level pressure over the North Pacific, causes a weakening of northerly mean winds over the Yellow/East China Sea during winter. This contributes to increase in the SST in the Yellow/East China Sea through the changes in the latent heat and sensible heat fluxes. © 2010 Elsevier Ltd.

Yoo S.-H.,Hanyang University | Manz H.,Empa - Swiss Federal Laboratories for Materials Science and Technology
Solar Energy Materials and Solar Cells | Year: 2011

A building integrated photovoltaic system as a shading device is used as an application and remodeling model. This study applies the simulation program SOLCEL and the computational fluid dynamics method to cases with solar irradiance components analysis and a ventilated double faade remodeling of the BIPV. For the validation of the theoretical work, experimental results of the Samsung Institute of Engineering and Construction Company building are used with a wind velocity of the weather data of Suwon area, Korea, where the real building is located. A photovoltaic system can be used only to generate electricity, but if a photovoltaic module can be used as an element of a double envelope, it could be more useful at the point of view of renewable energy usage and night insulation. Increase of PV module surface temperature is negative for power generation by installing PV module as an element of double envelope. A reasonable combination between renewable energy usage and power generation should be well analyzed for better usage of natural energy to design a BIPV. © 2010 Elsevier B.V. All rights reserved.

Biomolecules such as proteins, DNA, and RNA are macromolecules and can not cross the cell membrane. However, cell-penetrating peptide (CPP) has been shown to deliver therapeutic biomolecules successfully into cells. The various and widely used CPPs including TAT, VP22, and Antp are mostly non-human originated CPPs, and are limited by their potential toxicity and immunogenicity. We report here on a newly identified novel cell-penetrating sequence (LPIN; RRKRRRRRK) from the nuclear localization sequence (NLS) of human nuclear phosphatase, LPIN3. LPIN-EGFP recombinant protein was concentration- and time-dependently delivered into cells and localized to the nucleus as well as the cytoplasm. It penetrated the cell membrane by lipid raft-mediated endocytosis by binding to heparan sulfate proteoglycan. LPIN-EGFP was successfully delivered into primary mouse splenocytes in vitro and it could be delivered into various tissues including liver, kidney, and intestine in mice after intra-peritoneal injection. This research suggests that LPIN-CPP could be used in a drug delivery system to deliver therapeutic biomolecules including peptides, proteins, DNA, and RNA and without the limitations of non-human originated CPPs such as TAT-CPP.

Choi M.,Hanyang University | Jacobs J.M.,University of New Hampshire
Hydrological Processes | Year: 2011

Soil moisture state and variability control many hydrological and ecological processes as well as exchanges of energy and water between the land surface and the atmosphere. However, its state and variability are poorly understood at spatial scales larger than the fields (i.e. 1 km2) as well as the ability to extrapolate field scale to larger spatial scales. This study investigates soil moisture profiles, their spatial organization, and physical drivers of variability within the Walnut Creek watershed, Iowa, during Soil Moisture Experiment 2005 and relates the watershed scale findings to previous field-scale results. For all depths, the watershed soil moisture variability was negatively correlated with the watershed mean soil moisture and followed an exponential relationship that was nearly identical to that for field scales. This relationship differed during drying and wetting. While the overall time stability characteristics were improved with observation depth, the relatively wet and dry locations were consistent for all depths. The most time stable locations, capturing the mean soil moisture of the watershed within ± 0·9% volumetric soil moisture, were typically found on hill slopes regardless of vegetation type. These mild slope locations consistently preserve the time stability patterns from field to watershed scales. Soil properties also appear to impact stability but the findings are sensitive to local variations that may not be well defined by existing soil maps. Copyright © 2010 John Wiley & Sons, Ltd.

Chen D.Y.-K.,Seoul National University | Youn S.W.,Hanyang University
Chemistry - A European Journal | Year: 2012

The recent advent of transition-metal mediated C-H activation is revolutionizing the synthetic field and gradually infusing a "C-H activation mind-set" in both students and practitioners of organic synthesis. As a powerful testament of this emerging synthetic tool, applications of C-H activation in the context of total synthesis of complex natural products are beginning to blossom. Herein, recently completed total syntheses showcasing creative and ingenious incorporation of C-H activation as a strategic manoeuver are compared with their "non-C-H activation" counterparts, illuminating a new paradigm in strategic synthetic design. The total synthesis of natural products has been carried out showcasing the creative and ingenious application of C-H activation in the construction of complex molecular architectures that are compared with their "non-C-H activation" counterparts. These accomplishments stood as true testaments of the growing potential of C-H activation, and further cementing the power of this emerging synthetic technology (see figure). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Song T.,University of Maryland University College | Hu L.,University of Maryland University College | Paik U.,Hanyang University
Journal of Physical Chemistry Letters | Year: 2014

One dimensional (1D) silicon nanostructures have attracted significant interest as an anode material for lithium ion batteries (LIBs) as its 1D geometry accommodates the large volume change of the Si during cycling and enables facile electron transport during all stages of operation. Furthermore, the high aspect ratio of 1D Si nanostructures enables us to investigate atomic-scale mechanisms of the lithiation process and corresponding volume change behavior. Various 1D nanostructures with different morphologies and compositions have been explored to achieve a robust cycle performance, reversible morphological changes, and high rate capabilities. In this Perspective, we summarize the recent significant advances of 1D Si nanostructures and discuss electrode design strategies based on the recent geometry and composition engineering. © 2014 American Chemical Society.

Park J.H.,Hanyang University
Steel Research International | Year: 2013

The sulfide capacities of the CaO-SiO2-MnO(-Al2O 3-MgO) slags were measured at 1873 K over a wide composition range using a gas-slag equilibration method. The effects of MnO content and the MnO ↔ CaO substitution on the sulfide capacity of molten slag were also investigated based on the structural view of silicate melts. In the multicomponent silicate melts containing high MnO (up to about 50 wt%), the sulfide capacity mainly increased with increasing MnO content. Also, the sulfide capacity and the activity of MnO showed a linear relationship with a slope of unity, indicating that MnO is dominant component controlling the sulfur dissolution behavior into Ca-Mn-silicate melts. The sulfide capacity increased as MnO substituted for CaO in the high silica melts (>30 (±5) wt% SiO2), whereas it decreased by increasing the MnO/CaO ratio in the low silica melts (<30(±5) wt% SiO2). This tendency of sulfide capacity resulted in the clock-wisely rotating iso-capacity contours from MnO-free side to MnO-rich corner in Ca-Mn-silicate melts. The dissolution mechanism of sulfur in Ca-Mn-silicate melts can be explained by the "Competitive dissolution mechanism." The sulphide capacities of the CaO-SiO2-MnO(-Al2O3-MgO) slags are measured at 1873 K using a gas-slag equilibration method. The effects of MnO and the MnO↔CaO substitution on the sulphide capacity of molten slag are also investigated based on the structural view of silicate melts. The dissolution mechanism of sulphur in Ca-Mn-silicate melts can be explained by the "Competitive dissolution mechanism." Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cheng L.,Shanghai University | Ge X.-H.,Shanghai University | Sin S.-J.,Hanyang University
Journal of High Energy Physics | Year: 2014

Abstract: We present a type IIB supergravity solution dual to a spatially anisotropic N=4 super Yang-Mills plasma at finite U(1) chemical potential and finite temperature. The effective five-dimensional gravitational theory is a consistent Einstein-Maxwell-dilaton-Axion truncation of the gauged supergravity. We obtain the solutions both numerically and analytically. We study the phase structure and thermodynamic instabilities of the solution, and find new instabilities independent of the renormalization scheme. © 2014, The Author(s).

Koo B.,Hanbat National University | Yoo B.,Hanyang University
Surface and Coatings Technology | Year: 2010

Physical properties, such as surface morphology, microstructure, and stress, were investigated for electrodeposited NiFe soft magnetic thin films synthesized from a highly acidic electrolyte. The characteristics of the anomalous NiFe electrodeposition diminished when the temperature of the electrolyte increased. The FCC structure was the dominant microstructure of the NiFe alloys until the Fe content was increased to ~. 40%. The film stress was maximal when the composition was 60Ni40Fe. The coercivity of the NiFe alloy thin film decreased to 10. Oe when the composition was 80Ni20Fe. The stress and coercivity of NiFe thin films were highly related to the variation of the alloy composition, which caused a change in the grain size. © 2010 Elsevier B.V.

Yoo S.-H.,Hanyang University
Solar Energy | Year: 2011

The degree of efficiency of Building Integrated Photovoltaic (BIPV) as a shading device and the variation of the electrical power generation over 1. year in a real building has already been experimentally investigated in my earlier research. In this paper, the influence of the angle of the solar cell panel, albedo of earth, building azimuth, and of solar cell panels under shading on the power generation are theoretically studied to further optimize BIPV implementation. For the validation of the theoretical work, experimental results of the Samsung Institute of Engineering and Construction Company building are used with a wind velocity of the weather data (TRY, test reference year) of Suwon area, Korea. The efficiency of the BIPV system as a shading device was compared at different months. In this work, the simulation program SOLCEL, for the calculation of a shading/sunlit area on solar cell module and facade, surface temperature of solar cell module, effective solar irradiance on solar cell module and the power generation of a BIPV as a shading device, was developed and validated. The SOLCEL can be applied to develop a multi functional Building Integrated Photovoltaic which could improve power generation, thermal comfort, natural lighting, cooling and heating, etc. © 2011 Elsevier Ltd.

In case of delayed surgery, if an orbital floor fracture involves the infraorbital canal, adhesions may form between the infraorbital neurovascular bundle and herniated muscle, and manipulations to reduce the fracture may lead to unexpected bleeding due to injury of the infraorbital artery. The author reports a case of a white-eyed blow-out fracture patient, who visited our clinic one-and-a-half months after the injury. Exploration of the fracture confirmed intensive fibrosis of the infraorbital neurovascular bundle and the entrapped inferior rectus muscle at the fracture site. The author was able to reduce the muscle completely with the release of the fibrotic tissue around the nerve bundle by using a vessel loop to safely retract the neurovascular bundle upwards, and obtained good results. Copyright © 2014 by Mutaz B. Habal, MD.

Sin S.-J.,Hanyang University | Zhou Y.,Sogang University
Journal of High Energy Physics | Year: 2011

We study the relations between two different approaches to the holographic Renormalization Group (RG) flow at the dual gravity level: One is the radial evolution of the classical equation of motion and the other is the flow equation given by the holographic Wilsonian RG coming from the cut off independence. Apparently, the two flows look different. We give general proofs that the two flows are actually equivalent. The role of the momentum continuity (MC) is essential. We show that MC together with cutoff independence gives the evolution equation of the boundary values. Equivalence of conductivity flows in two paradigm has been shown as an explicit example. We also get the connecting formula of Green functions and AC conductivity at arbitrary slice in terms of its value at horizon for various geometry backgrounds. © SISSA 2011.

Kim N.S.,Hanyang University | van Wee B.,Technical University of Delft
International Journal of Sustainable Transportation | Year: 2014

This study aims to examine whether the intermodal freight system emits less CO2 than its road-based counterpart. Three types of freight systems are considered: a truck-only system, a rail-based intermodal freight system, and a vessel-based intermodal system. Furthermore, nine scenarios are designed in terms of four different power sources for an electrified rail-based intermodal system and three different sized ships for a vessel-based intermodal system. The results show intermodal systems generally emit less CO2 than the truck-only system. However, intermodal systems can emit more CO2 than truck-only systems under certain extreme conditions of electricity production, vessel size and detour factors. © 2014 Copyright Taylor and Francis Group, LLC.

Li Y.,Shanghai Normal University | Han Q.,Shanghai Normal University | Kim T.W.,Hanyang University | Shi W.,Shanghai Normal University
Nanoscale | Year: 2014

Nearly monodispersed wurtzite-dominant Cu2ZnSnS4 and zincblende-dominant Cu2ZnSnSe4 nanocrystals were successfully synthesized by mixing metal salts with heated thiourea or selenourea in oleylamine. A perspective of the structural relationship between quaternary and ternary semiconductors was investigated through the application of different anion sources to prepare Cu2SnS3 and Cu 2SnSe3 nanocrystals. Investigations on copper-based binary compounds found that CuSe (or CuS) and Cu2Se (or Cu1.96S, Cu9S5) nuclei were primarily responsible for the formation of zincblende or wurtzite structures, respectively. Further management over these binary intermediates corresponded to slight structural transformations of the quaternary nanocrystals which could be observed not only in XRD patterns, but from optical and electrical properties as well. According to these results, Cu2ZnGeS4 nanocrystals with wurtzite-dominant structures were first reported using SC(NH2) 2, which also verified that the binary semiconductors are the determinative factors. This journal is © the Partner Organisations 2014.

Jeong W.K.,Hanyang University
Journal of the Korean Medical Association | Year: 2011

Radiation exposure during fluoroscopy has been of consistent interest because fluoroscopy is used not only for diagnostic purposes such as upper gastrointestinal series but for many minimally-invasive treatments in various clinical fields. In 2000, the International Commission on Radiological Protection published the important report about the avoidance of radiation injuries from medical interventional procedures, and this report defined harm during fluoroscopic-guided interventional procedure and how to reduce the radiation dose of patients and staff. Two aspects of fluoroscopy exposure differ from other types of medical radiation exposure, including computed tomography. One is that the entrance surface dose during an interventional procedure may be very high, so the deterministic effects of radiation such as skin or corneal injury should be emphasized more than stochastic effects such as cancer risk. The other is that the variation in radiation exposure is great for the same kind of procedure, so it is very difficult to generate a reference level for the radiation dose. Therefore, it is necessary to develop a guideline for the use of fluoroscopy through a nationwide survey about irradiation during fluoroscopic examinations and fluoroscopy-guided intervention procedures. In conclusion, radiation exposure by fluoroscopic guided intervention is not negligible, and the practitioner should always aim to reduce radiation exposure during interventional procedures. © Korean Medical Association.

Park H.-K.,Hanyang University
Journal of the Korean Medical Association | Year: 2012

Evaluation systems can produce curricular change. Korean medical schools face a new responsibility to prepare students for the Korean Medical Licensing Examination (KMLE) clinical skills test (CST) that had been administered since 2009. Several innovations in medical education have resulted, including augmentation of hand-on skills training and a standardized patient program during clerkships. This review explored the results of a survey of 41 medical schools on the impact of the CST on medical education in Korea as of 2011. The majority of res-pondents reported having an independent skills training laboratory and conducting a clinical skills assessment during the third or fourth year of medical school. The preparatory under-graduate courses were perceived as helpful for self-confidence, communication with real patients, basic clinical skills for work, information sharing with patients, and getting the confi-dence of patients during internship and residency. However, an extreme policy emphasizing maintenance of a high pass rate has warped the curriculum with simple preparatory courses for the CST. The long-term educational outcomes of the CST of the KMLE must be evaluated again a few years later focused on searching for any relationship with a reduction in medical errors or increase in patient satisfaction in real practice. © Korean Medical Association.

Hangarter C.M.,University of California at Riverside | Chartuprayoon N.,University of California at Riverside | Hernandez S.C.,University of California at Riverside | Choa Y.,Hanyang University | Myung N.V.,University of California at Riverside
Nano Today | Year: 2013

Conducting polymers, or conjugated polymers, are a class of polymers containing a sp2 structure that permits delocalized transport of charge carriers. Here these polymers are examined in the context of nanoscale hybridization with carbon nanotubes, graphene, metal nanoparticles or metal oxide nanoparticles, to harness or amplify adsorption, catalytic reaction and transport behavior of additional material systems. The basis for enhancement in these hybrid nanostructures resides in four general structures in which conjugated polymers act as conduits that interface and respond to nanoparticle interactions or conversely play the role of the sensitizing agent to enhance sensitivity, lower detection limit, response time or selectivity of relatively inert substances, ultimately giving rise to high performance sensors. This review is focused on chemiresistive hybrid conducting polymer sensors for detection of gaseous chemicals discussing several recent reports along with strategies for further development of hybrid sensors. © 2013 Elsevier Ltd. All rights reserved.

Cho E.J.,Massachusetts Institute of Technology | Cho E.J.,Hanyang University | Buchwald S.L.,Massachusetts Institute of Technology
Organic Letters | Year: 2011

A method for the palladium-catalyzed trifluoromethylation of cyclohexenyl sulfonates has been developed. Various cyclohexenyl triflates and nonaflates underwent trifluoromethylation under mild reaction conditions using a catalyst system composed of Pd(dba) 2 or [(allyl)PdCl] 2 and the monodentate biaryl phosphine ligand tBuXPhos. The trifluoromethyl anion (CF 3 - ) or its equivalent for the process was generated in situ from TMSCF3 in combination with KF or TESCF3 in combination with RbF. © 2011 American Chemical Society.

Kim E.Y.,Hanyang University | Kim K.W.,Seoul National University
Aging and Mental Health | Year: 2014

Background: Recently, interest in cognitive training for older adults has grown significantly, reflecting a need for preserving the quality of life into late adulthood. In spite of increasing interest in cognitive rehabilitation, recent meta-analyses have questioned reported training gains and determined that cognitive gain from cognitive training might be no larger than the gain observed from active controls such as unspecific, non-cognitive activities.Aims: This paper presents a theoretical framework for clarifying specificity of cognitive training by exploring mechanisms of current cognitive and non-cognitive interventions for older adults. By differentiating compensatory aspects from the components of specific and non-specific stimulation in current training, two related strategies of interventions for age-related cognitive decline, i.e., stimulation versus compensation, are proposed.Overview: Current interventions for age-related cognitive decline are reviewed in terms of stimulation- and compensation-focused interventions. Stimulation-focused, cognitive and non-cognitive training, with or without specific targets, tend to result in general improvement in attention and sensory or other cognitive functions. Meanwhile, compensation-focused training is likely to be the most effective when the intervention specifically supports the frontally mediating activity in accordance with the direction of indigenous adjustments in the aging brain. Conclusions: It can be inferred that stimulation-focused training is to ameliorate the adverse effects of neurological aging, whereas compensation-focused cognitive training is primarily to facilitate compensatory adaptation in the brain. © 2013 Taylor & Francis.

Ryu H.-Y.,Inha University | Shim J.-I.,Hanyang University
Optics Express | Year: 2011

We investigate the effects of current spreading on the efficiency droop of InGaN blue light-emitting diodes with lateral injection geometry based on numerical simulation. Current crowding near the mesa edge and the decrease in the current spreading length with current density are shown to cause significant efficiency droop. It is found that the efficiency droop can be reduced considerably as the uniformity of current spreading is improved by increasing the resistivity of the p-type current spreading layer or decreasing the sheet resistance of the n-GaN layer. The droop reduction is well interpreted by the uniformity of carrier distribution in the plane of quantum wells. © 2011 Optical Society of America.

Park J.,Hyundai Motor Company | Park J.-H.,Hanyang University
International Journal of Automotive Technology | Year: 2012

Power distribution between an internal combustion engine and electric motors is one of main features of hybrid electric vehicles that improves their fuel economy. An equivalent fuel consumption minimization strategy can instantaneously identify the optimal power distribution by converting the battery power into the equivalent fuel power and minimizing the overall fuel consumption. To guarantee the effectiveness of the strategy, it is essential to find the proper value of the conversion factor used to obtain the equivalent fuel power. However, finding the proper value is not a straightforward process because it is necessary to consider the overall power conversion efficiencies and battery charge sustaining strategy for the target driving cycle in advance. In this study, a model-based parameter optimization method is introduced to find the optimal conversion factor. A hybrid electric vehicle simulation model capable of estimating fuel consumption was developed, and the optimal conversion factor was discovered using a genetic algorithm that evaluates its population members using the simulation model. A series of simulations and vehicle tests was conducted to verify the effectiveness of the optimized strategy, and the results show a distinct improvement in fuel economy. © 2012 The Korean Society of Automotive Engineers and Springer-Verlag Berlin Heidelberg.

Kim J.W.,Hanyang University | Clarkson W.A.,University of Southampton
Optics Communications | Year: 2013

Direct excitation of an arbitrary Laguerre-Gaussian (LG0n) doughnut mode in an end-pumped solid-state laser using a fiber-based pump beam conditioning scheme to produce a ring-shaped inversion distribution is reported. An analytical expression for the dependence of threshold pump power for a particular LG0n mode on the spatial overlap with the pump beam is derived and shows that the desired LG0n mode can be selectively excited through simple adjustment of the pump beam dimensions. This approach has been applied to a diode-laser pumped Nd:YAG laser to achieve selective lasing on the LG01, LG02 or LG03 mode. Predicted values for threshold pump power and beam propagation factor (M2) are in good agreement with measured values. The prospects for further improvement in laser performance will be discussed. © 2013 Elsevier B.V. All rights reserved.

Kundu B.,Jadavpur University | Kundu B.,Hanyang University
International Journal of Refrigeration | Year: 2010

For the analytical solution of a wet fin equation, a relationship between humidity ratio and temperature of the saturation air is necessary. A linearity of this relationship instead of the actual one was chosen by many researchers for the ease of analysis of fins for a specified geometric fin. This aforementioned linear relation does not satisfy in actual case and it can be correlated by humidity ratio as a polynomial function with temperature. In this work, an exercise is devoted to determine the optimum fin profile for both fully and partially wet longitudinal fins with a nonlinear saturation curve. For this establishment, temperature distribution in the fin can be expressed by a class of power law. From the optimization analysis, an optimality criterion is setup individually for the fully and partially wet surface conditions. The optimum fin profile and design variables have been determined as a function of thermo-psychrometric parameters. © 2010 Elsevier Ltd and IIR. All rights reserved.

As the popularity of electronic cigarettes (ECs) rises, there are growing concerns not only about the lack of a methodological basis for the quantification of various pollutants, but also the absence of proper regulations or guidelines for their production and distribution. Considering the urgent need for such guidelines, this study was carried out to explore the potent roles of key sampling variables in the quantitation of EC-produced aerosols/vapors: the sampling flow rate (or puff velocity), battery charge condition, and solution composition. All of these variables were evaluated in relation to the consumption rate of a EC solution. Accordingly, the effects of all these variables were explained very effectively when bound with the information regarding the consumption rate of the EC solution, namely the mass change tracking (MCT) approach. As such, MCT is regarded as a vital component to reduce the considerable uncertainties associated with the use of a simple criterion like pollutant mass per puff. © The Royal Society of Chemistry 2016.

Ahn B.D.,Yonsei University | Park J.-S.,Hanyang University | Chung K.B.,Dongguk University
Applied Physics Letters | Year: 2014

Device performance of InGaZnO (IGZO) thin film transistors (TFTs) are investigated as a function of hydrogen ion irradiation dose at room temperature. Field effect mobility is enhanced, and subthreshold gate swing is improved with the increase of hydrogen ion irradiation dose, and there is no thermal annealing. The electrical device performance is correlated with the electronic structure of IGZO films, such as chemical bonding states, features of the conduction band, and band edge states below the conduction band. The decrease of oxygen deficient bonding and the changes in electronic structure of the conduction band leads to the improvement of device performance in IGZO TFT with an increase of the hydrogen ion irradiation dose. © 2014 AIP Publishing LLC.

This paper presents the design and evaluation of a generalized topology discovery, operational monitoring, and provisioning (G-TOP) controller for a carrier-grade transport network. The G-TOP controller is a vendor-specific extension of the stateful PCE that integrates network topology discovery, path computation, and provisioning functions, but decouples the switch specific management framework. The G-TOP protocol enables the G-TOP controller to collect topology information, set up LSPs, and monitor state both from and to the management framework in a unified way. To validate the feasibility of the proposed framework, the author implemented a testbed using a multi-protocol label switching transport profile (MPLS-TP) switches and performed experimental testing. The experimental results show that the centralized control framework reduces provisioning time by approximately 68 ms and the autonomous management framework reduces fault recovery time by approximately 27 ms, while reducing the traffic load on the controller by several orders of magnitude compared to the OpenFlow approach. © 2015 IEEE.

Invasive pulmonary aspergillosis (IPA) is a significant cause of morbidity and mortality especially in immunocompromised patients, and extensive work has been done in the field of diagnostic imaging. The purpose of our study was to evaluate functional metabolic image findings of F-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET)/computed tomography (CT) in the patients with invasive and noninvasive forms of pulmonary aspergillosis (IPA and NIPA, respectively). We retrospectively reviewed 24 consecutive patients who had pulmonary aspergillosis among the patients who underwent F-FDG PET/CT to evaluate lung mass or fever of unknown origin. Demographic feature, multiplicity, visually analyzed F-FDG uptake patterns (isometabolic halo, isometabolic nodule, hypermetabolic nodule, or other), and the peak standardized uptake value (SUVpeak) of the pulmonary lesions on PET/CT were evaluated. Of these 24 patients, 8 were diagnosed with IPA and 16 with NIPA. Patients with IPA were significantly younger (48 vs 62 years), and immunocompromised conditions were more frequently observed in these cases (88% vs 6%). Multiple lesions were noted in 50% (4 of 8) and 19% (3 of 16) of IPA and NIPA patients, respectively, and the predominant patterns on F-FDG PET/CT were the hypermetabolic nodule pattern (6 of 8 patients, 75%) and the isometabolic halo pattern (8 of 16 patients, 50%) in IPA and NIPA patients, respectively. The isometabolic halo pattern was not observed in IPA patients. The median SUVpeak was 4.5 (range, 1.3-8.9) and 1.6 (range, 0.5-3.1) in IPA and NIPA, respectively. F-FDG PET/CT findings differ between IPA and NIPA patients. Pulmonary aspergillosis in immunocompromised status with a hypermetabolic nodule pattern on F-FDG PET/CT seems to have high possibility of IPA. In contrast, an isometabolic halo pattern and an isometabolic nodule pattern on F-FDG PET/CT seem to have high possibility of NIPA.

Kim T.-I.,Seoul National University | Kim S.W.,University of Utah | Kim S.W.,Hanyang University
Reactive and Functional Polymers | Year: 2011

Bioreducible polymers, which possess mainly disulfide linkages in the polymer structures, have appeared as ideal gene delivery carriers due to the high stability in extracellular physiological condition and bioreduction- triggered release of genetic materials, as well as decreased cytotoxicity because intracellular cytosol is a reducing environment containing high level of reducing molecules such as glutathione. This review will describe the initiation and recent advances in the development of bioreducible polymers for gene delivery, which includes reducibly cross-linked PEIs, polypeptides, polyion complex micelles, and poly(amido amine)s. There have been extensive researches performed to exhibit great gene delivery efficacy but still several important issues about pharmacokinetics or safety should be answered thoroughly for further rational design of bioreducible polymers having potentials in human gene delivery systems. © 2010 Elsevier Ltd. All rights reserved.

Kim T.H.,Hanyang University
The Tohoku journal of experimental medicine | Year: 2011

Idiopathic pulmonary fibrosis (IPF) is a progressive fibrotic lung disease and characterized by abnormal growth of fibroblasts and lung scarring. While the pathogenesis of IPF is not clearly understood, activation of transforming growth factor-β (TGF-β) and disruption of alveolar basement membrane seem to play important roles in leading to excess disruption of the matrix, which is associated with activated matrix metalloproteinase (MMP) and aberrant proliferation of myofibroblasts. The Wnt/β-catenin pathway is an important regulator of cellular proliferation and differentiation and abnormal activation of Wnt/β-catenin signal was observed in IPF. We examined whether inhibition of the Wnt/β-catenin pathway could attenuate pulmonary fibrosis in a bleomycin-induced murine model of pulmonary fibrosis. Pulmonary fibrosis was induced in C57BL/6N mice by intratracheal instillation of bleomycin. To inhibit the Wnt/β-catenin pathway, small interfering RNA (siRNA) for β-catenin was administered into trachea 2 h before bleomycin instillation and every 48 h afterward until sacrifice on day 14. The level of β-catenin expression was increased in the epithelial cells of bleomycin-administered mice. Intratracheal treatment with β-catenin siRNA significantly reduced β-catenin expression, pulmonary fibrosis and collagen synthesis in bleomycin-administered mice compared with controls, with no significant effect on the inflammatory response. The β-catenin-targeted siRNA also significantly decreased the levels of MMP-2 (P<0.01) and TGF-β (P<0.01) expression in the lung tissue. Blockade of the Wnt/β-catenin pathway by β-catenin siRNA decreased bleomycin-induced pulmonary fibrosis in the murine model. These findings suggest that targeting Wnt/β-catenin signaling may be an effective therapeutic approach in the treatment of IPF.

Lee Y.S.,University of Utah | Kim S.W.,University of Utah | Kim S.W.,Hanyang University
Journal of Controlled Release | Year: 2014

Most currently available cationic polymers have significant acute toxicity concerns such as cellular toxicity, aggregation of erythrocytes, and entrapment in the lung capillary bed, largely due to their poor biocompatibility and non-degradability under physiological conditions. To develop more intelligent polymers, disulfide bonds are introduced in the design of biodegradable polymers. Herein, the sustained innovations of biomimetic nano-sized constructs with bioreducible poly(disulfide amine)s demonstrate a viable clinical tool for the treatment of cardiovascular disease, anemia, diabetes, and cancer. © 2014 Elsevier B.V.

A tandem simulated moving bed (SMB) process for removal of sulfuric acid and acetic acid from sugars has been developed previously. This process consisted of two four-zone SMB units (Ring I and Ring II), in which the same adsorbent (Dowex99 resin) and the same column length were used. To improve the performance of such a tandem SMB process for sugar separation, it is worth adopting the strategy of making a difference between the column lengths of Ring I and Ring II. The results showed that such strategy could allow the adsorbent beds of both Ring I and Ring II to be fully utilized at the same time, which was impracticable in the previous tandem SMB mode. As a result, the tandem SMB based on such strategy could achieve higher productivity than the previous tandem SMB mode. In addition, the use of different adsorbents (Amberchrom-CG161C in Ring I and Dowex99 in Ring II) was proposed as the second strategy, which was confirmed to be highly effective in improving the productivity of the tandem SMB for sugar separation. Finally, a third strategy was proposed by combing the first and the second strategies. It was found that compared to the previous tandem SMB mode, the third strategy led to more than eleven times the productivity under the constraint of pressure drop ≤100. psi. This was mostly because the third strategy had a remarkable advantage over the previous tandem SMB mode in the aspects of bed utilization and selectivities, which stemmed from the use of different column lengths and the use of different adsorbents respectively. © 2013 Elsevier B.V.

Mason J.,Tulane University | Greiner T.,Hanyang University | Shrimpton R.,Tulane University | Sanders D.,University of the Western Cape | Yukich J.,Tulane University
International Journal of Epidemiology | Year: 2015

The prevalence of vitamin A (VA) deficiency, which affects about one-third of children in developing countries, is falling only slowly. This is despite extensive distribution and administration of periodic (4- to 6-monthly) high-dose VA capsules over the past 20 years, now covering a reported 80% of children in developing countries. This massive programme was motivated largely by an expectation of reducing child mortality, stemming from findings in the 1980s and early 90s. Efficacy trials since 1994 have in most cases not confirmed a mortality impact of VA capsules. Only one large scale programme evaluation has ever been published, which showed no impact on 1-6-year-old mortality (the DEVTA trial, ending in 2003, in Uttar Pradesh, India). Periodic high-dose VA capsules may have less relevance now with changing disease patterns (notably, reductions in measles and diarrhoea). High-dose VA 6-monthly does not reduce prevalence of the deficiency itself, estimated by low serum retinol. It is proposed that: (i) there is no longer any evidence that intermittent high-dose VA programmes are having any substantial mortality effect, perhaps due to changing disease patterns; (ii) frequent intakes of vitamin A in physiological doses -e.g. through food-based approaches, including fortification, and through regular low-dose supplementation-are highly effective in increasing serum retinol (SR) and reducing vitamin A deficiency; (iii) therefore a policy shift is needed, based on consideration of current evidence. A prudent phase-over is needed towards increasing frequent regular intakes of VA at physiological levels, daily or weekly, replacing the high-dose periodic capsule distribution programmes. Moving resources in this direction must happen sooner or later: it should be sooner. © The Author 2014.

Choi J.M.,Hanyang University
The Korean journal of gastroenterology = Taehan Sohwagi Hakhoe chi | Year: 2014

Colonic wall thickening is frequently encountered in various conditions, from acute or chronic inflammatory disease to colorectal carcinoma. Colonic wall thickening may be accompanied by calcifications in mucinous adenocarcinoma of the colon, leiomyosarco-ma of the colon, schistosomiasis japonica, and phlebosclerotic colitis. Phlebosclerotic colitis is a rare entity of chronic ischemic colitis associated with sclerosis and fibrosis of mesenteric veins. Although its development is usually insidious, and, thus its diagnosis can be delayed, characteristic findings in phlebosclerotic colitis are calcifications of mesenteric veins as well as colonic wall thickening with calcifications. We report on a 71-year-old woman who presented with chronic diarrhea and intermittent hematochezia, who was first misdiagnosed as mucinous adenocarcinoma of the colon, but finally diagnosed as a rare entity of chronic ischemic colitis, phlebosclerotic colitis. Differential points of phlebosclerotic colitis from other diseases, including leiomyosarcoma and schistosomiasis japonica, are also described.

Kim H.-J.,Hanyang University
International Journal of Infectious Diseases | Year: 2014

Tuberculosis is a significant public health problem that continues to be a major cause of morbidity and mortality worldwide. Tuberculous meningoencephalitis (TM) is the most common extrapulmonary lesion in tuberculosis. A 41-year-old female was thought to have TM. Tests to confirm the TM diagnosis were initially negative, including tuberculosis PCR and adenosine deaminase level in serum and cerebrospinal fluid (CSF). Anti-tuberculous medication and intravenous steroids were administered to her on the basis of brain imaging and lactate dehydrogenase electrophoresis in CSF, suggestive of the diagnosis of TM. Her neurological problems improved rapidly following treatment. Serologic and CSF markers were positive in PCR and culture after 60 days. Radiological findings are often nonspecific and TM is difficult to diagnose without an increased index of suspicion. The detection of paradoxical expansion of tuberculoma is very important in the maintenance of medication. Magnetic resonance imaging was used to detect paradoxical expansion of the tuberculoma using various methods, such as contrast-enhanced fluid-attenuated inversion recovery (CE-FLAIR) imaging. CE-FLAIR imaging conspicuously showed paradoxical expansion of the tuberculoma. If patients present with clear meningitis, without any identified pathogen, there is a need to constantly and scrupulously check for TM, including with the use of CE-FLAIR brain imaging. © 2014 The Authors.

In gadoxetic acid-enhanced liver magnetic resonance imaging(MRI), it is known that the pseudoglandular type of hepatocellular carcinoma (HCC) may demonstrate high signal intensity on 20-minutes delayed imaging unlike the microtrabecular counterpart. Herein we report a case of HCC which consisted of mixed components of hypo- and hyper-intensity in the hepatobiliary phase of gadoxetic acid-enhanced MRI, focusing on its imaging findings and pathologic features.

Youn S.,Hanyang University | Yang M.G.,College of Charleston | Hong P.,University of Toledo
International Journal of Production Economics | Year: 2012

In spite of the plentiful literature on the role of leadership in general, the role of integrative leadership as a critical implementation mechanism for supply chain has been rarely explored. Based on the literature review, this study presents a research model that defines integrative leadership grounded in goal congruence theory. Integrative leadership indicates that the extent to which three senior leaderships - Chief Executive Officer (CEO), Chief Information Officer (CIO) and Supply Chain Officer (SCO) - are congruent with the common goal of supply chain will lead to better supply chain implementation outcomes. Specifically, effective supply chain implementation outcomes are achieved through synergistic information flows enabled by integrative leadership. Structural Equation Model (SmartPLS) is used to test the hypothesized relationships through the use of empirical data of Korean 142 firms. The empirical results provide managerial insight on the impact of integrative leadership on intangible, value-based, and qualitative supply chain management performance goals. Future research issues are discussed as well. © 2010 Elsevier B.V. All rights reserved.

Park S.-M.,Hanyang University
Journal of Mental Health | Year: 2014

Background: The upward Korean suicide trend of recent years is mainly explained by a strong rise in suicide by older people. Aims: This study investigates the influence of physical and mental health factors on suicidal ideation among elderly people, who are either living alone or living with others. Methods: Cross-sectional data of 1743 older adults (65 years) who completed the 2009 Korea National Health and Nutrition Examination Survey were analysed. Results: The outstanding finding was that suffering a stroke was significantly associated with suicidal ideation among elderly people. A limitation in daily activities, experience of depressed feelings and high levels of stress were significantly associated with suicidal thoughts in both elderly people living alone and those living with others. Conclusions: The findings highlight the need for suicide-intervention services, which particularly target high-risk elderly people. Primary care should be provided to elderly people after suffering a stroke and/or experiencing a limitation in daily activities. © 2014 Shadowfax Publishing and Informa UK Limited.

Chang J.-W.,Hanyang University
Annals of Plastic Surgery | Year: 2016

ABSTRACT: Because frontotemporal dermoid cysts are superficial masses on the zygomaticofrontal suture, they are usually removed by simple direct excision in pediatric patients. Adult patients, however, require a more involved treatment approach because these cysts may be large and extend deeply into the surrounding tissue. From 2008 to 2015, 33 adult patients with frontotemporal dermoid cysts were treated in our clinic under a new treatment algorithm. Patients with a cyst smaller than 2 cm in diameter were treated using a direct excisional approach without a preoperative computed tomography (CT) evaluation. Patients with a cyst larger than 2 cm in diameter underwent a preoperative CT evaluation to determine the exact location of the cyst. If the cyst invaded the temporal fossa, a hemicoronal approach was used for excision. Cysts that did not cross the lateral orbital rim were removed using a direct excisional approach. Among the 33 patients in the study, 6 patients had cysts smaller than 2 cm in diameter, and 27 patients had cysts larger than 2 cm in diameter. Of the 27 patients with large dermoid cysts, 17 cysts showed temporal fossa invasion and 10 showed no signs of temporal fossa invasion. In all cases, the cyst was completely excised without rupture, and no instances of complications or recurrence were observed. In adults with frontotemporal dermoid cysts larger than 2 cm in diameter, preoperative CT evaluations should be performed. If the evidence suggests that a cyst has invaded the temporal fossa, a hemicoronal approach is required for complete excision. Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.

The dynamic stability behavior of damped laminated beam with various boundary conditions subjected to the uniformly distributed subtangential forces is investigated using the finite element formulation. The formal engineering approach of the mechanics for the thin-walled laminated beam based on kinematic assumptions consistent with Vlasov beam theory is used. An extended Hamilton's principle is employed to obtain the mass-, damping-, elastic stiffness-, geometric stiffness matrices, and the load correction stiffness matrix due to the subtangential forces, respectively. The method for the evaluation of critical values for divergence and flutter of the nonconservative systems is briefly introduced in case of considering and neglecting damping effects. Throughout numerical examples, the influence of various parameters on the dynamic stability behavior of the nonconservative laminated beam is newly investigated: (1) the variation of the divergence and flutter loads due to the nonconservativeness with respect to the fiber orientation, (2) the effect of boundary condition on the instability region of the divergence-flutter system, and (3) the influence of external and internal damping on the flutter load. © 2010 Elsevier Ltd.

Wang Y.,University of Manchester | Smith R.,University of Manchester | Kim J.-K.,Hanyang University
Applied Thermal Engineering | Year: 2012

Heat exchanger network retrofit plays an important role in energy saving in process industry. Many design methods for the retrofit of heat exchanger networks have been proposed during the last three decades. Conventional retrofit methods rely heavily on topology modifications which often result in a long retrofit duration and high initial costs. Moreover, the addition of extra surface area to the heat exchanger can prove difficult due to topology, safety and downtime constraints. Both of these problems can be avoided through the use of heat transfer enhancement in heat exchanger network retrofit. This paper presents a novel design approach to solve heat exchanger network retrofit problems based on heat transfer enhancement. An optimisation method based on simulated annealing has been developed to find the appropriate heat exchangers to be enhanced and to calculate the level of enhancement required. The physical insight of enhanced exchangers is also analysed. The new methodology allows several possible retrofit strategies using different retrofit methods be determined. Comparison of these retrofit strategies demonstrates that retrofit modification duration and payback time are reduced when heat transfer enhancement is utilised. Heat transfer enhancement can be also used as a substitute for increased heat exchanger network surface area to reduce retrofit investment costs. © 2011 Elsevier Ltd. All rights reserved.

Victor R.A.,University of Manchester | Kim J.-K.,Hanyang University | Smith R.,University of Manchester
Energy | Year: 2013

An optimisation model for the composition of mixed working fluids for (Organic Rankine Cycles) ORCsand Kalina cycles has been developed. The temperatures investigated were 100°C-250°C for the heat source and 30°C for the heat sink. The optimisation method of the composition was carried out with Simulated Annealing technique with the objective function of maximising the thermal efficiency of the cycle, based on 1MW of heat source. The results show that the pure component organic fluids are more energy-efficient than mixed organic fluids. The selection of organic working fluids was studied for achieving maximum cycle efficiency at a given operating temperature. The composition of the Kalina cycle was also optimised and it was found that for a maximum temperature of 250°C, the minimum ammonia concentration in the ammonia-water mixture was 73.8% mol fraction. A novel consideration of employing alcohol-water mixtures in the cycle was also investigated and the most efficient mixture at 250°C was methanol and water mixture when compared to the Kalina cycle and steam Rankine Cycle. The study showed overall that the optimal choice of working fluids for a particular type of cycle would depend on the operating temperature and pressure. The developed design method can be useful for engineers to evaluate the performance of the cycles considering a wide range of working fluids, and determines the optimal choice of working fluids and operating conditions of the cycle. © 2013 Elsevier Ltd.

Kochanska G.,University of Iowa | Kim S.,University of Iowa | Kim S.,Hanyang University
Developmental Psychology | Year: 2014

We propose a model linking the early parent- child mutually responsive orientation (MRO), children's temperament trait of effortful control, and their internalization of conduct rules. In a developmental chain, effortful control was posited as a mediator of the links between MRO and children's internalization. MRO was further posited as a moderator of the links between effortful control and internalization (i.e., moderated mediation): Variations in effortful control were expected to be more consequential for internalization in suboptimal relationships, with low MRO, than in optimal ones, with high MRO. The model was tested in 2 studies that employed comparable observational measures. In Family Study (N = 102 community mothers, fathers, and children), MRO was assessed at 25 months, effortful control at 38 months, and children's internalization at 67 months. In Play Study (N = 186 low-income, diverse mothers and children), MRO was assessed at 30 months, effortful control at 33 months, and children's internalization at 40 months. MRO was observed in lengthy naturalistic interactions, effortful control in standardized tasks, and internalized, rule-compatible conduct in parent- child interactions and in standardized paradigms without surveillance. Structural equation modeling analyses, with internalized, rule-compatible conduct modeled as a latent variable, supported moderated mediation across mother- and father- child relationships and both studies. In optimal, mutually responsive relationships, multiple mechanisms other than capacity for effortful control may also operate effectively to promote internalization, thus reducing the relative importance of variations in child temperament. © 2013 American Psychological Association.

Moon Y.S.,Hanyang University
Journal of Food Products Marketing | Year: 2013

As the public interest in health information has increased globally, the use of health benefits in food advertisements is becoming more essential for food marketing strategy. Consumers view a food product as healthy if it carries a health claim, whereas there has been an ongoing debate about the value of health claims as a strategy to help consumers' healthier food consumption. The present study attempted to examine the food commercials broadcast on Korean network television in terms of claim types and executional elements. Results indicate that television food advertising has made a wide number of implied "soft" health claims (e.g., "good for health") without substantial information and call into question whether consumers are misled or deceived by the executional elements used for presenting health messages. The findings of the study raise regulatory concerns about the provision of potentially confusing or misleading health messages in food advertising nationally as well as internationally and suggest further research in this area. © 2013 Copyright Taylor and Francis Group, LLC.

Nurunnabi M.,Korea National University of Transportation | Khatun Z.,Korea National University of Transportation | Huh K.M.,Chungnam National University | Park S.Y.,Korea National University of Transportation | And 3 more authors.
ACS Nano | Year: 2013

Photoluminescent graphene quantum dots (GQDs) have fascinating optical and electronic properties with numerous promising applications in biomedical engineering. In this work, we first studied the in vivo biodistribution and the potential toxicity of carboxylated photoluminescent GQDs. KB, MDA-MB231, A549 cancer cells, and MDCK normal cell line were chosen as in vitro cell culture models to examine the possible adverse effects of the carboxylated photoluminescent GQDs. The carboxylated GQDs are desirable for increased aqueous solubility. All cancer cells efficiently took up the carboxylated GQDs. No acute toxicity or morphological changes were noted in either system at the tested exposure levels. A long-term in vivo study revealed that the GQDs mainly accumulated in liver, spleen, lung, kidney, and tumor sites after intravenous injection. To reveal any potential toxic effect of the GQDs on treated mice, serum biochemical analysis and histological evaluation were performed. The toxicity results from serum biochemistry and complete blood count study revealed that the GQDs do not cause appreciable toxicity to the treated animals. Finally, we observed no obvious organ damage or lesions for the GQDs treated mice after 21 days of administration at 5 mg/kg or 10 mg/kg dosages. With adequate studies of toxicity, both in vitro and in vivo, photoluminescent GQDs may be considered for biological application. © 2013 American Chemical Society.

Yoon G.H.,Hanyang University
Journal of Computational Acoustics | Year: 2015

This research aims to develop a novel unified analysis method for an acoustic-porous-structure multiphysics interaction system when the porous medium is modeled by the empirical Delany-Bazley formulation. Multiphysics analysis of acoustic structure interaction is commonly performed by solving the linear elasticity and Helmholtz equations separately and enforcing a mutual coupling boundary condition. If the pressure attenuation from a porous material is additionally considered, the multiphysics analysis becomes highly intricate, because three different media (acoustic, porous, and elastic structures) with different governing equations and interaction boundary conditions should be properly formulated. To overcome this difficulty, this paper proposes the application of a novel mixed formulation to consider the mutual coupling effects among the acoustic, fibrous (porous), and elastic structure media. By combining the mixed finite element formulation with the Delany-Bazley formulation, a multiphysics simulation of sound propagation considering the coupling effects among the three media can be easily conducted. To show the validity of the present unified approach, several benchmark problems are considered. © 2015 IMACS.

Daytime downward longwave radiation (Rld) in clear sky and all sky conditions was estimated by various well-known physical or empirical models at two Korean regional flux monitoring network (KoFlux) sites which have not been included in previously published studies for Rld models' performance. The Brunt (1932) model performed the best clear sky Rld estimations at the KoFlux sites. The Maykut and Church (1973) model performed the best all sky Rld estimations at the KoFlux sites where the bias and root mean square error (RMSE) were 3.4 and 26.6Wm-2 at the Gwangneung site and 0.3 and 32.4Wm-2 at the Haenam site, respectively. Newly proposed global Rld model by Abramowitz et al. (2012) showed reasonable Rld estimations for the all sky conditions. While selected Rld models showed the reliable estimations under clear and all sky conditions, the systematic and random errors were still observed in this study. These errors were mostly caused by relatively simple estimations of the cloud cover fraction. More validation and calibration efforts should be conducted in a range of field conditions including different climatic regions and land cover types for better understanding of the model performance with uncertainties. © 2012 Elsevier B.V.

Inflammatory pseudotumor (IPT) is a pseudoneoplastic lesion that most commonly involves lung. We report a case of IPT of kidney associated with hepatocellular carcinoma. CT and PET/CT showed the features of renal cell carcinoma. After radical nephrectomy, histologic examination demonstrated acute pyelonephritis associated with papillary necrosis, and IPT involving renal parenchyma and capsule. Although renal IPT is a very rare tumor, awareness of its existence in the differential diagnosis of a renal mass is critical to avoid misdiagnosis. Clinician should carefully consider differential diagnosis and complications associated with acute or chronic pyelonephritis and papillary necrosis in diabetic patients, particularly.

Thai H.-T.,Hanyang University
International Journal of Engineering Science | Year: 2012

A nonlocal shear deformation beam theory is proposed for bending, buckling, and vibration of nanobeams using the nonlocal differential constitutive relations of Eringen. The theory, which does not require shear correction factor, accounts for both small scale effects and quadratic variation of shear strains and consequently shear stresses through the thickness of the beam. In addition, it has strong similarities with nonlocal Euler-Bernoulli beam theory in some aspects such as equations of motion, boundary conditions, and stress resultant expressions. The equations of motion are derived from Hamilton's principle. Analytical solutions of deflection, buckling load, and natural frequency are presented for a simply supported beam, and the obtained results compare well with those predicted by the nonlocal Timoshenko and Reddy beam theories. © 2011 Elsevier Ltd. All rights reserved.

The " partial port-closing" operation strategy for a four-zone simulated moving bed (SMB) chromatographic process for binary separation was developed to improve the SMB performance. This strategy included the partial extract-closing (PEC) and the partial raffinate-closing (PRC) operations. In case of the PEC operation, the extract port is made to be closed during the first-half stage of a switching period. During the latter-half stage, the extract port is made to be open. In case of the PRC operation, the raffinate port is made to be open during the first-half stage of a switching period. During the latter-half stage, the raffinate port is made to be closed. If the operating conditions are chosen properly in each operation using a highly efficient optimization tool, the product stream can be collected during only the period that the product is almost separated from impurity. During the other period that the product is contaminated with impurity, the collection of the product stream can be stopped by closing the product port. The uncollected product stream is then allowed to keep migrating through the adjacent zone within the SMB process. Such a partial port-closing operation including PEC and PRC was found to surpass a conventional SMB operation remarkably in throughput and product purity. © 2010 Elsevier B.V.

Ma Z.,Cornell University | Lee J.-W.,Hanyang University | Helmann J.D.,Cornell University
Nucleic Acids Research | Year: 2011

Bacillus subtilis PerR is a Fur family repressor that senses hydrogen peroxide by metal-catalyzed oxidation. PerR contains a structural Zn(II) ion (Site 1) and a regulatory metal binding site (Site 2) that, upon association with either Mn(II) or Fe(II), allosterically activates DNA binding. In addition, a third less conserved metal binding site (Site 3) is present near the dimer interface in several crystal structures of homologous Fur family proteins. Here, we show that PerR proteins with substitutions of putative Site 3 residues (Y92A, E114A and H128A) are functional as repressors, but are unexpectedly compromised in their ability to sense H2O2. Consistently, these mutants utilize Mn(II) but not Fe(II) as a co-repressor in vivo. Metal titrations failed to identify a third binding site in PerR, and inspection of the PerR structure suggests that these residues instead constitute a hydrogen binding network that modulates the architecture, and consequently the metal selectivity, of Site 2. PerR H128A binds DNA with high affinity, but has a significantly reduced affinity for Fe(II), and to a lesser extent for Mn(II). The ability of PerR H128A to bind Fe(II) in vivo and to thereby respond efficiently to H2O2 was restored in a fur mutant strain with elevated cytosolic iron concentration. © 2011 The Author(s).

Chen Z.,Argonne National Laboratory | Belharouak I.,Argonne National Laboratory | Sun Y.-K.,Hanyang University | Amine K.,Argonne National Laboratory
Advanced Functional Materials | Year: 2013

Lithium-ion batteries have been long considered a promising energy storage technology for electrification of the transportation system. However, the poor safety characteristics of lithium-ion batteries is one of several technological barriers that hinder their deployment for automobile applications. Within the field of battery research and development, titanium-based anode materials have recently attracted widespread attention due to their significantly better thermal stability than the conventional graphite anode. In this chapter, the fundamental properties and promising electrochemical performance of titanium-based anode materials will be discussed for applications in hybrid electric vehicles. Nanostructured titanium-based oxide materials have been long pursued as anode materials for safe, extremely long life, and high power lithium-ion batteries. The outstanding safety and electrochemical performance of titanium-based anodes originates from their relatively high working potential, much higher than the potential needed for graphitic anodes, to form solid electrolyte interphase. Compared to graphite, lithiated titanium-based anodes release a substantially smaller amount of heat under abuse conditions. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

BACKGROUND/AIMS: The incidence of symptomatic hepatitis A reportedly increased among 20- to 40-year-old Korean during the late 2000s. Vaccination against hepatitis A was commenced in the late 1990s and was extended to children aged <10 years. In the present study we analyzed the changes in the seroprevalence of IgG anti-hepatitis A virus (HAV) over the past 13 years.METHODS: Overall, 4903 subjects who visited our hospital between January 2001 and December 2013 were studied. The seroprevalence of IgG anti-HAV was analyzed according to age and sex. In addition, the seroprevalence of IgG anti-HAV was compared among 12 age groups and among the following time periods: early 2000s (2001-2003), mid-to-late 2000s (2006-2008), and early 2010s (2011-2013). The chi-square test for trend was used for statistical analysis.RESULTS: The seroprevalence of IgG anti-HAV did not differ significantly between the sexes. Furthermore, compared to the seroprevalence of IgG anti-HAV in the early 2000s and mid-to-late 2000s, that in the early 2010s was markedly increased among individuals aged 1-14 years and decreased among those aged 25-44 years (P<0.01). We also found that the seroprevalence of IgG anti-HAV in individuals aged 25-44 years in the early 2010s was lower than that in the early 2000s and mid-to-late 2000s.CONCLUSIONS: The number of symptomatic HAV infection cases in Korea is decreasing, but the seroprevalence of IgG anti-HAV is low in the active population.

The physics of structure formation and maintenance of nuclear bodies (NBs), such as nucleoli, Cajal bodies, promyelocytic leukemia bodies, and speckles, in a crowded nuclear environment remains largely unknown. We investigate the role of macromolecular crowding in the formation and maintenance of NBs using computer simulations of a simple spherical model, called Lennard-Jones (LJ) particles. LJ particles form a one-phase, dilute fluid when the intermolecular interaction is weaker than a critical value, above which they phase separate and form a condensed domain. We find that when volume-exclusive crowders exist in significant concentrations, domain formation is induced even for weaker intermolecular interactions, and the effect is more pronounced with increasing crowder concentration. Simulation results show that a previous experimental finding that promyelocytic leukemia bodies disappear in the less-crowded condition and reassemble in the normal crowded condition can be interpreted as a consequence of the increased intermolecular interactions between NB proteins due to crowding. Based on further analysis of the simulation results, we discuss the acceleration of macromolecular associations that occur within NBs, and the delay of diffusive transport of macromolecules within and out of NBs when the crowder concentration increases. This study suggests that in a polydisperse nuclear environment that is enriched with a variety of macromolecules, macromolecular crowding not only plays an important role in the formation and maintenance of NBs, but also may perform some regulatory functions in response to alterations in the crowding conditions. © 2012 by the Biophysical Society.

This article describes the assessment of a numerical procedure used to determine the UV lamp configuration and surface roughness effects on an open channel water disinfection UV reactor. The performance of the open channel water disinfection UV reactor was numerically analyzed on the basis of the performance indictor reduction equivalent dose (RED). The RED values were calculated as a function of the Reynolds number to monitor the performance. The flow through the open channel UV reactor was modelled using a k-ε model with scalable wall function, a discrete ordinate (DO) model for fluence rate calculation, a volume of fluid (VOF) model to locate the unknown free surface, a discrete phase model (DPM) to track the pathogen transport, and a modified law of the wall to incorporate the reactor wall roughness effects. The performance analysis was carried out using commercial CFD software (ANSYS Fluent 15.0). Four case studies were analyzed based on open channel UV reactor type (horizontal and vertical) and lamp configuration (parallel and staggered). The results show that lamp configuration can play an important role in the performance of an open channel water disinfection UV reactor. The effects of the reactor wall roughness were Reynolds number dependent. The proposed methodology is useful for performance optimization of an open channel water disinfection UV reactor. © 2016 Elsevier Ltd.

Zhao H.,City University of Hong Kong | Hui K.S.,Hanyang University | Hui K.N.,Pusan National University
Carbon | Year: 2014

We reported on the facile synthesis of N-doped multilayer graphene (N-MLG) from milk powder that uses melamine as a nitrogen-doping source with Fe 2+ ions as catalytic growth agents. We showed that milk powder could be used as a precursor for large-scale N-MLG synthesis through heat treatment at 1000 °C under N2 atmosphere for 45-120 min. In addition, heating time has a remarkable effect on N content and type in N-MLG. The resulting N-MLG exhibited higher catalytic activity than undoped graphene and carbon nanotubes (CNTs), as well as comparable catalytic activity to commercial Pt/C catalyst toward oxygen reduction reaction (ORR). Furthermore, the catalytic activity was sensitive to N content and type, particularly the ratio of pyridinic-N to total N atoms. Results showed that Fe atoms in N-MLG were found to function not as synergetic catalysts for ORR but as catalytic growth agents for N-MLG formation, thereby promoting and stabilizing N atoms. The present method could lead to the synthesis of bulk amounts of N-MLG, which is promising for applications in electrochemical energy devices, such as fuel cells and metal-air batteries. © 2014 Elsevier Ltd. All rights reserved.

Rangasamy B.,Hanyang University | Hwang J.Y.,Korea Institute of Science and Technology | Choi W.,University of North Texas
Carbon | Year: 2014

Various approaches to improve the efficiency of Lithium ion batteries (LiB) by using Si have been suggested because Si has the highest known lithium capacity. Although Si is more than ten times higher capacity than existing graphite anodes, Si anodes have limited applications due to its high volume change during cycling. Here we demonstrated graphene/Si-CuO quantum dots (Gr/Si-CuO QD) layered structure as an efficient LiB anode which prevents large volume expansion of Si due to the presence of CuO-Cu3Si. By Electrophoresis Deposition technique, the multi-layer of graphene and Si-CuO QD has been successfully fabricated followed by annealing process to form Cu 3Si interlayer as confirmed by High Resolution Transmission Electron Microscope-Energy Dispersive Spectroscopy, X-ray diffraction and Raman analyses. The annealed Gr/Si-CuO QD exhibit the initial gravimetric specific capacity of 2869 mAh g-1 which is five times higher than that of annealed graphene at 0.5C. After 100 cycles at 1C rate the capacity retains ∼71% and the excellent rate capability even at high C rate reveals controlled volume expansion owing to the multi layered architecture and the Cu3Si inter layer. The layered structure of Gr/Si-CuO QD electrode could be applied in next generation micro power sources. © 2014 Elsevier Ltd. All rights reserved.

Ren L.,City University of Hong Kong | Hui K.S.,City University of Hong Kong | Hui K.S.,Hanyang University | Hui K.N.,Pusan National University
Journal of Materials Chemistry A | Year: 2013

In this work, we report a low-cost technique for fabrication of a simple three-dimensional (3D) free-standing nickel nanoparticle/graphene aerogel with a graphene sheet network. The 3D composite architecture was formed through the self-assembly aggregation of graphene accompanied by nickel nanoparticle in situ loading on the graphene sheet during the hydrothermal reduction of graphene oxide and Ni ions. The obtained composite architecture was characterized using X-ray diffraction, Fourier transform infrared, and scanning electron microscopy. The electrocatalytic properties of the as-synthesized Ni/graphene aerogel for ethanol oxidation were investigated using cyclic voltammetry and chronoamperometry. A high peak current density of about 6 mA cm-2 for ethanol oxidation was recorded during ethanol oxidation under the test condition of adding 0.1 M ethanol in 0.1 M NaOH solution. This result revealed excellent electrocatalytic activity for ethanol oxidation, which shows great potential for direct application in ethanol fuel cells. This study provides a guide to preparing well-defined sponge-like three-dimensional metallic/graphene nanoarchitectures for fuel cell applications. This journal is © 2013 The Royal Society of Chemistry.

Jin J.-T.,Sejong University | Jeong J.-W.,Hanyang University
Energy | Year: 2013

The purpose of this paper is to suggest a simple way of determining the thermal characteristic of free-form buildings, which can be applied at an early stage of the design phase. The thermal load of a reference building estimated using TRNSYS 16 is compared with those for various free-form buildings that have the same envelope area as the reference building. A database of thermal load ratios (i.e. the ratio of the free-form building's thermal load over the reference building's thermal load) was generated. Then, polynomial equations returning the envelope heat gain, heat loss, and solar heat gain ratios were derived as a function of window area ratio and exterior wall area ratio of a free-form building. It was found that the proposed models are able to predict the heat gain, heat loss, and solar heat gain characteristics of a free-form building within 10% of discrepancy, compared with detailed thermal load simulation results. © 2012 Elsevier Ltd.

Kim J.-K.,Hanyang University
Chemical Engineering Journal | Year: 2011

A systematic approach using the graphical representation of water use and its system-wide manipulation is proposed for minimising freshwater and wastewater generation for discontinuous water systems. Design interactions of time-dependant water reuse and implications of storage tank in the network design have been fully addressed, and a new targeting and design method has been proposed to provide guidelines for achieving minimum freshwater requirements and to design the configuration of water re-use networks. Design complexity associated with simultaneous consideration of concentration and time constraints has been effectively dealt with in the proposed design method, which clearly provides benefits by reducing water consumptions and maintaining sustainable water usage. © 2011 Elsevier B.V.

Oh B.-G.,Hanyang University
Discrete and Computational Geometry | Year: 2014

This paper is about hyperbolic properties on planar graphs. First, we study the relations among various kinds of strong isoperimetric inequalities on planar graphs and their duals. In particular, we show that a planar graph satisfies a strong isoperimetric inequality if and only if its dual has the same property, if the graph satisfies some minor regularity conditions and we choose an appropriate notion of strong isoperimetric inequalities. Second, we consider planar graphs where negative combinatorial curvatures dominate, and use the outcomes of the first part to strengthen the results of Higuchi, Żuk, and, especially, Woess. Finally, we study the relations between Gromov hyperbolicity and strong isoperimetric inequalities on planar graphs, and give a proof that a planar graph satisfying a proper kind of a strong isoperimetric inequality must be Gromov hyperbolic if face degrees of the graph are bounded. We also provide some examples to support our results. © 2014 Springer Science+Business Media New York.

Park S.H.,Argonne National Laboratory | Yoon S.H.,Korea Advanced Institute of Science and Technology | Lee C.S.,Hanyang University
Applied Energy | Year: 2013

The main purpose of this study was to investigate how a narrow angle injector affects the combustion and exhaust emissions characteristics in a single-cylinder diesel engine fueled by diesel-bioethanol blends. This study focused on reducing HC and CO emissions in the exhaust emissions by the bioethanol blending of diesel. A narrow angle injector with an injection angle of 70° was used and compared with a conventional angle injector having a 156° injection angle. The bioethanol was blended with the conventional diesel up to 30% with 5% biodiesel. Experiments revealed that, in a narrow angle injector, the premixed combustion duration increased with bioethanol contents unlike the similar value of conventional injector. The premixed combustion phasing decreased with the increase of bioethanol in both injectors. The variation in the peak combustion pressure of the narrow angle injector was smaller than that of a conventional injector. In addition, the narrow angle injector induced a higher indicated mean effective pressure (IMEP) and a shorter ignition delay compared to the conventional injector. In terms of exhaust emissions characteristics, the low and stable ISHC and ISCO emissions can be achieved through the application of narrow angle injector to the diesel-bioethanol blends combustion. By the early injection combustion strategy, ISHC and ISCO emissions are significantly reduced. © 2013 Elsevier Ltd.

To report the three-year outcomes of macular laser photocoagulation following intravitreal injection of triamcinolone acetonide (IVTA) for diffuse diabetic macular edema (DME). A prospective, randomized controlled study was completed. Eighty-six eyes of 74 patients with diffuse DME were randomized into two groups. Eyes assigned to the combination group (n = 48) were subjected to macular laser photocoagulation three weeks after IVTA. Eyes in the IVTA group (n = 38) underwent IVTA alone. Central macular thickness was measured by optical coherence tomography, and the number of additional treatments and mean time to recurrence were assessed. Thirty-seven eyes in the combination group and 26 eyes in the IVTA group completed the three-year follow-up. Recurrence of DME after initial treatment was not observed for nine of the 37 (24.3%) eyes in the combination group or for one of the 26 (3.9$) eyes in the IVTA group (p = 0.028). DME was absent for 19.9 months after treatment in the combination group compared to 10.3 months in the IVTA group (p = 0.027). The mean number of additional treatments was 0.92 in the combination group and 1.88 in the IVTA group (p = 0.001). Results in the subset of subjects who completed the three-year follow-up demonstrated that laser photocoagulation following IVTA is more effective than IVTA monotherapy for diffuse DME. Combination therapy required fewer additional treatments and resulted in a lower recurrence rate than IVTA monotherapy.

Most polymeric vascular prosthetic materials have low patency rate for replacement of small diameter vessels (<5 mm), mainly due to failure to generate healthy endothelium. In this study, we present polydopamine-mediated immobilization of growth factors on the surface of polymeric materials as a versatile tool to modify surface characteristics of vascular grafts potentially for accelerated endothelialization. Polydopamine was deposited on the surface of biocompatible poly(L-lactide-co-ε-caprolactone) (PLCL) elastomer, on which vascular endothelial growth factor (VEGF) was subsequently immobilized by simple dipping. Surface characteristics and composition were investigated by using scanning electron microscopy, atomic force microscopy, and X-ray photoelectron spectroscopy. Immobilization of VEGF on the polydopamine-deposited PLCL films was effective (19.8 ± 0.4 and 197.4 ± 19.7 ng/cm(2) for DPv20 and DPv200 films, respectively), and biotin-mediated labeling of immobilized VEGF revealed that the fluorescence intensity increased as a function of the concentration of VEGF solution. The effect of VEGF on adhesion of HUVECs was marginal, which may have been masked by polydopamine layer that also enhanced cell adhesion. However, VEGF-immobilized substrate significantly enhanced proliferation of HUVECs for over 7 days of in vitro culture and also improved their migration. In addition, immobilized VEGF supported robust cell to cell interactions with strong expression of CD 31 marker. The same process was effective for immobilization of basic fibroblast growth factor, demonstrating the robustness of polydopamine layer for secondary ligation of growth factors as a simple and novel surface modification strategy for vascular graft materials.

Cha H.-J.,Sogang University | Yim H.,Hanyang University
Tumor Biology | Year: 2013

Genomic instability has been considered to be one of the prominent factors for carcinogenesis and the development of a number of degenerative disorders, predominantly related to the aging. The cellular machineries involved in the maintenance of genomic integrity such as DNA repair and DNA damage responses are extensively characterized by a large number of studies. The failure of proper actions of such cellular machineries may lead to the devastating effects mostly inducing cancer or premature aging, even with no acute exogenous DNA damage stimuli. In this review, we especially focus on the pathophysiological aspects of the defective DNA damage responses in carcinogenesis and premature aging. Clear understanding the causes of carcinogenesis and age-related degenerative diseases will provide novel and efficient approaches for prevention and rational treatment of cancer and premature aging. © 2013 International Society of Oncology and BioMarkers (ISOBM).

Gugliuzza A.,University of Calabria | Drioli E.,University of Calabria | Drioli E.,Hanyang University
Journal of Membrane Science | Year: 2013

This review intends to highlight the potential of the membrane science in developed clothing and protective textiles. In particular, the purpose is to provide an overview of the membrane use in wearable fabrics as well as indoor and outdoor protection. Membrane basics and related applications in the field of textiles are discussed by covering papers and patents focused on membrane materials and sustainable strategies for the creation of a large variety of innovative textile solutions. Breathing membranes along with barrier films are examined, discussing related advantages and limitations. A special section is dedicated to the development of ultra-smart textiles, which use adaptable membranes and actuators based on electro-active materials, smart gels, and shape memory polymers along with sensing compounds for self-cleaning, release and capture processes. Future directions of membrane science in sustainable marketplaces, including societal challenges, industrial competitiveness and excellence in science, are also examined. © 2013 Elsevier B.V.

Nagajyoti P.C.,Hanyang University | Lee K.D.,Dongguk University | Sreekanth T.V.M.,Dongguk University
Environmental Chemistry Letters | Year: 2010

Metal contamination issues are becoming increasingly common in India and elsewhere, with many documented cases of metal toxicity in mining industries, foundries, smelters, coal-burning power plants and agriculture. Heavy metals, such as cadmium, copper, lead, chromium and mercury are major environmental pollutants, particularly in areas with high anthropogenic pressure. Heavy metal accumulation in soils is of concern in agricultural production due to the adverse effects on food safety and marketability, crop growth due to phytotoxicity, and environmental health of soil organisms. The influence of plants and their metabolic activities affects the geological and biological redistribution of heavy metals through pollution of the air, water and soil. This article details the range of heavy metals, their occurrence and toxicity for plants. Metal toxicity has high impact and relevance to plants and consequently it affects the ecosystem, where the plants form an integral component. Plants growing in metal-polluted sites exhibit altered metabolism, growth reduction, lower biomass production and metal accumulation. Various physiological and biochemical processes in plants are affected by metals. The contemporary investigations into toxicity and tolerance in metal-stressed plants are prompted by the growing metal pollution in the environment. A few metals, including copper, manganese, cobalt, zinc and chromium are, however, essential to plant metabolism in trace amounts. It is only when metals are present in bioavailable forms and at excessive levels, they have the potential to become toxic to plants. This review focuses mainly on zinc, cadmium, copper, mercury, chromium, lead, arsenic, cobalt, nickel, manganese and iron. © 2010 Springer-Verlag.

Lee Y.H.,Korea University | Bae S.-C.,Hanyang University | Song G.G.,Korea University
International Journal of Rheumatic Diseases | Year: 2013

Objective: The aim of this study was to assess the effects of anti-tumor necrosis factor (TNF) agents or disease-modifying antirheumatic drugs (DMARDs) on hepatitis B virus (HBV) reactivation in hepatitis B surface antigen (HBsAg)-positive patients with rheumatic diseases. Methods: Evidence of HBV reactivation after anti-TNF therapy or DMARDs in HBsAg-positive patients with rheumatic disease was summarized by performing a systematic review. Results: A total of 122 HBsAg-positive rheumatic disease-positive patients undergoing treatment with an anti-TNF agent or with DMARDs were identified in nine studies. In eight of the studies, the anti-TNF agents used were etanercept in 56 cases, adalimumab in 25 cases and infliximab in 14 cases. Follow-up periods ranged from 6 to 52 months. Antiviral prophylaxis was administrated in 48 of the 122 patients (39.3%). HBV reactivation in HBsAg-positive patients taking an anti-TNF agent or DMARD was reported in 15 cases (15/122 = 12.3%). Ten of the 15 patients provided individual data on HBV reactivation: four patients had rheumatoid arthritis, four had ankylosing spondylitis and two had psoriatic arthritis; four received etanercept, and two received infliximab. In one of the four etanercept-treated cases in which the patient had elevated HBV-DNA levels, antiviral prophylaxis was also administered. Antiviral treatment was also administered in seven patients receiving other treatments: lamivudine in one, adefovir in one and entecavir in five. Clinical outcomes were satisfactory in all 10 cases of HBV reactivation. Conclusions: Hepatitis B virus reactivation was found in 15 (12.3%) patients among the 122 HBsAg-positive patients with rheumatic diseases treated with anti-TNF agents or DMARDs. © 2013 Asia Pacific League of Associations for Rheumatology and Wiley Publishing Asia Pty Ltd.

Moon H.,Hanyang University | Choi S.,Dankook University
IEEE Transactions on Vehicular Technology | Year: 2011

In this paper, a channel-adaptive random access transmission scheme is presented for time-division-duplex (TDD)-based wireless systems. In a TDD-based wireless system, using the channel reciprocity, the channel gain of an uplink (UL) can be estimated from that of a downlink. The channel-adaptive random access scheme allows the transmission of a random access packet only when the channel gain of the UL is higher than a predetermined threshold. With channel-adaptive random access, it is possible to reduce the power required for random access transmission drastically at the cost of slightly larger transmission delay. If the threshold is set to zero, the presented channel-adaptive scheme is exactly the same as the conventional random access scheme. Therefore, channel-adaptive random access provides system design flexibility with the tradeoff between transmission power and transmission delay. © 2011 IEEE.

Phosphatidylinositol 3-kinase (PI3K) plays several important roles in neuronal survival. Activation of the pathway is essential for the neuroprotective mechanisms of materials that shield neuronal cells from many stressful conditions. However, there have been no reports to date about the effect of the direct activation of the pathway in hypoxic injury of neuronal cells. We investigated whether the direct activation of the PI3K pathway inhibits neuronal cell death induced by hypoxia. Primary cultured cortical neurons (PCCNs) were exposed to hypoxic conditions (less than 1 mol% O2) and/or treated with PI3K activator. Hypoxia reduced the viability of PCCNs in a time-dependent manner, but treatment with PI3K significantly restored viability in a concentration-dependent manner. Among the signaling proteins involved in the PI3K pathway, those associated with survival, including Akt and glycogen synthase kinase-3β, were decreased shortly after exposure to hypoxia and those associated with cell death, including BAX, apoptosis-induced factor, cytochrome c, caspase-9, caspase-3, and poly(ADP-ribose) polymerase (PARP), were increased. However, treatment with PI3K activator normalized the expression levels of those signaling proteins. PARP activity and levels of ATP and NAD(+) altered by hypoxia were also normalized with direct PI3K activation. All these findings suggest that direct and early activation is important for protecting neuronal cells from hypoxic injury.

Kim R.B.,Hanyang University
Agricultural Economics | Year: 2012

Risks, including food risks, are found to be different between the perceptions of 'experts' and consumers, thus understanding the potential difference in the perceptions of the effective food risk management (FRM) between consumers and experts is important in developing effective FRM strategies. This information enables policy makers to integrate societal concerns and values into risk management and communication regarding food safety and to enhance the public confidence in the authorities' approach to the food safety management. The purpose of this study is to understand how consumers evaluate the quality of the food risk management practices that are performed by the government and to determine the underlying psychological factors influencing consumer evaluations of food risk management quality (FRMQ). A comparative survey study was conducted in China and Korea, and the measurement scales used in the structural model were found to be configurally and metrically invariant between these two countries. The results show the difference in the perception of Chinese and Korean consumers regarding their evaluation for the FRMQ. While the perceived expertise of food risk managers was found to be the most important determinant in China, the proactive consumer protection was found to be the most important one in Korea. The scepticism in risk assessment and the communication practice was found to be second most important factor both in China and Korea. These results shed lights at the future policy recommendations.

Lee H.,Hanyang University
IEEE Transactions on Fuzzy Systems | Year: 2011

This paper presents a robust adaptive control method for a class of multi-inputmulti-output (MIMO) nonlinear systems that are transformable to a parametric-strict-feedback form which has couplings among input channels and the appearance of parametric uncertainties in the input matrices. The proposed approach effectively combines the design techniques of robust adaptive control by backstepping and adaptive fuzzy-logic control in order to remove the matching-condition requirement and to provide boundedness of tracking errors, even under dominant model uncertainties and poor parameter adaptation. Unlike previous robust adaptive fuzzy controls of MIMO nonlinear systems, this research introduces the robustness terms explicitly in the controller structure to counteract the effects of model uncertainties and parameter-adaptation errors. Uniform boundedness of the MIMO nonlinear control system is proved, and simulation results further validate the effectiveness and performance of the proposed control method. © 2010 IEEE.

Kim S.-M.,Inje University | Oh J.-E.,Hanyang University
Journal of Sound and Vibration | Year: 2013

This paper employs modal filters for simultaneous and independent control of multiple vibration modes of a flexible structure embedded with a non-collocated pair of sensor and actuator. Each modal filter of second order is designed to be sensitive to the target mode for control while insensitive to the others. Based on the fact that there are only in- and out-of-phase modes in lightly and proportionally damped finite structures, those in-phase modes are controlled in the same way as that for collocated control using negative feedback, while those out-of-phase modes are controlled exactly in the opposite way using positive feedback. These two are equivalent as far as single mode control is concerned and are electrical realizations of a mechanical dynamic vibration absorber. Feedback control experiments were conducted on a cantilever beam embedded with a piezoelectric actuator at the root and an accelerometer at the end tip. The results reveal a number of peculiar advantages of using non-collocated control over collocated control. Non-collocated plants generally exhibit better high-frequency roll-off characteristics because there are weaker mechanical and electrical feedthrough couplings between non-collocated transducers. Furthermore, the high frequency control spillover can be greatly eliminated by appropriately adjusting the gains of modal filters. It is thus often possible to make the performance and robustness of non-collocated control as well as or even better than those using collocated control. © 2012 Elsevier Ltd. All rights reserved.

Yoon G.H.,Hanyang University
Journal of Sound and Vibration | Year: 2013

This research details a new acoustic topology optimization (ATO) framework with an empirical material formulation for fibrous material. Despite the importance of considering pressure attenuation not only by internal solid structures but also by fibrous (porous) structures in acoustic design, a systematic ATO approach with an empirical material formulation has not yet been proposed. Thus, in this paper, an empirical material formulation called the Delany-Bazley model is implemented for the development of an ATO framework for fibrous material with porosity close to 1. By means of the SIMP (solid isotropic material with penalization) interpolation functions developed for multiple structural materials, ATO processes for fibrous structures as well as internal solid structures are carried out. In addition, a heuristic filter method that allows fibrous material to emerge only at the boundaries or rims of an internal solid structure is presented. Finally, the effect of the pressure attenuation on the topological layout for fibrous materials is investigated by solving several illustrative topology optimization examples. © 2012 Elsevier Ltd. All rights reserved.

Bang J.H.,Hanyang University
Bulletin of the Korean Chemical Society | Year: 2012

Oxide substrates in semiconductor-sensitized solar cells (SSSCs) have a great impact on their performance. TiO2 has long been utilized as an oxide substrate, and other alternatives such as ZnO and SnO2 have also been explored due to their superior physical properties over TiO 2. In the development of high-performance SSSCs, it is of significant importance to understand the effect of oxides on the electron injection and charge recombination as these two are major factors in dictating solar cell performance. In addition, elucidating the relationship between these two critical processes and solar cell performance in each oxide is critical in building up the basic foundation of SSSCs. In this study, ultrafast pump-probe laser spectroscopy and open-circuit decay analysis were conducted to examine the characteristics of three representative oxides (TiO2, ZnO, and SnO2) in terms of electron injection kinetics and charge recombination, and the implication of results is discussed.

Cho E.C.,Hanyang University
Bulletin of the Korean Chemical Society | Year: 2012

The present study investigates how the thermal stability of retinol (vitamin A) encapsulated in polyester nanoparticles is influenced by the types of polyester used for the nanoparticles. A variety of polyester-retinol nanoparticles were prepared with various polyesters like: poly(ethylene adipate), PEA; poly(butylene adipate), PBA; poly(hexamethylene adipate), PHMA; and three polycaprolactones, PCL, of different molecular weights (M n ∼10, 40, and 80K). The chemical stability of retinol in these nanoparticles, monitored in an aqueous solution at 25 °C and 40 °C for 4 weeks, was high in the following order of the nanoparticles prepared with PHMA > PCL 40K > PCL 10K > PCL 80K > PBA∼PEA at 25 °C and PCL 10K > PCL 40K > PHMA > PCL 80K > PEA > PBA at 40 °C. More importantly, this study has also found that the thermal stability of the retinol in the nanoparticles was closely connected with the melting temperatures of polyesters and polyester nanoparticles. The results were further discussed with possible factors - such as sample preparation condition (or history) and miscibility between the polyesters and retinol - affecting T m of the polyesters and the nanoparticles.

Kim D.-M.,Dongshin University | Kim J.-O.,Hanyang University
IEEE Transactions on Smart Grid | Year: 2012

This paper presents an innovative approach to formulate a customer-oriented demand response (DR) program in the electricity market using the analytic hierarchy process (AHP). AHP could represent the mutual importance degrees of load reduction criteria from the various viewpoints of load-holders. Thus, the proposed DR program (DRP) could provide the reasonable decision-support process for load-holders, because the participation or nonparticipation is determined by the incentive payments corresponding to the specific load reduction conditions. The proposed DRP has the objective to maintain the system reliability at the emergency period, and it is designed as an incentive-based program (IBP) considering the real-time and by-directional operation. The modified IEEE 24-bus system for the case study is used to demonstrate the usefulness and applicability of the proposed approach, and the load profiles with the proposed DRP and the required incentive payments are obtained. The results show not only the enhancement to the system reliability but also the economic benefits within Pareto-improvement. © 2012 IEEE.

Nam J.-W.,Whitehead Institute For Biomedical Research | Nam J.-W.,Howard Hughes Medical Institute | Nam J.-W.,Massachusetts Institute of Technology | Nam J.-W.,Hanyang University | And 3 more authors.
Genome Research | Year: 2012

Thousands of long noncoding RNAs (lncRNAs) have been found in vertebrate animals, a few of which have known biological roles. To better understand the genomics and features of lncRNAs in invertebrates, we used available RNA-seq, poly(A)-site, and ribosome-mapping data to identify lncRNAs of Caenorhabditis elegans. We found 170 long intervening ncRNAs (lincRNAs), which had single- or multiexonic structures that did not overlap protein-coding transcripts, and about sixty antisense lncRNAs (ancRNAs), which were complementary to protein-coding transcripts. Compared to protein-coding genes, the lncRNA genes tended to be expressed in a stage-dependent manner. Approximately 25% of the newly identified lincRNAs showed little signal for sequence conservation and mapped antisense to clusters of endogenous siRNAs, as would be expected if they serve as templates and targets for these siRNAs. The other 75% tended to be more conserved and included lincRNAs with intriguing expression and sequence features associating them with processes such as dauer formation, male identity, sperm formation, and interaction with sperm-specific mRNAs. Our study provides a glimpse into the lncRNA content of a nonvertebrate animal and a resource for future studies of lncRNA function.

Kim Y.H.,Hanyang University
Plastic and Reconstructive Surgery | Year: 2011

Background: Superficial liposuction has found its application in maximizing and creating a lifting effect to achieve a better aesthetic result. Due to initial high complication rates, these procedures were generally accepted as risky. In a response to the increasing concerns over the safety and efficacy of superficial liposuction, the authors describe their 14-year experience of performing superficial liposuction and analysis of postoperative complications associated with these procedures. Methods: From March of 1995 to December of 2008, the authors performed superficial liposuction on 2398 patients. Three subgroups were incorporated according to liposuction methods as follows: power-assisted liposuction alone (subgroup 1), power-assisted liposuction combined with ultrasound energy (subgroup 2), and power-assisted liposuction combined with external ultrasound and postoperative Endermologie (subgroup 3). Statistical analyses for complications were performed among subgroups. Results: The mean age was 42.8 years, mean body mass index was 27.9 kg/m, and mean volume of total aspiration was 5045 cc. Overall complication rate was 8.6 percent (206 patients). Four cases of skin necroses and two cases of infections were included. The most common complication was postoperative contour irregularity. Power-assisted liposuction combined with external ultrasound with or without postoperative Endermologie was seen to decrease the overall complication rate, contour irregularity, and skin necrosis. There were no statistical differences regarding other complications. Conclusion: Superficial liposuction has potential risks for higher complications compared with conventional suction techniques, especially postoperative contour irregularity, which can be minimized with proper selection of candidates for the procedure, avoiding overzealous suctioning of superficial layer, and using a combination of ultrasound energy techniques. Copyright © 2011 by the American Society of Plastic Surgeons.

Cord blood (CB) has been used as an important and ethical source for hematopoietic stem cell transplantation (SCT) as well as cell therapy by manufacturing mesenchymal stem cell, induced pleuripotenti al stem cell or just isolating mononuclear cell from CB. Recently, the application of cell-based therapy using CB has expanded its clinical utility, particularly, by using autologous CB in children with refractory diseases. For these purposes, CB has been stored worldwide since mid-1990. In this review, I would like to briefly present the historical development of clinical uses of CB in the fields of SCT and cell therapy, particularly to review the experiences in Korea. Furthermore, I would touch the recent banking status of CB. © 2014 by The Korean Pediatric Society.

Han Y.,Hanyang University
IEEE Transactions on Consumer Electronics | Year: 2010

Motion data gloves are frequently used input devices that interpret human hand gestures for applications such as virtual reality and human-computer interaction. However, commercial motion data gloves are too expensive for consumer use, and this has limited their popularity. This paper presents an inexpensive motion data glove to overcome this obstacle. To lower costs, we designed our glove to use single-channel video instead of expensive motion-sensing fibers or multi-channel video. Our visual motion data glove is composed of an inexpensive consumer glove with attached thin-bar-type optical indicators and a closed-form reconstruction algorithm that can overcome the common disadvantages of single-channel video approaches, i.e., occlusion and the need for inconvenient iterative reconstruction algorithms. Our low-cost visual motion data gloves are used to interpret human hand gestures, and the resulting performance is evaluated. © 2006 IEEE.

Ahmad J.,Hanyang University
ICSTE 2010 - 2010 2nd International Conference on Software Technology and Engineering, Proceedings | Year: 2010

In this paper a fractional open circuit voltage based maximum power point tracker (MPPT) for photovoltaic (PV) arrays is proposed. The fractional open circuit voltage based MPPT utilizes the fact that the PV array voltage corresponding to the maximum power exhibits a linear dependence with respect to array open circuit voltage for different irradiation and temperature levels. This method is the simplest of all the MPPT methods described in the literature. The main disadvantage of this method is that the PV array is disconnected from the load after regular intervals for the sampling of the array voltage. This results in power loss. Another disadvantage is that if the duration between two successive samplings of the array voltage, called the sampling period, is too long, there is a considerable loss. This is because the output voltage of the PV array follows the unchanged reference during one sampling period. Once a maximum power point (MPP) is tracked and a change in irradiation occurs between two successive samplings, then the new MPP is not tracked until the next sampling of the PV array voltage. This paper proposes an MPPT circuit in which the sampling interval of the PV array voltage, and the sampling period have been shortened. The sample and hold circuit, which samples and holds the MPP voltage, has also been simplified. The proposed circuit does not utilize expensive microcontroller or a digital signal processor and is thus suitable for low cost photovoltaic applications. © 2010 IEEE.

Yeh S.-W.,Hanyang University | Ham Y.-G.,NASA | Ham Y.-G.,Universities Space Research Association | Lee J.-Y.,University of Hawaii at Manoa
Journal of Climate | Year: 2012

This study assesses the changes in the tropical Pacific Ocean sea surface temperature (SST) trend and ENSO amplitude by comparing a historical run of the WorldClimate Research Programme Coupled Model Intercomparison Project (CMIP) phase-5 multimodel ensemble dataset (CMIP5) and the CMIP phase-3 dataset (CMIP3). The resultsindicate that the magnitude of the SST trend in the tropical Pacific basin has been significantly reduced from CMIP3 to CMIP5, which may be associated with the overestimation of the response to natural forcing and aerosols by including Earth system models in CMIP5. Moreover, the patterns of tropical warming over the second halfof the twentieth century have changed from a La Nin~ a-like structure in CMIP3 to an El Nin~ o-like structure in CMIP5. Further analysis indicates that such changes in the background state of the tropical Pacific and an increase in the sensitivity of the atmospheric response to the SST changes in the eastern tropical Pacific haveinfluenced the ENSO properties. In particular, the ratio of the SST anomaly variance in the eastern and western tropical Pacific increased from CMIP3 to CMIP5,indcating that a center of action associated with the ENSO amplitude has shifted to the east. © 2012 American Meteorological Society.

Hsu S.-H.,University of Florida | Sigmund W.M.,University of Florida | Sigmund W.M.,Hanyang University
Langmuir | Year: 2010

A nearly perfect hydrophobic interface by dint of mimicking hairs of arthropods was achieved for the first time. These Γ-shape artificial hairs were made via a membrane casting technique on polypropylene substrates. This extreme hydrophobicity merely arises from microstructure modification, and no further chemical treatments are needed. The ultralow adhesion to water droplets was evaluated through, video assessment, and it is believed to be attributed to the mechanical response of the artificial hairs. The principle of this fabrication technique is accessible and is expected to be compatible with large-area fabrication of superhydrophobic interfaces. © 2010 American Chemical Society.

A five-zone simulated moving bed (SMB) process for ternary separation has been developed previously and applied to the purification of biochemicals in the literature. Although this process was effective to some degree in many of previous research studies, its separation performance was always limited by the presence of overlap between the highest-affinity and the intermediate-affinity solutes. Since a proper control of the overlap was almost impossible under the current configuration and operation method, the application scope of a conventional five-zone SMB was restricted within the separation tasks that permitted either relatively medium purities or low throughput. To overcome such a limitation, an efficient operation strategy for improving the five-zone SMB performance was proposed in this study. The core of the proposed strategy is to partially collect the product stream by alternate opening and closing of the extract-2 port, which is in charge of recovering the intermediate-affinity solute molecules. Simultaneously, the zone II flow rate during the port-opening state is adjusted properly for complete desorption of the intermediate-affinity solute in zone II. The application of such a strategy was found to improve the five-zone SMB performance dramatically. One of the noteworthy improvements was that all three products could be recovered with extremely high purities at the same time. Furthermore, a marked increase in the throughput could also be obtained under the given purity requirements. Therefore, the strategy proposed in this study is expected to substantially upgrade the five-zone SMB performance, allowing its application to the separation tasks that demand either high purities or high throughput. © 2010 American Chemical Society.

Shin Y.W.,Hanyang University
Korean journal of ophthalmology : KJO | Year: 2011

We report a rare case of optic nerve atrophy with severe disc cupping resulting from methanol poisoning. A 30-year-old man presented to the hospital complaining of decreased visual acuity in both eyes a day after drinking alcohol containing methanol. His initial visual acuity allowed for only visualizing hand motion and not corrected in either eye. Initial intraocular pressure was within normal limits in both eyes. Initial fundus examination showed optic disc swelling in both eyes. Four years later, he visited our hospital for an eye evaluation. Visual acuity in both eyes still only allowed for visualizing hand motion. No nystagmus was observed in either eye during the optokinetic nystagmus test, and no waves were found in a visual evoked potential test. No specific change was noted on brain magnetic resonance imaging. On fundus examination, there was disc pallor in both eyes and disc cupping with a high cup/disc (C/D) ratio above 0.9 in the left eye. C/D ratio of the right eye was 0.5. Methanol poisoning may induce glaucomatous disc cupping in the late stage as well as optic atrophy. One possible mechanism of disc cupping is ganglion cell loss due to acute demyelination of the retrobulbar optic nerve. This report is the first photographic evidence of methanol induced optic disc cupping in Korea. © 2011 The Korean Ophthalmological Society

Ryu H.,Hanyang University | Parsons D.,Massey University
Computers and Education | Year: 2012

Mobile learning has been built upon the premise that we can transform traditional classroom or computer-based learning activities into a more ubiquitous and connected form of learning. Tentative outcomes from this assertion have been witnessed in many collaborative learning activities, but few analytic observations on what triggers this collaboration have so far been made. However Social Flow, a concept framework that extends Csikszentmihalyi's flow theory, may help us to partially explain the triggering mechanism of collaborative mobile learning. Our case study in this article, where learners together explore a built environment as part of a simulated security guard training programme, describes how the concept of social flow in a collaborative learning space might sketch out what triggers an optimal learning experience in collaboration and what can be additionally achieved in a collaborative learning experience. In this learning context, collaborative mobile learning might be seen to prompt more knowledge generation and extra learning tasks by fostering greater motivation than other learning environments. © 2011 Elsevier Ltd. All rights reserved.

Kim H.,Hanyang University | Kim J.-S.,Korea Basic Science Institute | Kim J.-S.,Seoul National University
Nature Reviews Genetics | Year: 2014

Programmable nucleases-including zinc-finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs) and RNA-guided engineered nucleases (RGENs) derived from the bacterial clustered regularly interspaced short palindromic repeat (CRISPR)-Cas (CRISPR-associated) system-enable targeted genetic modifications in cultured cells, as well as in whole animals and plants. The value of these enzymes in research, medicine and biotechnology arises from their ability to induce site-specific DNA cleavage in the genome, the repair (through endogenous mechanisms) of which allows high-precision genome editing. However, these nucleases differ in several respects, including their composition, targetable sites, specificities and mutation signatures, among other characteristics. Knowledge of nuclease-specific features, as well as of their pros and cons, is essential for researchers to choose the most appropriate tool for a range of applications. © 2014 Macmillan Publishers Limited. All rights reserved.

The explosive growth of social media has intrigued many scholars to inquire into why people willingly share information with others. However, relatively little attention has been devoted to how people determine which information they share in the networked environment. In this study, a 2 (network density - dense vs. sparse) × 2 (knowledge - expert vs. novice) × 3 (information valence - negative vs. neutral vs. positive) online experiment was performed to examine how the three factors interact and cross over in shaping individuals' perceptions of the value of information for themselves and for others in the network. Results show that individuals' perceptions of information value are influenced not just by their level of knowledge, but also by how the network environment is structured. Implications for the findings are discussed. © 2013 Elsevier Ltd. All rights reserved.

Construction and demolition waste has been dramatically increased in the last decade, and social and environmental concerns on the recycling have consequently been increased. Recent technology has greatly improved the recycling process for waste concrete. This study investigates the fundamental characteristics of concrete using recycled concrete aggregate (RCA) for its application to structural concrete members. The specimens used 100% coarse RCA, various replacement levels of natural aggregate with fine RCA, and several levels of fly ash addition. Compressive strength of mortar and concrete which used RCA gradually decreased as the amount of the recycled materials increased. Regardless of curing conditions and fly ash addition, the 28. days strength of the recycled aggregate concrete was greater than the design strength, 40. MPa, with a complete replacement of coarse aggregate and a replacement level of natural fine aggregate by fine RCA up to 60%. The recycled aggregate concrete achieved sufficient resistance to the chloride ion penetration. The measured carbonation depth did not indicate a clear relationship to the fine RCA replacement ratio but the recycled aggregate concrete could also attain adequate carbonation resistance. Based on the results from the experimental investigations, it is believed that the recycled aggregate concrete can be successfully applied to structural concrete members. © 2011 Elsevier Ltd.

We examine the photocurrent effect in the electroabsorption modulator (EAM) under very high optical power and investigate its implication in the link radio-frequency (RF) gain. After reviewing the effect of the photocurrent in the EAM, using the voltage-source model with the device capacitance included, we demonstrate a possibility that the RF gain can be enhanced by resonance due to the photocurrent if the photocurrent decreases with device bias, exhibiting negative differential resistance. We explore an EAM with intrastep quantum wells showing blueshift to achieve the negative photocurrent resistance and demonstrate a case where an enhancement in the link RF gain is possible. © 2006 IEEE.

Bang J.H.,Hanyang University
Electrochimica Acta | Year: 2011

Hollow graphitic carbon spheres (HGCSs) with a high surface area are produced by the carbonization of hollow polymer spheres obtained by the polymerization of core/shell-structured pyrrole micelles. HGCSs are employed as a carbon support material in a direct methanol fuel cell catalyst, and their effect on the electrocatalytic activity toward methanol oxidation is investigated. Pt catalyst supported on HGCSs shows a better electrocatalytic activity compared to that on Vulcan XC-72, which has been commonly used in fuel cell catalysts. The observed enhancement in the electrocatalytic activity is attributed to the improved electronic conductivity and high surface area of HGCSs. © 2011 Elsevier Ltd.