Time filter

Source Type

Daegu, South Korea

Kyungpook National University is one of the most prestigious Korean national universities along with Seoul National University, and one of the ten Flagship Korean National Universities, representing the Gyeongbuk Province. It is located in the Daegu Metropolitan City, which is the capital city of the Gyeongbuk Province, South Korea. The University was originally founded as the Daegu Dong-in Hospital in 1907, and officially established in September 1946, merging and succeeding the former three colleges of Daegu Teacher's College, Daegu Agricultural College, and Daegu Medical College, although its history dates back to 1906. In 2008, KNU acquired Sangju National University as a new campus of the KNU system, which is now designated as "KNU Sangju", becoming one of the largest campus universities in South Korea. In 2012, KNU opened the KNU Global Plaza for a professional engagement, such as knowledge / technology exchange between KNU and industry, and for domestic and international events / conferences. It has 17 floors, and its office rooms and facilities on 8 to 15th floors are currently occupied by more than 50 research institutes and centres. Wikipedia.

Lee H.,Kyungpook National University
Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science | Year: 2013

The vibro-acoustic characteristics of in-plane vibration in a thick annular disc containing a narrow radial slot are investigated with a hybrid approach combining numerical or experimental results with pre-developed analytical calculations. Structural eigenfunctions for in-plane vibrations of the disc are approximated as linear combinations of eigenfunctions for a uniform disc that has same material properties and geometric dimensions except for the slot. Acoustic radiations from the normal modes of the disc are calculated using a theoretical solution introduced in previous work for the uniform disc along with the results from the approximations of structural eigenfunctions. Vibration and sound radiation from the disc due to a harmonic force fixed to the disc outer surface are investigated using the mode expansion method. The effects of the circumferential distance between the radial excitation and slot on the vibro-acoustic responses are investigated using the same method. Finally, contributions of sound radiations from two split vibration modes to the overall sound radiation from the sample disc are also investigated. Based on these results, it can be concluded that the procedure suggested in this study has good accuracy in calculating the in-plane vibro-acoustic properties of a thick annular disc with a radial slot. © IMechE 2012.

Park T.S.,Kyungpook National University
Journal of Mechanical Science and Technology | Year: 2013

Effects of unsteady flows past a confined square cylinder on wall heat transfer are investigated numerically. Two Reynolds numbers and several the gap distances of the square cylinder are considered to analyze the geometric effects on the wall heat transfer. The results show the detailed description of flow structure and attendant heat transfer caused by the variation of the gap distance. As the gap distance increases, the flow changes from steady asymmetric flow to symmetric vortex shedding having the inversion of the Karman vortex street. Also, the square cylinder induces intensive flow instabilities and significant alteration of the thermal boundary layer. As a result, the temperature distributions on the channel walls become steeper and wall heat transfer is increased. © 2013 The Korean Society of Mechanical Engineers and Springer-Verlag Berlin Heidelberg.

Lee S.B.,Kyungpook National University
Journal of the Korean Physical Society | Year: 2014

The conserved lattice gas model in one dimension, generated from various initial states, was intensively studied. The dynamic critical exponents α and ν associated with the decay of activeparticle densities and the correlation time, respectively, were found to depend drastically on the initial states. The perfectly-ordered initial state prepared by repeatedly placing the block '0011' yielded a standard critical behavior, with the critical exponents satisfying all the scaling relations. On the other hand, the natural initial states and the ordered initial states of blocks of odd numbers of particles yielded an exponent α slightly larger than that of an ordered state of '0011', but the data for active-particle densities did not satisfy scaling function. The exponents α and ν were also calculated from, respectively, the autocorrelation function and the persistence distribution of the active-particle densities, both in the steady states. The value of α was found to be close to the value for an ordered state of '0011' whereas the value of ν was consistent with that for the random initial states. © 2014 The Korean Physical Society.

Jang W.-S.,Yeungnam University | Lee D.-E.,Kyungpook National University | Choi J.-H.,Korea University
Automation in Construction | Year: 2012

Currently available wireless sensor networks (WSNs) provide the potential for collecting and monitoring construction job-site information in an efficient way. However, the unique characteristic of large scale and complicated job-site layout makes it difficult to reliably adopt WSNs. As the wireless network becomes denser, increased network traffic may degrade the overall reliability of the data acquisition system. In this paper, a numerical simulation with the IEEE802.15.4 standard was conducted to analyze the packet reception rate and the number of received bits using channel clear probability. In addition, a case study was implemented to evaluate the network traffic congestion, by configuring an ad-hoc network topology with the commercial product of the ZigBee module. It is confirmed that the reliability of the ad-hoc network is degraded due to the increased signal traffic caused by the increased number of active nodes, hop counts, transmission intervals, etc. © 2012 Elsevier B.V. All rights reserved.

Kim S.,National Institute of Health | Kim S.,Kyungpook National University
Journal of Korean Medical Science | Year: 2010

Salmonella enterica has been one of the most widespread foodborne pathogens in Korea. Between 1998 and 2007, a total of 9,472 Salmonella isolates were identified from foodborne and waterborne illness patients. During that time, Korea was transitioning into a developed country in industry as well as in its hygiene system. Although the isolation number of totalSalmonella including serovar Typhi has decreased since 1999, the isolation of rare Salmonella serovars has emerged. Three most prevalent serovars during 1998-2007 were S. enterica Typhi, S. enterica Enteritidis, and S. enterica Typhimurium. There were remarkable outbreaks caused by rare serovars such as S. enterica Othmarschen, S. enterica London and S. enterica Paratyphi A, and overseas traveler-associated infections caused by S. enterica Weltevreden and S. enterica Anatum. Salmonella serovars from overseas travelers made a diverse Salmonella serovar pool in Korea. This study is the first review of the status of the human Salmonella infection trendin a developing country during 1998- 2007. Newly emerging rare Salmonella serovars should be traced and investigated to control new type pathogens in the developed world. © 2010 The Korean Academy of Medical Sciences.

Kim J.G.,Kyungpook National University
Korean Journal of Internal Medicine | Year: 2013

Although medical treatment has been shown to improve quality of life and prolong survival, no significant progress has been made in the treatment of advanced gastric cancer (AGC) within the last two decades. Thus, the optimum standard first-line chemotherapy regimen for AGC remains debatable, and most responses to chemotherapy are partial and of short duration; the median survival is approximately 7 to 11 months, and survival at 2 years is exceptionally > 10%. Recently, remarkable progress in tumor biology has led to the development of new agents that target critical aspects of oncogenic pathways. For AGC, many molecular targeting agents have been evaluated in international randomized studies, and trastuzumab, an anti-HER-2 monoclonal antibody, has shown antitumor activity against HER-2-positive AGC. However, this benefit is limited to only ~20% of patients with AGC (patients with HER-2-positive AGC). Therefore, there remains a critical need for both the development of more effective agents and the identification of molecular predictive and prognostic markers to select those patients who will benefit most from specific chemotherapeutic regimens and targeted therapies. © 2013 The Korean Association of Internal Medicine.

Ku S.-K.,Daegu Haany University | Bae J.-S.,Kyungpook National University
Archives of Pharmacal Research | Year: 2014

Sulforaphane (SFN), a natural isothiocyanate that is present in cruciferous vegetables such as broccoli and cabbage, is effective in preventing carcinogenesis, diabetes and inflammatory responses. Here, the anticoagulant activities of SFN were examined by monitoring activated partial thromboplastin time (aPTT), prothrombin time, and the activities of thrombin (Factor IIa, FIIa) and activated factor X (FXa). And, the effects of SFN on expression of plasminogen activator inhibitor type 1 (PAI-1) and tissue-type plasminogen activator (t-PA) were evaluated in tumor necrosis factor-α activated human umbilical vein endothelial cells (HUVECs). Treatment with SFN resulted in prolonged aPTT and PT and inhibition of the activities of thrombin and FXa, as well as inhibited production of thrombin and FXa in HUVECs. In addition, SFN inhibited thrombin-catalyzed fibrin polymerization and platelet aggregation. SFN also elicited anticoagulant effects in mice. In addition, treatment with SFN resulted in significant reduction of the PAI-1 to t-PA ratio. Collectively, SFN possesses antithrombotic activities and offers a basis for development of a novel anticoagulant. © 2014 The Pharmaceutical Society of Korea.

Reddy M.S.P.,Yeungnam University | Lee J.-H.,Kyungpook National University | Jang J.-S.,Yeungnam University
Electronic Materials Letters | Year: 2014

The electrical characteristics and reverse leakage mechanisms of tetramethylammonium hydroxide (TMAH) surface-treated Ni/Au/Al2O3/GaN metal-insulator-semiconductor (MIS) diodes were investigated by using the current-voltage (I-V) and capacitance-voltage (C-V) characteristics. The MIS diode was formed on n-GaN after etching the AlGaN in the AlGaN/GaN heterostructures. The TMAH-treated MIS diode showed better Schottky characteristics with a lower ideality factor, higher barrier height and lower reverse leakage current compared to the TMAH-free MIS diode. In addition, the TMAH-free MIS diodes exhibited a transition from Poole-Frenkel emission at low voltages to Schottky emission at high voltages, whereas the TMAH-treated MIS diodes showed Schottky emission over the entire voltage range. Reasonable mechanisms for the improved device-performance characteristics in the TMAH-treated MIS diode are discussed in terms of the decreased interface state density or traps associated with an oxide material and the reduced tunneling probability. © 2014 The Korean Institute of Metals and Materials and Springer Science+Business Media Dordrecht.

Roh Y.,Kyungpook National University
Japanese Journal of Applied Physics | Year: 2014

Three-dimensional (3D) ultrasound imaging allows physicians to use ultrasound to view pathology as a volume in order to enhance the comprehension of a patient's anatomy. In this paper, the modality of 3D ultrasound imaging is described in accordance with the development of transducer technology. Two representative types of 3D imaging transducers are reviewed with description of the concept and operation principle of each type: mechanical transducer and matrix array transducer. Mechanical transducers are further divided into free-hand scanning and sequential scanning types. Matrix array transducers are also detailed into piezoelectric (single-unit and module-assembly type) transducers and capacitive micromachined ultrasound transducers. Advantages of each transducer and technical issues for further performance enhancement are discussed. © 2014 The Japan Society of Applied Physics.

Jeon Y.H.,Kyungpook National University
Korean Journal of Pain | Year: 2012

Spinal cord stimulation has become a widely used and efficient alternative for the management of refractory chronic pain that is unresponsive to conservative therapies. Technological improvements have been considerable and the current neuromodulation devices are both extremely sophisticated and reliable in obtaining good results for various clinical situations of chronic pain, such as failed back surgery syndrome, complex regional pain syndrome, ischemic and coronary artery disease. This technique is likely to possess a savings in costs compared with alternative therapy strategies despite its high initial cost. Spinal cord stimulation continues to be a valuable tool in the treatment of chronic disabling pain. © The Korean Pain Society, 2012.

An S.-Y.,Kyungpook National University
Imaging Science in Dentistry | Year: 2012

A 9-year-old girl visited our hospital, complaining of a rapid-growing and rigid swelling on the left posterior mandibular area. Panoramic radiograph showed a moderately defined multilocular honeycomb appearance involving the left mandibular body. CT scan revealed an expansile, multilocular osteolytic lesion and multiple fluid levels within cystic spaces. Bone scan demonstrated increased radiotracer uptake and angiography showed a highly vascularized lesion. The lesion was suspected as aneurysmal bone cyst (ABC) and preoperative embolization was performed, which minimize the extent of operation and the surgical complication. The lesion was treated by surgical curettage and lateral decortication with repositioning. No additional treatment such as a surgical reconstruction or bone graft was needed. Early diagnosis of ABC is very important and appropriate treatment should be performed considering several factors such as age, surgical complication, and possibility of recurrence. © 2012 by Korean Academy of Oral and Maxillofacial Radiology.

Kang S.-M.,Kyungpook National University | Lee H.-J.,Seoul National University
Cancer Letters | Year: 2013

MicroRNAs constitute a class of small noncoding RNAs that play roles in tumorigenesis. We found that NKX2-1 protein levels were generally high in the lung cancer tissues whereas miRNA-365 expression levels were downregulated. Ectopic miR-365 expression decreased NKX2-1 expression in lung cancer cell lines. Transfection of a miR-365 mimic led to reduced proliferation of lung cancer cells; conversely, a miR-365 inhibitor slightly increased cell proliferation. The NKX2-1 overexpression significantly increased the cell proliferation by overcoming the suppressive effect of miR-365. Our data suggest that miR-365 is an important regulator of NKX2-1 and can be a target for lung cancer therapies. © 2013 Elsevier Ireland Ltd.

Kwon O.,Kyungpook National University
Journal of Ecology and Environment | Year: 2013

The current status of Korean jewel beetle, Chrysochroa coreana is reported from the data collected in the five-year field survey (2008-2012). Despite the previous assumption of its endangered status, the beetle was recently found in the southwestern part of Korea frequently. However the local population was suffering from the inadequate management of its host plants, Celtis sinensis Persson. This study reports the restoration possibility of the beetle by the adequate management of its host plants. © 2013 The Ecological Society of Korea.

Kim K.,Keimyung University | Park H.,Kyungpook National University
Contraception | Year: 2012

Background: Although oral contraceptives (OCs) are widely used, their effects on lipid profile need monitoring according to current usage in different populations. Study Design: A cross-sectional study was conducted using data from 1541 participants aged 35-55 years collected by the 2005-2009 Korea National Health and Nutrition Examination Surveys. OC use, demographic characteristics and dietary intake were obtained from the participants by questionnaire, and lipid levels were determined by analysis of blood samples. Results: Longer duration of OC use was positively associated with increasing levels of high-density lipoprotein cholesterol (HDL-C) and decreasing levels of low-density lipoprotein cholesterol (LDL-C). After adjusting for demographic and dietary factors, the odds ratio (OR) of low HDL-C (< 50 mg/dL) was significantly decreased in the longer-term (> 12 months) OC users (OR=0.36, 95% confidence interval 0.24-0.52) compared with those who never used OCs. However, use of OCs was not associated with a risk of high total cholesterol (≥ 240 mg/dL), high LDL-C (≥ 130 mg/dL), high triglycerides (≥ 150 mg/dL) or high ratio of triglycerides to HDL-C (> 3.8). Conclusions: These data suggest that the use of OCs may reduce the risk of dyslipidemia, mainly due to the decreased risk of low HDL-C, in Korean women. © 2012 Elsevier Inc.

Yasumoto K.,Nanjing Forestry University | Jandieri V.,Kyungpook National University | Liu Y.,Nanjing Forestry University
Journal of the Optical Society of America A: Optics and Image Science, and Vision | Year: 2013

A self-contained coupled-mode formulation for coupled two-dimensional photonic-crystal waveguides (PCWs) is discussed. Using a perturbation theory, the first-order coupled-mode equations are systematically derived, which govern the evolution of the modal amplitude of individual PCWs in isolation. The coupled-mode equations are used to analyze the coupled symmetric PCWs consisting of a square lattice of circular dielectric rods or air holes. It is shown that the results are in good agreement with those obtained by the rigorous direct analysis of the coupled waveguide system. © 2012 Optical Society of America.

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

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

Kim Y.,Kyungpook National University
Qualitative Health Research | Year: 2014

The purpose of this article is to describe life experiences following suicide attempts from the perspective of older Korean adults. Both field notes and in-depth interviews with 35 elderly Koreans who had attempted suicide were analyzed through qualitative content analysis. With an underlying theme of "life with no way out for those who believe they do not even have any luck in dying," I classified the experiences of participants in the wake of a failed suicide attempt into four categories: (a) facing additional hardships including deteriorating physical health, (b) having more sadness and loneliness than before the suicide attempt, (c) deepening dependency on tranquilizers, and (d) seesawing between despair and faint hope. Based on these research findings, I make four recommendations regarding secondary preventive interventions for elderly suicide attempters. © The Author(s) 2014.

Kim D.-C.,Research South, Inc. | Ku S.-W.,Daegu Haany University | Bae J.-S.,Kyungpook National University
BMB Reports | Year: 2012

Curcumin, a polyphenol responsible for the yellow color of the curry spice turmeric, possesses antiinflammatory, antiproliferative and antiangiogenic activities. However, anticoagulant activities of curcumin have not been studied. Here, the anticoagulant properties of curcumin and its derivative (bisdemethoxycurcumin, BDMC) were determined by monitoring activated partial thromboplastin time (aPTT), prothrombin time (PT) as well as cell-based thrombin and activated factor X (FXa) generation activities. Data showed that curcumin and BDMC prolonged aPTT and PT significantly and inhibited thrombin and FXa activities. They inhibited the generation of thrombin or FXa. In accordance with these anticoagulant activities, curcumin and BDMC showed anticoagulant effect in vivo. Surprisingly, these anticoagulant effects of curcumin were better than those of BDMC indicating that methoxy group in curcumin positively regulated anticoagulant function of curcumin. Therefore, these results suggest that curcumin and BDMC possess antithrombotic activities and daily consumption of the curry spice turmeric might help maintain anticoagulant status.

Ghafoor K.,King Saud University | AL-Juhaimi F.Y.,King Saud University | Choi Y.H.,Kyungpook National University
Plant Foods for Human Nutrition | Year: 2012

Supercritical fluid extraction (SFE) technique was applied and optimized for temperature, CO2 pressure and ethanol (modifier) concentration using orthogonal array design and response surface methodology for the extract yield, total phenols and antioxidants from grape (Vitis labrusca B.) seeds. Effects of extraction temperature and pressure were found to be significant for all these response variables in SFE process. Optimum SFE conditions (44~46 °C temperature and 153~161 bar CO2 pressure) along with ethanol (<7 %) as modifier, for the maximum predicted values of extract yield (12.09 %), total phenols (2.41 mg GAE/ml) and antioxidants (7.08 mg AAE/ml), were used to obtain extracts from grape seeds. The predicted values matched well with the experimental values (12.32 % extract yield, 2.45 mg GAE/ml total phenols and 7.08 mg AAE/ml antioxidants) obtained at optimum SFE conditions. The antiradical assay showed that SFE extracts of grape seeds can scavenge more than 85 % of 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radicals. The grape seeds extracts were also analyzed for hydroxybenzoic acids which included gallic acid (1.21~3.84 μg/ml), protocatechuic acid (3.57~11.78 μg/ml) and p-hydroxybenzoic acid (206.72~688.18 μg/ml). © 2012 Springer Science+Business Media, Inc.

Hong S.-M.,Kyungpook National University | Jung B.-H.,Yongin Songdam College | Ruan D.,University of California at Los Angeles
Physics in Medicine and Biology | Year: 2011

Motion-adaptive radiotherapy aims to deliver ablative radiation dose to the tumor target with minimal normal tissue exposure, by accounting for real-time target movement. In practice, prediction is usually necessary to compensate for system latency induced by measurement, communication and control. This work focuses on predicting respiratory motion, which is most dominant for thoracic and abdominal tumors. We develop and investigate the use of a local dynamic model in an augmented space, motivated by the observation that respiratory movement exhibits a locally circular pattern in a plane augmented with a delayed axis. By including the angular velocity as part of the system state, the proposed dynamic model effectively captures the natural evolution of respiratory motion. The first-order extended Kalman filter is used to propagate and update the state estimate. The target location is predicted by evaluating the local dynamic model equations at the required prediction length. This method is complementary to existing work in that (1) the local circular motion model characterizes 'turning', overcoming the limitation of linear motion models; (2) it uses a natural state representation including the local angular velocity and updates the state estimate systematically, offering explicit physical interpretations; (3) it relies on a parametric model and is much less data-satiate than the typical adaptive semiparametric or nonparametric method. We tested the performance of the proposed method with ten RPM traces, using the normalized root mean squared difference between the predicted value and the retrospective observation as the error metric. Its performance was compared with predictors based on the linear model, the interacting multiple linear models and the kernel density estimator for various combinations of prediction lengths and observation rates. The local dynamic model based approach provides the best performance for short to medium prediction lengths under relatively low observation rate. Sensitivity analysis indicates its robustness toward the choice of parameters. Its simplicity, robustness and low computation cost makes the proposed local dynamic model an attractive tool for real-time prediction with system latencies below 0.4 s. © 2011 Institute of Physics and Engineering in Medicine.

Park J.,Kyungpook National University
Journal of Pediatric Surgery | Year: 2013

The combination of an H-type rectovestibular fistula (RVF) and a normal anus is a rare type of anorectal malformation, resulting in abnormal communication between the normal rectum and vestibule in girls. Among the surgical methods used to treat this condition are simple fistula resection and extensive perineal dissection, but postoperative fistula recurrence is frequent. We utilized the endorectal mucosal advancement flap technique on three patients with H-type RVFs and a normal anus, all of whom had favorable outcomes. © 2013 Elsevier Inc.

Graphene oxide (GO)-titania (TiO2) composite was synthesized using a chemical mixing process and its photocatalytic activity for the degradation of a toxic organic vapor (toluene) under different operational conditions was examined. The as-prepared GO-TiO2 and undoped TiO 2 photocatalysts were characterized using SEM, XRD, and UV-VIS-NIR spectra. Moreover, the photocatalytic degradation efficiency of the GO-TiO 2 composite was much higher than that of the P25 TiO2, with an average efficiency of the GO-TiO2 composite of 84% and an average efficiency of the TiO2 powder of just 13%. As the air flow rate increased from 1 to 4 L min-1, the average degradation efficiencies of toluene decreased from 86 to 32%. In addition, as the initial concentration increased from 0.1 to 1.0 ppm, the average degradation efficiencies of toluene decreased from 86 to 8%. Overall, the GO-TiO2 composite could be applied effectively for purification of gaseous toluene under optimal operational conditions. © 2013 Elsevier Ltd. All rights reserved.

Bae T.-W.,Kyungpook National University
Infrared Physics and Technology | Year: 2014

This paper presents a spatial and temporal bilateral filter (BF) to detect target trajectories, by extracting spatial target information using a spatial BF and temporal target information using a temporal BF. Background prediction when it is covered by targets is the key to small target detection. In order to apply the BF to a small target detection field for this purpose, this paper presents a novel spatial and temporal BF with an adaptive standard deviation to predict spatial background and temporal background profiles, based on analysis of the blocks surrounding a spatial and temporal filter window. In order to discriminate between the edge or object regions with a flat background and the target region spatially and temporally, spatial and temporal variances of the blocks surrounding the filter window are calculated in a spatial infrared (IR) image and temporal profile. The spatial and temporal variances adjust standard deviations of the spatial and temporal BF. Through this procedure, spatial background and temporal background profiles are predicted, and then small targets can be detected by subtracting the predicted spatial background (and temporal background profile) from the original IR image (and original temporal profile) and multiplying spatial and temporal target information. To compare existing target detection methods and the proposed method, signal-to-clutter ratio gain (SCRG) and background suppression factor (BSF) are employed for spatial performance comparison and receiver operating characteristics (ROC) is used for detection-performance comparison of the target trajectory. Experimental results show that the proposed method has a superior target detection rate and a lower false-alarm rate. © 2013 Elsevier Ltd. All rights reserved.

Kim H.S.,Kyungpook National University
Journal of Ecology and Environment | Year: 2013

The present study summarized the occurrence, distribution and autecology of 18 taxa in the class Euglenophyceae collected from several swamps, reservoir and mountain wetlands in the South Korea from 2009 to 2013. This paper deals with 18 taxa consisting of 3 taxa of Colacium Ehrenberg, 2 taxa of Phacus Dujardin, 13 taxa of Trachelomonas Ehrenberg, which are recorded for the first time in Korean freshwater algal flora. © 2013 The Ecological Society of Korea. All rights are reserved.

Kang J.-H.,Ewha Womans University | Paek S.-M.,Kyungpook National University | Choy J.-H.,Ewha Womans University
Chemical Communications | Year: 2012

A porous hybrid of titanate nanosheets with SnO2 nanoparticles has been realized by an exfoliation and reassembling route. The present nanohybrid shows a large reversible capacity of 860 mA h g-1 with a good capacity retention (about 60% retention of the initial capacity after 50 cycles).

Veluvolu K.C.,Kyungpook National University | Soh Y.C.,Nanyang Technological University
International Journal of Robust and Nonlinear Control | Year: 2011

Multiple sliding mode observers for state and unknown input estimations of a class of MIMO nonlinear systems are systematically developed in this paper. A new nonlinear transformation is formulated to divide the original system into two interconnected subsystems. The unknown inputs are assumed to be bounded and not necessarily Lipschitz, and do not require any matching condition. Under structural assumptions for the unknown input distribution matrix, the sliding mode terms of the nonlinear observer are designed to track their respective unknown inputs. Also, the unknown inputs can be reconstructed from the multiple sliding mode structurally. The conditions for asymptotic stability of estimation error dynamics are derived. Finally, simulation results are given to demonstrate the effectiveness of the proposed method. © 2011 John Wiley & Sons, Ltd.

Min J.K.,Pusan National University | Park I.S.,Kyungpook National University
International Journal of Heat and Mass Transfer | Year: 2011

Film flows are classified into non-wavy laminar, wavy laminar and turbulence along the Reynolds number or the flow stability. Since the wavy motions of the film flows are so intricate and nonlinear, the studies have largely been dependent upon the experimental way. The numerical approaches have been limited on the non-wavy flow regime. To track the free surface position, various numerical techniques such as the VOF (Volume of Fluids), the MAC (Marker and Cell) and the moving grid have been adopted. However those were for a more accurate estimation of the average film thickness and not for capturing the wavy motion. Because the wavy motion highly affects the heat transfer in the film flow, the profound concern for the wavy motion is significant. In this study, the wavy motions of the laminar wavy film flow with the Reynolds number 200-1000 are successfully found by the VOF and PLIC (Piecewise Linear Interface Calculation) method. The numerical results, including the average film thickness, and the wave's amplitude, frequency and velocity, are compared with the experimental results. © 2010 Elsevier Ltd. All rights reserved.

Pham A.-T.,University of Missouri | Lee J.-D.,Kyungpook National University | Shannon J.G.,University of Missouri | Bilyeu K.D.,University of Missouri
Theoretical and Applied Genetics | Year: 2011

The alteration of fatty acid profiles in soybean to improve soybean oil quality has been a long-time goal of soybean researchers. Soybean oil with elevated oleic acid is desirable because this monounsaturated fatty acid improves the nutrition and oxidative stability of soybean oil compared to other oils. In the lipid biosynthetic pathway, the enzyme fatty acid desaturase 2 (FAD2) is responsible for the conversion of oleic acid precursors to linoleic acid precursors in developing soybean seeds. Two genes encoding FAD2-1A and FAD2-1B were identified to be expressed specifically in seeds during embryogenesis and have been considered to hold an important role in controlling the seed oleic acid content. A total of 22 soybean plant introduction (PI) lines identified to have an elevated oleic acid content were characterized for sequence mutations in the FAD 2-1A and FAD2-1B genes. PI 603452 was found to contain a deletion of a nucleotide in the second exon of FAD2-1A. These important SNPs were used in developing molecular marker genotyping assays. The assays appear to be a reliable and accurate tool to identify the FAD 2-1A and FAD2-1B genotype of wild-type and mutant plants. PI 603452 was subsequently crossed with PI 283327, a soybean line that has a mutation in FAD2-1B. Interestingly, soybean lines carrying both homozygous insertion/deletion mutation (indel) FAD2-1A alleles and mutant FAD2-1B alleles have an average of 82-86% oleic acid content, compared to 20% in conventional soybean, and low levels of linoleic and linolenic acids. The newly identified indel mutation in the FAD2-1A gene offers a simple method for the development of high oleic acid commercial soybean varieties. © Springer-Verlag (outside the USA) 2011.

Park J.,Kyungpook National University
Journal of Neurosurgery | Year: 2015

The occurrence of an angiographic dimple or irregularity due to indentation of the contrast column by an intraluminal thrombus at the dome of a ruptured aneurysm is not uncommon and does not draw much clinical attention. However, an angiographic dimple at the base of the ruptured aneurysm or division of the parent artery can signify a rupture point close to the dimple and an intraluminal thrombus, which has utmost clinical significance as it is close to the parent artery and necessitates a different treatment strategy from rupture of the aneurysm dome. The author reports on 2 cases of an angiographic dimple following subarachnoid hemorrhage (SAH) and subsequent surgical exploration. In the first patient, a 57-year-old-woman, angiography revealed a basal dimple in a superiorly directed anterior communicating artery aneurysm. A pterional craniotomy was performed, which revealed a bilobed aneurysm harboring a superiorly directed unruptured lobule and inferiorly directed ruptured lobule. An intraluminal thrombus in the inferiorly directed lobule apparently obscured the lobule and caused the appearance of the basal dimple on the angiograms. In the second patient, a 40-year-old man who had been transferred to the author's institution because of an angiographic evaluation that did not show any aneurysm despite SAH in the basal cisterns, initial angiography revealed a subtle dimple on the superior wall of the anterior communicating artery (ACoA). On follow-up angiography, a very small aneurysm was seen at the site of the dimple. A craniotomy then revealed a very small ruptured and thrombosed aneurysm on the superior wall of the ACoA. © AANS, 2015.

Kang N.J.,Kyungpook National University | Shin S.H.,Konkuk University | Shin S.H.,Seoul National University | Lee H.J.,Seoul National University | And 2 more authors.
Pharmacology and Therapeutics | Year: 2011

Multiple lines of evidences suggest that oxidative stress induced by reactive oxygen species are closely related to multi-stage carcinogenesis. Polyphenols, a group of chemicals with more than one phenol unit or building block per molecule, have been recognized for possessing many health benefits including cancer-preventive effects mainly due to their antioxidant activity. However, polyphenols can directly bind with signaling molecules involved in carcinogenesis and regulate its activity. Moreover, it is noteworthy that the binding between the polyphenol and the target protein is determined by their structural relationship, which implies that different polyphenols have different target proteins, leading to divergent chemopreventive effects. Extracellular stimuli transmit signals into a cell by activating their target signaling cascades involved in carcinogenesis. As an example, Src family kinase, a family of proto-oncogenic tyrosine kinases activated by a variety of oxidative stress and proinflammatory agents, is known to regulate cell proliferation, differentiation, survival and angiogenesis. Src family kinase subsequently activates downstream signal cascades including mitogen-activated protein kinase, phosphoinositol-3-kinase, and nuclear factor-kappaB, thereby inducing cell proliferation and causing cancer. Recent studies demonstrate that polyphenols can directly target signaling cascades involved in inflammation and the development of cancer. Inhibition of the kinases by polyphenols contributes to the attenuation of carcinogenesis. Therefore, the development of polyphenols as direct inhibitors against target proteins is regarded as a rational approach for chemoprevention. This review describes and discusses recent results about the direct interactions of polyphenols and protein kinases in cancer chemoprevention. © 2011 Elsevier Inc.

Kwon O.-Y.,Gyeongsang National University | Park S.-P.,Kyungpook National University
Epilepsy and Behavior | Year: 2011

The quality of life (QOL) of individuals with well-controlled epilepsy (WCE) is often not considered. We therefore investigated predictors determining QOL in patients who had been seizure free at least 1. year on stable antiepileptic drug (AED) monotherapy. They were asked to complete self-report health questionnaires, including the Beck Depression Inventory (BDI), Adverse Event Profile (AEP), and Quality of Life in Epilepsy Inventory-31 (QOLIE-31). We looked for predictors of QOLIE-31 scores among the various demographic, socioeconomic, and clinical factors and BDI, and AEP scores. Depression symptoms were manifested by 18.7% of patients. People with depression symptoms were more likely to report adverse events than those without depression symptoms. The strongest predictor of QOL was BDI score, followed by AEP total score, years of education, and income. BDI score had 3.37 times the effect of AEP total score. In conclusion, QOL of patients with WCE is determined mainly by depressive symptoms. © 2011 Elsevier Inc.

Yang G.Y.,Kyungpook National University
Journal of orofacial pain | Year: 2010

AIMS: To examine the antinociceptive effects of N-Methyl-D-aspartate (NMDA) receptor NR2 subunit antagonists in a rat model of the facial formalin test. METHODS: Experiments were carried out on adult male Sprague-Dawley rats weighing 220 to 280 g. Anesthetized rats were individually mounted on a stereotaxic frame and a polyethylene tube was implanted for intracisternal injection and, 72 hours later, formalin tests were performed. NMDA receptor antagonists were administered intracisternally 10 minutes prior to subcutaneous injection of 5% formalin (50 MicroL) into the vibrissal pad. RESULTS: The intracisternal administration of 25, 50, or 100 Microg of memantine, an antagonist that acts at the NMDA ion channel site, significantly suppressed the number of scratches in the second phase of the behavioral responses to formalin. Intracisternal administration of a range of doses of 5,7-dichlorokynurenic acid, a glycine site antagonist, or DL-2-amino-5-phosphonopentanoate (AP-5), a nonselective NMDA site antagonist, produced significant antinociceptive effects in the second phase. Intracisternal administration of 1, 2.5, or 5 Microg of (2R,4S)-4-(3 Phosphonopropyl)-2-piperidine_carboxylic acid (PPPA), a competitive NR2A antagonist, significantly suppressed the number of scratches in the second phase, while only the highest dose of PPPA (5 Microg) significantly suppressed the number of scratches in the first phase. The antinociceptive effects of intracisternal injection of (alphaR, betaS)-alpha-(4Hydroxyphenyl)-_ methyl-4-(phenylmethyl)-1-Piperidinepropanol maleate(Ro 25-6981), a selective NR2B antagonist, were similar to those of PPPA. Injection of memantine, AP-5, Ro 25-6981, or vehicle did not result in any motor dysfunction. A low dose of PPPA (1 microg) or 5,7-dichlorokynurenic acid (2.5 microg) did not affect motor function. However, higher doses of PPPA and 5,7-dichlorokynurenic acid produced motor dysfunction. CONCLUSION: The present results suggest that central NR2 subunits play an important role in orofacial nociceptive transmission. Moreover, this data also indicate that targeted inhibition of the NMDA receptor NR2 subunit is a potentially important new treatment approach for inflammatory pain originating in the orofacial area.

Song H.S.,Seoul National University | Kwon O.S.,Seoul National University | Lee S.H.,Seoul National University | Park S.J.,Seoul National University | And 3 more authors.
Nano Letters | Year: 2013

In this study, we developed a human taste receptor protein, hTAS2R38-functionalized carboxylated polypyrrole nanotube (CPNT)-field effect transistor (FET) as a nanobioelectronic tongue (nbe-tongue) that displayed human-like performance with high sensitivity and selectivity. Taster type (PAV) and nontaster type (AVI) hTAS2R38s were expressed in Escherichia coli (E. coli) at a high level and immobilized on a CPNT-FET sensor platform. Among the various tastants examined, PAV-CPNT-FET exclusively responded to target bitterness compounds, phenylthiocarbamide (PTC) and propylthiouracil (PROP), with high sensitivity at concentrations as low as 1 fM. However, no significant changes were observed in the AVI-CPNT-FET in response to the target bitter tastants. This nbe-tongue exhibited different bitter-taste perception of compounds containing thiourea (N-C-S) moieties such as PTC, PROP, and antithyroid toxin in vegetables, which corresponded to the haplotype of hTAS2R38 immobilized on CPNTs. This correlation with the type of receptor is very similar to the human taste system. Thus, the artificial taste sensor developed in this study allowed for the efficient detection of target tastants in mixture and real food sample with a human-like performance and high sensitivity. Furthermore, our nbe-tongue could be utilized as a substitute for cell-based assays and to better understand the mechanisms of human taste. © 2012 American Chemical Society.

Kim G.W.,Kyungpook National University
International Journal of Automotive Technology | Year: 2015

This paper presents a piezoelectric energy harvester (PEH), which harvests electric power energy from torsional vibration induced by internal combustion (IC) engines. The PEH can generate electric power for a wireless sensor node system by simply attaching a compact cantilever beam structure to the surface of the rotating shaft. A prototype PEH is manufactured by using a commercial piezoelectric wafer and mounted on a torque converter (i.e., engine output). The primary harvesting performance of the PEH prototype is experimentally validated through laboratory tests using a low-inertia dynamometer. The frequency response function of the PEH is investigated to evaluate its harvesting capability. Finally, its potential application to a wireless shaft torque transducer is discussed. © 2015, The Korean Society of Automotive Engineers and Springer-Verlag Berlin Heidelberg.

Choe H.-J.,Seoul National University | Choe B.-H.,Kyungpook National University
World Journal of Gastroenterology | Year: 2014

Understanding the natural course of chronic hepatitis B virus (HBV) infection is very important for the management and treatment of chronic hepatitis B in children. Based on treatment guidelines, the management of HBV carriers and treatment of active hepatitis have been advancing and resulted in increased survival, as well as decreased risks of complications such as liver cirrhosis and hepatocellular carcinoma. Development of a continuing medical education (CME) program for primary physicians becomes an important responsibility of pediatric hepatologists. CME could prevent misdiagnosis and unnecessary treatment that could lead to liver complications or antiviral resistance. In addition, education of patients and their parents is necessary to achieve better therapeutic outcomes. © 2014 Baishideng Publishing Group Co., Limited. All rights reserved.

Jeon Y.H.,Kyungpook National University
Korean Journal of Pain | Year: 2015

Herpes zoster (HZ) is a transient disease caused by the reactivation of latent varicella zoster virus (VZV) in spinal or cranial sensory ganglia. It is characterized by a painful rash in the affected dermatome. Postherpetic neuralgia (PHN) is the most troublesome side effect associated with HZ. However, PHN is often resistant to current analgesic treatments such as antidepressants, anticonvulsants, opioids, and topical agents including lidocaine patches and capsaicin cream and can persist for several years. The risk factors for reactivation of HZ include advanced age and compromised cell-mediated immunity (CMI). Early diagnosis and treatment with antiviral agents plus intervention treatments is believed to shorten the duration and severity of acute HZ and reduce the risk of PHN. Prophylactic vaccination against VZV can be the best option to prevent or reduce the incidence of HZ and PHN. This review focuses on the pathophysiology, clinical features, and management of HZ and PHN, as well as the efficacy of the HZ vaccine.

Park S.-S.,Kyungpook National University
Journal of Geotechnical and Geoenvironmental Engineering | Year: 2010

A weakly cemented sand and gravel has been partly or entirely used in the construction of earth structures such as dams and retaining walls. Such cemented soils that are usually highly permeable can undergo repetitive wetting and drying during curing due to temporary rainfall or a change in the groundwater table. In this study, weakly cemented sand specimens with four different cement ratios were compacted at optimum water content and cured for 28 days. When the cemented sand specimens were exposed to repetitive wetting and drying during curing, their 28-day unconfined compressive strength was evaluated. Wetting for one day on the last day was found to decrease the unconfined compressive strength of cemented sand, whereas wetting for one day in the middle of curing resulted in an increase in strength. The strength reduction due to wetting on the last day decreases as the cement ratio increases. For a specimen under repetitive wetting and drying over 28-day curing, the strength increases as the number of wetting increases up to three cycles. After three cycles of wetting and drying, the strength either becomes constant or slightly decreases due to insufficient water for hydration and/or washing cementitious materials. © 2010 ASCE.

Choi Y.,Kyungpook National University
Software Testing Verification and Reliability | Year: 2014

Model checking is an effective technique used to identify subtle problems in software safety using a comprehensive search algorithm. However, this comprehensiveness requires a large number of resources and is often too expensive to be applied in practice. This work strives to find a practical solution to model-checking automotive operating systems for the purpose of safety analysis, with minimum requirements and a systematic engineering approach for applying the technique in practice. The paper presents methods for converting the Trampoline kernel code into formal models for the model checker SPIN, a series of experiments using an incremental verification approach, and the use of embedded C constructs for performance improvement. The conversion methods include functional modularization and treatment for hardware-dependent code, such as memory access for context switching. The incremental verification approach aims at increasing the level of confidence in the verification even when comprehensiveness cannot be provided because of the limitations of the hardware resource. We also report on potential safety issues found in the Trampoline operating system during the experiments and present experimental evidence of the performance improvement using the embedded C constructs in SPIN. Copyright © 2012 John Wiley & Sons, Ltd. This paper presents methods for converting the Trampoline kernel code into formal models for the model checker SPIN and a series of experiments using an incremental verification approach. The conversion methods include functional modularization and treatment for hardware-dependent code, such as memory access for context switching. It also reports on potential safety issues found in the Trampoline operating system during the experiments and presents experimental evidence of the performance improvement using the embedded C constructs in SPIN. © 2012 John Wiley & Sons, Ltd.

Cho S.Y.,Kyungil University | Park J.G.,Kyungpook National University
Journal of Institute of Control, Robotics and Systems | Year: 2014

This paper presents a fingerprint database construction method for WLAN RSSI (Received Signal Strength Indicator)- based indoor positioning. When RSSI is used for indoor positioning, the fingerprint method can achieve more accurate positioning than trilateration and centroid methods. However, a FD (Fingerprint Database) must be constructed before positioning. This step is a very laborious process. To reduce the drawbacks of the fingerprint method, a radio propagation model-based FD construction method is presented. In this method, an FD can be constructed by a simulator. Experimental results show that the constructed FD-based positioning has a 3.17m (CEP) error. In this paper, a spatial correlation method is presented to estimate the NLOS(Non-Line of Sight) error included in the FD constructed by a simulator. As a result, the NLOS error of the FD is reduced and the performance of the error compensated FD-based positioning is improved. The experimental results show that the enhanced FD-based positioning has a 2.58m (CEP) error that is a reasonable performance for indoor LBS (Location Based Service). © ICROS 2014.

Veluvolu K.C.,Kyungpook National University | Defoort M.,University of Lille Nord de France | Soh Y.C.,Nanyang Technological University
Journal of the Franklin Institute | Year: 2014

This paper develops a high gain observer with multiple sliding modes for simultaneous state and fault estimations for MIMO nonlinear systems. The novelty lies in the observer design that employs the combination of high-gain observer and sliding mode observer. The proposed observer does not impose the small-Lipschitz-constant condition on the system nonlinearity. By imposing a structural assumption on the nonlinear fault distribution matrix, the observability of the faults/unknown inputs w.r.t. the outputs is safeguarded and sliding modes are utilized for their reconstruction. The reconstruction of the faults from the sliding mode only relies on the output estimation error and thus can be implemented online together with the state estimation. Finally, an application to flexible joint robotic arm is used to illustrate the proposed method. © 2012 The Franklin Institute.

Bae J.-S.,Kyungpook National University
Blood | Year: 2011

A pathogenic role for high-mobility group box 1 (HMGB1) protein has been postulated in severe sepsis. Activated protein C (APC) is the only drug approved by the Food and Drug Administration for severe sepsis; however, its effect on HMGB1 signaling has never been investigated. Here, we monitored the effect of APC on the lipopolysaccharide-mediated release of HMGB1 and the HMGB1-mediated modulation of proinflammatory responses in HUVECs. APC potently inhibited the release of HMGB1 and down-regulated the adhesion of the monocytic cell line, THP-1, to HMGB1-activated endothelial cells. HMGB1 up-regulated proinflammatory responses by interacting with 3 pathogen-related pattern recognition receptors: TLR2 and TLR4 and the receptor for advanced glycation end products.APC not only inhibited HMGB1 release but also down-regulated the cell surface expression of all 3 HMGB1 receptors in endothelial cells. The protective effects of APC were mediated through endothelial cell protein C receptor (EPCR) and protease-activated receptor 1 (PAR-1). Interestingly, a thrombin derivative containing the Gla-domain of APC recapitulated all protective effects of APC with a 20- to 50-fold higher efficacy. These results suggest that the EPCR- and PAR-1 -dependent protective effects of APC in severe sepsis may partially be mediated through the inhibition of HMGB1 signaling and that the chimeric thrombin mutant has potential therapeutic utility for severe sepsis. © 2011 by The American Society of Hematology.

Bae J.-S.,Kyungpook National University
Journal of Cellular Biochemistry | Year: 2011

It is well known that the expression level of secretory group IIA phospholipase A 2 (sPLA 2-IIA) is elevated in inflammatory diseases and lipopolysaccharide (LPS) up-regulates the expression of sPLA 2-IIA in human umbilical vein endothelial cells (HUVECs). Recently, lower concentration thrombin could elicit anti-inflammatory responses in HUVECs. Here, the effects of lower concentration thrombin on the expression of sPLA 2-IIA in LPS-stimulated HUVECs were investigated. Prior treatment of cells with thrombin (25-75pM) inhibited LPS-induced sPLA 2-IIA expression by activating its receptor, protease-activated receptor-1 (PAR-1). And pretreatment of cells with either PI3-kinase inhibitor (LY294002) or cholesterol depleting agent (methyl-β-cyclodextrin, MβCD) abolished the inhibitory activity of thrombin against sPLA 2-IIA expression. Therefore, these results suggest that PAR-1 activation by lower concentration thrombin inhibited LPS mediated expression of sPLA 2-IIA by PAR-1 and PI3-kinase-dependent manner in lipid raft on the HUVECs. Copyright © 2011 Wiley-Liss, Inc.

Youn D.-H.,Kyungpook National University | Gerber G.,Semmelweis University | Sather W.A.,Aurora University
Neural Plasticity | Year: 2013

Over the last twenty years of research on cellular mechanisms of pain hypersensitivity, long-term potentiation (LTP) of synaptic transmission in the spinal cord dorsal horn (DH) has emerged as an important contributor to pain pathology. Mechanisms that underlie LTP of spinal DH neurons include changes in the numbers, activity, and properties of ionotropic glutamate receptors (AMPA and NMDA receptors) and of voltage-gated Ca2+ channels. Here, we review the roles and mechanisms of these channels in the induction and expression of spinal DH LTP, and we present this within the framework of the anatomical organization and synaptic circuitry of the spinal DH. Moreover, we compare synaptic plasticity in the spinal DH with classical LTP described for hippocampal synapses. © 2013 Dong-ho Youn et al.

PURPOSE:: The aim of this study was to improve the cytopathic effect (CPE) of antiamebic agents by combining with cellulose synthesis inhibitor as an encystation inhibitor. METHODS:: Cellulose synthesis inhibitors, 2,6-dichlorobenzonitrile (DCB) and isoxaben were used to block encystation of Acanthamoeba during cultivation. Cultured human corneal epithelial (HCE) cells and Acanthamoeba were treated with polyhexamethylene biguanide (PHMB) combined with cellulose synthesis inhibitors to evaluate the CPE as an antiamebic agent. RESULTS:: 0.02% PHMB showed a 51.9% CPE on HCE cells within 30 minutes but exhibited significant toxic effects on Acanthamoeba. At a level of 0.00125%, PHMB had no significant CPEs on HCE cells, whereas 100 μM DCB and 10 μM isoxaben significantly inhibited the formation of the inner cyst wall of Acanthamoeba during encystation, and Acanthamoeba trophozoites failed to convert into mature cysts. Although a low concentration (0.00125%) of PHMB was used, the novel combinations with 100 μM DCB or 10 μM isoxaben had 23.4% or 18.7% additional amebicidal effects on Acanthamoeba. However, 100 μM DCB and 10 μM isoxaben had no CPEs on HCE cells. CONCLUSIONS:: The combination of cellulose synthesis inhibitors with low concentrations of PHMB reduced the CPE on HCE cells and improved the amebicidal effect on Acanthamoeba by inhibition of encystation. © 2015 Wolters Kluwer Health, Inc. All rights reserved.

Woo H.,Kyungpook National University
Journal of clinical neuroscience : official journal of the Neurosurgical Society of Australasia | Year: 2013

The aim of this technical report is to report a new method for ventriculoperitoneal (VP) shunt placement by determining the angle and distance of the proximal shunt catheter trajectory in the coronal plane using a simple modification of a standard coronal MRI. A modified coronal MRI (mcMRI) was taken in the coronal plane, which included Kocher's point and a point 1cm anterior to the tragus. Using this mcMRI, the trajectory from Kocher's point to a target in the frontal horn may be determined, and the angle and distance of the proximal shunt catheter trajectory may also be obtained. We identified a "safety angle" for catheter insertion, which avoided contact with any intraventricular structures. In addition, the length of the proximal catheter was calculated using the mcMRI, which we defined as the "safety depth." Twenty VP shunt surgeries were performed using an individual safety angle and safety length as determined by a preoperative mcMRI. The ventriculostomy was successful on the first attempt in all patients. The accurate placement of the proximal catheter was confirmed using a postoperative mcMRI. Only one patient demonstrated a track hemorrhage around the catheter path on CT scans. Follow-up evaluations were performed 3 to 12 months after the shunt surgery. The mcMRI protocol is a simple modification of the standard coronal MRI and may important for the determination of an accurate angle and distance of the proximal catheter during free-hand ventriculostomy for VP shunt. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

Bae J.-S.,Kyungpook National University
Inflammation | Year: 2015

It is well known that the expression level of secretory group IIA phospholipase A2 (sPLA2-IIA) is elevated in inflammatory diseases and lipopolysaccharide (LPS) upregulates the expression of sPLA2-IIA in human umbilical vein endothelial cells (HUVECs). Orientin, a C-glycosyl flavonoid, is known to have anxiolytic, anti-oxidative, and anti-inflammatory activity. Here, orientin was examined for its effects on the expression and activity of sPLA2-IIA in HUVECs and mouse. Prior treatment of cells or mouse with orientin inhibited LPS-induced expression and activity of sPLA2-IIA. And orientin suppressed the activation of cytosolic phospholipase A2 (cPLA2) and extracellular signal-regulated kinase (ERK) 1/2 by LPS. Therefore, these results suggest that orientin may inhibit LPS-mediated expression of sPLA2-IIA by suppression of cPLA2 and ERK 1/2. © 2015, Springer Science+Business Media New York.

Choi H.-M.,Kyungpook National University | Ji C.-R.,North Carolina State University
Nuclear Physics A | Year: 2011

We investigate the light-front zero-mode contribution to the weak transition form factors between pseudoscalar and vector mesons using a covariant fermion field theory model in (3+1) dimensions. In particular, we discuss the form factors a-(q2) and f(q2) which have been suspected to have the zero-mode contribution in the q+=0 frame. While the zero-mode contribution in principle depends on the form of the vector meson vertex Γμ=γμ-(2k-PV)μ/D, the form factor f(q2) is found to be free from the zero mode if the denominator D contains the term proportional to the light-front longitudinal momentum fraction factor (1/x)n of the struck quark with the power n>0. Although the form factor a-(q2) is not free from the zero mode, the zero-mode contribution comes only either from the simple vertex Γμ=γμ term or from the other term just with a constant D (i.e. n=0), but not with the momentum-dependent denominator (i.e. D~(1/x)n with n>0). We identify the zero-mode contribution to a-(q2) and incorporate it as a convolution of the zero-mode operator with the initial- and final-state light-front wave functions. The covariance (i.e. frame independence) of our model has been checked by performing the light-front calculations both in the q+=0 and q+>0 frames. We present our numerical result of the B→ρ transition for an explicit demonstration of our findings. © 2011 Elsevier B.V.

Cho K.S.,Kyungpook National University | Song K.-W.,Pusan National University | Chang G.-S.,FITI Testing and Research Institute
Journal of Rheology | Year: 2010

We have found empirical scaling relations in nonlinear viscoelasticity of poly(ethylene oxide) (PEO) solutions under large amplitude oscillatory shear flow. The scaling relations superpose dimensionless nonlinear viscoelastic functions, such as the normalized amplitudes of elastic and viscous stresses and normalized Fourier intensities, measured at different strain amplitudes and frequencies on a single curve irrespective of the molecular weight and the concentration of the polymer solutions. The scaling relations reveal that the nonlinear viscoelastic functions are functions of dimensionless variable ζ ≡ γo cos δ (ω), where δ is the phase lag of linear viscoelasticity. The validity of our superposition was checked for PEO aqueous solutions under the conditions that concentration: 3

Kim J.G.,Kyungpook National University
Endocrinology and Metabolism | Year: 2014

Four proto-oncogenes commonly associated with well-differentiated thyroid carcinoma, rearranged during transfection (RET)/papillary thyroid cancer, BRAF, RAS, and PAX8/peroxisome proliferator activated receptor-γ, may carry diagnostic and prognostic significance. These oncogenes can be used to improve the diagnosis and management of well-differentiated thyroid carcinoma. Limited therapeutic options are available for patients with metastatic well-differentiated thyroid cancer, necessitating the development of novel therapies. Vascular endothelial growth factor (VEGF)- and RET-directed therapies such as sorafenib, motesanib, and sunitinib have been shown to be the most effective at inducing clinical responses and stabilizing the disease process. Further clinical trials of these therapeutic agents may soon change the management of thyroid cancer. © 2014 Korean Endocrine Society.

Min K.-J.,Keimyung University | Seo B.R.,Keimyung University | Bae Y.C.,Kyungpook National University | Yoo Y.H.,Dong - A University | Kwon T.K.,Keimyung University
Cell Death and Disease | Year: 2014

Thioridazine has been known as an antipsychotic agent, but it also has anticancer activity. However, the effect of thioridazine on tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) sensitization has not yet been studied. Here, we investigated the ability of thioridazine to sensitize TRAIL-mediated apoptosis. Combined treatment with thioridazine and TRAIL markedly induced apoptosis in various human carcinoma cells, including renal carcinoma (Caki, ACHN, and A498), breast carcinoma (MDA-MB231), and glioma (U251MG) cells, but not in normal mouse kidney cells (TMCK-1) and human normal mesangial cells. We found that thioridazine downregulated c-FLIP(L) and Mcl-1 expression at the post-translational level via an increase in proteasome activity. The overexpression of c-FLIP(L) and Mcl-1 overcame thioridazine plus TRAIL-induced apoptosis. We further observed that thioridazine inhibited the Akt signaling pathway. In contrast, although other phosphatidylinositol-3-kinase/ Akt inhibitors (LY294002 and wortmannin) sensitized TRAIL-mediated apoptosis, c-FLIP(L) and Mcl-1 expressions were not altered. Furthermore, thioridazine increased the production of reactive oxygen species (ROS) in Caki cells, and ROS scavengers (N-acetylcysteine, glutathione ethyl ester, and trolox) inhibited thioridazine plus TRAIL-induced apoptosis, as well as Akt inhibition and the downregulation of c-FLIP(L) and Mcl-1. Collectively, our study demonstrates that thioridazine enhances TRAIL-mediated apoptosis via the ROS-mediated inhibition of Akt signaling and the downregulation of c-FLIP(L) and Mcl-1 at the post-translational level. © 2014 Macmillan Publishers Limited.

Yu B.G.,Korea Aerospace University | Choi T.K.,Yonsei University | Kim W.,Kyungpook National University
Physical Review C - Nuclear Physics | Year: 2011

We present a Regge model for pion photoproduction which is basically free of parameters within the framework of the s-channel helicity amplitude. For completeness we take into account axial mesons a1(1260), b 1(1235) and tensor meson a2(1320) in addition to the primary π+ρ exchanges for charged pion photoproduction, while the axial meson h1(1170) exchange is added to the model of ω+ρ 0+b1 exchanges for the neutral case. The present model deals for the first time with the a2 and h1 Regge poles in the s-channel helicity amplitude. For model independence, we use coupling constants of all exchanged mesons determined from empirical decay widths or from the SU(3) relations together with consistency check with existing estimates that are widely accepted in other reaction processes. Based on these coupling constants the simultaneous description of four photoproduction channels is given. Within the Regge regime, s≫4M2 and -t<2 GeV2, cross sections and spin polarization asymmetries at various photon energies are analyzed and results are obtained in better agreement with experimental data without referring to any fitting procedure. The model confirms dominance of the nucleon Born term in the sharp rise of the charged pion cross section at very forward angles, while dominance of the ω exchange with the nonsense wrong signature zero leads to the deep dip in the neutral pion cross section. In contrast to existing models, however, our model for the charged pion case shows quite a different production mechanism due to the crucial role of the tensor meson a2 exchange in the cross section and spin polarization asymmetries. Also the axial meson b1 exchange is found to give a sizable contribution to the photon polarization asymmetry. In the neutral case, the role of the b 1 is not significant, but the isoscalar h1 exchange gives an important contribution to the dip-generating mechanism in the photon polarization, showing the isoscalar nature of the process with the ω. These findings demonstrate validity of the present model with the prompt use of the tensor meson a2 and axial meson h1 for a wider application. © 2011 American Physical Society.

Choi H.-M.,Kyungpook National University | Ji C.-R.,North Carolina State University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2011

We study the light-front zero-mode contribution to the tensor form factors Ti (i=1,2,3) for the exclusive rare P→Vl+l- decays using a covariant fermion field theory model in (3+1) dimensions. While the zero-mode contribution in principle depends on the form of the vector meson vertex Γμ=γμ-(2k-PV)μ/D, the three tensor form factors Ti (i=1,2,3) are found to be free from the zero mode if the denominator D contains the term proportional to the light-front energy or the longitudinal momentum fraction factor (1/x)n of the struck quark with the power n>0. Since the denominator D used in the light-front quark model (LFQM) has the power n=1/2, the three tensor form factors Ti (i=1,2,3) can be computed in LFQM safely without involving any complicate zero-mode contribution. The lack of zero-mode contribution benefits the phenomenology with LFQM. © 2011 Elsevier B.V.

Liu Y.,Daegu University | Lee S.M.,Kyungpook National University
IEEE Transactions on Fuzzy Systems | Year: 2016

In this paper, we investigate the problem of stability and stabilization for sampled-data fuzzy systems with state quantization. By using an input delay approach, the sampled-data fuzzy systems with state quantization are transformed into a continuous-time system with a delay in the state. The transformed system contains nondifferentiable time-varying state delay. Based on some integral techniques, some new stability and stabilization criteria are first proposed by a modified Lyapunov functional. Furthermore, in the case of no quantization, some new stability and stabilization criteria are also obtained. It is shown that the new stability and stabilization criteria can provide a larger upper bound of the sampling interval than some existing ones in the literature. Two simulation examples are given to show the effectiveness of the proposed design method. © 1993-2012 IEEE.

Lee C.,Kyungpook National University
Virology Journal | Year: 2015

The enteric disease of swine recognized in the early 1970s in Europe was initially described as "epidemic viral diarrhea" and is now termed "porcine epidemic diarrhea (PED)". The coronavirus referred to as PED virus (PEDV) was determined to be the etiologic agent of this disease in the late 1970s. Since then the disease has been reported in Europe and Asia, but the most severe outbreaks have occurred predominantly in Asian swine-producing countries. Most recently, PED first emerged in early 2013 in the United States that caused high morbidity and mortality associated with PED, remarkably affecting US pig production, and spread further to Canada and Mexico. Soon thereafter, large-scale PED epidemics recurred through the pork industry in South Korea, Japan, and Taiwan. These recent outbreaks and global re-emergence of PED require urgent attention and deeper understanding of PEDV biology and pathogenic mechanisms. This paper highlights the current knowledge of molecular epidemiology, diagnosis, and pathogenesis of PEDV, as well as prevention and control measures against PEDV infection. More information about the virus and the disease is still necessary for the development of effective vaccines and control strategies. It is hoped that this review will stimulate further basic and applied studies and encourage collaboration among producers, researchers, and swine veterinarians to provide answers that improve our understanding of PEDV and PED in an effort to eliminate this economically significant viral disease, which emerged or re-emerged worldwide. © 2015 Lee.

Ho Ha S.,Kyungpook National University | Krishnan R.,Carnegie Mellon University
Computers and Operations Research | Year: 2012

The recent economic crisis not only reduces the profit of retailer stores but also incurs the significant losses caused by increasing the late-payment rate of credit cards. Under this pressure, the scope of credit prediction needs to be broadened to the customer management after delinquency occurs. In doing so, this study clusters the credit card debtors in a retail company into homogeneous segments by using a self-organizing map. This study then develops credit prediction models to recognize the repayment patterns of each segment by using a Cox proportional hazard analysis. The credit prediction models are evaluated and the managerial implications of the study are provided. © 2010 Elsevier Ltd. All rights reserved.

Park J.J.,Kyungpook National University | Kim K.,Seoul National University
Deep-Sea Research Part II: Topical Studies in Oceanography | Year: 2013

The deep currents at 700-800. m depths from Argo float trajectories (including pre-Argo floats) have been compiled from 1999 to 2010 in the Japan/East Sea (JES). More than 14,000 velocities from the dataset provides the first view of interbasin-scale dependency in deep currents of the JES, such as mean circulation and eddy variability, especially with an emphasis on their topographic steering characteristics. The observational findings in this study are (1) The Argo observation exhibits dominance of cyclonic mean circulation in the entire JES yet with a distinct interbasin variability of its magnitude. The mean circulation is strongest in the eastern Japan Basin (JB), while overall currents in the Ulleung Basin (UB) are weaker than that in the eastern Japan Basin and western Yamato Basin (YB) by a factor of two to three. (2) The eddy kinetic energy (EKE) is maximum in the western Japan Basin where strong dipole structure of wind-stress curl in winter is located. The interior of each basin (the eastern JB, UB, and YB) has local maxima of the EKE a factor of four to five smaller than that in the western JB. (3) Cyclonic bottom following characteristics prevail in the bin-averaged velocities. However, the individual deep flows presumably containing temporal variability have a preference to follow topography not only with cyclonic flows (shallow depth to the right), but also anticyclonic flows (shallow depth to the left), especially when flows are highly energetic. Occurrence of anticyclonic flows is proportional to the local EKE level relative to mean kinetic energy, implying that such flows could exist only in a transient manner such as topographic Rossby waves. The Argo observations may demonstrate an asymmetry of stable cyclonic and unstable anticyclonic circulation in the marginal seas of the northern hemisphere as the previous theoretical modeling studies suggested. © 2012.

Yu B.G.,Korea Aerospace University | Choi T.K.,Yonsei University | Kim W.,Kyungpook National University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2011

The contribution of the tensor meson K2*(1430) exchange in the process γp→K+λ(σ0) is investigated within the Regge framework. Inclusion of the K2* exchange in the K(494)+K*(892) exchanges with the coupling constants chosen from the SU(3) symmetry leads to a better description of the production mechanism without referring to any fitting procedure. This shows the significance of the role of the tensor meson exchange to have the Regge theory basically free of parameters with the SU(3) symmetry a good approximation for the meson-baryon couplings. © 2011 Elsevier B.V.

Kwon T.Y.,Kyungpook National University
Journal of investigative and clinical dentistry | Year: 2012

The current paper reviews the curing mechanisms found in resin-based materials used in dentistry. Historical aspects of dental products and the associated curing mechanisms are reviewed. In comparison with common industrial procedures, curing methods employed for dental materials are relatively limited because of the need to polymerize quickly in the oral cavity at an ambient temperature. Heat-cure and self-cure dental resins utilize benzoyl peroxide initiator alone with a tertiary amine co-initiator. At present, most dental restorative composites use a camphorquinone-amine complex initiation, visible light-cure, one-component systems, although alternative photoinitiators have been researched and developed. A multiple curing mode in a dual-cure material is a complex combination of various initiation systems. The use of aryl sulfinic acid sodium salt to overcome adverse chemical interactions between simplified adhesives and self- or dual-cure composites is based on another self-cure polymerization mechanism, sulfinic acid-initiated polymerization, proposed by Hagger in 1948. The sodium salt of aryl sulfinic acid reacts with an acidic monomer in simplified adhesives, and is believed to produce radicals. Clinically, it is important to try to optimize the degree of conversion of resin-based materials using proper manipulation and adequate light-curing techniques to ensure the best outcome for materials used to restore teeth. © 2012 Blackwell Publishing Asia Pty Ltd.

Yang J.-M.,Kyungpook National University
Automatica | Year: 2015

This paper presents a fault tolerant controller for asynchronous sequential machines subject to unauthorized state transitions caused by adversarial inputs. The input/output machines are considered where direct access to the machine's state is unavailable. If the asynchronous machine satisfies some condition on transition feature and reachability, we can design a simple output feedback controller that needs neither a state observer nor output bursts. Despite insufficient knowledge of the current state, the proposed controller automatically counteracts any transient fault so that the closed-loop system can maintain the normal input/output behavior. © 2014 Elsevier. Ltd All rights reserved.

Park J.Y.,Kyungpook National University
Korean Journal of Chemical Engineering | Year: 2014

Colloidal lithography is an effective and facile strategy for highly ordered nanostructure arrays that is a simple, inexpensive, and high-throughput process with a broad choice of materials in manufacturing various lithographically patterned nanostructures on substrates. To develop such nanostructured systems, various nanofabrication techniques are employed on two-dimensional (2D) colloidal masks for evaporation, electrochemical deposition, etching, dewetting and mask replication. Ordered nanostructures associated with feature shapes and sizes can be diversified through a choice of methodology and a control of experimental conditions. This review presents an overview of colloidal crystals as a mask and nanostructure arrays (nanopillars, nanoring, nanopores) fabricated by colloidal lithography as well as introducing practical applications using ordered nanostructures. © 2014 Korean Institute of Chemical Engineers, Seoul, Korea.

Heo J.,Kyungpook National University
The Korean journal of gastroenterology = Taehan Sohwagi Hakhoe chi | Year: 2014

Although, the prevalence of Helicobacter pylori infection in Korea has declined owing to the eradication therapy, recent seropreva-lence of H. pylori infection is still reported to be as high as 54.4%. Until now, "standard regimen" for eradication of H. pylori has been conventional triple therapy consisting of proton pump inhibitor, amoxicillin, and clarithromycin. However, with the increase in antibiotic resistance, especially against clarithromycin, the eradication rate of conventional triple therapy has steadily declined during the past 13 years in Korea. Present eradication rate of standard triple therapy is reported to be less than 80%, which is the Maginot line of efficacy for the currently available regimen. Therefore, new first line eradication regimen is needed to enhance the eradication rate of H. pylori infection.

Park H.,Kyungpook National University | Kim K.,Keimyung University
Archives of Gerontology and Geriatrics | Year: 2012

We evaluated the association between alcohol consumption and blood lipid levels in elderly Korean men. This was a cross-sectional study consisting of men (n= 1893) aged 60 years and older from the Korea National Health and Nutrition Examination Survey (KNHANES) 2005-2009. Demographic characteristics and dietary intake were obtained from the participants using a questionnaire, and lipid levels were determined by blood-sample analyses. After adjusting for demographic and dietary factors, alcohol consumption was negatively associated with a risk for low high-density lipoprotein cholesterol (HDL-C) (p for trend < 0.001), whereas the risk for high triglycerides increased with increasing alcohol consumption (p for trend = 0.014). However, the odds ratios (ORs) of high non-HDL-C and the ratio of high triglycerides to HDL-C were not significantly different with alcohol drinking. These results suggest that light consumption of alcohol decreases the risk for dyslipidemia and that heavy alcohol consumption differentially affects lipid measures according to the amount of alcohol intake in elderly men. © 2011 Elsevier Ireland Ltd.

Kim H.-J.,Kyungpook National University
BMB Reports | Year: 2010

Glucocorticoids (GCs) are useful drugs for the treatment of various diseases, but their use for prolonged periods can cause severe side effects such as osteoporosis. GCs have a direct effect on bone cells, where they can arrest bone formation, in part through the inhibition of osteoblast. On the other hand, GCs potently suppress osteoclast resorptive activity by disrupting its cytoskeleton based on the inhibition of RhoA, Rac and Vav3 in response to macrophage colony-stimulating factor. GCs also interfere with microtubule distribution and stability, which are critical for cytoskeletal organization in osteoclasts. Thus, GCs inhibit microtubule-dependent cytoskeletal organization in osteoclasts, which, in the context of bone remodeling, further dampens bone formation. © 2003 KSBMB & Springer-Verlet.

Latt W.T.,Imperial College London | Veluvolu K.C.,Kyungpook National University | Ang W.T.,Nanyang Technological University
Sensors | Year: 2011

Position sensing with inertial sensors such as accelerometers and gyroscopes usually requires other aided sensors or prior knowledge of motion characteristics to remove position drift resulting from integration of acceleration or velocity so as to obtain accurate position estimation. A method based on analytical integration has previously been developed to obtain accurate position estimate of periodic or quasi-periodic motion from inertial sensors using prior knowledge of the motion but without using aided sensors. In this paper, a new method is proposed which employs linear filtering stage coupled with adaptive filtering stage to remove drift and attenuation. The prior knowledge of the motion the proposed method requires is only approximate band of frequencies of the motion. Existing adaptive filtering methods based on Fourier series such as weighted-frequency Fourier linear combiner (WFLC), and band-limited multiple Fourier linear combiner (BMFLC) are modified to combine with the proposed method. To validate and compare the performance of the proposed method with the method based on analytical integration, simulation study is performed using periodic signals as well as real physiological tremor data, and real-time experiments are conducted using an ADXL-203 accelerometer. Results demonstrate that the performance of the proposed method outperforms the existing analytical integration method. © 2011 by the authors; licensee MDPI, Basel, Switzerland.

Koo D.-M.,Kyungpook National University
Electronic Commerce Research and Applications | Year: 2016

This study investigates the effects of tie strength between the two communicators, recommender experience, and their interactions on electronic word-of-mouth message credibility and purchase intentions, and the mediated moderation on intention. Prior research has rarely addressed the fact that the effect of tie strength moderated by recommender experience is mediated by the effect of message credibility on intention. The final sample comprised 302 students who participated in a 3 (tie strength: strong vs. weak vs. no tie) by 2 (experience: high vs. low) between-subject experiment. Multivariate analysis of covariance and bias-corrected bootstrapping analysis using the PROCESS macro were used to test the hypotheses. The results showed that tie strength and recommender experience positively affect message credibility and intentions. Further, recommender experience moderates the effect of tie strength on intentions, while the moderating effects on intention are mediated by message credibility. While prior research suggests that negative recommendations from people with strong ties affect message effectiveness, the results of the present study deviate from this and show that recommendations from weak ties are as persuasive as those from strong ties when the message is delivered by recommenders with experience. © 2015 Elsevier B.V.

Im D.,Korea University | Moon E.,Korea University | Park Y.,Korea University | Lee D.,Lily S and C Co. | And 2 more authors.
Optics Letters | Year: 2014

The dark-line defect problem in the conventional polygon computer-generated hologram (CGH) is addressed. To resolve this problem, we clarify the physical origin of the defect and address the concept of phase-regularization. A novel synthesis algorithm for a phase-regularized polygon CGH for generating photorealistic defect-free holographic images is proposed. The optical reconstruction results of the phase-regularized polygon CGHs without the dark-line defects are presented. © 2014 Optical Society of America.

Kim E.-S.,Kyungpook National University
Review of Scientific Instruments | Year: 2014

We investigate a lattice design for a low-emittance, high-brilliance intermediate energy synchrotron light source that is being intensively performed in the world. We present the design results in detail for a non-achromatic double bend achromat lattice with an emittance of 1.1 nm and 597.6 m circumference. Each superperiod has 4 straight sections, 7 m, 5.4 m, and 2 × 2.8 m in length, giving a total of 60 straight sections in the ring. The lattice is designed to be flexible and also provides an achromatic optics with an emittance of 3.2 nm. The lattice provides high brilliance at a photon energy of a few tens of keV, which meets the requirements of hard X-ray synchrotron radiation users. We investigated the dynamic aperture in the lattice with machine errors using a simulation method that achieves the optimal tune for the ring. The low-emittance lattice provides sufficient dynamic aperture after closed orbit distortion correction. We show an estimate of variations of emittance, energy spread, and dynamic aperture due to a wiggler in the straight sections. We present the design of an injection scheme for full energy injection, the space allocation in injection section, and the particle dynamics of injected beam. Particle tracking after beam injection was performed to examine the validity of the injection scheme. Our design lattice shows good optimization in terms of the emittance, number of straight sections, brilliance, and circumference as a light source for 3.5 GeV beam energy. © 2014 AIP Publishing LLC.

Cisplatin is used widely for treatment of a variety of cancer diseases. Recently, however, the use of cisplatin is restricted because of its adverse effects such as hepatotoxicity. There is no study with current proteomics technology to evaluate cisplatin-induced hepatotoxicity, even if some studies have reported on the hepatotoxicity. In this study, proteomic as well as genomic analyses have been used for identification of proteins and genes that respond to cisplatin treatment in rat primary hepatocytes. To investigate the hepatotoxic effects of cisplatin, rat primary hepatocytes were treated with an IC(20) concentration for 24 h. From proteomic analysis based on label-free quantitation strategy, cisplatin induced 76 up-regulated and 19 down-regulated proteins among 325 distinct proteins. In the mRNA level, genomic analysis revealed 72 up-regulated and 385 down-regulated genes in the cisplatin-treated group. Based on these two analyses, 19 pathways were commonly altered, whereas seven pathways were identified only by proteomic analysis, and 19 pathways were identified only by genomic analysis. Overall, this study explained the mechanism of cisplatin-induced hepatotoxicity with two points of view: well known pathways including drug metabolism, fatty acid metabolism, and glycolysis/TCA cycle and little known pathways including urea cycle and inflammation metabolism, for hepatotoxicity of other toxic agents. Up-regulated proteins detected by proteomic analysis in the cisplatin-treated group: FBP1 (fructose 1,6-bisphosphatase 1), FASN (fatty acid synthase), CAT (catalase), PRDX1 (peroxiredoxin-1), HSPD1 (60-kDa heat shock protein), MDH2 (malate dehydrogenase 2), and ARG1 (arginase 1), and also down-regulated proteins in the cisplatin-treated group: TPM1 (tropomyosin 1), TPM3 (tropomyosin 3), and CTSB (cathepsin B), were confirmed by Western blot analysis. In addition, up-regulated mRNAs detected by microarray analysis in the cisplatin-treated group: GSTA2, GSTT2, YC2, TXNRD1, CYP2E1, CYP2C13, CYP2D1, ALDH17, ARG1, ARG2, and IL-6, and also down-regulated mRNAs: CYP2C12, CYP26B1, TPM1, and TPM3, were confirmed by RT-PCR analysis. In case of PRDX1, FASN, and ARG1, they were further confirmed by immunofluorescence analysis. Through the integrated proteomic and genomic approaches, the present study provides the first pathway map related to cisplatin-induced hepatotoxicity, which may provide new insight into the mechanism of hepatotoxicity.

Leaf surface features were investigated in the Tabu-No-Ki tree Machilus thunbergii by electron microscopy and white light scanning interferometry. Mature leaves of the tree were air-dried at room temperature and sputter-coated with platinum. The most prominent epicuticular wax structures of M. thunbergii leaves included granules, angular rodlets and transversely ridged rodlets. Wax granules were often observed on the adaxial leaf surface. Meanwhile, the abaxial leaf surface was characterized by transversely ridged rodlets in which the ridges were perpendicular to their longitudinal axis. Having several facets, the angular rodlets were straight and grew among clusters of transversely ridged rodlets. The adaxial leaf surface of M. thunbergii appeared to be smooth and less undulating than the abaxial leaf surface. Clusters of epicuticular waxes were predominant on the abaxial leaf surface. The average heights of the adaxial and abaxial leaf surfaces were 1.79 ± 0.58 and 3.65 ± 0.93 μm, respectively. The average roughness and root-mean-square roughness values were lower those on the adaxial surface than on the abaxial surface. These results suggest that the transversely ridged rodlets significantly contribute to the increased surface roughness on the abaxial leaf surface. © The Author 2012. Published by Oxford University Press [on behalf of Japanese Society of Microscopy]. All rights reserved.

Ando S.-I.,Sun Moon University | Oh Y.,Kyungpook National University | Oh Y.,Asia Pacific Center for Theoretical Physics
Physical Review C - Nuclear Physics | Year: 2014

The hypernucleus HeΛΛ6 is studied as a three-body (ΛΛα) cluster system in cluster effective field theory at leading order. We find that the three-body contact interaction exhibits the limit cycle when the cutoff in the integral equations is sent to the asymptotic limit and thus it should be promoted to leading order. We also derive a determination equation of the limit cycle which reproduces the numerically obtained limit cycle. We then study the correlations between the double Λ separation energy BΛΛ of HeΛΛ6 and the scattering length aΛΛ of the S-wave ΛΛ scattering. The role of the scale in this approach is also discussed. © 2014 American Physical Society.

Park S.-Y.,Sookmyung Womens University | Kim J.-S.,Kyungpook National University | Seo Y.-R.,Dongguk University | Sung M.-K.,Sookmyung Womens University
International Journal of Obesity | Year: 2012

Objective: Studies have indicated that obesity is associated with a higher risk of colorectal cancer. This study was performed to determine the effect of diet-induced obesity on the formation of azoxymethane (AOM)/dextran sodium sulfate (DSS)-induced colon tumors and to identify adiposity-related mechanisms. Methods: Male A/J mice were placed on either a high-fat diet (HFD; 45% of total calories from fat) or a normal diet (ND; 15% of calories from fat) for 12 weeks. To induce colon tumors, AOM was administered at a dose of 10 mg/kg body weight, followed by two cycles of DSS supply. Results: Study results indicated that the HFD group had twofold higher numbers of colonic tumors, as compared with the ND group. The HFD group also had significantly increased body weight and epididymal fat weight, which were associated with increases of serum insulin, insulin-like growth factor-1, leptin, epididymal fat pad leptin mRNA and colonic leptin receptor (Ob-R) mRNA. Animals on HFD showed higher expressions of Ob-R, insulin receptor, phosphorylated Akt, phosphorylated extracellular signal-regulated kinases, Bcl-xL and Cyclin D1 proteins in the colon. Conclusion: The results suggest that HFD-induced obesity facilitates colon tumor formation, possibly by regulating downstream targets of circulating adiposity-related factors via receptor-mediated signaling of the phosphatidylinositol 3-kinase/Akt pathway. © 2012 Macmillan Publishers Limited All rights reserved.

Howard S.G.,Collaborative on Health and the Environment | Lee D.-H.,Kyungpook National University
Journal of Epidemiology and Community Health | Year: 2012

The increasing incidence of type 1 diabetes (T1D) in children around the world is unexplained. Even though various environmental chemicals have been linked to the development of type 2 diabetes as well as other autoimmune diseases, the possibility that environmental chemicals may contribute to the development of T1D has not been adequately evaluated. There is preliminary epidemiological evidence that exposure to certain chemicals, such as N-nitroso compounds, air pollutants and persistent organic pollutants is associated with T1D. Environmental chemicals that can act as endocrine disruptors may affect the development and function of the immune system in ways that could promote autoimmunity, and thereby contribute to the development of T1D. As such, the potential low-dose effects of chemicals should be considered in both epidemiological and experimental study designs of T1D. If chemicals indeed contribute to the development of T1D, then this disease may be partly preventable.

Pagani J.H.,U.S. National Institutes of Health | Lee H.-J.,Kyungpook National University | Young W.S.,U.S. National Institutes of Health
Genes, Brain and Behavior | Year: 2011

Oxytocin (Oxt) and vasopressin (Avp) are important for a wide variety of behaviors and the use of transgenic mice lacking the peptides or their receptors, particularly when their loss is spatially and temporally manipulated, offers an opportunity to closely examine their role in a particular behavior. We used a cued fear conditioning paradigm to examine associative learning in three lines of transgenic mice: mice that constitutively lack vasopressin 1a (Avpr1a -/-) or Oxt receptors (Oxtr -/-) and mice that have Oxt receptor loss restricted to the forebrain that begins postweaning (Oxtr FB/FB). Oxtr -/- and Avpr1a -/- mice have normal conditioned freezing. Oxtr FB/FB mice have a reduction in freezing behavior during acquisition, as well as during context and cue retention. In addition to reduction of Oxtr in the central nucleus of the amygdala, in vitro receptor autoradiography showed that the Oxtr FB/FB mice have significantly reduced levels of Avpr1a only in that structure. Our results show that postweaning alteration of the distribution of Oxtr receptors is critically important for fear behavior, an effect mirrored in the neural structures that mediate it. While constitutive knockouts of Oxtr and Avpr1a are useful for identifying the neural underpinnings of some behaviors, compensatory mechanisms within some circuits may obscure other behavioral roles. © 2011.

Kim S.H.,Kyungpook National University | Yu X.,University of Nevada, Las Vegas
Aging and Mental Health | Year: 2010

Objectives: Limited health literacy has been shown to be associated with poor health status. However, research to date has not elucidated the factors that mediate the relationship between low literacy and poor health outcomes. The purpose of this study was to examine the mediating effect of self-efficacy on the relationship between health literacy and health status in Korean older adults. Method: A cross-sectional study of 103 community-dwelling Korean older adults was conducted from June 2007 to September 2007. Results: The study found that low health literacy was associated with poorer physical and mental health status, and the effect of health literacy on physical and mental health status was mediated through self-efficacy. Conclusion: The study suggests that interventions to improve the delivery of care for older adults with low health literacy need to include not only improving the readability of health-related materials, but also enhancing the self-efficacy of each individual. © 2010 Taylor & Francis.

Siggers M.,Kyungpook National University
European Journal of Combinatorics | Year: 2014

A pair of graphs (Hb, Hr) is highly Ramsey-infinite if there is some constant c such that for large enough n there are at least 2cn2 non-isomorphic graphs on n or fewer vertices that are minimal with respect to the property that when their edges are coloured blue or red, there is necessarily a blue copy of Hb or a red copy of Hr.We show that a pair of 3-connected graphs is highly Ramsey-infinite if and only if at least one of the graphs in non-bipartite. Further we show that the pair (Hb, Hr) is highly Ramsey infinite for Hr an odd cycle of girth ℓ and Hb any graph with no induced cycle of length ℓ or longer.In showing the above results, we continue the theory of gadgets called senders and determiners that has been developed over many earlier papers on Ramsey-infinite graphs. © 2013 Elsevier Ltd.

Ahn C.,Kyungpook National University
Journal of High Energy Physics | Year: 2014

For the N = 4 superconformal coset theory described by SU(N+2)/SU(N) (that contains a Wolf space) with N = 3, the N = 2 WZW affine current algebra with constraints is obtained. The 16 generators of the large N = 4 linear superconformal algebra are described by those WZW affine currents explicitly. By factoring out four spin- 1 2 currents and the spin-1 current from these 16 generators, the remaining 11 generators (spin-2 current, four spin- 3 2 currents, and six spin-1 currents) corresponding to the large N = 4 nonlinear superconformal algebra are obtained. Based on the recent work by Gaberdiel and Gopakumar on the large N = 4 holography, the extra 16 currents, with spin contents (1, 3/2, 3/2 2), (3/2, 2, 2, 5/2), (3/2, 2, 2, 5/2), and (2, 5/2, 5/2, 3) described in terms of N = 2 multiplets, are obtained and realized by the WZW affine currents. As a first step towards N = 4 W algebra (which is NOT known so far), the operator product expansions (OPEs) between the above 11 currents and these extra 16 higher spin currents are found explicitly. It turns out that the composite fields with definite U(1) charges, made of above (11 + 16) currents (which commute with the Wolf space subgroup SU(N = 3) × SU(2) × U(1) currents), occur in the right hand sides of these OPEs. Open Access, © 2014 The Authors.

Park H.,Kyungpook National University
Revue Roumaine de Chimie | Year: 2010

Perfluorinated chemicals (PFCs), as represented by perfluorooctanoate (PFOA: C 7F 15CO 2 -) and perfluorooctane sulfonate (PFOS: C 8F 17SO 3 -) have been widely used and detected over the globe. Their chemical inertness makes them highly resistant toward not only conventional treatments but also advanced oxidation processes. In this study, the hydrated electron-mediated reductive degradation of PFOX (X = A for PFOA and S for PFOS) was explored in an aqueous humic acid solution in which UV light is irradiated to excite humic acid, thereby ejecting electrons to the aqueous PFOX. The PFOX degradation was monitored with MS/MS and was further confirmed by quantifying fluorides. The quantum yield for the PFOX degradation was estimated to be as low as 10 -4. The F-index, the degree of defluorination ([F -] produced / [PFOX] degraded), was 0.7 and 2.3 for PFOA and PFOS, respectively, indicating they were partially degraded. In addition, it was determined that an electron-donating ethylenediaminetetraacetic acid (EDTA) is essentially required to inhibit the recombination between the oxidized humic acid and the hydrated electron; yet it appears to interfere with the one-electron-reduced PFOX behavior at a different degree depending on the varying ionic headgroups (carboxylate vs. sulfonate).

Lee -T.,Kyungpook National University | Gong Y.-D.,Dongguk University
Molecules | Year: 2012

This review covers the construction of drug-like 2H-benzopyrans and related libraries using solid-phase parallel synthesis. In this context, the preparation of substituted benzopyrans such as mono-, di- and trisubstituted benzopyran derivatives and additional ring-fused benzopyrans such as benzopyranoisoxazoles, benzopyranopyrazoles, six-membered ring-fused benzopyrans, and polycyclic benzopyrans are highlighted. © 2012 by the Authors.

Noh H.,Korea Astronomy and Space Science Institute | Hwang J.-C.,Kyungpook National University | Hwang J.-C.,Korea Institute for Advanced Study
Astrophysical Journal | Year: 2012

We compare the cosmological first-order post-Newtonian (1PN) approximation with the relativistic cosmological linear perturbation theory in a zero-pressure medium with the cosmological constant. We compare equations and solutions in several different gauge conditions available in both methods. In the PN method we have perturbation equations for density, velocity, and gravitational potential independently of the gauge condition to 1PN order. However, correspondences with these 1PN equations are available only in certain gauge conditions in the perturbation theory. Equations of perturbed velocity and the perturbed gravitational potential in the zero-shear gauge exactly coincide with the Newtonian equations, which remain valid even to 1PN order (the same is true for perturbed velocity identified in the comoving gauge), and equations of perturbed density in the zero-shear gauge and the uniform-expansion gauge coincide to 1PN order. We identify other correspondences available in different gauge conditions of the perturbation theory. © 2012. The American Astronomical Society. All rights reserved.

Yu M.,University of Edinburgh | Yun B.-W.,University of Edinburgh | Yun B.-W.,Kyungpook National University | Spoel S.H.,University of Edinburgh | Loake G.J.,University of Edinburgh
Current Opinion in Plant Biology | Year: 2012

S-nitrosylation, the covalent attachment of a nitric oxide (NO) moiety to a protein cysteine thiol to form an S-nitrosothiol (SNO) is rapidly emerging as a prototypic, redox-based post-translational modification during plant immune function. Here we review recently identified targets for S-nitrosylation and the consequences of these modifications in relation to the control of plant disease resistance. © 2012 Elsevier Ltd.

Paek S.-M.,Kyungpook National University | Kim Y.-I.,Yeungnam University
Journal of Alloys and Compounds | Year: 2014

X-ray absorption near edge structure (XANES) spectroscopy was performed at the Ta L3-edge to probe the bonding nature of tantalum and the conduction band minimum in d0 perovskites KTaO3, CaTaO2N, SrTaO2N, and BaTaO2N. The Ta L 3 absorption edge energy (E0) varied from 9882.2 to 9883.6 eV in the manner, KTaO3 > BaTaO2N > SrTaO 2N ≥ CaTaO2N. These chemical shifts and the Ta-O/N bond covalency were discussed based on the bonding geometry, electronegativity of the anion, and the electronegativity of dodecahedral cation. Deconvolution of the XANES white line peak allowed for the determinations of Ta 2p → 5d and 2p → continuum transition energies, from which we infer that the band gap window gradually shifts to lower energy region, going from BaTaO2N to SrTaO2N to CaTaO2N. © 2013 Elsevier B.V. All rights reserved.

Kang N.L.,Pusan National University | Choi S.D.,Kyungpook National University
Journal of Physics A: Mathematical and Theoretical | Year: 2010

A new nonlinear optical conductivity formula for a system of electrons interacting with phonons was derived using a reduction identity and a state-dependent projection technique introduced by the authors. The results include a general formula for the nonlinear optical conductivity of the general rank and the linear, first-order nonlinear and second-order nonlinear conductivity are calculated in terms of the linewidth. The linewidth term includes the electron and phonon distribution functions properly. Therefore, it is possible to explain the phonon emission and absorption in all electron transition processes in an organized manner. © 2010 IOP Publishing Ltd.

Park I.S.,Kyungpook National University
ISIJ International | Year: 2013

Intricate physical phenomena such as boiling heat transfer, free surface flow, and the moving of a cooling object (running hot plate) are included in the ROT (Run Out Table) cooling process of hot rolling. Mixed reciprocal actions are also included. Therefore, analyzing the process with considering all relevant phenomena simultaneously has been an important objective in this field for a long time. In the ROT process, cooling performance could be affected by the upstream process, and by various environmental factors such as refining, reheating, and the ambient temperature and humidity. In this study, with such disturbances numerically fixed, cooling capacities are compared by varying the arrangement of the cooling water supply nozzle. Generally, the cooling heat flux is known to vary in the plate running direction. Thus, clustering the nozzle in the upstream or downstream direction could affect the average cooling capacity of the facilities. The cooling histories, the heat fluxes on the plate surface, and the thickness of the Leidenfrost steam layer are compared for various nozzle arrangements. © 2013 ISIJ.

Schneiderman R.,Kyungpook National University
IEEE Signal Processing Magazine | Year: 2010

It's an age-old question: Are we alone in the universe? The fact is, we still don't know-for sure. But that hasn't stopped us from looking. And we're looking harder than ever. © 2006 IEEE.

Ha S.H.,Kyungpook National University
Information Sciences | Year: 2010

The increasing rate of late payments by credit card customers, which are caused by the recent economic downturn, is causing not only reduced profit margins but also significant sales losses for retail companies. Under pressure to increase revenues, credit prediction should be a part of customer delinquency management. In this study, a credit prediction model has been developed to manage delinquents holding retail credit cards. The hybrid model combines a Kohonen network and a Cox's proportional hazard model. A Kohonen network is used to cluster credit delinquents into homogeneous groups. A Cox's hazard model is used to analyze repayment patterns of delinquents in each group. The model estimates the expected time of credit recovery from delinquents. This model's prediction accuracy scored above 93%. © 2010 Elsevier Inc. All rights reserved.

Ok J.G.,University of Michigan | Kwak M.K.,University of Michigan | Kwak M.K.,Kyungpook National University | Huard C.M.,University of Michigan | And 2 more authors.
Advanced Materials | Year: 2013

A novel nanofabrication methodology for continuous, scalable, and geometry-tunable lithography is developed, named photo-roll lithography (PRL), by integrating photolithography with rollable processing. As a flexible mask attached to a quartz cylinder containing a UV source rolls over a photoresistcoated substrate, PRL realizes continuous photolithographic fabrication of various micro/nanoscale patterns with geometry that is tunable by controlling mask-substrate motions. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Kim S.O.,Kyungpook National University | Kim H.J.,Keimyung University
Journal of Medicinal Food | Year: 2013

This study evaluated the antiallodynic properties of berberine on cold and mechanical allodynia after streptozotocin (STZ)-induced diabetes using a rat model. Diabetic neuropathy was induced in rats by intraperitoneal injection of STZ. To measure cold and mechanical allodynia, a 4 C plate and von Frey filament were used, respectively. Cold and mechanical allodynia induced by diabetes were significantly decreased by single and repeated intraperitoneal treatment of amitriptyline at 10 mg/kg, and berberine at 10 and 20 mg/kg. The hepatic malondialdehyde, superoxide dismutase, catalase, and glutathione peroxidase activities were significantly increased in diabetic rats as compared with those in intact rats; however, in amitriptyline- and berberine-treated rats, they were significantly decreased as compared to the STZ control. The overall effects of berberine 20 mg/kg on cold and mechanical allodynia were quite similar to those of amitriptyline 10 mg/kg, and berberine exhibited similar antioxidant effects as the same dosage of amitriptyline. In conclusion, berberine (10 and 20 mg/kg) was observed to have antiallodynic effects against diabetes, which are presumed to be associated with antioxidative effects. It can be considered that the anti-inflammatory or antidepressant capacity of berberine could contribute to the antiallonynic effects shown in this study. © Mary Ann Liebert, Inc. and Korean Society of Food Science and Nutrition.

Kim Y.M.,University of Massachusetts Amherst | Cho H.U.,Pohang University of Science and Technology | Lee D.S.,Kyungpook National University | Park D.,Yonsei University | Park J.M.,Pohang University of Science and Technology
Water Research | Year: 2011

To improve the efficiency of total nitrogen (TN) removal, solid retention time (SRT) and internal recycling ratio controls were selected as operating parameters in a full-scale activated sludge process treating high strength industrial wastewater. Increased biomass concentration via SRT control enhanced TN removal. Also, decreasing the internal recycling ratio restored the nitrification process, which had been inhibited by phenol shock loading. Therefore, physiological alteration of the bacterial populations by application of specific operational strategies may stabilize the activated sludge process. Additionally, two dominant ammonia oxidizing bacteria (AOB) populations, Nitrosomonas europaea and Nitrosomonas nitrosa, were observed in all samples with no change in the community composition of AOB. In a nitrification tank, it was observed that the Nitrobacter populations consistently exceeded those of the Nitrospira within the nitrite oxidizing bacteria (NOB) community. Through using quantitative real-time PCR (qPCR), nirS, the nitrite reducing functional gene, was observed to predominate in the activated sludge of an anoxic tank, whereas there was the least amount of the narG gene, the nitrate reducing functional gene. © 2011 Elsevier Ltd.

Kim D.-Y.,Kyungpook National University
Cell Biochemistry and Function | Year: 2016

Expression of each gene can be controlled at several steps during the flow of genetic information from DNA to protein. Tight regulation of gene expression is especially important for stem cells because of their greater ripple effects, compared with terminally differentiated cells. Dysregulation of gene expression arising in stem cells can be perpetuated within the stem cell pool via self-renewal throughout life. In addition, transcript profiles within stem cells can determine the selective advantage or disadvantage of each cell, leading to changes in cell fate, such as a tendency for proliferation, death, and differentiation. The identification of neural stem/progenitor cells (NSPCs) and greater understanding of their cellular physiology have raised the possibility of using NSPCs to replace damaged or injured neurons. However, an accurate grasp of gene expression control must take precedence in order to use NSPCs in therapies for neurological diseases. Recently, accumulating evidence has demonstrated the importance of post-transcriptional regulation in NSPC fate decisions. In this review, we will summarize and discuss the recent findings on key mRNA modulators and their vital roles in NSPC homeostasis. © 2016 John Wiley & Sons, Ltd.

Kim G.-W.,Kyungpook National University | Kim J.,Inha University
Smart Materials and Structures | Year: 2013

This paper presents a bio-inspired mechanism for the performance enhancement of piezoelectric power generation in vibration energy harvesting. A compliant bistable mechanism for vibration energy harvesting was explored based on the negative stiffness inspired by the auditory hair bundle structures. The proposed mechanism consists of a compliant, four-bar linkage system to mimic the hair bundle structure inside an inner ear. Our initial prototype energy harvester demonstrates that the compliant bistable mechanism featuring negative stiffness outperforms the conventional vibration energy harvester in the infra-low frequency range (1-10 Hz). © 2013 IOP Publishing Ltd.

Kim K.M.,Kyungpook National University
Korean journal of ophthalmology : KJO | Year: 2011

To report the effectiveness of home-based pencil push-ups (HBPP) therapy for patients with symptomatic convergence insufficiency. Data was collected prospectively on 16 patients who were diagnosed with convergence insufficiency beginning in January 2009. The study group was composed of ten male and six female patients. The duration of symptoms, refractive error, distant and near deviation angles, and near point of convergence (NPC) prior to and after 12 weeks of HBPP therapy were measured in all patients. The mean age of the patients was 19.3 years. The mean deviation angle of exophoria was 3 prism diopters (PD) at distant and 11.2 PD at near. The mean value of NPC prior to HBPP therapy was 36.3 cm; however, the near point of accommodation was within the normal range. After 12 weeks of HBPP therapy, the mean deviation angle of exophoria decreased to orthophoric at distant and 4 PD at near. The mean value of NPC decreased to 14.4 cm. Twelve weeks of HBPP therapy appears to be an easy, cost-free and effective therapy for patients with symptomatic convergence insufficiency.

Park E.,Kyungpook National University
Water Resources Research | Year: 2010

This paper develops a Markov chain-based geostatistical model for multidimensional field predictions of the categorical attributes. An efficient conditional probability equation that considers directional asymmetry was derived, and a computational algorithm was devised with numerical code. The developed model was applied to two-dimensional case studies and compared with the representative conventional sequential indicator simulation (SIS) model. On the basis of engaged comparisons with the SIS model, it was concluded that this new model performs as well as or better than the SIS model, especially for lithologic predictions and structural estimations for the case studies with sparse sampled data, which is more or less realistic. The model was also applied to a three-dimensional case and validated by its plausible results. It is expected that the developed Markov chain-based geostatistical model will become a sound option for multidimensional subsurface predictions in cases when the heterogeneities and uncertainties in the media properties are an important issue. Copyright © 2010 by the American Geophysical Union.

Some studies have suggested that coagulation disorders may be implicated in osteonecrosis of the femoral head (ONFH). The C677T polymorphism of the 5, 10-methylenetetrahydrofolate reductase (MTHFR) gene has been postulated to be a genetic risk factor for venous thromboembolism and osteonecrosis in Caucasians, but this relationship has not been established in other populations. In this study, we conducted case-control analysis of whether MTHFR polymorphisms are associated with ONFH in Korean patients. Fifteen single nucleotide polymorphisms (SNPs) were selected and genotyped in 443 ONFH patients and 273 control subjects using the TaqMan 5' allelic discrimination assay. Comparison of ONFH and control subjects using logistic regression models revealed no statistically significant differences in the frequencies of the MTHFR polymorphisms and haplotypes. Further analysis stratified by etiology also showed no association. These results suggest that MTHFR polymorphisms play no significant role in susceptibility to ONFH in the Korean population.

Tuzlukov V.,Kyungpook National University
WSEAS Transactions on Communications | Year: 2013

In this paper, we consider the problem of multiple-input multiple-output (MIMO) radars employing the generalized detector (GD) based on the generalized approach to signal processing in noise (GASP) and using the space-time coding to achieve a desired diversity. To that end, we derive a suitable GD structure after briefly outlining the model of the received target return signal. GD performance is expressed in closed form as a function of the clutter statistical properties and of the space-time code matrix. We investigate a particular case when GD requires a priori knowledge of the clutter covariance, i.e., the decision statistics under the null hypothesis of "a no" target is an ancillary statistic in the sense that it depends on the actual clutter covariance matrix but its probability density function (pdf) is functionally independent of such a matrix. Therefore, threshold setting is feasible with no a priori knowledge as to the clutter power spectrum. As to the detection performance, a general integral form of the probability of detection is provided, holding independent of the searched object fluctuation model. The formula is not analytically manageable, nor does it appear to admit general approximate expressions, which allow giving an insightful look in the MIMO radar system behaviour. We thus restrict our attention to the case of Rayleigh-distributed target attenuation (Swerling-1 model). To code construction we use an information-theoretic approach and compare conditions for code optimality with ones for classical Chernoff bound. This approach offers a methodological framework for space-time coding in MIMO radar systems constructed based on GASP, as well as simple and intuitive bounds for performance prediction.

Bae J.-S.,Kyungpook National University | Rezaie A.R.,Saint Louis University
BMB Reports | Year: 2013

High mobility group box 1 (HMGB1) is involved in the pathogenesis of vascular diseases. Unlike activated protein C (APC), the activation of PAR-1 by thrombin is known to elicit proinflammatory responses. To determine whether the occupancy of EPCR by the Gla-domain of APC is responsible for the PAR-1-dependent antiinflammatory activity of the protease, we pretreated HUVECs with the PC zymogen and then activated PAR-1 with thrombin. It was found that thrombin downregulates the HMGB1-mediated induction of both TNF-α and IL-6 and inhibits the activation of both p38 MAPK and NF-κB in HUVECs pretreated with PC. Furthermore, thrombin inhibited HMGB1-mediated hyperpermeability and leukocyte adhesion/ migration by inhibiting the expression of cell adhesion molecules in HUVECs if EPCR was occupied. Collectively, these results suggest the concept that thrombin can initiate proinflammatory responses in vascular endothelial cells through the activation of PAR-1 may not hold true for normal vessels expressing EPCR under in vivo conditions. © 2013 by the The Korean Society for Biochemistry and Molecular Biology.

This paper describes a new method for the fabrication of poly(ε-caprolactone) (PCL) spherical particles with uniform, well-controlled diameters in the range of 100 to 900 nm. This method uses capillary force lithography (CFL) technique to pattern a thin film of PCL into an array of discrete disks, followed by their transformation into spherical beads under thermal annealing. When the diameter of the disks was fixed, the size of the resultant beads was only determined by the thickness of the PCL film. To demonstrate their use in the controlled release of a drug, an organic dye was loaded into the polymer particles. The loaded dye molecules could be released with different profiles depending on the crystalline microstructure of the polymer particles. © The Royal Society of Chemistry 2015.

Islam M.S.,University of Dhaka | Yeum J.H.,Kyungpook National University | Das A.K.,University of Dhaka
Journal of Colloid and Interface Science | Year: 2012

Poly(vinyl acetate-methyl methacrylate) (VAc-MMA) copolymer microspheres were prepared using suspension polymerization at low temperature initiated with 2,2'-azobis(2,4-dimethyl valeronitrile) (ADMVN). The poly(VAc-MMA) copolymer microspheres can be used over a large area where homopolymers, polyvinyl acetate (PVAc) and methyl methacrylate (PMMA) microspheres are capable of being put to use. The prepared microspheres were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). Obtained copolymer microspheres which have 200μm average diameter and higher thermal stability than those of homopolymer. © 2011.

Baek J.,Samsung | Yun B.-J.,Kyungpook National University
IEEE Transactions on Instrumentation and Measurement | Year: 2010

The posture of a user is one of the contextual information that can be used for mobile applications and the treatment of idiopathic scoliosis. This paper describes a method for monitoring the posture of a user during operation of a mobile device in three activities such as sitting, standing, and walking. The user posture monitoring system (UPMS) proposed in this paper is based on two major technologies. The first involves a tilt-angle measurement algorithm (TAMA) using an accelerometer. Unlike most previous studies, it is based on a relative computation using the dot product from the time-series acceleration data. Because TAMA does not require a physical calibration by a user, it is more robust and accurate compared to other methods that rely on absolute computations. The second technology is an effective signal-processing method that eliminates the motion acceleration component of the accelerometer signal using a second-order Butterworth low-pass filter (SLPF). Because the posture of a user is only related to the gravity acceleration component, the motion acceleration components should be removed. The TAMA and UPMS are implemented on a personal digital assistant (PDA). They are evaluated to verify the possibility of application to a mobile device. Additionally, a posture-based intelligent control interface in context-aware computing that reacts to the posture of a PDA user is implemented on the PDA to complement the poor user interface (UI) of the mobile device, and its results are presented. © 2006 IEEE.

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

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

Paul A.,Kyungpook National University
Proceedings of the 2013 Research in Adaptive and Convergent Systems, RACS 2013 | Year: 2013

In this paper, a graph based M2M optimization in an IoT environment is presented. A parallel reconfigurable M2M architecture with multiple dynamic reconfigurable unit in an IoT scenario is modeled using a directed acyclic graph (DAG) to represent the whole environment. Parallel M2M establish communication within the network and are partitioned and reconfigured dynamically for large scale network such as IoT. Simulation were performed for multiple M2M array for different state, timing and power consumption along with the scheduling scheme are considered. © 2013 Author.

Park J.-H.,Hongik University | Ryu Y.-H.,Kyungpook National University | Lee J.-H.,Hongik University
IEEE Transactions on Antennas and Propagation | Year: 2010

We present mu-zero resonance (MZR) antennas that use an artificial mu-negative (MNG) transmission line (TL). The equivalent circuit for verifying the peculiarity of the MNG TL is derived and analyzed. To operate the MZR antenna properly, the antenna is fed by magnetic coupling. The analysis and design of the MZR antenna are performed according to theory and simulation based on a dispersion diagram and field distribution. The surface current distribution shows that the radiation mechanism of the MZR antenna is essentially identical to that of a small-loop antenna. Applying the novel concept of the MZR antenna, a dual-band MZR antenna using two MZR antennas with different MZR frequencies is proposed. The radiation characteristics of the antenna are simulated and measured at two frequencies. The measured characteristics show agreement with the simulated results. It is confirmed that the characteristics of the MZR antenna, including the efficiency, gain, and fractional bandwidth, are suitable for a multiband antenna. © 2010 IEEE.

BACKGROUND/AIMS: Transient elastography as performed using the Fibroscan is a useful noninvasive method for evaluating hepatic fibrosis. However, recent studies have found that liver stiffness measurement (LSM) values are inappropriately elevated in acute hepatitis or in the acute flare state of chronic hepatitis, suggesting that the LSM value obtained by the Fibroscan is not a reliable marker for fibrosis. We retrospectively evaluated the clinical factors influencing the LSM value obtained using transient elastography as performed using the Fibroscan in patients with chronic liver disease. METHODS: A total of 298 patients who were followed in Kungpook National University Hospital from November 2007 to May 2008 due to previously established liver cirrhosis or chronic liver disease were investigated using the Fibroscan, laboratory test, ultrasound, and/or abdominal computed tomography. RESULTS: The 298 patients were aged 47.8+/-12.9 years (mean+/-SD). The cut-off value for a diagnosis of liver cirrhosis was 12.5 kPa (as used in previous studies). Thirty-six patients (15%) and 202 patients (85%) with chronic liver disease without clinical manifestation of cirrhosis had LSMs of >12.5 kPa and <12.5 kPa, respectively. Multivariate analysis revealed that LSM values were unusually increased in patients with chronic liver disease who were older (P=0.007) or who had increased gamma glutamyltranspeptidase (GGT) (P=0.022), decreased albumin (P=0.015), or increased total bilirubin (P=0.009). CONCLUSIONS: This study reveals that age, GGT, and albumin are clinical factors influencing LSM values. This reinforces the need to interpret LSM values in the context of a defined diagnosis, biochemical data, radiologic examination, and other clinical findings.

Kim S.,Kyungpook National University | Garrison G.,Belmont University
International Journal of Information Management | Year: 2010

Radio Frequency Identification (RFID), once a niche technology, is rapidly gaining the attention of retailers as a key enabler in their supply chain. As RFID moves into the mainstream, it is poised to replace the standard barcode as the technology that identifies and tracks products throughout the supply chain. In an attempt to gain competitive advantages, some retailers have begun the transition to RFID while others have been reluctant to embrace it. This study investigates South Korean retailers to identify key organizational characteristics that positively drive the evaluation of RFID. Further, this study assesses the impact one's evaluation has on the adoption and integration of RFID within their respective firm. Results from 278 adopting organizations show organizational needs (Ubiquity and Performance Gaps), perceived factors (Benefits and Cost Savings), and organizational readiness (Financial Resources and Technological Knowledge) have a significant influence on RFID Evaluation; and evaluation impacts its adoption, and integration. © 2010 Elsevier Ltd. All rights reserved.

On occasion, the wall of the aneurysm base can be the rupture site of the lesion, which poses a unique challenge for treatment. Although there has already been a report of the angiographic depiction of a basal rupture of a saccular aneurysm by a small outpouching at the aneurysm neck, this is the first report of saccular aneurysms in which a basal rupture was angiographically depicted as a stalk-like narrow neck due to a thrombus sealing the rupture point and occupying the lumen of the aneurysm base. The author reports on 2 such cases: a 49-year-old woman who presented with a basal rupture of a saccular aneurysm arising at the middle cerebral artery bifurcation, and a 44-year-old man who presented with rupture of a saccular aneurysm arising at the junction of the A2 segment and the anterior communicating artery. In both cases, a pterional craniotomy allowed the surgeon to determine that the base of the aneurysm was ruptured, and he surgically obliterated the aneurysm. Microsuture reconstruction and clipping of the aneurysm neck were successful in obliterating the ruptured aneurysm and avoiding any compromise of the parent artery. ©1944-2011 by the American Association of Neurosurgeons.

Islam M.S.,University of Dhaka | Yeum J.H.,Kyungpook National University
Colloids and Surfaces A: Physicochemical and Engineering Aspects | Year: 2013

Nanofibers composed of pullulan (PULL), poly(vinyl alcohol) (PVA) and silver (Ag) were prepared using an electrospinning method in aqueous solutions. Field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR), thermal gravimetric analysis (TGA), antibacterial activity, and mechanical measurement were undertaken in order to characterize the PULL/PVA/Ag nanofiber morphology and properties. XRD and FTIR data demonstrated that there were good interactions between PULL and PVA possibly caused by hydrogen bonds. Moreover, XRD data and TEM images support the coexistence of a Ag and PULL/PVA blend matrix where Ag nanoparticles are well distributed. The study shows that the thermal stability in the mid-point temperature of the degradation and tensile strength of PULL could be increased with blending of PVA. It was also found that the Ag content could increase thermal stability and intensify antibacterial activity of the blend nanofibers. Since PULL and PVA are water-soluble and biocompatible polymers, the blended system can be considered one of the best materials for the preparation of excellent antibacterial nanofibers confirmed by a preservation test showing that the prepared material is suitable as a new preservative. © 2013 Elsevier B.V.

Jo W.-K.,Kyungpook National University
Journal of the Air and Waste Management Association | Year: 2013

This study synthesized multiwall carbon nanotube (MWNT)-titania (TiO2) composites and examined their characteristics and photocatalytic performance for the cleaning of gas-phase benzene, toluene, ethyl benzene, and o-xylene (BTEX) under simulated indoor conditions. Optical and spectral surveys of the as-synthesized composite confirmed that the TiO2 nanoparticles were bound intimately to the MWNT networks. The photocatalytic performance was evaluated using an annular-type reactor inner-coated with MWNT-TiO2 or Degussa P25 TiO2. The composite revealed gas removal ability superior to that of stand-alone TiO2. This composite was also less affected by humidity during toluene decomposition compared to the previous result obtained from a stand-alone TiO2. Unlike another previous result obtained from the TiO2, the performance of the composite was not affected by changes in input concentration (IC) within a simulated indoor air quality range (0.1-1.0 ppm) but it decreased significantly when the IC was increased to 5 and 10 ppm. As the flow rate was decreased from 4.0 to 1.0 L min-1, the average efficiency for the target compounds increased to 95% or ∼100%. The MWNT-TiO2 composite could be applied effectively to the decomposition for BTEX under certain simulated indoor conditions. Unlike water applications, there are few reports of gas-phase applications of multiwall carbon nanotubes (MWCNT)-TiO2 composites. This study found that MWCNT-TiO2 composites showed performance in the removal of toxic gaseous aromatic superior to that of stand-alone TiO2. In addition, the pollutant degradation efficiency of the composite was less affected by humidity than for a stand-alone TiO2 unit within a simulated indoor relative humidity range. Moreover, unlike the TiO2 unit, the composite's performance was not affected by variations in the input concentrations within the simulated indoor air quality (IAQ) range. In addition, the decomposition efficiencies increased to 100% with decreasing flow rate. © 2013 Copyright 2013 A&WMA.

Hessari P.,Kyungpook National University | Shin B.-C.,Chonnam National University
Computers and Mathematics with Applications | Year: 2013

A spectral collocation approximation of first-order system least squares for incompressible Stokes equations was analyzed in Kim et al. (2004) [12], and finite element approximations for incompressible Navier-Stokes equations were developed in Bochev et al. (1998,1999) [9,10]. The aim of this paper is to analyze the first-order system least-squares pseudo-spectral method for incompressible Navier-Stokes equations. The paper will be an extension of the result in Kim et al. (2004) [12] to the Navier-Stokes equations. Our least-squares functional is defined by the sum of discrete spectral norms of a first-order system of equations corresponding to the Navier-Stokes equations based on Legendre-Gauss-Lobatto points. We show its ellipticity and continuity over an appropriate product space, and spectral convergences of discretization errors are derived in the H1-norm and the L2-norm in each variable. Finally, we present some numerical examples. © 2013 Elsevier Ltd. All rights reserved.

Veluvolu K.C.,Kyungpook National University | Ang W.T.,Nanyang Technological University
International Journal of Medical Robotics and Computer Assisted Surgery | Year: 2010

Background: Physiological tremor is the main cause of imprecision in microsurgical procedures/robotics applications. Existing methods, such as weighted-frequency Fourier linear combiner (WFLC), rely on estimating the tremor under the assumption that it has a single dominant frequency. This paper focuses on developing a new algorithm for accurate tremor filtering in real time. Methods: A study conducted on several novice subjects and microsurgeons showed the tremor to contain several dominant frequencies in a band, rather than a single dominant frequency. Based on the tremor characteristics, a new algorithm band-limited multiple Fourier linear combiner (BMFLC) has been developed to estimate a band of signals with multiple dominant frequencies. A separation procedure to separate the intended motion/drift from the tremor portion is also discussed. Results: A simulation study was first conducted to validate the theoretical development on recorded tremor data. The experimental set-up was designed to study the real-time performance of the proposed algorithm. Tremor sensing using accelerometers is also discussed, with the proposed algorithm. Our experiments showed that the developed BMFLC algorithm had an average tremor compensation of 64% compared to 43% for the WFLC algorithm in real-time for one degree of freedom (1-DOF) cancellation of tremor. Conclusions: The BMFLC algorithm can be applied for the three axes separately and 3-DOF cancellation of tremor can be achieved. Further research is required to deal with complex gestures involved during microsurgery. Copyright © 2010 John Wiley & Sons, Ltd.

Yang J.,Seoul National University | Son J.S.,Seoul National University | Yu J.H.,Seoul National University | Joo J.,Kyungpook National University | Hyeon T.,Seoul National University
Chemistry of Materials | Year: 2013

The shape-controlled synthesis of colloidal semiconductor nanocrystals has attracted a lot of interest because of their shape-dependent physical and chemical properties. With the growing understanding of the shape evolution, several successful syntheses of two-dimensional (2D) nanocrystals have been reported. In this review, we focus on the recent advances in the colloidal synthesis of 2D CdSe nanoribbons with a wurtzite structure. 2D lamellar assemblies of CdSe clusters are generated in the early stage of the synthesis, and then they direct the formation of 2D structure. The dense organic layers on the {112Ì...0} facets significantly stabilize the 2D nanoribbons. The nanoribbons exhibit unique optical properties originating from the strong 1D quantum confinement within their extremely uniform and thin thickness. Interestingly, a large amount of manganese(II) ions can be incorporated into CdSe nanoribbons via a nucleation-controlled doping process. A high doping concentration and the strong confinement effect of the nanoribbons result in enhanced magneto-optical properties that are suitable for spintronic device applications. CdS nanoribbons have a very similar formation pathway, which suggests the cluster-assembled approaches can potentially be extended to various other materials. © 2013 American Chemical Society.

Zhang Y.,Scripps Research Institute | Fonslow B.R.,Scripps Research Institute | Shan B.,Scripps Research Institute | Baek M.-C.,Scripps Research Institute | And 2 more authors.
Chemical Reviews | Year: 2013

Bottom-up protein analysis refers to the characterization of proteins by analysis of peptides released from the protein through proteolysis. When bottom-up analysis is performed on a mixture of proteins it is called shotgun proteomics, which provides an indirect measurement of proteins through peptides derived from proteolytic digestion of intact proteins. In a typical shotgun proteomics experiment, the peptide mixture is fractionated and subjected to LC-MS/MS analysis. Peptide identification is achieved by comparing the tandem mass spectra derived from peptide fragmentation with theoretical tandem mass spectra generated from in silico digestion of a protein database. Because peptides can be either uniquely assigned to a single protein or shared by more than one protein, the identified proteins may be further scored and grouped based on their peptides. One or more protein or peptide fractionation techniques can be applied prior to MS analysis and database searching.

Park J.,Kyungpook National University
Journal of Pediatric Surgery | Year: 2010

Esophageal atresia with or without tracheoeosphageal fistula is a frequent congenital malformation that may be associated with other congenital anomalies. The combination of heterotopic pancreas of the esophagus and pure esophageal atresia, however, is rare. We treated a patient with esophageal atresia without tracheoesophageal fistula (type A) associated with heterotopic pancreas of the esophagus and stomach who developed a gastric perforation. © 2010 Elsevier Inc. All rights reserved.

Ko M.-J.,Ewha Womans University | Cheigh C.-I.,Kyungpook National University | Chung M.-S.,Ewha Womans University
Food Chemistry | Year: 2014

Subcritical water (about 10 MPa) is an excellent solvent for extracting non-polar flavonoids by varying the temperature-dependent dielectric constant. This study determined the optimum conditions for subcritical water extraction (SWE), such as the time and temperature, for extracting flavonoids from eight plants, and their dependence on the chemical structure of flavonoids (polarity of side chains and the presence of sugar, and double bonds). Flavonoids having an OH side chain (quercetin at 170 °C/10 min) were optimally extracted at lower temperatures than O-CH3 (isorhamnetin at 190 °C/15 min) and H (kaempferol at 190 °C/15 min) side chains. The optimal temperatures of the glycoside forms including sugar, such as quercitrin (110 C/5 min), spiraeoside (150 °C/15 min), and isoquercitrin (150 °C/15 min), were lower than of the less-polar aglycones (170 °C/10 min and 190 °C/15 min). Apigenin, having double bonds, was extracted well at a higher temperature (190 °C/15 min) than naringenin (170 °C/15 min) in SWE. © 2013 Elsevier Ltd.

Cho S.,Stanford University | Kim K.R.,Ulsan National Institute of Science and Technology | Park B.-G.,Stanford University | Kang I.M.,Kyungpook National University
IEEE Transactions on Electron Devices | Year: 2011

This paper presents a radio-frequency (RF) model and extracted model parameters for junctionless silicon nanowire (JLSNW) metaloxidesemiconductor field-effect transistors (MOSFETs) using a 3-D device simulator. JLSNW MOSFETs are evaluated for various RF parameters such as cutoff frequency fT, gate input capacitance, distributed channel resistances, transport time delay, and capacitance by the drain-induced barrier lowering effect. Direct comparisons of high-frequency performances and extracted parameters are made with conventional silicon nanowire MOSFETs. A non-quasi-static RF model has been used, along with SPICE to simulate JLSNW MOSFETs with RF parameters extracted from 3-D-simulated Y-parameters. The results show excellent agreements with the 3-D-simulated results up to the high frequency of fT. © 2010 IEEE.

Park S.,Kyungpook National University
ISIJ International | Year: 2011

The cooling of the steel strip in ROT (run out table) of the hot rolling process is very important in that the ROT is the final process to control the mechanical properties of the final products. In general the products are cooled by the circular water jets which makes the comparatively thick residual water layer about 100-200 mm with the supplied flow rate on the plate. The basic phenomenon governing this cooling process is the boiling heat transfer. The boiling phenomenon is one of the most well-understood heat transfer mechanism by the past a few decades research. However, almost all the results have been reached through experimentation. This paper focuses on the boiling heat transfer on the moving hot plate with a fully numerical approach. The simulation was conducted only in a very high temperature region (over the Leidenfrost temperature) where the film boiling can be kept steadily on the plate. The film (the steam layer) was regarded as the heat resistance whose capacity (actually the steam layer thickness) varied with the plate surface temperature and the flow rate and temperature of the water jet. To fix the steam layer thickness showing a very different spatially distribution on the plate, the continuity for the temperature and heat flux at the interface between the cooling water and the steam layer is satisfied by the iterative procedure for the effective thermal conductivity of the 1st cell on the plate wall. © 2011 ISIJ.

French A.M.,Kyungpook National University
Journal of Internet Banking and Commerce | Year: 2011

Service Science is the basis of information system and web services that ascribe to the provider/client model. This paper developments a methodology that can be used in the development of web services such as websites, web applications and eCommerce. The goal is to development a methodology that will add structure to a highly unstructured problem to assist in the development and success of web services. The new methodology proposed will be called the Web Development Life Cycle (WDLC) and adapted from existing methodologies and applied to the context of web development. This paper will outline in detail the proposed phases of the WDLC. © Aaron French, 2011.

Park S.-S.,Kyungpook National University
Construction and Building Materials | Year: 2011

A series of unconfined compression tests were performed on specimens of fiber-reinforced cemented sand (FRCS) to evaluate how fiber inclusion affects the measured strength and ductility characteristics of cemented sand. Lightly cemented sand with three different cement ratios (2, 4, and 6% by weight of soil) was mixed with four different fiber ratios (0, 0.3, 0.6, and 1% by weight of soil) and then compacted into a cylindrical specimen. Polyvinyl alcohol (PVA) fiber, which adheres well to cement, was randomly distributed throughout the cemented sand. The test results indicate that the inclusion of PVA fiber has a significant effect on both the unconfined compressive strength (UCS) and the axial strain at peak strength. The increase in the UCS was most apparent in the 2% cemented specimen wherein the UCS increased more than three times as the fiber ratio increased up to 1%. The ductile behavior of the FRCS is quantified by the deformability index, D, which is a ratio of the axial strain at peak strength of fiber-reinforced specimen to that of non-fiber-reinforced specimen. In the cases of 1% fiber ratio, the values of D were greater than four, regardless of cement ratios. © 2010 Elsevier Ltd. All rights reserved.

Kim Y.,Kyungpook National University
Educational Gerontology | Year: 2013

As the prevalence of suicide among the elderly has developed in recent years into one of the more serious social problems in South Korea, preventing these elderly suicides has emerged as a national priority. Korean social workers play a major role in the recent elderly suicide prevention efforts that were implemented starting in 2007. The purpose of this qualitative study is to investigate the ways in which social work practitioners perceive, assess, and intervene in suicidal behavior by their elderly clients. Semistructured interviews were conducted with 14 social workers involved with elderly suicide prevention. Both in-depth interviews and field notes were analyzed through qualitative content analysis. Three main themes emerged from the data analysis: (a) an understanding of late-life suicide within an ecological framework with existential thought, (b) the challenges and barriers that hinder the provision of assistance to suicidal older adults, and (c) the assertion that elderly suicide prevention is to promote both well-being and well-dying. The findings revealed ways in which social workers incorporate unique perspectives into working with suicidal elderly clients. They also presented perceived challenges facing intervention and ways in which those challenges might be addressed. Identifying social workers' field experiences with suicidal older adults may contribute to the empirical knowledge base needed to better develop effective suicide prevention strategies. The implications for gerontological education and training are highlighted. © 2013 Copyright Taylor and Francis Group, LLC.

Phloroglucinol plays an important role in oxidative stress, inflammatory responses, and matrix metalloproteinase (MMP) regulation. However, the barrier protective functions of phloroglucinol are not well studied. The objective of this study was to fill this gap. We did this by investigating the barrier protective activities of phloroglucinol on lipopolysaccharide (LPS)-induced barrier disruption in human endothelial cells measured by cellular permeability, monocytes adhesion, and migration toward human endothelial cells. The results showed that phloroglucinol inhibited LPS-induced barrier hyperpermeability, monocyte adhesion, and migration. These inhibitory effects were significantly correlated with the inhibitory functions of phloroglucinol on LPS-induced cell adhesion molecules. Furthermore, LPS-induced nuclear factor-κB (NF-κB) and tumor necrosis factor-κB (TNF-κB) release from human umbilical vein endothelial cells (HUVECs) was inhibited by phloroglucinol. Given these results, phloroglucinol could be a candidate as a therapeutic agent for various systemic inflammatory diseases. © 2011 Springer Science+Business Media, LLC.

Seo H.,Woods Hole Oceanographic Institution | Kwon Y.-O.,Woods Hole Oceanographic Institution | Park J.-J.,Kyungpook National University
Journal of Geophysical Research: Atmospheres | Year: 2014

The East/Japan Sea (EJS) is a semi-enclosed marginal sea located in the upstream of the North Pacific storm track, where the leading modes of wintertime interannual variability in sea surface temperature (SST) are characterized by the basin-wide warming-cooling and the northeast-southwest dipole. Processes leading to local and remote atmospheric responses to these SST anomalies are investigated using the Weather Research and Forecast (WRF) model. The atmosphere in direct contact with anomalous diabatic forcing exhibits a linear and symmetric response with respect to the sign, pattern, and magnitude of SST anomalies, producing increased (decreased) wind speed and precipitation response over warm (cold) SSTs. This local response is due to modulation of both the vertical stability of the marine atmospheric boundary layer and the adjustment of sea level pressure, although the latter provides a better explanation of the quadrature relationship between SST and wind speed. The linearity in the local response suggests the importance of fine-scale EJS SSTs to predictability of the regional weather and climate variability. The remote circulation response, in contrast, is strongly nonlinear. An intraseasonal equivalent barotropic ridge emerges in the Gulf of Alaska as a common remote response independent of EJS SST anomalies. This downstream blocking response is reinforced by the enhanced storm track variability east of Japan via transient eddy vorticity flux convergence. Strong nonlinearity in remote response implies that detailed EJS SST patterns may not be critical to this downstream ridge response. Overall, results demonstrate a remarkably far-reaching impact of the EJS SSTs on the atmospheric circulation. Key Points Atmospheric response to EJS SST is studied with a hemispheric WRF model EJS SST anomalies lead to a downstream equivalent barotropic high Synoptic transient eddies play a crucial role via vorticity flux convergence ©2013. American Geophysical Union. All Rights Reserved.

Park H.,Kyungpook National University | Park Y.,Pohang University of Science and Technology | Kim W.,Pohang University of Science and Technology | Choi W.,Pohang University of Science and Technology
Journal of Photochemistry and Photobiology C: Photochemistry Reviews | Year: 2013

This paper reviews recent studies on the semiconductor photocatalysis based on surface-modified TiO2 of which application is mainly focused on environmental remediation. TiO2 photocatalysis that is based on the photoinduced interfacial charge transfer has been extensively studied over the past four decades. A great number of modification methods of semiconductor photocatalysts have been developed and investigated to accelerate the photoconversion, to enable the absorption of visible light, or to alter the reaction mechanism to control the products and intermediates. In this regard, various modification methods of TiO2 are classified according to the kind of surface modifiers (metal-loading, impurity doping, inorganic adsorbates, polymer coating, dye-sensitization, charge transfer complexation) and their effects on photocatalytic reaction mechanism and kinetics are discussed in detail. Modifying TiO2 in various ways not only changes the mechanism and kinetics under UV irradiation but also introduces visible light activity that is absent with pure TiO2. Each modification method influences the photocatalytic activity and mechanism in a way different from others and the observed modification effects are often different depending on the test substrates and conditions even for the same modification method. Better understanding of the modification effects on TiO2 photocatalysis is necessary to obtain reliable results, to assess the photoconversion efficiency more quantitatively, and to further improve the modification methods. © 2012 Elsevier B.V.

Lee J.,Kyungpook National University
Current Medical Imaging Reviews | Year: 2013

The purpose of quantitative evaluation of cardiac images is to acquire more objective, accurate, and delicate numeric data than from the results of qualitative observation. By quantitative analysis, the prediction of cardiovascular risk and the depiction of subtle changes have become more reliable. Until cardiac computed tomography (CT) and magnetic resonance imaging (MRI) were introduced 10 years ago, echocardiography had been traditionally used for cardiac morphology imaging. Based on technical advancements, cardiovascular CT and MRI started to be used for quantitative evaluation of cardiovascular structures. In this article, quantitative evaluation techniques in cardiovascular imaging will be discussed with an emphasis on CT and MRI. © 2013 Bentham Science Publishers.

Choi I.-H.,CleanSys Tele Monitoring Yeongnam Center | Jo W.-K.,Kyungpook National University
Aerosol and Air Quality Research | Year: 2011

Real monitoring data are required for the validation of models or methods used to estimate industrial emission inventories of air pollutants. As such, the current study investigated the industrial emissions of four major and three other hazardous air pollutants in four infareas of the Yeongnam area in Korea over five years (2005 through 2009), using direct stack monitoring concentrations, which were obtained from tel-monitoring systems. Yearly variations in the industrial emissions of the target pollutants depended upon the infareas and chemical types. For example, the total suspended particulate (TSP) emissions in Geongnam increased for two consecutive years (2007 and 2008) and then, decreased in 2009, whereas the industrial CO emissions in Ulsan sharply increased since 2007. For TSP, primary metal manufacturing (PMM) and Power, electricity and gas supplying companies (PEGSC) were two major industrial emission sources. PEGSC exhibited the highest source for both SO 2 and NO x emissions, followed by PMM and petroleum and petrochemical companies in descending order. For CO emissions, PPM exhibited the highest source, followed by municipal waste treatment and intermediate waste treatment facilities in descending order. Both NH 3 and HF were emitted primarily from two infareas (Ulsan and Geongbuk), which have fertilizer production companies. Both Geongnam and Geongbuk exhibited the highest and the second highest HCl emissions, presumably due to emissions during the acid treatment processes of various metals. Most of the industry categories, which are associated with fuel combustions or waste incineration, exhibited the highest and the second highest emission proportions for NO x and SO 2, respectively. Maximum emissions were observed in the winter or summer season, while minimum emissions were observed in the spring or fall season, presumably due to increased energy utilizations for residential as well as industrial heating and cooling. © Taiwan Association for Aerosol Research.

Kim Y.H.,Korea Basic Science Institute | Kim S.,Kyungpook National University
Journal of the American Society for Mass Spectrometry | Year: 2010

Positive-ion atmospheric pressure chemical ionization (APCI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) analyses of petroleum sample were performed with higher sensitivity by switching the solvent composition from toluene and methanol or acetonitrile to a one-component system consisting only of toluene. In solvent blends, molecular ions were more abundant than were protonated ions with increasing percentages of toluene. In 100% toluene, the double-bond equivalence (DBE) distributions of molecular ions obtained by APCI MS for each compound class were very similar to those obtained in dopant assisted atmospheric pressure photo ionization (APPI) MS analyses. Therefore, it was concluded that charge-transfer reaction, which is important in toluene-doped APPI processes, also plays a major role in positive-ion APCI. In the DBE distributions of S1, S2, and SO heteroatom classes, a larger enhancement in the relative abundance of molecular ions at fairly specific DBE values was observed as the solvent was progressively switched to toluene. This enhanced abundance of molecular ions was likely dependent on molecular structure. © 2010 American Society for Mass Spectrometry.

Park E.,Kyungpook National University
Water Resources Research | Year: 2012

The concept of the hybrid water table fluctuation (WTF) method for recharge rate estimation was revisited. To estimate the recharge rate, a physically based WTF equation was established. The concept of transient fillable porosity was proposed and computed with unsaturated hydraulics models. The developed model is tested by applying to the water table fluctuation data from Hongcheon, Korea. In the applications, the recharge and fillable porosity estimates were found to be most sensitive to nonlinearity in the unsaturated water content profile and permeability. Also, the water table level drift, which does not originate from precipitation, serves as a major source of estimation error. © 2012. American Geophysical Union. All Rights Reserved.

Mantica C.A.,University of Milan | Suh Y.J.,Kyungpook National University
International Journal of Geometric Methods in Modern Physics | Year: 2014

In this paper, we introduce the notion of recurrent conformal 2-forms on a pseudo-Riemannian manifold of arbitrary signature. Some theorems already proved for the same differential structure on a Riemannian manifold are proven to hold in this more general contest. Moreover other interesting results are pointed out; it is proven that if the associated covector is closed, then the Ricci tensor is Riemann compatible or equivalently, Weyl compatible: these notions were recently introduced and investigated by one of the present authors. Further some new results about the vanishing of some Weyl scalars on a pseudo-Riemannian manifold are given: it turns out that they are consequence of the generalized Derdziński-Shen theorem. Topological properties involving the vanishing of Pontryagin forms and recurrent conformal 2-forms are then stated. Finally, we study the properties of recurrent conformal 2-forms on Lorentzian manifolds (space-times). Previous theorems stated on a pseudo-Riemannian manifold of arbitrary signature are then interpreted in the light of the classification of space-times in four or in higher dimensions. © 2014 World Scientific Publishing Company.

Lee J.,Kyungpook National University
The international journal of cardiovascular imaging | Year: 2011

With the suggestion of coronary artery calcium as an indicator of coronary artery disease 30 years ago, intense and controversial discussion regarding coronary artery calcium has been ongoing. Diverse techniques for evaluation of coronary artery calcium were suggested and validation of its feasibility has been followed up. Following establishment of reference standards, coronary artery calcium became widely utilized in clinical practice and scientific research. Originally coronary artery calcium scoring techniques were developed for prediction of cardiovascular risk. Additionally, coronary artery calcium scoring has been utilized as an indicator for other medical events. Recently, coronary artery calcium scoring used to be applied as a reference standard during scientific research. In this article, the topic of coronary artery calcium, from its introduction to its current usefulness, was discussed from the viewpoints of coronary artery calcium scoring techniques, imaging modalities, validation of the techniques, clinical feasibility of coronary artery calcium scoring beyond traditional cardiovascular risk prediction, and utilization of coronary artery calcium scoring as a reference standard. Popular coronary calcium scoring techniques comprises of Agatston, volume, and mass scores. Through validation of these techniques, pros and cons of each technique were analyzed and proper utility could be suggested. In parallel, the reference standards for Agatston and volume scores were established by age, sex, and race. Through the vigorous controversies, nowadays, the clinical feasibility of coronary artery calcium score as a surrogate marker of cardiovascular risk was acknowledged in the literature.

Ahn B.-C.,Kyungpook National University
Clinical Nuclear Medicine | Year: 2016

ABSTRACT: Although radioiodines are widely used to localize metastatic differentiated thyroid cancer (DTC), TcO4 also can be used because it is a substrate for the sodium-iodide symporter protein. The use of TcO4 has advantages over radioiodine, namely, easy availability, dispensability of iodine restriction, and early imaging time. However, its low sensitivity precludes its practical application. Scintigraphic detectability of DTC using sodium-iodide symporter substrates is related to the serum TSH levels. Here, I report a case with multiple metastatic lesions of DTC that were detected upon TSH-stimulated TcO4 scintigraphy, but not with non–TSH-stimulated scintigraphy using the same tracer. Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.

Lee D.-H.,Kyungpook National University | Lind P.M.,Uppsala University | Jacobs Jr. D.R.,University of Minnesota | Jacobs Jr. D.R.,University of Oslo | And 3 more authors.
Diabetes Care | Year: 2011

OBJECTIVE - Persistent organic pollutants (POPs), lipophilic chemicals that accumulate mainly in adipose tissue, have recently been linked to type 2 diabetes. However, evidence from prospective studies is sparse. This study was performed to evaluate prospective associations of type 2 diabetes with selected POPs among the elderly. RESEARCH DESIGN AND METHODS - Nineteen POPs (14 polychlorinated biphenyl [PCB] congeners, 3 organochlorine pesticides, 1 brominated diphenyl ether, and 1 dioxin) were measured in plasma collected at baseline in 725 participants, aged 70 years, of the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS). RESULTS - After adjusting for known type 2 diabetes risk factors, including obesity, odds ratios (ORs) (95% CIs) for type 2 diabetes at age 75 years (n = 36) according to the quintiles of a summary measure of concentrations of PCBs (vs. the lowest quintile) were 4.5, 5.1, 8.8 (1.8-42.7), and 7.5 (1.4-38.8) (P trend<0.01). Among organochlorine pesticides, adjusted ORs across concentrations of trans-nonachlor showed that P trend = 0.03. Adjusted ORs (95% CIs) across quintiles of the sum of three organochlorine pesticides were 1.1, 1.6, 1.5, and 3.4 (1.0-11.7) (P trend = 0.03). Neither brominated diphenyl ether 47 nor dioxin was significantly associated with incident diabetes. The sum of PCBs improved reclassification significantly when added to traditional risk factors for diabetes. CONCLUSIONS - Despite the small number of incident cases, this study found that environmental exposure to some POPs substantially increased risk of future type 2 diabetes in an elderly population. © 2011 by the American Diabetes Association.

Jung H.Y.,Leibniz Institute for Solid State and Materials Research | Yi S.,Kyungpook National University
Intermetallics | Year: 2014

Nanocrystallization effect of primary Fe23M6-type phase (M: C or B) on magnetic properties of Fe-based bulk metallic glass (BMG) has been investigated. Under controlled microstructural modification with Fe23M6-type phase, the soft magnetic properties of Fe 76.5C6Si3.3B5.5P8.7 (at.%) BMG were significantly improved: saturation magnetization (Ms) and initial permeability (μi) of the alloy were dramatically enhanced from 1.35 T and 3500 to 1.57 T and 9890, respectively. The present study about introducing medium range atomic orderings and nanocrystallization of Fe23M6-type structure in amorphous matrix suggests a strategy to enhance the soft magnetic properties of ferromagnetic BMGs having the primary crystallized phase Fe23M6. This result provides useful insight to develop soft magnetic nanocrystalline materials, stating from BMG precursor with large glass forming ability. © 2014 Elsevier Ltd. All rights reserved.

Metasedimentary rocks of the Pyeongan Supergroup in the northeastern flank of the Taebaeksan Basin, South Korea, commonly contain two Al2SiO5 polymorphs (And+Ky and And+Sil), or more rarely, three coexisting Al2SiO5 polymorphs. Lower-grade rocks preserve chloritoid+andalusite±kyanite in muscovite-chlorite phyllite, and higher-grade rocks contain andalusite+sillimanite (±kyanite)+staurolite±garnet in mica schists. Kyanite and sillimanite occur as partial paramorphs after andalusite. Textural relations and relative metamorphic P-T conditions of the Al2SiO5-bearing mineral assemblages suggest a crystallization sequence of andalusite→kyanite→sillimanite, with the growth of staurolite and garnet in the kyanite and sillimanite stability fields. Metamorphic P-T conditions determined from geothermobarometry, compositional isopleths of chloritoid and garnet, and petrogenetic grids in the MnO-K2O-FeO-MgO-Al2O3-SiO2-H2O (MnKFMASH), MnKFMASH-T(TiO2)-O(Fe2O3), and Mn-N(Na2O)-C(CaO)-KFMASH systems could be divided into two regimes temporally: a clockwise path at lower temperature (LT)/medium pressure (MP) conditions, and higher temperature (HT)/low pressure (LP) conditions. The peak metamorphic P-T conditions for regional LT/MP metamorphism are ca. 5.0-6.0kbar at 550-580°C, and those for HT/LP metamorphism are ca. 3.0-4.8kbar and 590-610°C. Kyanite paramorphs after andalusite may result from a LT/MP clockwise P-T path associated with a rapid contractional deformation during the early to middle Mesozoic, and then sillimanite paramorphs after andalusite may have been formed by magmatic heating due to the later intrusion of leucocratic granite. © 2010 Elsevier B.V.

Mantica C.A.,University of Milan | Suh Y.J.,Kyungpook National University
International Journal of Geometric Methods in Modern Physics | Year: 2012

In this paper, we introduce a new kind of Riemannian manifold that generalize the concept of weakly Z-symmetric and pseudo-Z-symmetric manifolds. First a Z form associated to the Z tensor is defined. Then the notion of Z recurrent form is introduced. We take into consideration Riemannian manifolds in which the Z form is recurrent. This kind of manifold is named (ZRF) n. The main result of the paper is that the closedness property of the associated covector is achieved also for rank(Z kl) > 2. Thus the existence of a proper concircular vector in the conformally harmonic case and the form of the Ricci tensor are confirmed for(ZRF) n manifolds with rank(Z kl) > 2. This includes and enlarges the corresponding results already proven for pseudo-Z-symmetric (PZS) n and weakly Z-symmetric manifolds (WZS) n in the case of non-singular Z tensor. In the last sections we study special conformally flat (ZRF) n and give a brief account of Z recurrent forms on Kaehler manifolds. © 2012 World Scientific Publishing Company.

Group I metabotropic glutamate receptors (mGluR1 and 5) have been implicated in long-term potentiation (LTP), a persistent increase of synaptic efficiency, in the central nervous system including the spinal trigeminal nucleus (Vsp). In the ascending pathway from the caudalis (Vc) to the oralis (Vo) subnuclus in Vsp, it has been shown that the activation of group I mGluRs (mGluR1 and 5) with their agonist (S)-3,5-dihydroxyphenylglycine (DHPG) produces a delayed type of LTP of excitatory synaptic transmission and this LTP was mediated by mGluR1. Further, this study attempts to pharmacologically characterize essential signaling components for the expression of DHPG-induced LTP. As a result, it is found that the group I mGluRs essentially use G protein-mediated activation of the phospholipase C (PLC) pathway to express the LTP. However, recruited signaling molecules following the activation of PLC are differentially involved in the expression of LTP: i.e. IP3 receptor, intracellular Ca2+ rise, CaMKII and ERK function as positive regulators, whereas PKC as a negative regulator. Furthermore, both L-type voltage-dependent Ca2+ channel and canonical transient receptor potential channel positively contribute to the expression of LTP. Taken together, these results suggest that signaling molecules recruited by the activation of group I mGluRs collaboratively or oppositely control the optimal expression of synaptic plasticity at excitatory synapses in the Vo. © 2014 Elsevier Inc.

Ahn B.-C.,Kyungpook National University
Journal of Drug Targeting | Year: 2014

Radionuclide-based theranostic strategy has been widely used in diagnosis and treatment of patients with hyperthyroidism or differentiated thyroid cancer for a long time, and sodium iodide symporter gene is the radionuclide-based reporter gene used in theranostics. Theranostics, which is a promising approach, offering the ideal combination of accurate diagnosis and successful therapy in various clinical fields, is expected to become a key area of personalized medicine. Rapid advancements in biotechnologies using theranostic reporter genes and theranostic radiochemistry have led to development of the concept of theranostics using radionuclide-based imaging reporter genes; the theranostic approach is almost ready for application in a limited arena of clinics. In order to fulfill both the diagnostic and therapeutic purposes, theranostics with radionuclide-based imaging reporter requires use of successful combinations of various components, such as radionuclide-based reporter genes, promoters/enhancers that regulate expression of reporter genes, delivery vectors/vehicles, imaging or therapeutic probes and prodrugs, transductional and transcriptional targeting strategies, transgene amplification systems, etc. In this review, overview and recent updates on theranostics using radionuclide-based imaging reporter genes will be discussed. © 2014 Informa UK Ltd. All rights reserved.

Mantica C.A.,University of Milan | Suh Y.J.,Kyungpook National University
International Journal of Geometric Methods in Modern Physics | Year: 2012

In this paper we introduce a new notion of Z-tensor and a new kind of Riemannian manifold that generalize the concept of both pseudo Ricci symmetric manifold and pseudo projective Ricci symmetric manifold. Here the Z-tensor is a general notion of the Einstein gravitational tensor in General Relativity. Such a new class of manifolds with Z-tensor is named pseudo Z symmetric manifold and denoted by (PZS) n. Various properties of such an n-dimensional manifold are studied, especially focusing the cases with harmonic curvature tensors giving the conditions of closeness of the associated one-form. We study (PZS) n manifolds with harmonic conformal and quasi-conformal curvature tensor. We also show the closeness of the associated 1-form when the (PZS) n manifold becomes pseudo Ricci symmetric in the sense of Deszcz (see [A. Derdzinsky and C. L. Shen, Codazzi tensor fields, curvature and Pontryagin forms, Proc. London Math. Soc. 47(3) (1983) 1526; R. Deszcz, On pseudo symmetric spaces, Bull. Soc. Math. Belg. Ser. A 44 (1992) 134]). Finally, we study some properties of (PZS) 4 spacetime manifolds. © 2012 World Scientific Publishing Company.

Kind T.,University of California at Davis | Liu K.-H.,University of California at Davis | Liu K.-H.,Kyungpook National University | Lee D.Y.,University of California at Davis | And 4 more authors.
Nature Methods | Year: 2013

Current tandem mass spectral libraries for lipid annotations in metabolomics are limited in size and diversity. We provide a freely available computer-generated tandem mass spectral library of 212,516 spectra covering 119,200 compounds from 26 lipid compound classes, including phospholipids, glycerolipids, bacterial lipoglycans and plant glycolipids. We show platform independence by using tandem mass spectra from 40 different mass spectrometer types including low-resolution and high-resolution instruments. © 2013 Nature America, Inc. All rights reserved.

Chang H.-U.,Kyungpook National University
Journal of Astronomy and Space Science | Year: 2013

Parameters associated with solar minimum have been studied to relate them to solar activity at solar maximum so that one could possibly predict behaviors of an upcoming solar cycle. The number of active days has been known as a reliable indicator of solar activity around solar minimum. Active days are days with sunspots reported on the solar disk. In this work, we have explored the relationship between the sunspot numbers at solar maximum and the characteristics of the monthly number of active days. Specifically, we have statistically examined how the maximum monthly sunspot number of a given solar cycle is correlated with the slope of the linear relationship between monthly sunspot numbers and the monthly number of active days for the corresponding solar cycle. We have calculated the linear correlation coefficient r and the Spearman rank-order correlation coefficient rs for data sets prepared under various conditions. Even though marginal correlations are found, they turn out to be insufficiently significant (r ̃ 0.3). Nonetheless, we have confirmed that the slope of the linear relationship between monthly sunspot numbers and the monthly number of active days is less steep when solar cycles belonging to the "Modern Maximum" are considered compared with rests of solar cycles. We conclude, therefore, that the slope of the linear relationship between monthly sunspot numbers and the monthly number of active days is indeed dependent on the solar activity at its maxima, but that this simple relationship should be insufficient as a valid method to predict the following solar activity amplitude. © The Korean Space Science Society.

Kang J.-H.,Ewha Womans University | Paek S.-M.,Kyungpook National University | Hwang S.-J.,Ewha Womans University | Choy J.-H.,Ewha Womans University
Journal of Materials Chemistry | Year: 2010

Porous structure of layered manganate pillared with titania nanoparticles has been realized by the exfoliation and reassembling route. First, the layered protonic manganese oxide, H0.13MnO2·0.7H 2O, is exfoliated by the intercalation of tetrabutylammonium (TBA) ions, and then the exfoliated manganate nanosheets are reassembled in the presence of titania nanoparticles, which results in porous nanohybrid materials. X-Ray diffraction (XRD), cross-sectional transmission electron microscopy (TEM), and Mn K-edge X-ray absorption spectroscopy (XAS) analyses clearly show that the titania nanoparticles with a diameter of 1 nm are successfully intercalated into the two dimensional manganate lattice without any deterioration of electronic structure and local symmetry of Mn ion. According to the N2 adsorption-desorption isotherms, the present nanohybrid is determined to be highly porous with a high specific surface area (106 m 2 g-1), which is 10 times larger than that (11 m 2 g-1) of the pristine. Finally, electrochemical experiments demonstrate that the specific capacity of the present pillared material is 288 mA h g-1, which is significantly larger than the theoretical value (193 mA h g-1) from the physical mixture of the pristine potassium birnessite and titania nanoparticles. © 2010 The Royal Society of Chemistry.

Yoon G.H.,Kyungpook National University
International Journal for Numerical Methods in Engineering | Year: 2010

This paper outlines a new procedure for topology optimization in the steady-state fluid-structure interaction (FSI) problem. A review of current topology optimization methods highlights the difficulties in alternating between the two distinct sets of governing equations for fluid and structure dynamics (hereafter, the fluid and structural equations, respectively) and in imposing coupling boundary conditions between the separated fluid and solid domains. To overcome these difficulties, we propose an alternative monolithic procedure employing a unified domain rather than separated domains, which is not computationally efficient. In the proposed analysis procedure, the spatial differential operator of the fluid and structural equations for a deformed configuration is transformed into that for an undeformed configuration with the help of the deformation gradient tensor. For the coupling boundary conditions, the divergence of the pressure and the Darcy damping force are inserted into the solid and fluid equations, respectively. The proposed method is validated in several benchmark analysis problems. Topology optimization in the FSI problem is then made possible by interpolating Young's modulus, the fluid pressure of the modified solid equation, and the inverse permeability from the damping force with respect to the design variables. © 2009 John Wiley & Sons, Ltd.

Li Q.,Xinjiang University | Yi S.,Kyungpook National University
Metals and Materials International | Year: 2014

Effects of fluxing treatment on the glass forming ability and magnetic properties of Fe-based amorphous alloys prepared using industrial raw materials have been studied. The partially amorphous Fe76Si8P 9C7 rod with the diameter of 1 mm was prepared by suction casting technique from the fluxed master alloy based on the industrial raw materials, while the alloy rod with the diameter of 1 mm obtained from the un-fluxed master alloy does not involve any amorphous phase. Melt spun ribbons prepared using the fluxed master exhibited lower the coercivity H c and power loss than those for ribbons prepared using the un-fluxed master alloy. These beneficial effects should be attributed to the purification of the master alloy through flux treatments. The results reveal that fluxing technique can play an important role in the development of Fe-based bulk metallic glasses using industrial raw materials with relatively low purities. © 2014 The Korean Institute of Metals and Materials and Springer Science+Business Media Dordrecht.

Lee J.S.,Korea Research Institute of Chemical Technology | Jhung S.H.,Kyungpook National University
Microporous and Mesoporous Materials | Year: 2010

Porous aluminum-trimesate (MIL-96), one of the metal-organic frameworks (MOFs), has been synthesized hydrothermally under autogeneous pressure in water as the solvent. The MIL-96 adsorbs nitrogen readily at liquid nitrogen temperature to show permanent porosity (SBET = 532 m2/g, SLangmuir = 700 m2/g). Moreover, the desorption of adsorbed nitrogen does not to show any hysteresis between the adsorption and desorption isotherms. A vapor-phase adsorption study (temperature: 30-110 °C) shows that MIL-96 can uptake aromatic compounds such as p-xylene, m-xylene and 1,3,5-TMB (trimethylbenzene). However, a larger molecule such as 1,3,5-TiPB (triisopropylbenzene) is only negligibly adsorbed on MIL-96. The adsorption rate of 1,3,5-TMB (even at a high temperature of 70 °C) is very slow compared with that of p-xylene (at 30 °C). Very interestingly, the adsorption capacity of 1,3,5-TMB increases with increasing adsorption temperature (up to 90 °C), which is very rare because an adsorption is usually an exothermic process. All of these results may be explained by the fact that the MIL-96 has a pore size similar to a kinetic diameter of 1,3,5-TMB. Moreover, the results may suggest that the framework of MIL-96 is flexible and the lattice vibrates more widely at high temperature to increase the effective pore size. The flexible structure of MIL-96 demonstrated in this study may enlarge the applications of MOFs for the storage of chemicals and controlled release such as drug delivery. © 2009 Elsevier Inc. All rights reserved.

Hwang J.-C.,Kyungpook National University | Noh H.,Korea Astronomy and Space Science Institute
Monthly Notices of the Royal Astronomical Society | Year: 2013

In 1988 Bardeen suggested a pragmatic formulation of cosmological perturbation theory which is powerful in practice to employ various fundamental gauge conditions easily depending on the character of the problem. The perturbation equations are presented without fixing the temporal gauge condition and are arranged so that one can easily impose fundamental gauge conditions by simply setting one of the perturbation variables in the equations equal to zero. In this way one can use the gauge degrees of freedom as an advantage in handling problems. Except for the synchronous gauge condition, all the other fundamental gauge conditions completely fix the gauge mode, and consequently, each variable in such a gauge has a unique gauge-invariant counterpart, so that we can identify the variable as the gauge-invariant one. Here, we extend Bardeen's linear formulation to the fully non-linear order in perturbations, with the gauge advantage kept intact. The perturbation equations are exact (except for ignoring the transverse-tracefree part of the metric), and from these we can easily derive the higher order perturbation equations in a gauge-ready form. We consider scalar- and vector-type perturbations of an ideal fluid in a flat background; we also present the minimally coupled scalar field and the multiple components of ideal fluid cases. As applications, we present fully non-linear density and velocity perturbation equations in Einstein's gravity in the zero-pressure medium, vorticity generation from pure scalar-type perturbation and fluid formulation of a minimally coupled scalar field, all in the comoving gauge. We also present the equation of gravitational waves generated from pure scalar- and vector-type perturbations. © 2013 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society.

Hole doped manganites Pr0.7Ca0.3MnO3 (PCMO) and La0.7Ca0.3MnO3(LCMO) films have been epitaxially grown on the electron doped Nb:SrTiO3 (NSTO) substrates by pulsed laser deposition. The rectifying characteristic observed in the currentvoltage (IV) measurement was better in the PCMO/NSTO junction than in the LCMO/NSTO one. A resistance switching behavior in the IV curves was observed with decrease of the Au electrode size and it was thought to be due to Schottky barrier at the NSTO/Au contact. The temperature dependence of the threshold voltage, which shows a dramatic increase of the current, varied slightly around the metalinsulator transition temperature of the LCMO. These results suggest that the measurement of IV characteristics in these pn junctions can be largely affected by the electrode size and the temperature. The photocurrent and the photovoltage across the pn junctions in zero external bias were quickly switched by on/off of visible or UV light. This result suggests that the photo-carriers can be generated in both the p-type and the n-type layers. © 2010 Elsevier B.V. All rights reserved.

Lee I.-K.,Kyungpook National University
Diabetes and Metabolism Journal | Year: 2014

The pyruvate dehydrogenase complex (PDC) is an emerging target for the treatment of metabolic syndrome. To maintain a steady-state concentration of adenosine triphosphate during the feed-fast cycle, cells require efficient utilization of fatty acid and glucose, which is controlled by the PDC. The PDC converts pyruvate, coenzyme A (CoA), and oxidized nicotinamide adenine dinucleotide (NAD+) into acetyl-CoA, reduced form of nicotinamide adenine dinucleotide (NADH), and carbon dioxide. The activity of the PDC is up- and down-regulated by pyruvate dehydrogenase kinase and pyruvate dehydrogenase phosphatase, respectively. In addition, pyruvate is a key intermediate of glucose oxidation and an important precursor for the synthesis of glucose, glycerol, fatty acids, and nonessential amino acids. © 2014 Korean Diabetes Association.

Kim K.-H.,LG Corp | Jeung Y.-C.,Yeungnam University | Lee D.-C.,Yeungnam University | Kim H.-G.,Kyungpook National University
IEEE Transactions on Power Electronics | Year: 2012

This paper proposes a low-voltage ride-through scheme for the permanent magnet synchronous generator (PMSG) wind power system at the grid voltage sag. The dc-link voltage is controlled by the generator-side converter instead of the grid-side converter (GSC). Considering the nonlinear relationship between the generator speed ω m and the dc-link voltage V dc, a dc-link voltage controller is designed using a feedback linearization theory. The GSC controls the grid active power for a maximum power point tracking. The validity of this control algorithm has been verified by simulation and experimental results for a reduced-scale PMSG wind turbine simulator. © 2006 IEEE.

Kim K.W.,Kyungpook National University
Journal of Electron Microscopy | Year: 2013

The leaf surface features of the biomass plant Miscanthus sinensis were investigated by electron and ion beam microscopy. Fully developed leaves were collected from the plant, air-dried and examined by field emission scanning electron microscopy. Stomata and longitudinal stripes were present on both the adaxial and abaxial leaf surfaces. Longitudinally aggregated rodlets surrounded the stomata and formed hollow cylinders or chimney-like structures. With varying lengths up to ∼10 μm, the rodlets were curved (<1 μm in diameter) and almost occluded the stomata. As another type of epicuticular wax, platelets were observed in the vicinity of the stomata. The platelets were arranged into rather radially assembled clusters. As a novel approach for cross sectioning native epicuticular waxes, focused ion beam milling allowed precise in situ cutting of the stomata and epicuticular waxes. The longitudinally aggregated rodlets of the stomatal chimneys of M. sinensis were derived from the stomatal guard cells. These results suggest that the epicuticular waxes of M. sinensis can be categorized as stomatal chimneys (Strelitzia type) and rosettes (Fabales type). Combined electron and ion beam microscopy can help unravel the ultrastructure and vertical profile of epicuticular waxes in a range of plant taxa. © The Author 2013. Published by Oxford University Press [on behalf of The Japanese Society of Microscopy]. All rights reserved.

In this study, Ag2S nanoparticles are synthesized and used as the active material for two-terminal resistance switching memory devices. Sintered Ag2S films are successfully crystallized on plastic substrates with synthesized Ag2S nanoparticles, after a relatively low-temperature sintering process (200 °C). After the sintering process, the crystallite size is increased from 6.8 nm to 80.3 nm. The high ratio of surface atoms to inner atoms of nanoparticles reduces the melting point temperature, deciding the sintering process temperature. In order to investigate the resistance switching characteristics, metal/Ag2S/metal structures are fabricated and tested. The effect of the electrode material on the non-volatile resistive memory characteristics is studied. The bottom electrochemically inert materials, such as Au and Pt, were critical for maintaining stable memory characteristics. By using Au and Pt inert bottom electrodes, we are able to significantly improve the memory endurance and retention to more than 103 cycles and 104 sec, respectively. © 2016 Author(s).

Ku S.-K.,Daegu Haany University | Bae J.-S.,Kyungpook National University
BMB Reports | Year: 2014

Enzymatic oxidation of pyrogallol was efficiently transformed to an oxidative product, purpurogallin (PPG). Here, the anticoagulant activities of PPG were examined by monitoring activated partial thromboplastin time (aPTT), prothrombin time (PT), and the activities of thrombin and activated factor X (FXa). And, the effects of PPG on expression of plasminogen activator inhibitor type 1 (PAI-1) and tissue-type plasminogen activator (t-PA) were evaluated in tumor necrosis factor (TNF)-α activated human umbilical vein endothelial cells (HUVECs). Treatment with PPG resulted in prolonged aPTT and PT and inhibition of the activities of thrombin and FXa, as well as inhibited production of thrombin and FXa in HUVECs. In addition, PPG inhibited thrombin-catalyzed fibrin polymerization and platelet aggregation. PPG also elicited anticoagulant effects in mice. In addition, treatment with PPG resulted in significant reduction of the PAI-1 to t-PA ratio. Collectively, PPG possesses antithrombotic activities and offers a basis for development of a novel anticoagulant. © 2014 by the The Korean Society for Biochemistry and Molecular Biology.

Park S.,Keimyung University | Lee Y.J.,Kyungpook National University
Journal of Biological Physics | Year: 2014

An enhanced mechanical compliance is considered to be a mechanical indicator for metastatic cancer cells. Our study using atomic force microscopy (AFM) revealed that breast cancer cells agreed well with this hypothesis. However, prostate cancer cells displayed a reverse correlation; less metastatic prostate cancer cells were more mechanically compliant. Two-dimensional AFM force spectroscopy was performed to characterize dual mechanical properties - the cell-substrate adhesion as well as the mechanical compliance. Interestingly, prostate cancer cells displayed a strong positive correlation between the cell-substrate adhesion and metastatic potential. However, there was no clearly observable correlation between the cell-substrate adhesion and the metastatic potential despite variations in mechanical compliance of breast cancer cells. These results suggest that the correlation between the dual mechanical signatures and metastatic potential be uniquely identified for cancer cells originating from different organs. We postulate that this correlation could reveal which step of cancer progression is favorable in terms of physical interaction between cancer cells and micro-environments. We expect that based on the "seed and soil hypothesis", the identification of the dual mechanical phenotypes, could provide a new insight for understanding how a dominant metastatic site is determined for cancer cells originating from specific organs. © 2014 Springer Science+Business Media.

Kim S.-W.,Kyungpook National University
Journal of the Korean Medical Association | Year: 2015

Prevention of healthcare-associated infection (HAI) is an essential part of patient safety. HAIs are associated with significant mortality, morbidity, and increasing healthcare cost. Major HAIs include urinary tract infection, pneumonia, surgical site infection, bacteremia, and C. difficile colitis. Surveillance for HAIs is essential to prevent these infections. Active strategies, such as the 'bundle' approach, should be implemented for the effective prevention of HAIs. The Korean regulatory certification system for hospitals is a powerful driver in the maintenance of the infection surveillance, control and prevention process. Additional driving forces for the reduction of HAIs include financial incentives and convincing clinical practice guidelines. Therefore, there is a need for solid regulatory and financial support and a suitable cultural environment for the prevention of HAIs. © Korean Medical Association

Lee T.,Kyungpook National University | Seo Y.H.,Keimyung University
Bioorganic and Medicinal Chemistry Letters | Year: 2013

Heat shock protein 90 (Hsp90) is a molecular chaperone that plays an important role in regulating the maturation and stabilization of many oncogenic proteins. In an attempt to discover a new class of Hsp90 inhibitors, a series of 1,3,5-triazine compounds were rationally designed, synthesized, and their biological activities were evaluated. Compound 3b was found to degrade Hsp90's client proteins of Her2, Met and Akt and to induce the expression level of Hsp70. The binding mode of 3b in the ATP-binding site of Hsp90 was predicted by the molecular docking. © 2013 Elsevier Ltd. All rights reserved.

Baek J.,University of Alaska Fairbanks | Kim H.S.,Kyungpook National University
Energy Economics | Year: 2013

The effects of economic growth on the environment in Korea, for a given level of energy consumption, and fossil fuels and nuclear energy in electricity production, are examined in a dynamic cointegration framework. To that end, the autoregressive distributed lag (ARDL) approach is used. We find empirical evidence supporting the existence of the environmental Kuznets curve (EKC) hypothesis for Korea; that is, economic growth indeed plays a favorable role in influencing environmental outcomes. It is also found that, in both the short- and long-run, nuclear energy has a beneficial effect on environmental quality, whereas fossil fuels in electricity production and energy consumption have a detrimental effect on the environment. © 2012 Elsevier B.V.

Choi H.,Kyungpook National University | Van Riper M.,University of North Carolina at Chapel Hill
Journal of Intellectual Disability Research | Year: 2014

Background: It is estimated that more than 500 infants with Down syndrome (DS) are born each year in Korea. DS affects not only these individuals, but family members as well. Some siblings deal successfully with the challenges of living with a child with DS and adapt well while others struggle or fail to adapt. The aims of this descriptive study were to explore how Korean mothers of children with DS perceive the adaptation of their typically developing (TD) children aged 4 to 19 and how family variables contribute to sibling adaptation. Method: This descriptive, cross-sectional study was conducted with 105 Korean mothers. Results: Most mothers indicated that their TD children were not experiencing psychological or behavioural problems; however, many described problems in the sibling relationship. It was found that family factors (i.e. condition management effort, condition management ability, child's daily life, parental mutuality, family hardiness and social support) were strong predictors of sibling psychological, behavioural and relational adaptation. Demographic characteristics of the child with DS, the mother and the family appeared to significantly influence sibling adaptation. Conclusions: These findings highlight the importance of familial contexts in understanding sibling adaptation. Knowledge of family factors associated with better adaptation in Korean siblings of child with DS will facilitate the development of culturally appropriate interventions for these children and their families. In addition, an awareness of demographic characteristics associated with sibling adaptation will help health care professionals identify siblings who are at increased risk of experiencing difficulties in adapting. © 2014 MENCAP and International Association of the Scientific Study of Intellectual and Developmental Disabilities and John Wiley & Sons Ltd.

Lee Y.M.,Kyungpook National University
Journal of Cellular Biochemistry | Year: 2011

Runt-related (RUNX) family proteins function as context-dependent transcription factors during developmental processes such as hematopoiesis, neurogenesis, and osteogenesis. RUNX3 is involved in a variety of physiological processes including neurogenesis, thymopoiesis, and dendritic cell maturation. A large amount of information indicates that RUNX3 may be a tumor suppressor. Recent data suggest that the molecular mechanism responsible for RUNX3 deficiency in numerous cancers is a primarily epigenetic silencing. The present review focuses on the regulation of RUNX3 gene expression by histone modification, emphasizing histone methylation at the RUNX3 promoter and inactivation of protein itself. Inactivation of the promoter and protein can be the results of various chemical modifications, including methylation by histone methyltransferase. Inactivation of RUNX3 may contribute to the tumor initiation, progression and pathogenesis in specific microenvironmental contexts. Finally, this review describes the reactivation of RUNX3 by epigenetic regulatory agents. © 2010 Wiley-Liss, Inc.

Park T.S.,Kyungpook National University | Kim S.-K.,Korea Aerospace Research Institute
Numerical Heat Transfer; Part A: Applications | Year: 2015

Computational tools of turbulent combustion have practical applications for various fields including liquid rocket engines, but some numerical issues are still presented for solving supercritical combustion. In the present study, several of these numerical issues are studied and discussed. Turbulent flow and thermal fields of gaseous hydrogen/cryogenic liquid oxygen flame at supercritical pressure are simulated by a turbulence model. To realize real-fluid combustions, the modified Soave-Redlich-Kwong (SRK) equations of state (EOS) are implemented into the flamelet model with a look-up table as functions of mean and variance of mixture fraction, scalar dissipation rate, enthalpy, and pressure. For supercritical combustion flows, modified forms of the pressure implicit with splitting of operator (PISO) algorithm for solving the pressure-velocity linked equation are introduced. From a comparison of instantaneous temperature distributions for gaseous hydrogen/cryogenic liquid oxygen flame at supercritical pressure, the capability of each method based on the different solution sequence is examined and the effective sequence is explored. The results show that the updated mixture fraction reflected in the pressure correction loop is a critical factor for numerical stability. Also, the relative performance of six convection schemes for supercritical combustion is discussed. Copyright © 2015 Taylor & Francis Group, LLC.

Kang I.M.,Kyungpook National University
Journal of Semiconductor Technology and Science | Year: 2010

The radio frequency (RF) model of SOI FinFETs with gate length of 40 nm is verified by using a 3-dimensional (3-D) device simulator. This paper shows the equivalent circuit model which can be used in the circuit analysis simulator. The RMS modeling error of Y-parameter was calculated to be only 0.3%.

Kim G.-W.,Kyungpook National University
Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering | Year: 2012

This paper presents a new systematic gear shift modelling approach for the real-time powertrain control and simulation of a multi-stepped automatic-transmission-based powertrain system such as parallel-type hybrid electric vehicles. The power/on 1 → 2 upshift modelling of a six-speed automatic transmision which is the main element of a Lepelletier-type planetary gear set is first performed to illustrate the procedure of the proposed gear shift modelling. A condensed algebraic formulation of the gear shift for each state is derived for a computationally efficient calculation based on the system matrix obtained from all governing equations. Finally, a non-linear shift simulation and brief open-loop shift control using MATLAB/Stateflow® are performed to demonstrate the effectiveness of the proposed gear shift model. © 2012 IMechE.

Bowles S.,Santa Fe Institute | Choi J.-K.,Kyungpook National University
Proceedings of the National Academy of Sciences of the United States of America | Year: 2013

The advent of farming around 12 millennia ago was a cultural as well as technological revolution, requiring a new systemof property rights. Among mobile hunter-gatherers during the late Pleistocene, food was almost certainly widely shared as it was acquired. If a harvested crop or the meat of a domesticated animal were to have been distributed to other group members, a late Pleistocene would-be farmer would have had little incentive to engage in the required investments in clearing, cultivation, animal tending, and storage. However, the new property rights that farming required-secure individual claims to the products of one's labor-were infeasible because most of the mobile and dispersed resources of a forager economy could not cost-effectively be delimited and defended. The resulting chicken-and-egg puzzle might be resolved if farming had been much more productive than foraging, but initially it was not. Our model and simulations explain how, despite being an unlikely event, farming and a new system of farming-friendly property rights nonetheless jointly emerged when they did. This Holocene revolution was not sparked by a superior technology. It occurred because possession of the wealth of farmers-crops, dwellings, and animals-could be unambiguously demarcated and defended. This facilitated the spread of new property rights that were advantageous to the groups adopting them. Our results thus challenge unicausal models of historical dynamics driven by advances in technology, population pressure, or other exogenous changes. Our approach may be applied to other technological and institutional revolutions such as the 18th- and 19th-century industrial revolution and the information revolution today.

Kim T.H.,Daegu Haany University | Ku S.-K.,Daegu Haany University | Bae J.-S.,Kyungpook National University
Food and Chemical Toxicology | Year: 2012

High mobility group box 1 (HMGB1) protein is secreted by activated cells of the innate immune system and/or released by injured tissues and necrotic cells; HMGB1 up-regulates proinflammatory cytokines in several inflammatory diseases. Kaempferol-3-O-sophoroside (KP) was isolated from the leaves of cultivated mountain ginseng. KP has antitumor, antioxidative, antiallergic and antidiabetic activities, but the effects of KP on HMGB1-mediated proinflammatory responses have not been studied. In this study, we monitored the effect of KP on the lipopolysaccharide (LPS)-mediated release of HMGB1 and the HMGB1-mediated modulation of proinflammatory responses in human endothelial cells. We found that KP potently inhibited the release of HMGB1 by LPS and inhibited LPS- or HMGB1-mediated barrier permeability and expression of cell adhesion molecules. Further studies revealed that KP inhibited cell surface receptor of HMGB1, toll-like receptor (TLR) 2/4, but not the receptor for advanced glycation end products (RAGE). Collectively, these results suggest that KP possesses anti-inflammatory responses against HMGB1-mediated proinflammatory responses, thereby endorsing its usefulness as a therapy for vascular inflammatory diseases. © 2011 Elsevier Ltd.

Qian W.,Michigan State University | Cha H.,Michigan State University | Cha H.,Kyungpook National University | Peng F.Z.,Michigan State University | Tolbert L.M.,University of Tennessee at Knoxville
IEEE Transactions on Power Electronics | Year: 2012

This paper presents an alternative to the traditional dc-dc converter interfacing the battery with the inverter dc bus in plug-in hybrid electric vehicle (HEV) traction drives. The boost converter used in commercial HEVs meets with obstacles when it comes to upgrading the power rating and achieving high efficiency while downsizing the converter. A four-level flying-capacitor dc-dc converter is explored that can overcome these drawbacks by dramatically reducing the inductance requirement. A special case of the four-level converter, the 3X dc-dc converter, operates at three discrete output/input voltage ratios, thus further reducing the inductance requirement to a minimal value (almost zero). When further compared to its switched-capacitor dc-dc converter counterparts, the 3X dc-dc converter can be operated at variable output/input voltage ratios without sacrificing efficiency, and it lowers the capacitance requirement by utilizing the parasitic inductance. The operating principle, current ripple analysis, the transient control to limit the inrush current, and power loss analysis are introduced. Experimental results of a 55-kW prototype are provided to demonstrate the principle and analysis of this topology. © 2011 IEEE.

Yoon J.P.,Kyungpook National University | Chung S.W.,Konkuk University | Kim S.H.,Seoul National University | Oh J.H.,Seoul National University
Journal of Shoulder and Elbow Surgery | Year: 2013

Hypothesis: The lift-off, internal rotation lag sign, belly-press, and bear-hug tests are widely used toevaluate the integrity of the subscapularis. We hypothesized that these tests might reflect different types of subscapularis tears and sought to ascertain whether these tests accurately determine the severity of the internal rotation strength deficit and fatty degeneration. Methods: Isokinetic testing and the 4 clinical tests were used preoperatively to evaluate 312 patients who had undergone arthroscopic rotator cuff surgery. Of these, 37 patients had a full-thickness subscapularis tear, 96had a partial-thickness tear, and 179 had no tear. Results: For differentiating any tears from an intact subscapularis, the most sensitive test was the belly-press test (27.8%), and the most specific test was the lift-off test (100%). For differentiating a full-thickness tear from a partial tear, the most sensitive test was the belly-press test (56.8%), and the most specific was the lift-off test (96.9%). A positive lift-off test also most reflected loss of internal rotation strength (mean, 72.2%; 95% confidence interval, 61.9-82.5), followed by the internal rotation lag sign (55.1%; 44.2-66.1) and the belly-press test (45.9%; 36.4-54.4). Conclusions: A positive lift-off test was highly specific for the detection of a full-thickness subscapularis tear and to reflect severe fatty degeneration. The lift-off, internal rotation lag sign, belly-press, and bear-hug tests sequentially predict internal rotation strength deficit and provide discrimination of internal rotation strength impairment. © 2013 Journal of Shoulder and Elbow Surgery Board of Trustees.

Jandieri V.,Kyungpook National University | Yasumoto K.,Nanjing Forestry University | Liu Y.,Nanjing Forestry University
Journal of the Optical Society of America B: Optical Physics | Year: 2012

Cylindrical electromagnetic bandgap structures excited by a dipole source are analyzed by a rigorous semianalytical method using the T-matrix approach and reflection and transmission matrices of cylindrical harmonic wave expansions as the basis. Resonance and stopband characteristics in the transmission spectra of the cylindrical bandgap structures for the excited cylindrical harmonic waves are studied. The relationship between the transmission spectra of the cylindrical harmonic waves and the radiation patterns of the dipole source in both H-plane and E-plane is numerically investigated for three different configurations of cylindrical bandgap structures and different locations of the dipole source with respect to the cylindrical bandgap structures. © 2012 Optical Society of America.

Jo D.,Kyungpook National University
Journal of Mechanical Science and Technology | Year: 2016

To predict local interfacial area in a packed bed under the trickling flow, a wavy annular flow model was developed by introducing the shape of waves in a thin liquid film. The trickling flowin a packed bed was approximated by an annular flow through a number of equivalent channels in which the continuous gas and liquid were completely separated by a wavy interface. Film thicknesses were measured by parallel wire probes to estimate the wave structure on the interface. By integrating the interfacial areas over a certain time period, the time-averaged local interfacial area was evaluated from a low to high interaction flow regime: 1) from trickling to bubbly flow and 2) from trickling to pulsing flow. The interfacial area predicted by the wavy annular flow model in the trickling flow was moderately higher than those predicted with the empirical correlations developed by others. The results show that the interfacial area increases more significantly as the flow regime changes from trickling to pulsing flow than that increases as the flow regime changes from trickling to bubbly flow. As a result, the wave structure on the interface should be considered to predict more accurate interfacial area in a packed bed. © 2016, The Korean Society of Mechanical Engineers and Springer-Verlag Berlin Heidelberg.

Park S.-Y.,Dongguk University | Kim J.-E.,Kyungpook National University
Gene | Year: 2013

Osterix (Osx) is a transcription factor required for osteoblast differentiation during intramembranous and endochondral ossification. Recently, several reports have described novel functions of Osx in chondrocyte differentiation. In an in vitro study, in which the effects of Osx gene silencing were examined in mouse chondrogenic ATDC5 cells, chondrocyte marker genes were found to be expressionally downregulated and chondrocyte differentiation reduced. On the other hand, in vivo studies based on chondrocyte-specific Osx knockouts demonstrated impaired endochondral bone formation with delayed chondrocyte differentiation and reduced cartilage matrix ossification. However, little is known about the mechanism or targets of Osx involved in the control of chondrocyte differentiation. Here, we attempted to high-density of Affymetrix GeneChip microarray to investigate global gene expression profile changes caused by Osx knockdown in ATDC5 chondrocytes. The mRNA expressions of 112 genes were significantly modified by Osx knockdown: 68 genes were upregulated and 44 genes downregulated. Functional categories of gene expression classified by gene ontology demonstrated that genes related to cell adhesion, development, and signal transduction were highly affected by Osx knockdown. The expressions of differential genes, such as Sfrp2, Sema3a, Nox4, Rgs4, Zfp521, Has2, Sox6, Scn2a1, Sirpa, and Thbs2, were validated by quantitative real-time PCR. This study shows that expression profiling can be used to identify genes that are transcriptionally modified following Osx knockdown and to reveal the molecular mechanism of chondrocyte differentiation regulated by Osx. © 2013 Elsevier B.V.

Lim D.,Kyungpook National University
Advanced Studies in Theoretical Physics | Year: 2015

The p-adic q-integral(or q-Volkenborn integration) was defined by Kim(see [9,10]). From p-adic q-integrals' equations, we can derive various q-extension of Bernoulli numbers and polynomials(see [1-21]). In [4], D.S.Kim and T.Kim have studied Daehee numbers and polynomials and their applications. For the twisted Daehee numbers and polynomials are investigate in [17]. In [11], Kim-Lee-Mansour-Seo introduced the q-analogue of Daehee numbers and polynomials which are called q-Daehee numbers and polynomials. In [16], Park investigated twisted version of Daehee polynomials as numbers with q-parameter, which related with usual Bernoulli numbers and polynomials. Lim considered in [13], the modified q-Daehee numbers and polynomials which are different from the q-Daehee numbers and polynomials of Kim-Lee-Mansour- Seo. For the twisted version of Daehee polynomials, In this paper, we give some useful properties and identities of twisted modified q-Daehee numbers and polynomials related with twisted q-Bernoulli numbers and polynomials. © 2015 Dongkyu Lim.

Hwang Y.H.,Konyang University | Kim M.K.,Konyang University | Kim D.W.,Kyungpook National University
Ophthalmology | Year: 2016

Purpose To investigate the prevalence, features, associated factors, and reproducibility of segmentation errors in macular ganglion cell inner plexiform layer (GCIPL) thickness measurement as determined by optical coherence tomography (OCT). Design Cross-sectional study. Participants Five hundred thirty-eight glaucomatous and healthy eyes from 290 subjects with OCT-measured macular GCIPL thickness were enrolled. Eyes with macular disorders, including epiretinal membrane, macular degeneration, macular hole, and myopic maculopathy, were excluded. Methods By inspecting 128 cross-sectional OCT B-scan images per eye, the presence (yes vs. no), layer (anterior vs. posterior border), location (quadrants), and area (diffuse vs. focal) of macular GCIPL segmentation error were investigated. The effects of age, refractive error, mean deviation of visual field test, circumpapillary retinal nerve fiber layer thickness obtained by OCT, and signal strength of OCT scan on the presence of macular GCIPL segmentation errors were evaluated. In eyes with segmentation errors, repeated OCT examinations were performed to investigate the reproducibility of the segmentation errors. Main Outcome Measures The prevalence, features, associated factors, and reproducibility of macular GCIPL segmentation errors were assessed. Results Among the 538 eyes, 52 eyes (9.7%) showed segmentation errors in macular GCIPL thickness measurement. The most common features of segmentation errors were that they affected both the anterior and posterior borders, were located at the nasal quadrant (centered to the fovea), and were diffuse. In univariate analysis, the presence of segmentation error was associated significantly with younger age (P < 0.001), higher degree of myopia (P < 0.001), and lower signal strength of OCT scan (P = 0.038). In multivariate analysis, only higher degree of myopia was associated significantly with the presence of segmentation error (P < 0.001). In repeated examinations, segmentation errors were reproducible in 24 eyes (46.2%). In other cases, the features of segmentation errors changed or disappeared. Conclusions Although the OCT segmentation algorithm accurately detected macular GCIPL thickness in most eyes without macular disorders, in some cases, segmentation errors were found, especially in myopic eyes. In repeated examinations, approximately half of the errors were nonreproducible. These findings should be considered when assessing macular GCIPL thickness using OCT. © 2016 American Academy of Ophthalmology.

Kim C.,Kyungpook National University | Johnson N.F.,University of Kentucky | Gold B.T.,University of Kentucky
Cortex; a journal devoted to the study of the nervous system and behavior | Year: 2014

Daily life requires people to monitor and resolve conflict arising from distracting information irrelevant to current goals. The highly influential conflict monitoring theory (CMT) holds that the anterior cingulate cortex (ACC) detects conflict and subsequently triggers the dorsolateral prefrontal cortex (DLPFC) to regulate that conflict. Multiple lines of evidence have provided support for CMT. For example, performance is faster on incongruent trials that follow other incongruent trials (iI), and is accompanied by reduced ACC and increased DLPFC activation (the conflict adaptation effect). In this fMRI study, we explored whether ACC-DLPFC conflict signaling can result in behavioral adjustments beyond on-line contexts. Participants completed a modified version of the Stroop conflict adaptation paradigm which tested for conflict adaptation effects on the current (N) trial associated with not only the immediately preceding (N - 1) trial, but also 2-back (N - 2) trials. Results demonstrated evidence for direct relationships between ACC activity on N - 2 trials and both N trial DLPFC activity and behavioral adjustment when intervening trials were congruent (i.e., icI). In contrast, when N - 1 trials were incongruent (i.e., iiI), ACC-DLPFC signaling failed and conflict adaptation was absent. These results provide new evidence demonstrating that the conflict monitor-controller maintains previously experienced conflict in the service of subsequent behavioral adjustment. However, the processing of multiple, temporally proximal conflict signals takes a toll on the working memory (WM) system, which appears to require resetting in order to adapt our behavior to frequently changing environmental demands. Copyright © 2013 Elsevier Ltd. All rights reserved.

Jeong H.-S.,Kangwon National University | Kim D.-W.,Hanyang University | Jeong Y.U.,Kyungpook National University | Lee S.-Y.,Kangwon National University
Journal of Power Sources | Year: 2010

To improve the thermal shrinkage of the separators that are essential to securing the electrical isolation between electrodes in lithium-ion batteries, we develop a new separator based on a ceramic composite membrane. Introduction of microporous, ceramic coating layers onto both sides of a polyethylene (PE) separator allows such a progress. The ceramic coating layers consist of nano-sized alumina (Al2O3) powders and polymeric binders (PVdF-HFP). The microporous structure of the ceramic coating layers is observed to be crucial to governing the thermal shrinkage as well as the ionic transport of the ceramic composite separators. This microporous structure is determined by controlling the phase inversion, more specifically, nonsolvent (water) contents in the coating solutions. To provide a theoretical basis for this approach, a pre-investigation on the phase diagram for a ternary mixture comprising PVdF-HFP, acetone, and water is conducted. On the basis of this observation, the effect of phase inversion on the morphology and air permeability (i.e. Gurley value) of ceramic coating layers is systematically discussed. In addition, to explore the application of ceramic composite separators to lithium-ion batteries, the influence of the structural change in the coating layers on the thermal shrinkage and electrochemical performance of the separators is quantitatively identified. © 2009 Elsevier B.V. All rights reserved.

Shin J.Y.,Yonsei University | Park H.J.,Yonsei University | Kim H.N.,Yonsei University | Oh S.H.,Yonsei University | And 3 more authors.
Autophagy | Year: 2014

Current evidence suggests a central role for autophagy in Alzheimer disease (AD), and dysfunction in the autophagic system may lead to amyloid-β (Aβ) accumulation. Using in vitro and in vivo AD models, the present study investigated whether mesenchymal stem cells (MSC s) could enhance autophagy and thus exert a neuroprotective effect through modulation of Aβ clearance In Aβ-treated neuronal cells, MSC s increased cellular viability and enhanced LC3-II expression compared with cells treated with Aβ only. Immunofluorescence revealed that MSC coculture in Aβ-treated neuronal cells increased the number of LC3-II -positive autophagosomes that were colocalized with a lysosomal marker. Ultrastructural analysis revealed that most autophagic vacuoles (AVs) in Aβ-treated cells were not fused with lysosomes, whereas a large portion of autophagosomes were conjoined with lysosomes in MSC s cocultured with Aβ-treated neuronal cells. Furthermore, MSC coculture markedly increased Aβ immunoreactivity colocalized within lysosomes and decreased intracellular Aβ levels compared with Aβ-treated cells. In Aβ-treated animals, MSC administration significantly increased autophagosome induction, final maturation of late AVs, and fusion with lysosomes. Moreover, MSC administration significantly reduced the level of Aβ in the hippocampus, which was elevated in Aβ-treated mice, concomitant with increased survival of hippocampal neurons. Finally, MSC coculture upregulated BEC N1/Beclin 1 expression in AD models. These results suggest that MSC s significantly enhance autolysosome formation and clearance of Aβ in AD models, which may lead to increased neuronal survival against Aβ toxicity. Modulation of the autophagy pathway to repair the damaged AD brain using MSC s would have a significant impact on future strategies for AD treatment.© 2014 Landes Bioscience.

Park J.,Kyungpook National University | Hopkins J.T.,Brigham Young University
Clinical Journal of Sport Medicine | Year: 2013

OBJECTIVE:: To examine the immediate effects of experimentally induced anterior knee pain (AKP) on involuntary and voluntary quadriceps strength and activation. DESIGN:: Crossover 3 × 3 randomized controlled laboratory study with repeated measures. SETTING:: Human Performance Research Center, Brigham Young University. PARTICIPANTS:: Thirteen neurologically sound volunteers (age, 21.9 ± 3.2 years). INTERVENTIONS:: Subjects underwent 3 different conditions (pain, sham, and control). To induce AKP and sham condition, 5% sodium chloride and 0.9% sodium chloride (total volume of 1.0 mL for each condition), respectively, were injected into the infrapatellar fat pad on the dominant leg. No injection was performed for the control condition. MAIN OUTCOME MEASURES:: The vastus medialis peak Hoffmann reflex normalized by the peak motor response (H:M ratio) was used to measure involuntary quadriceps activation. Quadriceps central activation ratio (CAR) using maximal isometric knee extension torque (N·m) was calculated to assess voluntary quadriceps activation. The visual analog scale was used to measure pain perception. RESULTS:: Our pain model increased perceived pain immediately after the 5% hypertonic saline injection and pain lasted for 12 minutes on average (F40,743 = 16.85, P < 0.001). During the pain condition, subjects showed a 12% decrease in H:M ratio (F2,59 = 8.64, P < 0.001), a 34% decrease in maximal isometric knee extension torque (F2,59 = 5.89, P < 0.01), and a 5% decrease in CAR (F2,59 = 3.83, P = 0.03). CONCLUSIONS:: Our data showed that joint pain may be an independent factor to alter function of the muscles surrounding the painful joint. Both involuntary and voluntary inhibitory pathways may play a role in an immediate reduction of muscle activation. © 2013 by Lippincott Williams & Wilkins.

Mallipeddi R.,Kyungpook National University | Suganthan P.N.,Nanyang Technological University
International Journal of Bio-Inspired Computation | Year: 2014

Unit commitment problem (UCP) which has a significant influence on secure and economic operation of power systems is considered to be one of the most difficult optimisation problems due to the number/type of variables and constraints present. To provide quality solutions to UCP several solution methodologies that include deterministic and stochastic search algorithms have been proposed. Deterministic and stochastic algorithms have their own share of advantages and disadvantages. In this paper, we provide a literature survey on the algorithms developed for UCP and try to compare their performance on some standard benchmark problems by taking the results from the literature. The literature survey along with the performance comparison will be useful for the researchers in the area of power engineering. Copyright © 2014 Inderscience Enterprises Ltd.

Jandieri V.,Kyungpook National University | Yasumoto K.,Kyushu University
IEEE Transactions on Antennas and Propagation | Year: 2011

A semi-analytical approach for analyzing two-dimensional electromagnetic scattering by layered cylindrical arrays of circular rods periodically distributed along concentrically layered circular rings is presented. The method uses the T-matrix of a circular rod in isolation, the reflection and transmission matrices of a cylindrical array expressed in terms of the cylindrical harmonic waves as the basis and the generalized reflection and transmission matrices for a layered cylindrical structure. Using the method, the scattering of plane waves impinging on the cylindrical arrays from the exterior region and the radiation from a line source located inside the cylindrical arrays are numerically investigated. Numerical examples demonstrate that the layered cylindrical arrays are effective for forming a directed beam in the scattered and radiated fields. © 2006 IEEE.

Jeon Y.,Kyungpook National University
Journal of Anesthesia | Year: 2012

Purpose: Pain on propofol injection is a common adverse effect. This study examined the effect of a combination of nitroglycerin and lidocaine on pain during propofol injection compared to lidocaine alone. Methods: In a double-blind, prospective trial, 90 patients scheduled to undergo elective plastic surgery were allocated randomly to three groups, to receive lidocaine 20 mg (n = 30), a combination of lidocaine 20 mg and nitroglycerin 0.1 μg/kg (n = 30), or normal saline as a placebo (n = 30), with venous occlusion for 1 min, followed by the administration of 25 % of the total calculated dose of propofol (2 mg/kg) into a dorsal hand vein. The pain intensity during the propofol injection was assessed using a four-point scale (0 = none, 1 = mild, 2 = moderate, 3 = severe). Hemodynamic variables-mean arterial pressure and heart rate-were measured during the preoperative and intraoperative periods. Results: A significantly higher proportion of patients in the placebo group (83 %) experienced pain compared to the lidocaine and combination groups (43 and 7 %, respectively; both, P < 0.01). The incidence of pain in the combination group was lower than that in the lidocaine group (P < 0.01). The pain score (median) was lower in the lidocaine (0) and combination (0) groups than in the placebo group (2); (P < 0.01). The hemodynamic variables were similar in the three groups. Conclusion: A combination of nitroglycerin 0.1 μg/kg and lidocaine 20 mg with venous occlusion for 1 min was more effective than lidocaine 20 mg alone in decreasing pain during propofol injection. © 2012 Japanese Society of Anesthesiologists.

Park C.-G.,Chonbuk National University | Hwang J.-C.,Kyungpook National University | Hwang J.-C.,Korea Institute for Advanced Study | Noh H.,Korea Astronomy and Space Science Institute
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012

Axion as a coherently oscillating scalar field is known to behave as cold dark matter in all cosmologically relevant scales. For conventional axion mass with 10 -5eV, the axion reveals a characteristic damping behavior in the evolution of density perturbations on scales smaller than the Solar System size. The damping scale is inversely proportional to the square root of the axion mass. We show that the axion mass smaller than 10 -24eV induces a significant damping in the baryonic density power spectrum in cosmologically relevant scales, thus deviating from the cold dark matter in the scale smaller than the axion Jeans scale. With such a small mass, however, our basic assumption about the coherently oscillating scalar field is broken in the early Universe. This problem is shared by other dark matter models based on the Bose-Einstein condensate and the ultralight scalar field. We introduce a simple model to avoid this problem by introducing evolving axion mass in the early Universe and present observational effects of a present-day low-mass axion on the baryon density power spectrum, the cosmic microwave background radiation temperature power spectrum, and the growth rate of baryon density perturbation. In our low-mass axion model, we have a characteristic small-scale cutoff in the baryon density power spectrum below the axion Jeans scale. The small-scale deviations from the cold dark matter model in both matter and cosmic microwave background radiation power spectra clearly differ from the ones expected in the cold dark matter model mixed with the massive neutrinos as a hot dark matter component. © 2012 American Physical Society.

Mantica C.A.,University of Milan | Suh Y.J.,Kyungpook National University
International Journal of Geometric Methods in Modern Physics | Year: 2016

In this paper we present some new results about n(≥ 4)-dimensional pseudo-Z symmetric space-times. First we show that if the tensor Z satisfies the Codazzi condition then its rank is one, the space-time is a quasi-Einstein manifold, and the associated 1-form results to be null and recurrent. In the case in which such covector can be rescaled to a covariantly constant we obtain a Brinkmann-wave. Anyway the metric results to be a subclass of the Kundt metric. Next we investigate pseudo-Z symmetric space-times with harmonic conformal curvature tensor: a complete classification of such spaces is obtained. They are necessarily quasi-Einstein and represent a perfect fluid space-time in the case of time-like associated covector; in the case of null associated covector they represent a pure radiation field. Further if the associated covector is locally a gradient we get a Brinkmann-wave space-time for n > 4 and a pp-wave space-time in n = 4. In all cases an algebraic classification for the Weyl tensor is provided for n = 4 and higher dimensions. Then conformally flat pseudo-Z symmetric space-times are investigated. In the case of null associated covector the space-time reduces to a plane wave and results to be generalized quasi-Einstein. In the case of time-like associated covector we show that under the condition of divergence-free Weyl tensor the space-time admits a proper concircular vector that can be rescaled to a time like vector of concurrent form and is a conformal Killing vector. A recent result then shows that the metric is necessarily a generalized Robertson-Walker space-time. In particular we show that a conformally flat (PZS)n, n ≥ 4, space-time is conformal to the Robertson-Walker space-time. © 2016 World Scientific Publishing Company.

Ha Y.-C.,Chung - Ang University | Cho M.-R.,Catholic University of Daegu | Park K.H.,Chung General Hospital | Kim S.-Y.,Kyungpook National University
Clinical Orthopaedics and Related Research | Year: 2010

Background: Prolonged use of bisphosphonates in patients with osteoporosis reportedly induces femoral insufficiency fractures. However, the natural course of these fractures and how to treat them remain unknown. Questions/purposes: We determined the rates of fracture displacement and subsequent operations of undisplaced insufficiency fractures of the femur in patients treated with prolonged bisphosphonate therapy. Patients and Methods: We retrospectively collected and reviewed the clinical course of 11 patients (14 fractures) who had been diagnosed as having an insufficiency fracture of the femur after prolonged use (mean, 4.5 years; range, 3-10 years) of bisphosphonate. All patients were women with a mean age of 68 years (range, 57-82 years). The fracture site was subtrochanteric in six and femoral shaft in eight. The minimum followup was 12 months (mean, 27 months; range, 12-60 months). Results: During the followup period, secondary displacement of the fracture occurred in five of the 14 fractures after a mean of 10 months (range, 1-19 months). Three fractures were treated with internal fixation using a compression hip screw and two with intramedullary nailing. Because five additional fractures were treated surgically owing to intractable pain, surgery was performed in 10 of 14 insufficiency fractures during the followup period. All 10 fractures healed during followup. The remaining four patients (four fractures) not undergoing any surgery had persistent pain. Conclusions: Femoral insufficiency fractures after prolonged bisphosphonate therapy seldom healed spontaneously and most patients had surgery either for fracture displacement or persistent pain. Level of Evidence: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence. © 2010 The Association of Bone and Joint Surgeons®.

Baek N.,Kyungpook National University
Wireless Personal Communications | Year: 2016

With modern integrated development environment, support for error reporting and debugging features becomes more important. In the case of 3D graphics libraries, the most widely used 3D graphics library of Open Graphics Library (OpenGL) has introduced the KHR debug extension, and it becomes the core feature of OpenGL version 4.3 and later. In contrast, existing OpenGL family implementations are lack of these features and hard to update the existing device drivers, including Raspberry Pi, Odroid, Arduino, etc. Especially, single board mobile computing devices are easy to lack up-to-date extensions for their existing system libraries. In this paper, we represent a dynamically-linked library (DLL) wrapping approach to support the KHR debug extension even on the old OpenGL ES 1.1 versions, which are most widely used on single board mobile computing devices. Our prototype implementation shows full features of the KHR debug extension and works well with existing OpenGL ES 1.1 application programs. This enhancement to the OpenGL ES 1.1 enables the application programmers to use more up-to-date debugging features with traditional graphics drivers. © 2016 Springer Science+Business Media New York

Park T.S.,Kyungpook National University
Journal of Supercritical Fluids | Year: 2012

Turbulent flows of liquid nitrogen jets at near-critical and supercritical pressures are investigated by turbulence models (RANS) and a large eddy simulation (LES). To consider real-fluid effects, two real-fluid equations of state (EOS) are implemented into the numerical procedure and the normalized static enthalpy is introduced to describe the turbulent mixing under supercritical conditions. The pressure-velocity-density coupling is obtained by the modified PISO algorithm. The relative performance of six convection schemes and the predictions of four turbulence models for the different EOSs are compared with the available data. From the results, the suitable adoption of real-fluid EOS is more significant than the selection of turbulence model for the numerical performance. Additionally, the effects of SGS models are examined for the LES predictions using the different EOSs. The importance of real-fluid EOS is similarly found in the LES results. The coherent structures are strongly dependent on the different EOSs than SGS models. The results display that the selected RANS models need to be extended for supercritical fluid flows. Finally, the effects of turbulence models and SGS models on the jet spreading rate are discussed. © 2012 Elsevier B.V.

Park S.S.,Kyungpook National University
Journal of the Korean Medical Association | Year: 2013

Currently, the number of reports of propofol abuse in the general population and among physicians has increased, arousing public concerns about drug abuse. It is especially easy for physicians to access various drugs, and thus they are prone to abuse drugs. However, the data on physicians' drug abuse in the Republic of Korea remains insufficient. In this article, we estimated the state of current drug abuse among the Korean general population and the assumed rate and tendency toward drug abuse among physicians based on published data. The current prevalence of drug abuse in Korea is around 4%, and the physicians' rate may not differ from that of the general population. According to the data on drug-related crime in Korea, 1% of such crimes are associated with medical personnel. Opioids are used more frequently by medical personnel than the general population (6.2% vs. 18.1%). Even though drug abuse is commonly related to personality problems and comorbid psychological disorders, social and environmental factors are also important. Burnout problems due to the stresses of a heavy workload in the hospital with sleep deprivation, rapidly expanding medical knowledge, and increasing government regulations are additional important causes of drug abuse among physicians. However, few studies on drug abuse and physician burnout have been performed in Korea. Although the rate of physicians' drug abuse is similar to that in the general population, the prevalence is disturbing because physicians are responsible for the health and well-being of the general population. Therefore, detailed research about physicians' drug abuse and burnout is needed, and proper solutions to prevent and treat drug abuse should be established. © Korean Medical Association.

This study examined the photocatalytic oxidation of gas-phase trichloroethylene (TCE) and 2-propanol, at indoor levels, over titanium dioxide (TiO2) irradiated with light-emitting diodes (LED) under different operational conditions. TiO2 powder baked at 450 °C exhibited the highest photocatalytic decomposition efficiency (PDE) for TCE, while all photocatalysts baked at different temperatures showed similar PDEs for 2-propanol. The average PDEs of TCE over a three hour period were four, four, five, and 51% for TiO2 powders baked at 150, 250, 350, and 450 °C, respectively. The average PDEs of 2-propanol were 95, 97, 98, and 96% for TiO2 powders baked at 150, 250, 350, and 450 °C, respectively. The ratio of anatase at 2Θ = 25.2° to rutile at 2Θ = 27.4° was lowest for the TiO2 powder baked at 450 °C. Although the LED-irradiated TiO2 system revealed lower PDEs of TCE and 2-propanol when compared to those of the eight watt, black-light lamp-irradiated TiO2 system, the results for the PDEs normalized to the energy consumption were reversed. Other operational parameters, such as relative humidity, input concentrations, flow rate, and feeding type were also found to influence the photocatalytic performance of the UV LED-irradiated TiO2 system when applied to the cleaning of TCE and 2-propanol at indoor air levels. © 2013 by the authors.

Bae J.-S.,Kyungpook National University
Food and Chemical Toxicology | Year: 2011

Phloroglucinol is the monomeric units of phlorotannins abundant in brown algae. Several biological effects of phloroglucinol have been reported, however, antithrombotic and profibrinolytic activities of phloroglucinol have not been studied yet. In this study, the anticoagulant properties of phloroglucinol were determined by assays of activated partial thromboplastin time (aPTT), prothrombin time (PT) and cell based thrombin and activated factor X (FXa) generation activities. And the effects of phloroglucinol on the expression of plasminogen activator inhibitor type 1 (PAI-1) and tissue-type plasminogen activator (t-PA) were tested in tumor necrosis factor-α (TNF-α) activated human endothelial cells (HUVECs). I found that phloroglucinol prolonged aPTT and PT significantly and inhibited thrombin and FXa generation in HUVECs. Furthermore, phloroglucinol inhibited TNF-α induced PAI-1 production. I then used pathway inhibitors to investigate which step of the TNF-α induced signaling pathway was targeted by phloroglucinol. I observed that the c-Jun N-terminal kinase (JNK) inhibitor increased the inhibitory effects of phloroglucinol, whereas the nuclear factor factor-κB (NF-κB) and the extracellular signal-regulated kinase (ERK) inhibitor did not. Therefore these results suggest that phloroglucinol possess antithrombotic and profibrinolytic activities and that NF-κB and ERK pathways are possible targets of phloroglucinol in the regulation of TNF-α stimulated PAI-1 production in HUVECs. © 2011 Elsevier Ltd.

Hwang J.-C.,Kyungpook National University | Noh H.,Korea Astronomy and Space Science Institute
Journal of Cosmology and Astroparticle Physics | Year: 2013

We prove that in the infinite speed-of-light limit (i.e., non-relativistic and subhorizon limits), the relativistic fully nonlinear cosmological perturbation equations in two gauge conditions, the zero-shear gauge and the uniform-expansion gauge, exactly reproduce the Newtonian hydrodynamic perturbation equations in the cosmological background; as a consequence, in the same two gauge conditions, the Newtonian hydrodynamic equations are exactly recovered in the Minkowsky background.

Noh H.,Korea Astronomy and Space Science Institute | Park C.-G.,Chonbuk National University | Hwang J.-C.,Kyungpook National University | Hwang J.-C.,Korea Institute for Advanced Study
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2013

We prove that the axion as a coherently oscillating scalar field acts as a cold dark matter (CDM) to the second-order perturbations in all cosmological scales including the super-horizon scale. The proof is made in the axion-comoving gauge. For a canonical mass, the axion pressure term causes deviation from the CDM only on scales smaller than the Solar System size. Beyond such a small scale the equations of the axion fluid are the same as the ones of the CDM based on the CDM-comoving gauge which are exactly identical to the Newtonian equations to the second order. We also show that the axion fluid does not generate the rotational (vector-type) perturbation even to the second order. Thus, in the case of axion fluid, we have the relativistic/Newtonian correspondence to the second order, even considering the rotational perturbation. Our analysis is made in the presence of the cosmological constant, and can be easily extended to the realistic situation including other components of fluids and fields. © 2013 Elsevier B.V.

Suh Y.J.,Kyungpook National University
Journal of Geometry and Physics | Year: 2010

In this paper, first we introduce the full expression for the Ricci tensor of a real hypersurface M in complex two-plane Grassmannians G2(Cm+2) from the equation of Gauss. Next we prove that a Hopf hypersurface in complex two-plane Grassmannians G2(Cm+2) with commuting Ricci tensor is locally congruent to a tube of radius r over a totally geodesic G2(Cm+1). Finally it can be verified that there do not exist any Hopf Einstein hypersurfaces in G2(Cm+2). © 2010 Elsevier B.V.

Park B.-D.,Kyungpook National University | Kadla J.F.,University of British Columbia
Thermochimica Acta | Year: 2012

This study investigated thermal degradation kinetics of multi-walled carbon nanotubes (MWCNTs) reinforced resole phenol-formaldehyde (PF) resin/cellulose nanocomposite, using thermogravimetry (TG) analysis as a function of the content or surface treatment of MWCNTs with or without a surfactant. FT-IR spectroscopy showed that the oxidation provided hydroxyl or carboxyl groups with MWCNT's surface while the silanization resulted in the silane attachment to MWCNT's surface. Conventional TG (CTG) thermograms demonstrated six thermal degradation steps, corresponding to various components of the nanocomposite, and also showed that the use of surfactant hastened thermal decomposition of the nanocomposite. The activation energy (E) obtained by the Kissinger method slightly increased as the MWCNT content increased while that of the cellulose degradation was independent on the MWCNT content. Both the oxidation and silanization treatments of MWCNTs' surface resulted in an increase of the E values compared to that of the control sample. The activation energy (E α) based on the isoconversional method increased up to α = 0.5, and then was rapidly elevated to fluctuations. The activation energy (E m) based on the temperature modulated TG (MTG) analysis was within the range of the E value calculated by the Kissinger method for the thermal degradation of cellulose, a main component of the nanocomposite. These results show that MTG method provides similar activation energy to that of CTG method for thermal degradation of the nanocomposite, and indicate that MTG method be efficiently used to obtain activation energy without many scans from multiple heating rates. © 2012 Elsevier B.V. All rights reserved.

This paper pertains to the use of topology optimization based on the internal element connectivity parameterization (I-ECP) method for nonlinear dynamic problems. When standard density-based topology optimization methods are used for nonlinear dynamic problems, they typically suffer from two main numerical difficulties, element instability and localized vibration modes. As an alterative approach, the I-ECP method is employed to avoid element instability and a new patch mass model in the I-ECP formulation is developed to control the problem of localized vibration modes. After the I-ECP based formulation is developed, the advantages of the proposed method are checked with several numerical examples. © 2009 Elsevier Ltd. All rights reserved.

Ahn C.,Kyungpook National University
Journal of High Energy Physics | Year: 2012

Starting from SO(N) current algebra, we construct two lowest primary higher spin-4 Casimir operators which are quartic in spin-1 fields. For N is odd, one of them corresponds to the current in the WB N-1/2 minimal model. For N is even, the other corresponds to the current in the WD N/2 minimal model. These primary higher spin currents, the generators of wedge subalgebra, are obtained from the operator product expansion of fermionic (or bosonic) primary spin- N/2 field with itself in each minimal model respectively. We obtain, indirectly, the three-point functions with two real scalars, in the large N 't Hooft limit, for all values of the 't Hooft coupling which should be dual to the three-point functions in the higher spin AdS 3 gravity with matter. © SISSA 2012.

Park J.-W.,Kyungpook National University
Advanced Studies in Theoretical Physics | Year: 2014

In this paper, we construct new q-extension of Bernoulli polynomials with weight α and weak weight β, and multiple Bernoulli polynomials with weight α and weak weights β1,..., βk. These q-Bernoulli polynomials are useful to study various identities of Carlitz's q-Bernoulli numbers. © 2014 Jin-Woo Park.

Lee S.J.,Kyungpook National University
The Korean journal of gastroenterology = Taehan Sohwagi Hakhoe chi | Year: 2011

Recent studies suggest that the prevalence of gastroesophageal reflux disease (GERD) is increasing in Korea. However, studies on risk factors for GERD have yielded inconsistent results. The aims of this study were to compare clinical features between symptomatic syndromes without esophageal injury (=non-erosive disease [NED]) and syndromes with esophageal injury (=erosive disease [ED]), and to determine risk factors associated ED. A total of 450 subjects who visited gastroenterology clinics of six training hospitals in Daegu from March 2008 to April 2010 were consecutively enrolled. The subjects were asked to complete a questionnaire which inquired about gastroesophageal reflux symptoms. The questionnaire also included questions about smoking, alcohol drinking, consumption of coffee, use of drugs, exercise, and other medical history. The subjects were subdivided into NED and ED groups. The proportion of subjects in each NED and ED group was 172 (38.2%) and 278 (61.8%). Male gender, smoking, alcohol drinking, consumption of coffee, large waist circumference, infrequent medication of antacids, aspirin and NSAIDs, infrequent and mild GERD symptoms were all significantly associated with ED on univariate analysis. Age, hiatal hernia, diabetes mellitus, body mass index, change in weight during 1 year, and number of typical GERD symptoms were not independent risk factors for ED. However, the association between ED and alcohol drinking, infrequent medication of antacids, mild typical GERD symptoms remained as strong risk factors after adjustments on multivariate logistic analysis. Independent risk factors associated with ED were alcohol drinking, infrequent medication of antacids and mild typical GERD symptoms.

Veluvolu K.C.,Kyungpook National University | Ang W.T.,Nanyang Technological University
Sensors | Year: 2011

Accurate filtering of physiological tremor is extremely important in robotics assisted surgical instruments and procedures. This paper focuses on developing single stage robust algorithms for accurate tremor filtering with accelerometers for real-time applications. Existing methods rely on estimating the tremor under the assumption that it has a single dominant frequency. Our time-frequency analysis on physiological tremor data revealed that tremor contains multiple dominant frequencies over the entire duration rather than a single dominant frequency. In this paper, the existing methods for tremor filtering are reviewed and two improved algorithms are presented. A comparative study is conducted on all the estimation methods with tremor data from microsurgeons and novice subjects under different conditions. Our results showed that the new improved algorithms performed better than the existing algorithms for tremor estimation. A procedure to separate the intended motion/drift from the tremor component is formulated. © 2011 by the authors; licensee MDPI, Basel, Switzerland.

Choi S.-I.,Kyungpook National University
Advanced Powder Technology | Year: 2016

Control over the shape of platinum nanocrystals has received great interests owing to their correlations with structure sensitive catalytic reactions such as CO/HC oxidation, NO x reduction, H2 oxidation, O2 reduction, and petroleum reforming. Pt octahedra and cubes are the well-known model catalysts for the low-index (111) and (100) faceted nanocrystals, respectively. In this work, a facile synthesis of Pt octahedra and cubes was conducted by manipulating the reduction kinetics. The reduction kinetics for the Pt precursor was altered by adjusting the volume ratio of oleylamine (OAm) and oleic acid (OAc) as the co-stabilizers and the coordination ligands in the reaction mixture. The morphologies of well-controlled Pt octahedra and cubes were observed by typical transmission electron microscopy. © 2016 The Society of Powder Technology Japan.

Choi M.-K.,Dankook University | Song I.-S.,Inje University | Song I.-S.,Kyungpook National University
Biopharmaceutics and Drug Disposition | Year: 2012

The study sought to investigate the effect of genetic variants of OCT1 (OCT1-P283L and -P341L) and OCT2 (OCT2-T199I, -T201M and -A270S), which were identified in a Korean population, on the transport of lamivudine in vitro and to compare the substrate dependent effects of OCT1 and OCT2 variants with 1-methyl-4-phenylpyridinium (MPP +), tetraethyl ammonium (TEA), metformin and lamivudine as substrates for these transporters. When the transport kinetics of lamivudine uptake in oocytes overexpressing OCT1 and OCT2 wild-type (WT) and variant proteins were measured, lamivudine uptake mediated by OCT1-WT was saturable, and uptake was decreased in oocytes expressing OCT1-P283L and -P341L variants compared with that in OCT1-WT. The Cl int of lamivudine in oocytes expressing OCT1-P283L was decreased by 85.1% compared with OCT1-WT, whereas it was decreased by 48.7% in oocytes expressing OCT1-P341L. The Cl int of lamivudine in oocytes expressing OCT2-T199I, -T201M and -A270S was decreased by 86.2%, 88.9% and 73.6%, respectively, compared with OCT2-WT. When comparing various substrates such as MPP +, TEA, metformin and lamivudine, the effects of the OCT1 genetic polymorphisms on their uptake were not identical. However, contrary to the case of OCT1, the uptake of MPP +, TEA, metformin and lamivudine in oocytes expressing OCT2-T199I, -T201M and -A270S variants was decreased significantly compared with that in oocytes expressing OCT2-WT. In conclusion, the effect of genetic variations of OCT1 and OCT2 on the uptake of MPP +, TEA, metformin and lamivudine was substrate-dependent. Copyright © 2012 John Wiley & Sons, Ltd.

Kim T.H.,Daegu Haany University | Ku S.-K.,Daegu Haany University | Bae J.-S.,Kyungpook National University
Journal of Cellular Biochemistry | Year: 2012

In order to develop new anticoagulant agents, two single compounds (eckol and dieckol) were isolated from Eisenia bicyclis and examined their anticoagulant activities by monitoring activated partial thromboplastin time (aPTT), prothrombin time (PT) as well as cell-based thrombin and activated factor X (FXa) generation activities. And the effects of eckol and dieckol on the expression of plasminogen activator inhibitor type 1 (PAI-1) and tissue-type plasminogen activator (t-PA) were tested in tumor necrosis factor-α (TNF-α) activated human umbilical vein endothelial cells (HUVECs). Data showed that eckol and dieckol prolonged aPTT and PT significantly and inhibited thrombin and FXa activities. They also inhibited the generation of thrombin or FXa in HUVECs. In accordance with these anticoagulant activities, eckol or dieckol showed anticoagulant effect in vivo. Furthermore, eckol and dieckol inhibited TNF-α induced PAI-1 production and the ratio between PAI-1 and t-PA was found to be significantly decreased by eckol and dieckol. Surprisingly, these anticoagulant and profibrinolytic effects of dieckol were better than those of eckol indicating that hydroxyl group in eckol positively regulated anticoagulant function of eckol. Therefore, these results suggest that eckol or dieckol possesses antithrombotic activities and provides a possibility to develop as an agent for the anticoagulation.© 2012 Wiley Periodicals, Inc.

Ahn B.-C.,Kyungpook National University
Clinical Nuclear Medicine | Year: 2016

Retrosternal goiter is one of the common causes of anterior mediastinal masses. Scintigraphic diagnosis of retrosternal goiter plays an important role in avoiding invasive diagnostic procedures, and SPECT acquisition may enhance the diagnostic sensitivity of this technique as compared with planar scintigraphy. Here, I report a case of retrosternal goiter that was demonstrated on SPECT/CT obtained with 99mTc pertechnetate, but not on planar scintigraphy with the same tracer. © 2015 Wolters Kluwer Health, Inc. All rights reserved.

Suh Y.J.,Kyungpook National University
Journal of Geometry and Physics | Year: 2013

In this paper we introduce a new notion of Reeb parallel Ricci tensor for real hypersurfaces in complex two-plane Grassmannians G2(Cm+2). Next we give a complete classification of Hopf real hypersurfaces in complex two-plane Grassmannians G2(Cm+2) with Reeb parallel Ricci tensor. © 2012 Elsevier B.V.

Park T.S.,Kyungpook National University
Numerical Heat Transfer; Part A: Applications | Year: 2013

Turbulent flows and related heat transfer in a regenerative cooling passage of liquid rocket engine are investigated by turbulence models. At a constant mass flow rate, threedimensional characteristics of flow and heat transfer are studied by changing the aspect ratio under constant or variable heat flux conditions. The cooling passage shows different flow structures, which cannot be found in a straight duct, because the heated wall has a convex-concave-convex curvature. So, the streamwise velocity and secondary flows are varied by the geometrical feature of curvature inversion. From these characteristics the thermal field in the cooling passage is discussed depending on the variation of crosssectional area and the aspect ratio. Also, the influences of aspect ratio coupled to the thermal boundary condition are investigated. Finally, the geometric effects on the local heat transfer and the change of flow structure are scrutinized. Copyright © Taylor & Francis Group, LLC.

Tuzlukov V.,Kyungpook National University
Circuits, Systems, and Signal Processing | Year: 2011

The generalized receiver (GR) based on a generalized approach to signal processing (GASP) in noise is investigated in a direct-sequence code-division multiple access (DS-CDMA) wireless communication system with frequency-selective channels. We consider four avenues: linear equalization with finite impulse response (FIR) beamforming filters; channel estimation and spatially correlation; optimal combining; and partial cancellation. We investigate the GR with simple linear equalization and FIR beamforming filters. Numerical results and simulation show that the GR with FIR beamforming filters surpasses in performance the optimum infinite impulse response beamforming filters with conventional receivers, and can closely approach the performance of GR with infinite impulse response beamforming filters. Channel estimation errors are taken into consideration so that DS-CDMA wireless communication system performance will not be degraded under practical channel estimation. GR takes an estimation error of a maximum likelihood (ML) multiple-input multiple-output (MIMO) channel estimation and GR spatially correlation into account in computation of minimum mean square error (MMSE) and log-likelihood ratio (LLR) of each coded bit. The symbol error rate (SER) performance of DS-CDMA employing GR with a quadrature sub-branch hybrid selection/maximal-ratio combining (HS/MRC) scheme for 1-D modulations in Rayleigh fading is obtained and compared with that of conventional HS/MRC receivers. Procedure of selecting a partial cancelation factor (PCF) for the first stage of a hard-decision partial parallel interference cancellation (PPIC) of the GR employed in DS-CDMA wireless communication system is proposed. A range of optimal PCFs is derived based on the Price's theorem. Computer simulation results show superiority in bit error rate (BER) performance that is very close to that potentially achieved and surpasses the BER performance of the real PCF for DS-CDMA systems discussed in literature. © 2011 Springer Science+Business Media, LLC.

Molecular imaging, defined as the visual representation, characterization and quantification of biological processes at the cellular and subcellular levels within intact living organisms, can be obtained by various imaging technologies, including nuclear imaging methods. Imaging of normal thyroid tissue and differentiated thyroid cancer, and treatment of thyroid cancer with radioiodine rely on the expression of the sodium iodide symporter (NIS) in these cells. NIS is an intrinsic membrane protein with 13 transmembrane domains and it takes up iodide into the cytosol from the extracellular fluid. By transferring NIS function to various cells via gene transfer, the cells can be visualized with gamma or positron emitting radioisotopes such as Tc-99m, I-123, I-131, I-124 and F-18 tetrafluoroborate, which are accumulated by NIS. They can also be treated with beta- or alpha-emitting radioisotopes, such as I-131, Re-186, Re-188 and At-211, which are also accumulated by NIS. This article demonstrates the diagnostic and therapeutic applications of NIS as a nuclear reporter gene for trafficking cells and a thera-peutic gene for treating cancers. © Ivyspring International Publisher.

Han O.H.,Korea Basic Science Institute | Han O.H.,Chungnam National University | Han O.H.,Kyungpook National University
Progress in Nuclear Magnetic Resonance Spectroscopy | Year: 2013

The article focuses on NMR investigations of electrochemical reactions and dynamic properties closely related to electrochemical reactions in low temperature FCs operating in acidic conditions such as polymer electrolyte membrane FCs and direct alcohol FCs, mainly reported over the last 10 years. The first in situ NMR investigation of FCs was carried out with a homemade toroid cavity detector NMR probe dedicated for in situ NMR analyses of the electrochemical reactions on the different anode catalysts, such as carbon supported PtRu, and Pt in real direct methanol FCs. Compounds in the anode exhausts of direct ethanol FCs have been detected under operating conditions by using high performance liquid chromatography and gas chromatography, however, sequential trapping of the electrochemical reaction products was necessary to convert the products to chemicals detectable by high performance liquid chromatography and a cold trap to collect anode products was used for the gas chromatography analyses.

Ahn C.,Kyungpook National University
Journal of High Energy Physics | Year: 2012

We consider N = 2 Kazama-Suzuki model on CP N = SU(N+1)/SU(N)×U(1). It is known that the N = 2 current algebra for the supersymmetric WZW model, at level k, is a nonlinear algebra. The N = 2 W 3 algebra corresponding to N = 2 was recovered from the generalized GKO coset construction previously. For N = 4, we construct one of the higher spin currents, in N = 2 W 5 algebra, with spins (2, 5/2, 5/2,3). The self-coupling constant in the operator product expansion of this current and itself depends on N as well as k explicitly. We also observe a new higher spin primary current of spins (3,7/2,7/2,4). From the behaviors of N = 2,4 cases, we expect the operator product expansion of the lowest higher spin current and itself in N = 2 W N+1 algebra. By taking the large (N, k) limit on the various operator product expansions in components, we reproduce, at the linear order, the corresponding operator product expansions in N = 2 classical W cl∞ algebra which is the asymptotic symmetry of the higher spin AdS 3 supergravity found recently. © 2012 SISSA.

Kim J.Y.,Chungnam National University | Kim S.Y.,Kyungpook National University
Investigative Ophthalmology and Visual Science | Year: 2011

PURPOSE. To compare the prophylactic effects of intravenous moxifloxacin and vancomycin for Staphylococcus epidermidis endophthalmitis in a rabbit model. METHODS. Albino rabbits (n = 60) were divided into three groups. Intravenous moxifloxacin was injected into 20 animals (group 1), and intravenous vancomycin was injected into 20 animals (group 2). In group 3, 20 animals received 0.9% normal saline. After these prophylactic intravenous injections, the right eyes of the 60 rabbits were injected intravitreally with 105 colony-forming units of S. epidermidis. Intravenous antibiotic injection was repeated on days 1, 2, and 3 after infection. Clinical features were evaluated on days 1, 3, 5, and 7 after infection, and 10 eyes per group were then enucleated for histopathologic examination. Vitreous aspirates were obtained for bacterial culture on days 1, 3, 5, and 7 after infection from the other 10 eyes per group. RESULTS. The moxifloxacin group showed significant clinical effects at days 1, 3, 5, and 7 (P =0.019, < 0.001, < 0.001, and < 0.001, respectively); bacteriologic results at days 1, 3, 5, and 7 (P = 0.001, 0.002, 0.01, and 0.002, respectively); and histopathologic results, with less severe inflammation and relatively well-preserved retinal architecture. However, no difference was detected between the vancomycin group and control group in any aspect examined. CONCLUSIONS. Intravenously administered moxifloxacin showed a significant prophylactic effect against S. epidermidis endophthalmitis. Thus, intravenous moxifloxacin may be a useful prophylactic medication against postoperative endophthalmitis. © 2011 The Association for Research in Vision and Ophthalmology, Inc.

Lee D.W.,Internal Medicine | Jeon S.W.,Kyungpook National University
Diagnostic and Therapeutic Endoscopy | Year: 2012

Popularity of endoscopic submucosal dissection (ESD) has shown an increase during the last decade, and may, for the time being, be the most important technique in treatment of early gastrointestinal cancer or a premalignant lesion. This technique has advantages in the aspect of en bloc resection, which enables evaluation of the completeness of resection and other pathologic characteristics; however, it has limitation in terms of complications, compared to endoscopic mucosal resection (EMR). Bleeding and perforation are the most common complications encountered during the procedure. These complications can cause embarrassment for the endoscopist and hamper performance of the procedure, which can result in an incomplete resection. To overcome these obstacles during performance of the procedure, we should be familiar with management of complications. In particular, beginners who start performing ESD should have full knowledge of and be in good handling of the method of hemostasis using hemoclips or electrocoagulation for management of complications. Various methods, procedures, and equipment are under development, which will provide us with powerful tools for achievement of successful ESD without complications in the near future. © 2012 Dong Wook Lee and Seong Woo Jeon.

Yang J.-M.,Kyungpook National University | Kwak S.W.,Keimyung University
Information Sciences | Year: 2014

This paper presents a control scheme for input/output asynchronous sequential machines with disturbance inputs. An unobservable and uncontrollable disturbance input can infiltrate into asynchronous machines and provoke unauthorized state transitions. We present the existence condition for a corrective controller that automatically counteracts the effects of disturbance inputs and restores desirable behavior to the controlled machine. Unlike input/state asynchronous machines, access to the machine's state is not available in the control procedure of input/output machines, so the control scheme requires state observation and fault detection modules. As a case study, the architecture of an asynchronous clock divider with the corrective controller is implemented and experimental verification on FPGA is provided for showing the applicability of the proposed controller. © 2013 Elsevier Inc. All rights reserved.

Jandieri V.,Kyungpook National University | Yasumoto K.,Kyushu University
Optics Communications | Year: 2011

A semi-analytical approach for a periodic planar array formed by a finite number of circular cylinders is presented using a model of layered cylindrical arrays. The method consists in extracting the reflection and transmission matrices of a cylindrically periodic array of circular cylinders and then obtaining the characteristics of layered structures by using a recursive formula. © 2011 Elsevier B.V. All rights reserved.

Veluvolu K.C.,Kyungpook National University | Soh Y.C.,Nanyang Technological University
IET Control Theory and Applications | Year: 2011

This study considers the design of sliding mode observers for fault reconstruction and state estimations. In the sliding-mode observer design the switching terms are designed such that the faults are tracked and reconstructed from their respective sliding surfaces. As the fault reconstruction relies only on output estimation error, the reconstruction can be performed online with the state estimation. The stability condition for the reduced-order system is analysed and the feedback gain is designed such that the reduced-order system is stable. An application example to robotic manipulator is examined to demonstrate the effectiveness of the proposed method in reconstruction of unknown inputs/faults. © 2011 The Institution of Engineering and Technology.

Tuzlukov V.,Kyungpook National University
Eurasip Journal on Advances in Signal Processing | Year: 2011

Symbol error rate (SER) of quadrature subbranch hybrid selection/maximal- ratio combining (HS/MRC) scheme for 1-D modulations in Rayleigh fading under employment of the generalized receiver (GR), which is constructed based on the generalized approach to signal processing (GASP) in noise, is investigated. N diversity input branches are split into 2 N in-phase and quadrature subbranches. M -ary pulse amplitude modulation, including coherent binary phase-shift keying (BPSK), with quadrature subbranch HS/MRC is investigated. GR SER performance for quadrature HS/MRC and HS/MRC schemes is investigated and compared with the conventional HS/MRC receiver. Comparison shows that the GR with quadrature subbranch HS/MRC and HS/MRC schemes outperforms the traditional HS/MRC receiver. Procedure of partial cancellation factor (PCF) selection for the first stage of hard-decision partial parallel interference cancellation (PPIC) using GR employed by direct-sequence code-division multiple access (DS-CDMA) systems under multipath fading channel in the case of periodic code scenario is proposed. Optimal PCF range is derived based on Price's theorem. Simulation confirms that the bit error rate (BER) performance is very close to potentially achieved one and surpasses the BER performance of real PCF for DS-CDMA systems discussed in the literature. © 2011 Vyacheslav Tuzlukov.

Yoon E.-J.,Kyungpook National University
Turkish Journal of Electrical Engineering and Computer Sciences | Year: 2011

Remote mutual authentication is an important part of security, along with confidentiality and integrity, for systems that allow remote access over untrustworthy networks, like the Internet. In 2006, Shieh-Wang pointed out the weakness of Juang's remote mutual authentication scheme using smart card and further proposed a novel remote user authentication scheme using smart card. However, this paper demonstrates that Shieh-Wang's scheme still does not provide perfect forward secrecy and is vulnerable to a privileged insider's attack. We also present an improved scheme based on the Elliptic Curve Diffie-Hellman problem (ECDHP) and secure one-way hash function, in order to isolate such security problems. © TÜBITAK.

BACKGROUND: The purpose of this study was to evaluate the prognostic implication of findings of intratumoral metabolic heterogeneity on pretreatment (18)F-FDG PET/CT scans in patients with invasive ductal carcinoma (IDC) of the breast.METHODS: One hundred and twenty-three female IDC patients who underwent pretreatment 18F-fluorodeoxyglucose positron-emission tomography/computed tomography ((18)F-FDG PET/CT) scans were retrospectively evaluated in this study. The heterogeneity factor (HF) defined as the derivative (dV/dT) of a volume threshold function from 40% to 80%, was computed for each primary tumor. Other metabolic PET parameters (maximum standardized uptake value [SUVmax], metabolic tumor volume [MTV], and total lesion glycolysis [TLG]) were measured. The HF was compared with clinicopathologic factors and other PET parameters. Univariate and multivariate analyses for the overall survival (OS) were performed.RESULTS: The HF ranged from 0.02 to 6.72 (mean, 0.35 ± 0.82) and significantly correlated with MTV (r = 0.955; p < 0.0001) and TLG (r = 0.354; p = 0.0001). The HF was significantly higher (implying more heterogeneity) in tumors with higher T and N stages. The optimal cut-off values for the OS determined using a receiver operating characteristic (ROC) curve were 0.34 for the HF, 5.6 for SUVmax, 8.55 cm(3) for MTV, and 14.43 for TLG. The OS rate among the 123 patients was 86.2%. T stage (1, 2 vs. 3, 4), N stage (0, 1 vs. 2, 3), M stage (0 vs. 1), ER status (+ vs. -), SUVmax (≤ 5.6 vs. > 5.6), MTV (≤ 8.55 cm(3) vs. > 8.55 cm(3)), TLG (≤ 14.43 vs. > 14.43), and HF (< 0.34 vs. ≥ 0.34) affected the OS on univariate analysis. After adjustment for the effects of TNM stage and ER status, the HF and MTV were significant predictors of OS. Among the PET parameters, the best prognostic factor for OS was the HF.CONCLUSIONS: Intratumoral metabolic heterogeneity correlated closely with the MTV and significantly affected the OS in IDC patients. The HF may act as a robust surrogate marker for the prediction of OS in IDC patients.

The aim of this study was to determine the efficacy of dietary administration of Lactobacillus pentosus PL11 on growth performance and the immune and antioxidant systems in Japanese eel Anguilla japonica challenged with Edwardsiella tarda. A total of 75 Japanese eels (24.63±0.83 g) were grouped into 5 treatment diets which were a control diet (C) without E. tarda and 4 treatment diets with E. tarda challenge, including C for E. tarda challenge (NC), C plus L. pentosus PL11 supplemented diet (108 cfu g-1) (T-PL11), C plus L. pentosus KCCM 40997 supplemented diet (108 cfu g-1) (T-Lp) and C plus Weissella hellenica DS-12 supplemented diet (108 cfu g-1) (T-Wh) for 5 weeks (4 week before and 1 week after challenge). The results showed enhanced growth performance in fish fed the diet containing L. pentosus PL11 compared to others. The growth performance parameters including specific growth rate (SGR) and weight gain (WG), feed intake (FI), feed conversion ratio (FCR) and survival were significantly (P<0.05) higher in fish maintained on L. pentosus PL11 supplemented diet compared to C and NC. T-PL11 group also shows a significant increase in the levels of plasma immunoglobulin M, CAT and SOD activities compared to NC. Hematological parameters and mieloperoxidase were significantly better in fish fed the L. pentosus PL11 supplemented diet than in the control. L. pentosus PL11 supplementation recover the reduced expression of SOD, CAT and heat shock protein 70 genes in liver and intestine in pathogen challenged fishes. In conclusion the result of the current study demonstrated L. pentosus PL11 potential as an alternative to antibiotic supplementation to improve the growth and health performance of Japanese eel (A. japonica). Copyright © 2012 Elsevier Ltd. All rights reserved.

Suk K.,Kyungpook National University
Expert Review of Proteomics | Year: 2010

Glial cells in the CNS are likely to communicate with other glial cells and neurons through secreted proteins. Glia-derived proteins also participate in neuroinflammation, which is a major component of neurodegenerative disease. Cerebrospinal fluid (CSF) is the biological fluid that best reflects the physiological or pathological conditions of the CNS. Proteins secreted from glial cells are often detected in the CSF. One of the major cellular sources of the highly abundant CSF proteins is glia. Combined analysis of secreted proteins of glial cells and CSF proteins of patients with inflammatory CNS disorders can provide new knowledge to the field of glia biology and neuron-glia interaction. The comparative analysis of the glia secretome and the CSF proteome would also facilitate the targeted proteomics-based discovery of new biomarkers for brain disease. Omics and systems biology approaches to glia and neuroinflammation will be a focus of future investigation and will enable an integrative understanding of inflammatory CNS disorders, such as neurodegenerative disease. © 2010 Expert Reviews Ltd.

Jung K.-H.,Yeungjin College | Yoo K.-Y.,Kyungpook National University
Information Sciences | Year: 2014

This paper proposes a new data hiding method for binary images that relies on block masking to distribute keys to two parts and then authenticates the right authorized part. The proposed method divides a cover image into small sub-blocks and designs key pairs that determine both where the bit is to be embedded and whether it is possible to embed it there. Furthermore, the key pairs are required to extract the secret data from the stego-image. Experimental results demonstrate a higher capacity and less distortion compared with previous methods since almost all data are hidden in the edge areas. © 2014 Elsevier Inc. All rights reserved.

Shin K.Y.,Kyungpook National University
The Korean journal of hepatology | Year: 2011

Radiofrequency ablation (RFA) is performed as an alternative to surgical resection for primary or secondary liver malignancies. Although RFA can be performed safely in most patients, early and late complications related to mechanical or thermal damage occur in 8-9.5% cases. Hemocholecyst, which refers to hemorrhage of the gallbladder, has been reported with primary gallbladder disease or as a secondary event associated with hemobilia. Hemobilia, defined as hemorrhage in the biliary tract and most commonly associated with accidental or iatrogenic trauma, is a rare complication of RFA. Here we report a case of hemocholecyst associated with hemobilia after RFA for hepatocellular carcinoma that was successfully managed by laparoscopic cholecystectomy.

Won K.A.,Kyungpook National University
Journal of orofacial pain | Year: 2012

To investigate nociceptive behavior and the immunoreactivity of microglia and phosphorylated-p38 (p-p38) mitogen-activated protein kinase (MAPK) following intracisternal administration of SB203580, a p38 MAPK inhibitor, or minocycline, a microglia inhibitor, in rats with temporomandibular joint (TMJ) inflammation. The number of nociceptive behavioral responses was recorded for nine successive 5-minute intervals following formalin injections into the left TMJ. SB203580 or minocycline was administered intracisternally 2 hours prior to the formalin injection. Statistical analysis used one-way analysis of variance followed by least significant difference post-hoc analysis. Results: The intra-articular injection of formalin increased the expression of p-p38 MAPK in the ipsilateral medullary dorsal horn. Most of the p-p38 MAPK co-localized with OX42, a microglial marker, but not with GFAP, an astrocyte marker. Intracisternal injections of SB203580 (0.5, 1, or 5 Μg) attenuated the number of nociceptive behavioral responses and the expression of p-p38 MAPK in the medullary dorsal horn. Intracisternal injections of minocycline (25 or 50 Μg) also attenuated the responses and the expression of OX42 and p-p38 MAPK in the medullary dorsal horn. These findings suggest that p38 MAPK in microglia plays an important role in the central processing of inflammatory TMJ nociception in rats. The data further indicate that a targeted blockade of the microglial p38 MAPK pathway is a potentially important new treatment strategy for inflammatory TMJ nociception.

Tuzlukov V.,Kyungpook National University
Digital Signal Processing: A Review Journal | Year: 2011

In this paper, we investigate a generalized receiver (GR) constructed on the basis of the generalized approach to signal processing (GASP) in noise employing by direct-sequence code-division multiple access (DS-CDMA) downlink wireless communication system with multipath fading. Transmitted signaling technique is based on using the orthogonal unified complex Hadamard transform spreading sequences. The use of GR allows us to maintain the orthogonality between users and reduce the multipath fading effect and interference from other users. A general multipath-fading model is assumed. Bit-error rate (BER) performance of system is evaluated by means of the signal-to-interference-plus- noise ratio (SINR) at the output of GR employed by DS-CDMA downlink wireless communication system. Using the orthogonal unified complex Hadamard transform spreading sequences as the transmitted signaling technique, we obtain that SINR at the GR output is independent of the phase offsets between different paths. If the Walsh-Hadamard (WH) spreading sequences are used as the transmitted signaling technique, the SINR at the output of GR employed by the same system is a function of squared cosine of path phase offsets. As a result, the BER performance of the last DS-CDMA downlink wireless communication system is worse in comparison with that of the first system. Comparative analysis between the BER performance of DS-CDMA downlink wireless communication systems employing both the GR and the Rake receiver, which consists of a bank of correlation receivers, with each individual receiver correlating with a different arriving multipath component, shows us a superiority of the first system over the second one both at high and low SINRs. © 2011 Elsevier Inc. All rights reserved.

Kim J.Y.,Kyungpook National University
The Korean journal of gastroenterology = Taehan Sohwagi Hakhoe chi | Year: 2011

Hepatocellular carcinoma (HCC) is one of the most common malignant neoplasms occuring worldwide. Although surgical resection still remains the treatment of choice for HCC, radiofrequency ablation (RFA) has emerged as reliable alternatives to resection. It is less invasive and can be repeated after short intervals for sequential ablation in case of multiple lesions. The most common complication of RFA is liver abscess, and bile duct injury such as bile duct stricture has been reported. This is a case report of a rare complication of abscesso-colonic fistula after RFA for HCC. The case was treated by percutaneous abscess drainage and antibiotics and occlusion of abscesso-colonic fistula with n-butyl-2-cyanoacrylate embolization.

Ahn C.,Kyungpook National University
Journal of Geometry and Physics | Year: 2012

The squashed and stretched 7-dimensional internal metric preserving U(1)×U(1)×U(1) R symmetry possesses an Einstein-Kahler 2-fold which is a base manifold of 5-dimensional Sasaki-Einstein L p,q,r space. The r(transverse to the domain wall)-dependence of the two 4-dimensional supergravity fields, that play the role of geometric parameters for squashing and stretching, makes the 11-dimensional Einstein-Maxwell equations consistent not only at the two critical points but also along the whole N=2 supersymmetric RG flow connecting them. The Ricci tensor of the solution has a common feature with the previous three 11-dimensional solutions. The 4-forms preserve only U(1) R symmetry for other generic parameters of the metric. We find an exact solution to the 11-dimensional Einstein-Maxwell equations corresponding to the lift of the 4-dimensional supersymmetric RG flow. © 2012 Elsevier B.V.

Vandenberg L.N.,Tufts University | Colborn T.,The Endocrine Disruption Exchange | Hayes T.B.,University of California at Berkeley | Heindel J.J.,U.S. National Institutes of Health | And 8 more authors.
Endocrine Reviews | Year: 2012

For decades, studies of endocrine-disrupting chemicals (EDCs) have challenged traditional concepts in toxicology, in particular the dogma of "the dose makes the poison," because EDCs can have effects at low doses that are not predicted by effects at higher doses. Here, we review two major concepts in EDC studies: low dose and nonmonotonicity. Low-dose effects were defined by the National Toxicology Program as those that occur in the range of human exposures or effects observed at doses below those used for traditional toxicological studies. Wereview the mechanistic data for low-dose effects and use a weight-of-evidence approach to analyze five examples from the EDC literature. Additionally, we explore nonmonotonic dose-response curves, defined as a nonlinear relationship between dose and effect where the slope of the curve changes sign somewhere within the range of doses examined. We provide a detailed discussion of the mechanisms responsible for generating these phenomena, plus hundreds of examples from the cell culture, animal, and epidemiology literature. We illustrate that nonmonotonic responses and low-dose effects are remarkably common in studies of natural hormones and EDCs. Whether low doses of EDCs influence certain human disorders is no longer conjecture, because epidemiological studies show that environmental exposures to EDCs are associated with human diseases and disabilities. We conclude that when nonmonotonic dose-response curves occur, the effects of low doses cannot be predicted by the effects observed at high doses. Thus, fundamental changes in chemical testing and safety determination are needed to protect human health. © 2012 by The Endocrine Society.

Choi Y.,Kyungpook National University
Proceedings - International Symposium on Software Reliability Engineering, ISSRE | Year: 2011

Model checking is an effective technique used to identify subtle problems in software safety. Its comprehensive search method on system state space provides high-level confidence regarding verification results, and its automated counterexample generation facility is a useful tool for tracing potential safety bugs. However, this comprehensiveness requires a large amount of resources and is often too expensive to be applied in practice. This work reports our experience with the software safety analysis of the Trampoline operating system using model checking. Trampoline OS is an open source operating system for automotive electronic/electrical devices based on the OSEK/VDX international standard. We present methods for converting the Trampoline kernel code into formal models and a series of experiments using an incremental verification approach. The conversion methods include functional modularization and treatment for hardware-dependent code, such as context-switching behavior. The incremental verification approach aims at increasing the level of confidence in the verification even when comprehensiveness cannot be provided due to the limitations of the hardware resource. We also report on a safety bug found in the Trampoline kernel during the experiments. © 2011 IEEE.

Park B.S.,Seoul National University | Song J.T.,Kyungpook National University | Seo H.S.,Seoul National University
Nature Communications | Year: 2011

Small ubiquitin-related modifier (SUMO) is a small polypeptide that modulates protein activity and regulates hormone signalling, abiotic and biotic responses in plants. Here we show that AtSIZ regulates nitrogen assimilation in Arabidopsis through its E3 SUMO ligase function. Dwarf plants of siz1-2 flower early, show abnormal seed development and have high salicylic acid content and enhanced resistance to bacterial pathogens. These mutant phenotypes are reverted to wild-type phenotypes by exogenous ammonium but not by nitrate, phosphate or potassium. Decreased nitrate reductase activity in siz1-2 plants resulted in low nitrogen concentrations, low nitric oxide production and high nitrate content in comparison with wild-type plants. The nitrate reductases, NIA1 and NIA2, are sumoylated by AtSIZ1, which dramatically increases their activity. Both sumoylated and non-sumoylated NIA1 and NIA2 can form dimers. Our results indicate that AtSIZ1 positively controls nitrogen assimilation by promoting sumoylation of NRs in Arabidopsis. © 2011 Macmillan Publishers Limited. All rights reserved.

Cho K.S.,Kyungpook National University
Korea Australia Rheology Journal | Year: 2012

We suggest a new interpretation on time-temperature superposition from the viewpoint of differential geometry and invented a viscoelastic function, called intrinsic phase angle, which is the arc length of the curve in plot of sinδ versus cosδ. The intrinsic phase angle gives a new master curve which is equivalent to conventional one without determination of shift factor. We also developed new plots based on the intrinsic phase angle and applied them to characterization of chain architecture of nonlinear polymers. Although new plots of intrinsic phase angle are similar to van Gurp-Palmen plot, they show the relation between structures of complex fluids and their rheology more clearly. © 2012 The Korean Society of Rheology and Springer.

Kwon Y.,Kookmin University | Lee J.,Kyungpook National University
Transportation Research Part A: Policy and Practice | Year: 2014

Previous research has examined asymmetric effects of fuel price uncertainty on energy demand. If we consider that energy demand is related to travel demand, the changes in fuel prices may have asymmetric effects on highway travel demand via fuel price uncertainty. In other words, when in general fuel price is steadily rising, the highway traffic volume decreases by a small percentage. On the other hand, the highway traffic volume increases by a large percentage when fuel prices are falling. We hypothesize that the uncertainty in fuel prices generates this kind of asymmetric effect on highway traffic volume in Korea. We use the Korean monthly fuel price and highway traffic volume data from 2001 to 2009, and define the intra-month (weekly) fuel price changes as monthly fuel price volatility which is a proxy for monthly fuel price uncertainty. We found that the direction of the change in fuel prices had asymmetric effects on highway travel demand and that the fuel price uncertainty led drivers to respond asymmetrically to the changes in fuel prices. © 2014 Elsevier Ltd.

Ju Y.-G.,Kyungpook National University
Optical and Quantum Electronics | Year: 2016

The tolerance of a free space optical interconnection was analyzed using the image motion method and a ray tracing software. The theoretical analysis indicated that the decentering between a vertical-cavity surface-emitting laser and a micro-lens is the most critical alignment error to the image motion and should be controlled carefully during fabrication. In addition, the reduced divergence angle due to the micro-lens reduced the sensitivity of the decentering error in a collimating lens to image motion. In addition, we suggest that the use of the alignment holes and balls on the substrate enables precise passive alignment between a VCSEL and micro-lens. © 2016, Springer Science+Business Media New York.

Choi Y.,Kyungpook National University
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2013

This work suggests a method for systematically constructing an environment model for automotive operating systems compliant with the OSEK/VDX international standard by introducing a constraint specification language, OSEK-CSL, and defining its underlying formal models. OSEK-CSL is designed for specifying constraints of OSEK/VDX using a pre-defined set of constraint types identified from the OSEK/VDX standard. Each constraint specified in OSEK-CSL is interpreted as a context-free language and is converted into push-down automata using NuSMV, which allows automated test sequence generation using LTL model checking. This approach supports selective applications of constraints and thus is able to control the "degree" of test sequences with respect to test purposes. An application of the suggested approach demonstrates its effectiveness in identifying safety problems. © 2013 Springer-Verlag.

Lee S.B.,Kyungpook National University
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2016

Surface growth by the conserved-noise restricted solid-on-solid model is investigated on diluted lattices, i.e., on percolation networks that are embedded in two spatial dimensions. The growth exponent β and the roughness exponent α are defined, respectively, by the mean-square surface width via W2(t)∼t2β and the mean-square saturated width via Wsat2(L)∼L2α, where L is the system size. These are measured on both an infinite network and a backbone network and the results are compared with power-counting predictions obtained using the fractional Langevin equation. While the Monte Carlo results on deterministic fractal substrates show excellent agreement with the predictions [D. H. Kim and J. M. Kim, Phys. Rev. E 84, 011105 (2011)PLEEE81539-375510.1103/PhysRevE.84.011105], the results on critical percolation networks deviate by 8%-12% from these predictions. © 2016 American Physical Society.

Lee S.B.,Kyungpook National University
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2014

The critical behavior of absorbing phase transitions for two typical models in the Manna universality class, the conserved Manna model and the conserved lattice gas model, both on a square lattice, was investigated using the natural initial states. Various critical exponents were estimated using the static and dynamic simulations. The exponents characterizing dynamics of active particles differ considerably from the known exponents obtained using the random initial states, whereas those associated with the steady-state quantities remain the same. The critical exponents for both models were consistent with errors of less than 1% and satisfied the known scaling relations; thus, the known violation of scaling relations for models with a conserved field was resolved using the natural initial states. The results differed by 7%∼12% from the directed percolation values. © 2014 American Physical Society.

Benetatos P.,Kyungpook National University
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2014

The statistical mechanics of polymers grafted on surfaces has been the subject of intense research activity because of many potential applications. In this paper, we analytically investigate the conformational changes caused by a single crosslink on two ideal (Gaussian) chains grafted onto a rigid planar surface. Both the crosslink and the surface reduce the number of allowed configurations. In the absence of the hard substrate, the sole effect of the crosslink is a reduction in the effective Kuhn length of a tethered chain. The crosslink-induced shrinkage (collapse) of the grafted chains (mushrooms) turns out to be a reduction in the variance of the distribution of the height of the chain rather than a reduction of the height itself. © 2014 American Physical Society.

Park H.,Kyungpook National University | Kim K.,Keimyung University
Alcohol and Alcoholism | Year: 2012

Aims: Alcohol consumption is known to be closely related with alterations in blood lipid levels as well as in blood pressure. The objective of this study was to evaluate the association between alcohol consumption and blood lipid levels in hypertensive men. Methods: A cross-sectional study involving participants (n = 2014) aged 20-69 years from the Korea National Health and Nutrition Examination Survey, 1998-2009. Demographic characteristics, dietary intake and medical history were obtained from the participants by questionnaire, and lipid levels were determined by analysis of blood samples. Results: After adjusting for demographic and dietary factors, alcohol consumption was negatively associated with risk of low high-density lipoprotein cholesterol [HDL-C; odds ratio (OR): 0.29, 95% confidence interval (CI): 0.22-0.40 in heavy (≥30 g/day) drinkers; P for trend <0.001], whereas the risk of high triglycerides increased with increasing alcohol consumption (OR: 2.04, 95% CI: 1.53-2.72 in heavy drinkers; P for trend <0.001). However, the OR of high non-HDL-C and the ratio of high triglycerides to HDL-C did not change significantly with an increase in alcohol consumption. Conclusion: These data suggest that alcohol consumption differentially affected lipid measures according to the amount of alcohol intake in hypertensive men. © The Author 2012. Medical Council on Alcohol and Oxford University Press. All rights reserved.

Choi C.H.,Kyungpook National University
Chemical Physics Letters | Year: 2012

A new definition of atomic charge, Mean Gradient Charge (MGC) is proposed on the basis of 'induced atomic gradient'. Conceptually the connection between electric response to external point charge and Coulomb's law made exact, providing a unique way of extracting atomic charges from quantum mechanical calculations without any numerical ambiguities. Furthermore MGC is relatively invariant with respect to molecular rotation, choices of basis set and even correlation treatments. Preliminary test calculations show that MGC values are in between Mulliken and NPA charges. © 2011 Elsevier B.V. All rights reserved.

Choi C.H.,Kyungpook National University | Fedorov D.G.,Japan National Institute of Advanced Industrial Science and Technology
Chemical Physics Letters | Year: 2012

The fragment molecular orbital (FMO) method is combined with the multipole method (MM) to reduce the quadratic scaling of the electrostatic terms. MM is applied to the energy and gradient of the well-separated interfragment interactions, and the gradient of the one electron electrostatic potential. The accuracy is controlled using the rigorous criteria based on the multipole expansion. Test calculations on ice surfaces using the 6-31G and 6-31++G basis sets show that MM is accurate and significantly accelerates FMO, although some quadratically scaling terms remain to be improved. © 2012 Elsevier B.V. All rights reserved.

Lee S.-H.,Kyungpook National University
Experimental and Therapeutic Medicine | Year: 2013

In this study, to assess whether aqueous and ethanol fractions of Angelica keiskei induce acute skin irritation and phototoxicity, acute skin irritancy and phototoxicity tests were performed. The skin of rabbits or guinea pigs was treated with these fractions (100 mg/dose) and whether the animals sustained significant skin damage was determined. The data demonstrated that the aqueous and ethanol fractions of Angelica keiskei did not induce acute toxicity in the skin of the animals, as assessed by anatomical and pathological observations. The results from the present study suggest that these aqueous and ethanol fractions of Angelica keiskei have promising potential uses as cosmetic ingredients that do not induce significant levels of skin irritation or phototoxicity.