Daegu, South Korea
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.

Time filter

Source Type

Kyungpook National University | Date: 2015-11-10

The present disclosure relates to a novel peptide for preventing or treating bone diseases. Further, the present disclosure relates to a polynucleotide encoding the peptide, a vector including the polynucleotide, a host cell transformed by the vector, and a method for producing the peptide by using the host cell. Furthermore, the present disclosure relates to a composition for preventing or treating bone diseases, including the novel peptide. The novel peptide according to the present disclosure induces mobilization of hematopoietic stem cells to blood and causes a decrease in the number of osteoclasts, and, thus, decreases bone erosion caused by osteoclasts, thereby suppressing progress of an osteoporotic lesion. Further, the novel peptide is safe since it does not cause rejection in the body. Furthermore, since the novel peptide is formed of 16 short amino acids, a low dose of the peptide can relieve symptoms of osteoporosis.

Kyungpook National University | Date: 2015-11-10

The present disclosure relates to a novel peptide for preventing or treating bone diseases. Further, the present disclosure relates to a polynucleotide encoding the peptide, a vector including the polynucleotide, a host cell transformed by the vector, and a method for producing the peptide by using the host cell. Furthermore, the present disclosure relates to a composition for preventing or treating bone diseases, including the novel peptide. The novel peptide according to the present disclosure induces mobilization of hematopoietic stem cells to blood and causes a decrease in the number of osteoclasts, and, thus, decreases bone erosion caused by osteoclasts, thereby suppressing progress of an osteoporotic lesion. Further, the novel peptide is safe since it does not cause rejection in the body. Furthermore, since the novel peptide is formed of 15 short amino acids, a low dose of the peptide can relieve symptoms of osteoporosis.

Providedis a method for estimating a disparity search range to which multi-level disparity image partition is applied, and a stereo image matching device using the same in that a disparity histogram of a previous disparity image is analyzed at the time of stereo matching of a continuous image, the disparity image is divided into various sizes of image blocks, and a disparity search range is estimated on the basis of a disparity value having the number of pixels equal to or more than a predetermined threshold value for each image block, thereby decreasing a calculation amount while improving a stereo matching rate of the next frame.

and Technology Inc. and Kyungpook National University | Date: 2017-04-05

An optical tracking system includes a marker part, an image forming part, and a processing part. The marker part includes a pattern having particular information and a first lens. First and second image forming parts include second and third lenses and first and second image forming units. The processing part determines the posture of the marker part from a first coordinate conversion formula between a coordinate on the pattern surface of a pattern and first pixel coordinate on a first image of the pattern, and a second coordinate conversion formula between a coordinate on the pattern surface of the pattern and second pixel coordinate on a second image of the pattern, the second coordinate conversion formula including the rotation conversion between the first pixel coordinate and the second pixel coordinate and tracks the marker part by using the posture of the marker part.

and Technology Inc. and Kyungpook National University | Date: 2017-04-05

An optical tracking system comprises a marker part, an image forming part, and a processing part. The marker part includes a pattern having particular information and a first lens which is spaced apart from the pattern and has a first focal length. The image forming part includes a second lens having a second focal length and an image forming unit which is spaced apart from the second lens and forms an image of the pattern by the first lens and the second lens. The processing part determines the posture of the marker part from a coordinate conversion formula between a coordinate on the pattern surface of the pattern and a pixel coordinate on the image of the pattern, and tracks the marker part by using the determined posture of the marker part. Therefore, the present invention can accurately track a marker part by a simpler and easier method.

Kyungpook National University | Date: 2017-03-15

The present invention relates to a mobile terminal system for the remote starting and management of a vehicle, and provides a mobile terminal system for the remote starting and management of a vehicle, the system comprising: a wrist watch terminal provided in a wrist watch form, generating a response signal by being converted from an idle state into an activated state when a wake-up signal wirelessly transmitted from the outside is received, wirelessly transmitting the response signal to the outside, and performing a task for communicating with a vehicle on the basis of a real-time operating system; and a vehicle terminal provided to the vehicle, wirelessly transmitting the wake-up signal to the outside of the vehicle, receiving the response signal wirelessly transmitted from the wrist watch terminal by responding to the wake-up signal, and controlling an operation of the vehicle by analyzing the response signal.

Kyungpook National University | Date: 2017-02-08

A bone traction device and a fracture reduction system including the same are disclosed. The disclosed bone traction device comprises: a base; a support vertically disposed on the base; a traction shaft provided at the support in a perpendicular direction and driven in forward and backward directions; and a double-joint part connected to the traction shaft so as to be bent in multiple stages with respect to the driving direction of the traction shaft.

The present invention provides a method for preparing an implant including preparing a mixed etching composition including hydrogen peroxide and a water-soluble carbonate compound and oxidatively etching an implant made of titanium or a titanium alloy by immersing the same in the etching composition; a titanium or titanium alloy implant prepared by oxidative etching with a mixed etching composition including hydrogen peroxide and a water-soluble carbonate compound; and a composition for treating surface of an implant containing hydrogen peroxide and a water-soluble carbonate compound. Further, the present invention relates to a titanium or titanium alloy implant which is prepared by oxidative etching with a mixed etching composition including hydrogen peroxide and a basic solution and on which surface bumps having continuous or discontinuous line-shaped open channel structures in nanoscale are irregularly formed, and a preparation method thereof. The surface of the titanium alloys treated with the mixed etching composition including hydrogen peroxide and a carbonate compound or the etching composition containing hydrogen peroxide and a basic solution of the present invention includes micrometer-sized bumps and channel-shaped nanometer-sized bumps, and thus has an increased surface area, and can not only improve wettability, but also effectively promote cell proliferation and osteocyte differentiation. In addition, the composition includes no chemical compounds such as a strong acid, etc. and is thus environmentally friendly, and such compounds can be prevented from remaining on the surface, which can improve biocompatibility, and therefore, the composition can be useful for implant surface treatment.

Kyungpook National University | Date: 2017-04-19

The present invention relates to a scintillator, method for manufacturing the same and applications of scintillator. The scintillator has a chemical formula of Tl_(2)ABC_(6):yCe, wherein A includes at least one alkali element; B includes at least one trivalent element; C includes at least one halogen element; and y is greater than 0 and equal to or smaller than 1.

Ali H.,Kyungpook National University | Park C.W.,Kyungpook National University
Journal of the Taiwan Institute of Chemical Engineers | Year: 2017

Malodorous emissions from industrial and household sewage systems cause harmful effects on nearby human populations and the environment. Eco-friendly malodor removing systems utilize bacteria to control unpleasant odors from sewage systems. Heat transfer is a vital factor in industrial system designs because microorganisms require an optimum water temperature to function efficiently. A numerical study was conducted to estimate the heat transfer rate in the water basin of a malodor removing system. Flow-deflecting baffles were utilized to reduce heat loss in the basin. Heat transfer was reduced by installing a rotating drum to increase gas dissolution by an improved liquid circulation. The average and local heat transfer coefficients, Nusselt number, and temperature distribution were evaluated to estimate heat loss in the water basin. This study proposes an empirical relation to generalize the numerical results for calculating heat transfer rates. Results showed that using baffles and rotating drum reduced heat transfer in the basin. Furthermore, the heat transfer coefficient was increased by raising the superficial gas velocity and bubble size. © 2017 Taiwan Institute of Chemical Engineers.

Atchudan R.,Yeungnam University | Edison T.N.J.I.,Yeungnam University | Perumal S.,Kyungpook National University | Lee Y.R.,Yeungnam University
Applied Surface Science | Year: 2017

Nitrogen-doped graphitic carbon sheets (N-GCSs) were prepared from the extract of unripe Prunus persica fruit by a direct hydrothermal method. The synthesized N-GCSs were examined by high resolution transmission electron microscopy (HRTEM), nitrogen adsorption-desorption isotherms, X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FT-IR) spectroscopy. HRTEM showed that the synthesized carbon sheets were graphitic with lattice fringes and an inter-layer distance of 0.36 nm. Doping with the nitrogen moiety present over the synthesized GCSs was confirmed by XPS, FT-IR spectroscopy, and energy dispersive X-ray spectroscopy elemental mapping. The fruit extract associated with hydrothermal-carbonization method is economical and eco-friendly with a single step process. The resulting carbon sheets could be modified and are promising candidates for nano-electronic applications, including supercapacitors. The synthesized N-GCSs-2 provided a high specific capacitance of 176 F g−1 at a current density of 0.1 A g−1. This electrode material has excellent cyclic stability, even after 2000 cycles of charge-discharge at a current density of 0.5 A g−1. © 2016 Elsevier B.V.

Khan A.A.,Kyungpook National University | Cha H.,Kyungpook National University
ECCE 2016 - IEEE Energy Conversion Congress and Exposition, Proceedings | Year: 2016

In this paper, a novel three-phase buck-boost ac-ac converter is proposed. It requires only three inductors and six switches. The proposed converter has no current shoot-through related problems and eliminates the PWM dead times, which results in greatly enhanced system reliability. The proposed converter allow the use of MOSFET without conducting body diode, therefore the reverse recovery issues and related loss of MOSFET body diode can be eliminated. The use of MOSFET in conjunction with external diode reduces the power loss, and the converter can be designed at higher switching frequency to reduce the volume of passive components. A 1 kW hardware prototype of the proposed three-phase buck-boost ac-ac converter is fabricated and tested. The detailed analysis followed by experimental results are provided to prove the novelty of the proposed converter. © 2016 IEEE.

Rath J.J.,Kyungpook National University | Defoort M.,University of Valenciennes and Hainaut‑Cambresis | Karimi H.R.,Polytechnic of Milan | Veluvolu K.C.,Kyungpook National University | Veluvolu K.C.,Nanyang Technological University
IEEE Transactions on Industrial Electronics | Year: 2017

The control of an automotive suspension system using hydraulic actuators is a highly complex nonlinear control task dealing with system nonlinearities, external disturbances, and uncertainties. In this work, an output feedback active suspension control scheme is proposed to achieve a ride comfort while maintaining the road holding for the vehicle. To design the controller, the states of the nonlinear system are first estimated using a highgain observer where the suspension stroke is the only measurable output. The controller is then designed using a recursive derivative nonsingular higher order terminal sliding mode approach that avoids singularity. The practical stability for the closed-loop observer-controller pair is established. Simulation results for the quarter-wheel vehicle over various road conditions demonstrate the effectiveness of the proposed control in improving the suspension performance in both the time and frequency domains. © 2016 IEEE.

Kim J.,Kyungpook National University | Han K.,Kyungpook National University
IET Communications | Year: 2017

Bluetooth low energy (BLE) has received much attention from researchers as one of the prominent solutions for short-range communication. The applications of BLE are growing rapidly and there are many issues to be resolved for establishing the deployment of it. Practically, BLE devices may experience a lot of collisions during discovery process due to contention among devices, particularly in a crowded environment. With an increasing number of BLE devices, discovery latency and energy consumption rise exponentially, which could degrade the quality of service required by user applications. In this study, the authors propose an enhanced discovery mechanism by employing a backoff strategy for BLE devices to reduce collisions during advertisement process. Through experimental and mathematical analysis, the proposed mechanism has shown its effectiveness in terms of discovery latency and energy consumption in crowded BLE networks. © The Institution of Engineering and Technology 2017.

Objective: Cases of a ruptured pericallosal artery aneurysm with a high risk of intraoperative premature rupture and technical difficulties for proximal vascular control require a technique for the early and safe establishment of proximal vascular control. Methods: A combined pterional or subfrontal approach exposes the bilateral A1 segments or the origin of the ipsilateral A2 segment of the anterior cerebral artery (ACA) for proximal vascular control. Proximal control far from the ruptured aneurysm facilitates tentative clipping of the rupture point of the aneurysm without a catastrophic premature rupture. The proximal control is then switched to the pericallosal artery just proximal to the aneurysm and its intermittent clipping facilitates complete aneurysm dissection and neck clipping. Results: Three such cases are reported: a ruptured pericallosal artery aneurysm with a contained leak of the contrast from the proximal side of the aneurysm, a low-lying ruptured pericallosal artery aneurysm with irregularities on its proximal wall, and a multilobulated ruptured pericallosal artery aneurysm with the parasagittal bridging veins hindering surgical access to the proximal parent artery. In each case, the proposed combined pterional-interhemispheric or subfrontal-interhemispheric approach was successfully performed to establish proximal vascular control far from the ruptured aneurysm and facilitated aneurysm clipping via the interhemispheric approach. Conclusion: When using an anterior interhemispheric approach for a ruptured pericallosal artery aneurysm with a high risk of premature rupture, a pterional or subfrontal approach can be combined to establish early proximal vascular control at the bilateral A1 segments or the origin of the A2 segment. © 2017 The Korean Neurosurgical Society.

Kim D.-C.,Kyungpook National University | Yeo S.-D.,Kyungpook National University
Korean Journal of Chemical Engineering | Year: 2017

The crystal habit of tamoxifen was modified using antisolvent crystallization techniques. Tamoxifen was crystallized from organic solvents using two different antisolvents (water and carbon dioxide). The habit of the precipitated crystals was modified by changing the process conditions, such as the solution and antisolvent mixing rate, the organic solvent, the presence of ultrasonic waves, and the addition of external additives. Particle size, crystal habit, particle aspect ratio and powder XRD patterns of the precipitated tamoxifen crystals were measured. With water as the antisolvent, the particle size of tamoxifen was significantly reduced compared to that of the raw material. When the antisolvent was carbon dioxide, the particle size was an order of magnitude greater than that of the raw material. The average aspect ratio of the tamoxifen crystals ranged from 1.8 to 16.2. The presence of ultrasonic waves caused a significant reduction in the aspect ratio, as well as the particle size. Furthermore, the addition of external additives was found to influence the crystal habit of tamoxifen. © 2017 Korean Institute of Chemical Engineers, Seoul, Korea

Jang J.-H.,Kyungpook National University | Park S.-Y.,Kyungpook National University
Sensors and Actuators, B: Chemical | Year: 2017

Functionalized cholesteric liquid crystal (CLC) double emulsion droplets (DEDs) were prepared from nematic LCs of MLC-2132 doped with (S)-4-cyano-4′-(2-methylbutyl)biphenyl (CB15) by using a microfluidic method, employing glass capillaries with a combined co-flow and flow-focusing geometry. Both planar (P) and homeotropic (H) anchoring on the surfaces of the CLC DEDs could be achieved using poly(vinyl alcohol) (PVA) and a mixture of sodium dodecyl sulfate (SDS)/polysorbate 80 (TWEEN 80), respectively. The H configuration was unstable when used with SDS alone, and hence required the use of a mixture of SDS and TWEEN 80. The P/P, P/H, H/P, and H/H configurations on the inner/outer surfaces exhibited different surface morphologies, which were observed in reflection-mode bright-field image patterns. The P/P configuration displayed a distinct, circular central spot with a reflection color that represented the helical pitch of the CLC, since the planar orientation of the mesogenic groups caused a parallel orientation of helical layers relative to the droplet surface, (which meets the Bragg reflection condition). The P/H, H/P, and P/P images observed from the same mode exhibited small, black circular spots assembled in a pseudo-hexagonal fashion, with reflected colored light coming from the boundary regions between the circular spots. This result indicated that the small, circular spots were due to the perpendicular orientation of the helical layers that resulted from the homeotropic orientation of the mesogenic groups (which does not meet the Bragg reflection condition). The CLC DEDs coated with poly(acrylic acid)-b-poly(4-cyanobiphenyl-4′-oxyundecylacrylate) (PAA-b-LCP) on the outer surface (CLC DEDPAA) were pH-responsive. When the inner surface was controlled to have a P configuration with water, the central, circular reflection color pattern changed to a small, black circular spot pattern with increasing pH. This indicated that protonation and deprotonation of the carboxylic group of PAA occurred, which in turn led to planar (tangential) and perpendicular (homeotropic) orientations, respectively. These pH-sensitive, mono-dispersed CLC DEDs have potential use as biosensors, where immobilization of the ligands causes local changes in pH in response to analytes. © 2016 Published by Elsevier B.V.

Saeed M.,Kyungpook National University | Kim M.-H.,Kyungpook National University
Applied Thermal Engineering | Year: 2017

Flow misdistribution that severely affects the thermal and hydraulic performance of heatsinks is caused by inefficient shapes of collector and distributor headers. In the current study, an analytical model has been developed and tested numerically ensuring uniform flow distribution of coolant within the heatsink channels while keeping the distributor and collector header sizes minimum. The mathematical model was coded in Matlab © and effects of the different geometric parameters on pressure drop in the header and on the size of the header have been reported. Proposed header shapes for different configurations of channel geometry were tested numerically using a commercial code ANSYS-CFX. Moreover, the thermal and hydraulic performance of the heatsink with proposed header geometries has been reported for different configurations of channel geometries. Also, with the intention of estimating the effectiveness of the header design, thermal and hydraulic performance of heatsinks with optimized headers were also compared with the performance of the heatsinks with conventional header designs. © 2016 Elsevier Ltd

Usman A.,Kyungpook National University | Park C.W.,Kyungpook National University
Tribology International | Year: 2017

A number of inevitable factors distort the liner circular bore, resulting in asymmetry of piston ring-liner (PRL) contact in the circumferential direction. The limited conformability of a piston ring causes a gap in PRL contact, which has significant effect on the tribological performance of the interface. Recent developments in ring surface modification through laser surface texturing have shown promising results in improving tribological characteristics. Analyses of a textured piston ring are often based on ideal circular liner bore, which is contrary to actual engine operating conditions. In this study, asymmetric PRL contact of a textured piston ring in a distorted bore is considered, and the 2D Reynolds equation is solved with a mass-conserving cavitation algorithm. In addition, asperity interaction in mixed lubrication, axial ring dynamics, variable ring conformability, and realistic engine oil rheology are considered in the investigation of tribological performance of a non-axisymmetric textured PRL interface. Results show that optimized surface textures improve the tribological performance of a PRL interface, whereas textures with large lateral aspect ratios have a detrimental effect. The surface texturing-induced increase in oil transport to the combustion chamber remains minimal. © 2016 Elsevier Ltd

Shbat M.S.,Kyungpook National University | Tuzlukov V.,Kyungpook National University
APCC 2012 - 18th Asia-Pacific Conference on Communications: "Green and Smart Communications for IT Innovation" | Year: 2012

A great problem for LTE networks employed large number of femtocells using the self optimization and configuration capabilities is to reduce the operational efforts. The handover process is a key element that has to be considered to improve efficiently the performance of the adopted femtocell technology and LTE network. This paper is devoted to a femtocell-to-femtocell handover approach based on simple feedback technique and existence of interface working as signalling system (SS). This interface allows us to exchange the priority lists and other signalling messages between femtocells, and helps us to overcome the drawbacks to use the public internet serving as control messages paths to handle the handover process. © 2012 IEEE.

Kim C.M.,Kyungpook National University | Kim G.M.,Kyungpook National University
Micromachines | Year: 2017

We present a 1600 parallel microchamber microfluidic device for fast sample array preparation using the immiscibility of two liquids. The trapping efficiency and size of the arrayed sample in the microchambers of a parallel microfluidic device were analyzed at various flow rates. The trapping efficiency of the sample was also inspected according to the position of the microchamber. Samples were successfully arrayed using the device. The trapping efficiency of the sample was 98.69% at 1 mL/h. The trapping efficiency and diameter of the sample decreased as the flow rate increased. Trapping efficiencies also changed according to the position of the microchambers. As the distance of the microchambers from the inlet increased, the sample trapping efficiency decreased. This tendency occurred more clearly at higher flow rates. © 2017 by the authors.

Baek N.,Kyungpook National University | Baek N.,Dassomey.com Inc.
Lecture Notes in Electrical Engineering | Year: 2017

OpenGL SC 2.0 is a newly specified 3D graphics standard, derived from the OpenGL ES 2.0, as its safety-critical profile. In this paper, we represent the high-level design scheme of the OpenGL SC 2.0 context and rendering system. We also show the detailed implementation strategy, for its step-by-step implementation works. These implementation schemes are the fundamental and theoretical frameworks for the OpenGL SC 2.0 system implementation. In near future, we will implement all the OpenGL SC 2.0 API functions and its theoretical background, from the OpenGL SC 2.0 system implementations. © Springer Nature Singapore Pte Ltd. 2017.

Oh J.,Kyungpook National University | Lee N.K.,Chonbuk National University
Biotechnology and Bioprocess Engineering | Year: 2017

Transactive response DNA binding protein 43 kDa (TDP-43, encoded by the TARDBP gene) is involved in transcriptional regulation and alternative splicing process. TDP-43 proteins are located in the nucleus and shuttles transcripts to the cytoplasm in normal neurons; however, they are observed in the forms of cytoplasmic inclusions in the degenerating cells. The abnormal accumulation of TDP-43 proteins is a pathologic feature of neurodegenerative diseases, such as Lou Gehrig’s disease and dementia including frontotemporal lobar degeneration and Alzheimer’s disease. In this study, we examined whether schizandrin, a main effective compound of Schisandra chinensis (Turcz.), so called omija in Korean, reduces TDP-43 accumulation in the hippocampal neurons in vitro. An immortalized mouse hippocampal neuronal cell line, HT22 cells, were treated with a proteasome inhibitor, MG132, in the absence or presence of schizandrin. We found that schizandrin treatment increased HT22 cell viability and reduced MG132-induced cytoplasmic accumulation of TDP-43. Our results suggest that schizandrin may be a promising compound for development of functional food materials beneficial to the neuronal protection against TDP-43 proteinopathies. © 2017, The Korean Society for Biotechnology and Bioengineering and Springer-Verlag Berlin Heidelberg.

Usman A.,Kyungpook National University | Park C.W.,Kyungpook National University
International Journal of Engine Research | Year: 2017

Road vehicles account for a substantial portion of energy consumed by transportation. A large amount of this energy is lost to overcome friction within vehicle engines, in which the piston compression rings are a major source of such parasitic losses. The internal losses of engines increase several times in the case of unfavorable warm-up conditions. Recent developments in surface modification showed promising results in improving the frictional behavior of piston rings. Analyses are often idealized, such as isothermal conditions and unrealistic engine operating conditions. This study presents a numerical investigation of the frictional behavior of mixed-hydrodynamic interaction in a textured piston compression ring-cylinder liner during the warm-up process. The transient Reynolds equation is solved with a mass-conserving cavitation algorithm, realistic oil rheology, and practical engine operating conditions. Several multigrade and monograde oils are considered to draw comprehensive conclusions. The results show that ring surface texturing substantially reduces energy loss during the entire warm-up phase. © Institution of Mechanical Engineers.

Aslam Noon A.,Kyungpook National University | Kim M.-H.,Kyungpook National University
Wear | Year: 2017

Sediment particles flowing through the turbine components erode the surface in interaction. Erosive wear of hydro turbine components generally depends on different parameters such as concentration, size and shape of the sediments particle, velocity of flow, properties of the base material of the turbine components and operating hours of the turbine. Tarbela Dam Hydel Project (TDHP) located in the Himalayan range in Pakistan is facing the same problem. The sediments particle have caused damage to the plant equipment, mainly to the turbine components; stay vanes, guide vanes, runner and draft tube. As a result, these components are disassembled and refurbished almost every year. Analysis have been performed on one of the Francis turbine units to predict the effect of sediment particles concentration, size and shape on erosion rate. Gradual removal of the base material has changed the profiles of various components of the turbine and also has weaken its structure. One of the major concerns of these effects is the continuous loss of turbine hydraulic efficiency. The governing equations of fluid flow are solved numerically on an unstructured grid using FEM based software ANSYS CFX. Finnie erosion model is used to compute average erosion rates. Simulation results are compared with the actual site data. The CFD analysis showed good agreement with the results of experimental work done previously using similar kind of geometries and operating conditions. © 2017 Elsevier B.V.

Choi K.S.,Kyungpook National University
Iranian Journal of Veterinary Research | Year: 2017

Bovine viral diarrhea virus (BVDV) is an economically important pathogen of the livestock industry worldwide. BVDV is classified into cytopathic (cp) and noncytopathic (ncp), depending on its effects on cultured cells. BVDV is known to alter the host's immune response. Of this, major histocompatibility complex (MHC) class II molecules play a central role in the development and function of the immune system, and are comprised of two types, DR and DQ, in cattle. In this study, we investigated the expression of MHC class II on monocytes infected with ncp BVDV1 or ncp BVDV2. Using flow cytometry (P < 0.01), mRNA level quantification (quantitative real time RT -PCR, P < 0.01), and western blot (P < 0.001), we found that the expressions of MHC class IIDQ was significantly decreased in ncp BVDV2-infected monocytes compared with that in ncp BVDV1-infected cells. Furthermore, interferon gamma (IFNγ) production was markedly decreased in ncp BVDV2-infected monocytes (P < 0.001) compared to those with ncp BVDV1 infection. These findings suggest that ncp BVDV2 causes reduced expressions of MHC class II DQ and a decreased production of IFNγ, resulting in evasion of immune recognition and suppression of the antiviral defense mechanism of the innate immune response. Consequently, the results demonstrate that ncp BVDV1 and ncp BVDV2 interact differently with the host innate immune response. Thus, our data provide insight into the mechanism by which, unlike ncp BVDV1, ncp BVDV2 impairs antigen presentation, fails to control the viral infection, and causes more severe disease.

Nawaz M.,Kyungpook National University | Miran W.,Kyungpook National University | Jang J.,Kyungpook National University | Lee D.S.,Kyungpook National University
Applied Catalysis B: Environmental | Year: 2017

In this study, the three-dimensional (3D) reduced graphene oxide/TiO2 (RGOT) aerogel was synthesized by a facile one-step hydrothermal treatment, and its photocatalytic efficiency was evaluated in the photodegradation of recalcitrant carbamazepine (CBZ) in aqueous solution. RGOT exhibited high adsorption and an almost two-fold higher photodegradation ability than bare TiO2 as more than 99% CBZ removal was observed within 90 min in 10 ppm aqueous solution of the latter. The mass ratio of TiO2 in the RGOT aerogel substantially affected CBZ adsorption and photocatalytic degradation, with the optimal TiO2/GO ratio in RGOT found to be 2:1. The chemical bonding between TiO2 and GO and the effective reduction of the latter during RGOT synthesis were also considered to achieve high photocatalytic efficiency, because the physical mixture of GO and TiO2 showed a lower photocatalytic CBZ degradation ability than bare TiO2. The macroporous 3D structure, abundant surface sites for anchoring the catalyst, effective charge separation, and mass transportation of CBZ near the photocatalyst surface are the attractive features of RGOT aerogels, promoting their use in resolving environmental issues. © 2016 Elsevier B.V.

Wahid A.,Kyungpook National University | Kim D.,Kyungpook National University
International Conference on ICT Convergence | Year: 2012

We propose a connectivity-based routing protocol (named CRP) for underwater wireless sensor networks (UWSNs). CRP considers the reliability issue due to high error rate in UWSNs. Hence, during forwarding, a node with the highest connectivity to the sink is selected as a next forwarding node. Using the NS-2 simulator, CRP is compared against a localization-free routing protocol in UWSNs (i.e. H2-DAB). Simulation results prove that CRP shows increased performance improvements over H2-DAB. © 2012 IEEE.

Kim S.-Y.,University of Ulsan | Park S.-P.,Kyungpook National University
Journal of Oral and Facial Pain and Headache | Year: 2016

Aims: To measure the prevalence of cutaneous allodynia in Korean patients with migraine and to characterize the differential risks of migraine-associated factors and psychiatric disorders in its development. Methods: The study included consecutive patients with migraine who visited headache clinics at two tertiary care hospitals. Questionnaires including the 12-item Allodynia Symptom Checklist (ASC-12) and the Migraine Disability Assessment (MIDAS) were administered to the patients. The Mini International Neuropsychiatric Interview-Plus, Version 5.0.0 (MINI), was performed to diagnose current major depressive disorder (MDD) and current generalized anxiety disorder (GAD). To determine the predictive factors of cutaneous allodynia, a two-step logistic regression model was used. Results: A total of 332 patients were eligible for the study. Chronic migraine (CM) was present in 140 patients (42.2%). Current MDD and current GAD were identified in 73 (21.9%) and 59 patients (17.7%), respectively. Cutaneous allodynia was present in 48 patients (14.5%). Univariate analyses indicated that cutaneous allodynia was associated with female gender, CM, medication overuse headache, headache intensity, photophobia, phonophobia, MIDAS grade, current MDD, and current GAD. Multivariate analyses revealed that current MDD was the strongest risk factor for cutaneous allodynia (adjusted odds ratio [AOR] = 4.552; 95% confidence intervals [CI] = 2.300-9.007; P = .000), followed by CM (AOR = 3.666; 95% CI = 1.787-7.521; P = .000) and photophobia (AOR = 2.707; 95% CI = 1.340-5.469; P = .005). Conclusion: Korean patients with migraine have a low prevalence of cutaneous allodynia. Both depression and migraine-associated features are important factors in the occurrence of cutaneous allodynia. © 2016 by Quintessence Publishing Co Inc.

Mantica C.A.,University of Milan | Suh Y.J.,Kyungpook National University
Reviews in Mathematical Physics | Year: 2017

In this paper, we study the properties of weakly conformally symmetric pseudo- Riemannian manifolds focusing particularly on the (Formula presented.)-dimensional Lorentzian case. First, we provide a new proof of an important result found in literature; then several new others are stated. We provide a decomposition for the conformal curvature tensor in (Formula presented.). Moreover, some important identities involving two particular covectors are stated; for example, it is proven that under certain conditions the Ricci tensor and other tensors are Weyl compatible. Topological properties involving the vanishing of the first Pontryagin form are then stated. Further, we study weakly conformally symmetric 4-dimensional Lorentzian manifolds (space-times): it is proven that one of the previously defined covectors is null and unique up to a scaling. Moreover, it is shown that under certain conditions, the same vector is an eigenvector of the Ricci tensor and its integral curves are geodesics. Finally, it is stated that such space-time is of Petrov type N with respect to the same vector. © 2017 World Scientific Publishing Company

Kang U.,Kyungpook National University | Park H.,Kyungpook National University
Journal of Materials Chemistry A | Year: 2017

The development of low-cost photocatalysts capable of selectively producing liquid chemicals from CO2 and water with efficiency and durability comparable to typical photosynthetic values remains a great challenge. Herein, we report a facile, environmentally benign synthesis of CuFeO2 and CuO binary films by electrodeposition, and demonstrate that these binary films produce only liquid formate from aqueous CO2 at ∼1% energy efficiency, while driving O2 evolution from water on a wired Pt plate under continuous irradiation of simulated sunlight (AM 1.5G; 100 mW cm-2) over 24 h. The formate production is confirmed by quantitative analysis of H13CO2 - produced from 13CO2. A time-resolved photoluminescence study reveals the sub-nanosecond charge transfer in binary CuFeO2 and CuO films, wherein the aqueous CO2 is adsorbed. An as-synthesized photocatalyst film with a three dimensional, double layer configuration shows the continued production of formate for over 17 d. However, the crystalline structure and elemental state of the used photocatalysts undergo gradual chemical reduction. Such a deformation can be thermally healed by recycling the weekly used samples via oxidative annealing. Thus, a single photocatalyst sample produces formate continuously for 35 d. © The Royal Society of Chemistry.

Lee H.,Kyungpook National University | Hwang J.-S.,National Academy of Agricultural Science | Lee D.G.,Kyungpook National University
Biochemical Journal | Year: 2017

Centipedes, a type of arthropod, reportedly produce antimicrobial peptides as part of an innate immune response. Scolopendin (SPSEKAGLQPVGRIGRMLKK) is a novel antimicrobial peptide derived from Scolopendra subspinipes mutilans. Many antifungal agents have more than one type of cell death mechanism. Although scolopendin is involved in membrane perturbation, the corresponding intracellular changes require further investigation. Therefore, we assessed the cell morphology and calcium ion concentration of the cytosol and mitochondria of scolopendin-treated cells. The treated cells were shrunken, and calcium ion homeostasis was disrupted in both the cytosol and mitochondria. These conditions attenuated mitochondrial homeostasis, disrupting mitochondrial membrane potential and cytochrome c levels. Fungal cells treated with scolopendin exhibited various apoptotic phenotypes such as reactive oxygen species accumulation, phosphatidylserine exposure, chromatin condensation, and nuclear fragmentation. Scolopendin-induced cell death also triggered metacaspase activation. In conclusion, treatment of Candida albicans with scolopendin induced the apoptotic response, which in turn led to mitochondrial dysfunction, metacaspase activation, and cell death. The antimicrobial peptide scolopendin from the centipede S.s. mutilans demonstrated a novel apoptotic mechanism as an antifungal agent. © 2017 The Author(s); published by Portland Press Limited on behalf of the Biochemical Society.

Jeong D.-U.,Yonsei University | Choi J.-Y.,Kyungpook National University | Kim D.-W.,Yonsei University
Journal of Cellular Physiology | Year: 2017

Nkx3.2, the vertebrate homologue of Drosophila bagpipe, has been implicated as playing a role in chondrogenic differentiation. In brief, Nkx3.2 is initially expressed in chondrocyte precursor cells and later during cartilage maturation, its expression is diminished in hypertrophic chondrocytes. In addition to Nkx3.2 expression analyses, previous studies using ex vivo chick embryo cultures and in vitro cell cultures have suggested that Nkx3.2 can suppress chondrocyte hypertrophy. However, it has never been demonstrated that Nkx3.2 functions in regulating chondrocyte hypertrophy during cartilage development in vivo. Here, we show that cartilage-specific and Cre-dependent Nkx3.2 overexpression in mice results in significant postnatal dwarfism in endochondral skeletons, while intramembranous bones remain unaltered. Further, we observed significant delays in cartilage hypertrophy in conditional transgenic ciTg-Nkx3.2 mice. Together, these findings confirm that Nkx3.2 is capable of controlling hypertrophic maturation of cartilage in vivo, and this regulation plays a significant role in endochondral ossification and longitudinal bone growth. J. Cell. Physiol. 232: 78–90, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Tran L.H.,Kyungpook National University | Jung S.,Kyungpook National University
International Journal of Molecular Sciences | Year: 2017

We examined the effects of light quality on growth characteristics and porphyrin biosynthesis of rice seedlings grown under different wavelengths from light emitting diodes (LEDs). After 10 days of exposure to various wavelengths of LEDs, leaf area and shoot biomass were greater in seedlings grown under white and blue LEDs than those of green and red LEDs. Both green and red LED treatments drastically decreased levels of protoporphyrin IX (Proto IX) and Mg-porphyrins compared to those of white LED, while levels of Mg-Proto IX monomethyl ester and protochlorophyllide under blue LED were decreased by 21% and 49%, respectively. Transcript levels of PPO1 were greatly upregulated in seedlings grown under red LED compared to white LED, whereas transcript levels of HO2 and CHLD were upregulated under blue LED. Overall, most porphyrin biosynthetic genes in the Fe-porphyrin branch remained almost constant or upregulated, while most genes in the Mg-porphyrin branch were downregulated. Expression levels of nuclear-encoded photosynthetic genes Lhcb and RbcS noticeably decreased after exposure to blue and red LEDs, compared to white LED. Our study suggests that specific wavelengths of LED greatly influence characteristics of growth in plants partly through altering the metabolic regulation of the porphyrin biosynthetic pathway, and possibly contribute to affect retrograde signaling. © 2017 by the authors. Licensee MDPI, Basel, Switzerland.

Jo W.-K.,Kyungpook National University | Kumar S.,Aston University | Isaacs M.A.,Kyungpook National University | Lee A.F.,Aston University | And 2 more authors.
Applied Catalysis B: Environmental | Year: 2017

A family of titania derived nanocomposites synthesized via sol-gel and hydrothermal routes exhibit excellent performance for the photocatalytic degradation of two important exemplar water pollutants, oxytetracycline and Congo Red. Low loadings of Co3O4 nanoparticles dispersed over the surfaces of anatase TiO2 confer visible light photoactivity for the aqueous phase decomposition of organics through the resulting heterojunction and reduced band gap. Subsequent modification of these Co3O4/TiO2 composites by trace amounts of graphene oxide nanosheets in the presence of a diamine linker further promotes both oxytetracycline and Congo Red photodegradation under simulated solar and visible irradiation, through a combination of enhanced photoresponse and consequent radical generation. Radical quenching and fluorescence experiments implicate holes and hydroxyl radicals as the respective primary and secondary active species responsible for oxidative photodegradation of pollutants. © 2016 Elsevier B.V.

Kim Y.G.,Kyungpook National University | Jo W.-K.,Kyungpook National University
International Journal of Hydrogen Energy | Year: 2017

In this study, photocatalytic hydrogen production over metal-incorporated CdS and ZnO (M/CdS/ZnO) nanocomposites under simulated solar light illumination was investigated. M/CdS/ZnO samples were synthesized by photodepositing a metal into CdS/ZnO powders. All photocatalysts showed increased hydrogen production with an increase in the light exposure time. The M/CdS/ZnO samples exhibited better hydrogen production yields than the CdS/ZnO nanocomposites, which in turn showed higher hydrogen production yields than pure ZnO did. The hydrogen production yields of the CdS/ZnO samples increased as the CdS/ZnO weight ratio increased from 0.01 to 0.10. However, they decreased with further increases in CdS loading, although the light absorption edges of the CdS/ZnO samples were further extended to the visible region. Pt/CdS/ZnO and Pd/CdS/ZnO exhibited similar hydrogen production yields, which were higher than the Ni/CdS/ZnO yield. The hydrogen production yield of Pt (0.5%)/CdS/ZnO was higher than that of Pt (0.1%)/CdS/ZnO. Notably, the hydrogen production yield of CdS/Pt/ZnO was lower than that of Pt/CdS/ZnO. Among three different electron donors (Na2S + Na2SO3, methanol, and lactic acid solutions), the Na2S + Na2SO3 solution led to the highest hydrogen production yield. A tentative mechanism for photocatalytic hydrogen production over M/CdS/ZnO nanocomposites under solar light irradiation, using a Na2S + Na2SO3 solution as an electron donor, was proposed. In summary, M/CdS/ZnO photocatalysts can be utilized efficiently for photocatalytic hydrogen production with solar light exposure through proper control of operating parameters. © 2017 Hydrogen Energy Publications LLC.

Khan M.,Kyungpook National University | Park S.-Y.,Kyungpook National University
Biosensors and Bioelectronics | Year: 2017

We developed a new technology that uses backscattering interferometry (BSI) to quantitatively measure nematic liquid crystal (NLC)-based biosensors, those usually relied on texture reading for on/off signals. The LC-based BSI comprised an octadecyltrichlorosilane (OTS)-coated square capillary filled with 4-cyano-4′-pentylbiphenyl (5CB, a nematic LC at room temperature). The LC/water interface in the capillary was functionalized by a coating of poly(acrylicacid-b-4-cyanobiphenyl-4′-oxyundecylacrylate) (PAA-b-LCP) and immobilized with the enzymes glucose oxidase (GOx) and horseradish peroxidase (HRP) through covalent linkage to the PAA chains (5CBPAA-GOx:HRP) for glucose detection. Laser irradiation of the LC near the LC/water interface resulted in backscattered fringes with high contrast. The change in the spatial position of the fringes (because of the change in the orientation of the LC caused by the GOx:HRP enzymatic reaction of glucose) altered the output voltage of the photodetector when its active area was aligned with the edge of one of the fringes. The change in the intensity at the photodetector allowed the detection limit of the instrument to be as low as 0.008 mM with a linear range of 0.02–9 mM in a short response time (~60 s). This LC-based BSI technique allows for quantitative, sensitive, selective, reproducible, easily obtainable, and interference-free detection in a large linear dynamic range and for practical applications with human serum. © 2016 Elsevier B.V.

Lee H.,Kyungpook National University | Shin M.,Kyungpook National University
BioData Mining | Year: 2017

Background: The problem of discovering genetic markers as disease signatures is of great significance for the successful diagnosis, treatment, and prognosis of complex diseases. Even if many earlier studies worked on identifying disease markers from a variety of biological resources, they mostly focused on the markers of genes or gene-sets (i.e., pathways). However, these markers may not be enough to explain biological interactions between genetic variables that are related to diseases. Thus, in this study, our aim is to investigate distinctive associations among active pathways (i.e., pathway-sets) shown each in case and control samples which can be observed from gene expression and/or methylation data. Results: The pathway-sets are obtained by identifying a set of associated pathways that are often active together over a significant number of class samples. For this purpose, gene expression or methylation profiles are first analyzed to identify significant (active) pathways via gene-set enrichment analysis. Then, regarding these active pathways, an association rule mining approach is applied to examine interesting pathway-sets in each class of samples (case or control). By doing so, the sets of associated pathways often working together in activity profiles are finally chosen as our distinctive signature of each class. The identified pathway-sets are aggregated into a pathway activity network (PAN), which facilitates the visualization of differential pathway associations between case and control samples. From our experiments with two publicly available datasets, we could find interesting PAN structures as the distinctive signatures of breast cancer and uterine leiomyoma cancer, respectively. Conclusions: Our pathway-set markers were shown to be superior or very comparable to other genetic markers (such as genes or gene-sets) in disease classification. Furthermore, the PAN structure, which can be constructed from the identified markers of pathway-sets, could provide deeper insights into distinctive associations between pathway activities in case and control samples. © 2017 The Author(s).

Kwak K.-H.,Kyungpook National University
Korean Journal of Anesthesiology | Year: 2017

Postdural puncture headache (PDPH) is a common complication after inadvertent dural puncture. Risks factors include female sex, young age, pregnancy, vaginal delivery, low body mass index, and being a non-smoker. Needle size, design, and the technique used also affect the risk. Because PDPH can be incapacitating, prompt diagnosis and treatment are mandatory. A diagnostic hallmark of PDPH is a postural headache that worsens with sitting or standing, and improves with lying down. Conservative therapies such as bed rest, hydration, and caffeine are commonly used as prophylaxis and treatment for this condition; however, no substantial evidence supports routine bed rest and aggressive hydration. An epidural blood patch is the most effective treatment option for patients with unsuccessful conservative management. Various other prophylactic and treatment interventions have been suggested. However, due to a lack of conclusive evidence supporting their use, the potential benefits of such interventions should be weighed carefully against the risks. This article reviews the current literature on the diagnosis, risk factors, pathophysiology, prevention, and treatment of PDPH. © the Korean Society of Anesthesiologists, 2017.

Ahn D.,Kyungpook National University | Sohn J.H.,Kyungpook National University | Jeon J.H.,Kyungpook National University
Journal of Clinical Endocrinology and Metabolism | Year: 2016

Context: Postoperative thyroid hormone replacement for hypothyroidism following hemithyroidectomy is usually administered without fully understanding the clinical characteristics of the condition. Objective: We aimed to evaluate the clinical characteristics of hypothyroidism following hemithyroidectomy, along with its actual incidence and risk factors. Design, Setting, and Patients: We conducted a retrospective cohort study involving 405 patients undergoing hemithyroidectomy between 2004 and 2011. The mean follow-up duration was 56.4 mo. Intervention: Standardized routine measurement of thyroid function at regular intervals, along with strict criteria for thyroid hormone replacement, was introduced. Main Outcome Measure: The development and clinical course of hypothyroidism following hemithyroidectomy including spontaneous normalization of thyroid function or the need for treatment were evaluated. Results: Hypothyroidism developed in 226 patients (55.8%) after hemithyroidectomy. A preoperative TSH level ≥ 2 mIU/L (odds ratio [OR], 5.517; 95% confidence interval [CI], 3.540-8.598; P < .001), and the coexistence of Hashimoto's thyroiditis (OR, 1.996; 95% CI, 1.107-3.601; P = .022) were found to be independent risk factors for the development of hypothyroidism. Among 222 subclinical hypothyroidism cases, 149 (67.1%) exhibited spontaneous recovery; subgroup analysis of these patients suggested that age ≥ 46 y (OR, 2.395; 95% CI, 1.266-4.533; P = .007) and preoperative TSH level ≥ 2.6 mIU/L (OR, 2.444; 95% CI, 1.330-4.492; P = .004) were independent risk factors for unrecovered subclinical hypothyroidism following hemithyroidectomy. Conclusions: The use of thyroid hormone replacement for subclinical hypothyroidism that develops after hemithyroidectomy should be carefully considered with close followup, while considering the likelihood of the spontaneous return to euthyroidism. Copyright © 2016 by the Endocrine Society.

Lee J.M.,Kyungpook National University
Diabetes and Metabolism Journal | Year: 2017

Chronic endoplasmic reticulum (ER) stress culminating in proteotoxicity contributes to the development of insulin resistance and progression to type 2 diabetes mellitus. Pharmacologic interventions targeting several different nuclear receptors have emerged as potential treatments for insulin resistance. The mechanistic basis for these antidiabetic effects has primarily been attributed to multiple metabolic and inflammatory functions. Here we review recent advances in our understanding of the association of ER stress with insulin resistance and the role of nuclear receptors in promoting ER stress resolution and improving insulin resistance in the liver. © 2017 Korean Diabetes Association.

Park D.,Kyungpook National University | Park J.-S.,Kyungpook National University
European Neurology | Year: 2017

Objective: The aim of this study was to analyze the pattern of trunk muscles involvement through a muscle MRI, in relation to the clinical data of patients diagnosed with myotonic dystrophy type 1 (DM1). Materials and Methods: Patients with DM1 who visited the neurology department were enrolled (n = 19). In all patients, the fatty degeneration of the muscle MRI in the lower cervical, upper thoracic, middle thoracic, and lumbosacral spine extensor muscle group and trunk flexor muscle group was evaluated. Clinical data, including CTG repeats, spinal deformity were analyzed to find the correlations with the fatty degeneration of trunk muscles in the muscle MRI. Results: All DM1 patients who presented with very mild to severe functional status showed T1-weghted high intensity signals in the upper-thoracic spine extensor muscle group. The sum MRI score of the spine extensor muscle group showed a significant correlation with the 6-min walking test, and Cobb's angle. Conclusions: DM1 frequently affects the trunk muscles, even in the early stage of disease progression, regardless of disease severity or age of onset. Among the para-vertebral muscles, the selective involvement of spine extensor muscles may explain the cause of spinal deformities, which mirrors the functional status of DM1. © 2017 S. Karger AG, Basel

BACKGROUND: Propofol is associated with pain during injection, which is stressful to patients. The present study was designed to investigate the analgesic effect of pretreatment with remifentanil and esmolol in minimizing propofol injection pain, compared with placebo.METHODS: In a randomized, double-blind, prospective trial, 120 patients, scheduled for elective dental surgery under general anesthesia, were randomized to 1 of the 4 treatment arms (n = 30 each) receiving normal saline, remifentanil 0.35 μg/kg, esmolol 0.5 mg/kg, and 1 mg/kg before administration of propofol. During injection of 1% propofol 0.5 mg/kg, pain was evaluated by a 4-point score (0 = none, 1 = mild, 2 = moderate, 3 = severe). Any adverse effects such as hypotension and bradycardia were recorded during the perioperative periods.RESULTS: In all, 120 patients completed this study. There were no significant differences in terms of demographic data. The incidence of pain on injection of propofol was 11 (36.7%) with remifentanil 0.35 μg/kg, 12 (40%) with esmolol 0.5 mg/kg, and 11 (36.7%) with esmolol 1 mg/kg, compared with 25 (83.3%) with normal saline (respectively, P < 0.05). There were no significant differences in the incidence of pain between groups with remifentanil 0.35 μg/kg, and esmolol 0.5 mg/kg and 1 mg/kg. There were no emergence reactions such as hypotension and bradycardia in all groups.CONCLUSIONS: Pretreatment with esmolol 0.5 mg/kg and 1 mg/kg and remifentanil 0.35 μg/kg equally decreased pain during propofol injection.

Kim P.,Kyungpook National University | Kim S.,Kyungpook National University
Physica A: Statistical Mechanics and its Applications | Year: 2017

Most complex networks contain community structures. Detecting these community structures is important for understanding and controlling the networks. Most community detection methods use network topology and edge density to identify optimal communities; however, these methods have a high computational complexity and are sensitive to network forms and types. To address these problems, in this paper, we propose an algorithm that uses an interaction optimization process to detect community structures in complex networks. This algorithm efficiently searches the candidates of optimal communities by optimizing the interactions of the members within each community based on the concept of greedy optimization. During this process, each candidate is evaluated using an interaction-based community model. This model quickly and accurately measures the difference between the quantity and quality of intra- and inter-community interactions. We test our algorithm on several benchmark networks with known community structures that include diverse communities detected by other methods. Additionally, after applying our algorithm to several real-world complex networks, we compare our algorithm with other methods. We find that the structure quality and coverage results achieved by our algorithm surpass those of the other methods. © 2016 Elsevier B.V.

In unstructured wireless sensor networks (WSNs), which consist of a dense collection of sensor nodes deployed randomly, the communication and processing capabilities of sensor nodes can be limited owing to their small embedded batteries and available bandwidth. Power management is therefore one of the most important issues to consider in the implementation of WSNs. As a result, decentralized detection, in which the fusion center makes the final decision to use data partially processed by local nodes, is more attractive than centralized detection in unstructured WSNs. This paper proposes a more efficient and effective method for solving the power allocation problem as a constrained optimization problem: to schedule power allocation in a distributed WSN using correlated observations and amplify-and-forward local processing at sensor nodes so that the WSN detects a constant signal while maintaining a sufficient fusion error probability threshold. To accomplish this goal, this paper proposes using Deb’s method, which does not require a penalty parameter when handling the constraints of the optimization problem. Additionally, representative optimization algorithms based on swarm intelligence are used, i.e., particle swarm optimization, ant colony optimization for continuous domains ((Formula presented.)), and artificial bee colony. Through a simulation, their performance is compared for several different WSNs to determine the best algorithm for solving the power allocation problem. © 2017 Springer Science+Business Media New York

News Article | May 4, 2017
Site: www.cemag.us

A recent study, affiliated with UNIST, has proposed the possibility of in situ human health monitoring simply by wearing a contact lens with built-in wireless smart sensors. This study has been jointly conducted by Professor Jang-Ung Park of Materials Science and Engineering, Professor Chang Young Lee of Life Science, and Professor Franklin Bien of Electrical and Computer Engineering at UNIST in collaboration with Professor Hong Kyun Kim of Ophthalmology and Professor Kwi-Hyun Bae of Internal Medicine at Kyungpook National University (KNU). In the study, the research team unveiled a smart contact lens sensor that could help monitor biomarkers for intraocular pressure (IOP), diabetes mellitus, and other health conditions. The research team expects that this research breakthrough could lead to the development of biosensors capable of detecting and treating various human diseases, and used as a component of next-generation smart contact lens-related electronic devices. Diabetes is the most common cause of high blood sugar levels. Hyperglycemia is a condition in which an excessive amount of glucose circulates in the blood plasma. If this condition persists for more than two hours, a patient will be diagnosed with diabetes. Since blood sugar can be measured with tears, many attempts have been made to monitor diabetes with contact lenses. Despite numerous studies in the last several decades, the biggest drawback with conventional smart contact lenses was thought to be poor wearability. The electrodes used in existing smart contact lenses are opaque, and therefore obscure the view when wearing it. Moreover, because they lens-shaped firm plastic material, many people complain of comfort issues with contact lens wear which made wearing them impossible. Park and his research team solved these issues by developing a sensor based on transparent and flexible materials. Their new smart contact lens sensors use electrodes made of highly stretchable and transparent graphene sheets and metal nanowires. Using this sensor, patients with diabetes and glaucoma may one day be able to self-monitor blood glucose levels and eye pressure. Through the embedded wireless antenna in the contact lens sensor, patients can also transmit their health information, which allows real-time monitoring of their health conditions, as well. In addition, because the system uses wireless antenna to read sensor information, no separate power source, like battery is required for the smart contact lens sensors.

News Article | April 17, 2017
Site: www.materialstoday.com

From an electron's point of view, graphene must be a hair-raising thrill ride. For years, scientists have observed that electrons can blitz through graphene at velocities approaching the speed of light, far faster than they can travel through silicon and other semiconducting materials. Graphene, therefore, has been touted as a promising successor to silicon, potentially leading to faster, more efficient electronic and photonic devices. But manufacturing pristine graphene – a single, perfectly flat, ultrathin sheet of carbon atoms, precisely aligned and linked together like chicken-wire – is extremely difficult. Conventional fabrication processes often generate wrinkles, which can derail an electron's bullet-train journey, significantly limiting graphene's electrical performance. Now engineers at Massachusetts Institute of Technology (MIT) have found a way to make graphene with fewer wrinkles, and to iron out those wrinkles that do still appear. After fabricating and then flattening out the graphene, the researchers tested its electrical conductivity. They found each sheet exhibited uniform performance, meaning that electrons flowed freely across the sheet, at similar speeds, even across previously wrinkled regions. In a paper published in the Proceedings of the National Academy of Sciences, the researchers report that their techniques successfully produce wafer-scale ‘single-domain’ graphene – single layers of graphene that are uniform in both atomic arrangement and electronic performance. "For graphene to play as a main semiconductor material for industry, it has to be single-domain, so that if you make millions of devices on it, the performance of the devices is the same in any location," says Jeehwan Kim, assistant professor in the departments of Mechanical Engineering and Materials Science and Engineering at MIT. "Now we can really produce single-domain graphene at wafer scale." Kim's co-authors include Sanghoon Bae, Samuel Cruz and Yunjo Kim from MIT, along with researchers from IBM, the University of California at Los Angeles and Kyungpook National University in South Korea. The most common way to make graphene involves chemical vapor deposition (CVD), a process in which carbon atoms are deposited onto a crystalline substrate such as copper foil. Once the copper foil is evenly coated with a single layer of carbon atoms, scientists submerge the entire thing in acid to etch away the copper. What remains is a single sheet of graphene, which researchers then pull out from the acid. Unfortunately, the CVD process can result in the formation of relatively large, macroscropic wrinkles in the graphene, due to the roughness of the underlying copper itself and the process of pulling the graphene out from the acid. The alignment of carbon atoms is not uniform across the graphene, creating a ‘polycrystalline’ state in which graphene resembles an uneven, patchwork terrain, preventing electrons from flowing at uniform rates. In 2013, while working at IBM, Kim and his colleagues developed a method for fabricating wafers of single-crystalline graphene, in which the orientation of the carbon atoms is exactly the same throughout a wafer. Rather than copper foil, his team produced single-crystalline graphene on a silicon carbide wafer with an atomically smooth surface, albeit with tiny, step-like wrinkles on the order of several nanometers. They then used a thin sheet of nickel to peel off the top-most graphene from the silicon carbide wafer and place it on a silicon wafer, in a process known as layer-resolved graphene transfer. In their new paper, Kim and his colleagues discovered that, with a slight modification, this layer-resolved graphene transfer process can iron out the steps and tiny wrinkles in silicon carbide-fabricated graphene. Before transferring the layer of graphene onto a silicon wafer, the team oxidized the silicon, creating a layer of silicon dioxide that naturally exhibits electrostatic charges. When the researchers then deposited the graphene, the silicon dioxide effectively pulled graphene's carbon atoms down onto the wafer, flattening out its steps and wrinkles. Kim says this ironing method would not work on CVD-fabricated graphene, as the wrinkles generated through CVD are much larger, on the order of several microns. "The CVD process creates wrinkles that are too high to be ironed out," Kim notes. "For silicon carbide graphene, the wrinkles are just a few nanometers high, short enough to be flattened out." To test whether the flattened, single-crystalline graphene wafers were single-domain, the researchers fabricated tiny transistors on multiple sites on each wafer, including across previously wrinkled regions. "We measured electron mobility throughout the wafers, and their performance was comparable," Kim says. "What's more, this mobility in ironed graphene is two times faster. So now we really have single-domain graphene, and its electrical quality is much higher [than graphene-attached silicon carbide]." Kim says that while there are still challenges to adapting graphene for use in electronics, the group's results give researchers a blueprint for how to reliably manufacture pristine, single-domain, wrinkle-free graphene at wafer scale. "If you want to make any electronic device using graphene, you need to work with single-domain graphene," Kim says. "There's still a long way to go to make an operational transistor out of graphene. But we can now show the community guidelines for how you can make single-crystalline, single-domain graphene." This story is adapted from material from MIT, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

News Article | May 4, 2017
Site: phys.org

This study has been jointly conducted by Professor Jang-Ung Park of Materials Science and Engineering, Professor Chang Young Lee of Life Science, and Professor Franklin Bien of Electrical and Computer Engineering at UNIST in collaboration with Professor Hong Kyun Kim of Ophthalmology and Professor Kwi-Hyun Bae of Internal Medicine at Kyungpook National University (KNU). In the study, the research team unveiled a smart contact lens sensor that could help monitor biomarkers for intraocular pressure (IOP), diabetes mellitus, and other health conditions. The research team expects that this research breakthrough could lead to the development of biosensors capable of detecting and treating various human diseases, and used as a component of next-generation smart contact lens-related electronic devices. Diabetes is the most common cause of high blood sugar levels. Hyperglycemia is a condition in which an excessive amount of glucose circulates in the blood plasma. If this condition persists for more than two hours, a patient will be diagnosed with diabetes. Since blood sugar can be measured with tears, many attempts have been made to monitor diabetes with contact lenses. Despite numerous studies in the last several decades, the biggest drawback with conventional smart contact lenses was thought to be poor wearability. The electrodes used in existing smart contact lenses are opaque, and therefore obscure the view when wearing it. Moreover, because they lens-shaped firm plastic material, many people complain of comfort issues with contact lens wear which made wearing them impossible. Professor Park and his research team solved these issues by developing a sensor based on transparent and flexible materials. Their new smart contact lens sensors use electrodes made of highly stretchable and transparent graphene sheets and metal nanowires. Using this sensor, patients with diabetes and glaucoma may one day be able to self-monitor blood glucose levels and eye pressure. Through the embedded wireless antenna in the contact lens sensor, patients can also transmit their health information, which allows real-time monitoring of their health conditions, as well. In addition, because the system uses wireless antenna to read sensor information, no separate power source, like battery is required for the smart contact lens sensors. Intraocular pressure measurement can be achieved using the dielectric layers. The dielectric layer is an electrically non-conductive layer, characterized by polarity that divides both positive and negative charges. The thickness of this layer changes from thinning as the intraocular pressure increases, to thickening as the intraocular pressure decreases. The IOP sensor, embedded in the contact lenses senses this and transmits the information to the wireless antenna. According to the research team, their newly-developed smart lenses with built-in pressure-sensing and glucose-monitoring sensors could still detect blood glucose and IOP despite the deformation of the contact lenses. The sensor characteristics were also maintained even when exposed to various substances in human tears. "It was observed that the live rabbit did not show any abnormal behavior when wearing the contact lens sensor," says Joohee Kim (Combined M.S./Ph.D. student of Materials Science and Engineering), the first author of the study. The contact lens sensor characteristics are not changed when the lens is deformed. Even when the sensor exposed to various materials in human tears the characteristics were maintained, and flexibility and stretchability were also excellent. Furthermore, since the electronic sensor is inserted into the soft contact lens, the feeling of wearing it is also excellent. "This study can be used to diagnose diseases (diabetes and glaucoma) by implementing two types of transparent electronic sensors in the production of smart contact lens sensors," said Professor Park. "We are now a step closer to the implementation of a fictional idea for a smart contact lens in the films, like "Minority Report" and "Mission: Impossible". More information: Joohee Kim et al, Wearable smart sensor systems integrated on soft contact lenses for wireless ocular diagnostics, Nature Communications (2017). DOI: 10.1038/ncomms14997

News Article | May 4, 2017
Site: www.eurekalert.org

A recent study, affiliated with UNIST has proposed the possibility of in situ human health monitoring simply by wearing a contact lens with built-in wireless smart sensors. This study has been jointly conducted by Professor Jang-Ung Park of Materials Science and Engineering, Professor Chang Young Lee of Life Science, and Professor Franklin Bien of Electrical and Computer Engineering at UNIST in collaboration with Professor Hong Kyun Kim of Ophthalmology and Professor Kwi-Hyun Bae of Internal Medicine at Kyungpook National University (KNU). In the study, the research team unveiled a smart contact lens sensor that could help monitor biomarkers for intraocular pressure (IOP), diabetes mellitus, and other health conditions. The research team expects that this research breakthrough could lead to the development of biosensors capable of detecting and treating various human diseases, and used as a component of next-generation smart contact lens-related electronic devices. Diabetes is the most common cause of high blood sugar levels. Hyperglycemia is a condition in which an excessive amount of glucose circulates in the blood plasma. If this condition persists for more than two hours, a patient will be diagnosed with diabetes. Since blood sugar can be measured with tears, many attempts have been made to monitor diabetes with contact lenses. Despite numerous studies in the last several decades, the biggest drawback with conventional smart contact lenses was thought to be poor wearability. The electrodes used in existing smart contact lenses are opaque, and therefore obscure the view when wearing it. Moreover, because they lens-shaped firm plastic material, many people complain of comfort issues with contact lens wear which made wearing them impossible. Professor Park and his research team solved these issues by developing a sensor based on transparent and flexible materials. Their new smart contact lens sensors use electrodes made of highly stretchable and transparent graphene sheets and metal nanowires. Using this sensor, patients with diabetes and glaucoma may one day be able to self-monitor blood glucose levels and eye pressure. Through the embedded wireless antenna in the contact lens sensor, patients can also transmit their health information, which allows real-time monitoring of their health conditions, as well. In addition, because the system uses wireless antenna to read sensor information, no separate power source, like battery is required for the smart contact lens sensors. Intraocular pressure measurement can be achieved using the dielectric layers. The dielectric layer is an electrically non-conductive layer, characterized by polarity that divides both positive and negative charges. The thickness of this layer changes from thinning as the intraocular pressure increases, to thickening as the intraocular pressure decreases. The IOP sensor, embedded in the contact lenses senses this and transmits the information to the wireless antenna. According to the research team, their newly-developed smart lenses with built-in pressure-sensing and glucose-monitoring sensors could still detect blood glucose and IOP despite the deformation of the contact lenses. The sensor characteristics were also maintained even when exposed to various substances in human tears. "It was observed that the live rabbit did not show any abnormal behavior when wearing the contact lens sensor," says Joohee Kim (Combined M.S./Ph.D. student of Materials Science and Engineering), the first author of the study. The contact lens sensor characteristics are not changed when the lens is deformed. Even when the sensor exposed to various materials in human tears the characteristics were maintained, and flexibility and stretchability were also excellent. Furthermore, since the electronic sensor is inserted into the soft contact lens, the feeling of wearing it is also excellent. "This study can be used to diagnose diseases (diabetes and glaucoma) by implementing two types of transparent electronic sensors in the production of smart contact lens sensors," said Professor Park. "We are now a step closer to the implementation of a fictional idea for a smart contact lens in the films, like "Minority Report" and "Mission: Impossible". The results of the study have been published in the March issue of the renowned scientific journal, Nature Communications. It was carried out with the support of the 2017 CooperVision Science and Technology (S&T) Awards Program. Joohee Kim, et al. "Wearable Smart Sensor Systems Integrated On Soft Contact Lenses For Wireless Ocular Diagnostics", Nature Communications, (2017).

News Article | May 4, 2017
Site: www.rdmag.com

A new contact lens with built-in wireless smart sensors can help doctors diagnose patients with diabetes and glaucoma. Researchers from Ulsan National Institute of Science and Technology (UNIST) in South Korea, in collaboration with researchers from Kyungpook National University, have developed the lens, which could assist with monitoring biomarkers for intraocular pressure, diabetes mellitus and other health conditions. This new technology is expected to lead to the development of biosensors that can detect and treat several diseases and be used as a component of next-generation smart contact lens-related electronic devices. “This study can be used to diagnose diseases (diabetes and glaucoma) by implementing two types of transparent electronic sensors in the production of smart contact lens sensors,” Jang-Ung Park, a professor of Materials Science and Engineering at UNIST, said in a statement. "We are now a step closer to the implementation of a fictional idea for a smart contact lens in the films, like ‘Minority Report’ and ‘Mission: Impossible’.” According to the study, the researchers conducted in-vivo and in-vitro tests using a live rabbit and bovine eyeball. The lenses demonstrated reliable operation. Contact lenses are considered suitable to monitor diabetes because blood sugar can be measured with tears. However, conventional smart contact lenses are often not used due to poor wearability. Existing smart contact lenses use electrodes that are opaque, which can obscure the view when they are worn. The lenses are also made of firm plastic, which are considered by many to be uncomfortable. The new lens’s sensor is based on transparent and flexible materials and the lens itself is made with electrodes comprised of highly stretchable and transparent graphene sheets and metal nanowires. With the sensor, patients with diabetes and glaucoma could in the future be able to self-monitor their blood glucose levels and eye pressure. Patients can transmit their health information in real-time using the embedded wireless antenna in the lens. The wireless antenna also does not require a separate power source like a battery. The intraocular pressure measurement is achieved by using an electrically non-conductive layer characterized by polarity that divides both positive and negative charges called a dielectric layer. The thickness of the layer changes from thinning, as the intraocular pressure increases, to thickening, as the pressure decreases, while the intraocular pressure sensor transmits the information to the wireless antenna. The study was published in Nature Communications.

News Article | May 4, 2017
Site: www.rdmag.com

A new contact lens with built-in wireless smart sensors can help doctors diagnose patients with diabetes and glaucoma. Researchers from Ulsan National Institute of Science and Technology (UNIST) in South Korea, in collaboration with researchers from Kyungpook National University, have developed the lens, which could assist with monitoring biomarkers for intraocular pressure, diabetes mellitus and other health conditions. This new technology is expected to lead to the development of biosensors that can detect and treat several diseases and be used as a component of next-generation smart contact lens-related electronic devices. “This study can be used to diagnose diseases (diabetes and glaucoma) by implementing two types of transparent electronic sensors in the production of smart contact lens sensors,” Jang-Ung Park, a professor of Materials Science and Engineering at UNIST, said in a statement. "We are now a step closer to the implementation of a fictional idea for a smart contact lens in the films, like ‘Minority Report’ and ‘Mission: Impossible’.” According to the study, the researchers conducted in-vivo and in-vitro tests using a live rabbit and bovine eyeball. The lenses demonstrated reliable operation. Contact lenses are considered suitable to monitor diabetes because blood sugar can be measured with tears. However, conventional smart contact lenses are often not used due to poor wearability. Existing smart contact lenses use electrodes that are opaque, which can obscure the view when they are worn. The lenses are also made of firm plastic, which are considered by many to be uncomfortable. The new lens’s sensor is based on transparent and flexible materials and the lens itself is made with electrodes comprised of highly stretchable and transparent graphene sheets and metal nanowires. With the sensor, patients with diabetes and glaucoma could in the future be able to self-monitor their blood glucose levels and eye pressure. Patients can transmit their health information in real-time using the embedded wireless antenna in the lens. The wireless antenna also does not require a separate power source like a battery. The intraocular pressure measurement is achieved by using an electrically non-conductive layer characterized by polarity that divides both positive and negative charges called a dielectric layer. The thickness of the layer changes from thinning, as the intraocular pressure increases, to thickening, as the pressure decreases, while the intraocular pressure sensor transmits the information to the wireless antenna. The study was published in Nature Communications.

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.

Lee E.-S.,Kyungpook National University | Jeon C.-J.,Kyungpook National University
Neuroscience | Year: 2014

Single-cell injection with lipophilic dyes following immunocytochemistry is extremely valuable for revealing the morphology of a cell expressing a protein of interest, and is a more reliable technique for cell type classification than standard morphological techniques. This study focuses on calretinin (CR), which is used as a selective marker for distinct subpopulations of neurons in the rabbit retina. The present study used single-cell injection after immunocytochemistry to describe the density and types of CR-containing retinal ganglion cells (RGCs) in rabbit. The density of CR-immunoreactive cells in the rabbit RGC cell layer was 426cells/mm2. CR-containing RGCs were identified by immunocytochemistry and were then iontophoretically injected with a lipophilic dye, DiI. Subsequently, confocal microscope was used to characterize the morphology of CR-immunoreactive RGCs based on their dendritic field size, branching pattern, and stratification of the inner plexiform layer. Our results show that 10 morphologically different types of rabbit RGCs expressed CR. CR-containing RGCs were heterogeneous in their morphology. This approach to integrate the selective expression of a particular protein with spatial patterns of dendritic arborization will lead to a better understanding of RGCs. © 2014 IBRO.

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.

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.

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.

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.

Lee D.-H.,Kyungpook National University | Porta M.,Autonomous University of Barcelona | Jacobs Jr. D.R.,University of Minnesota | Jacobs Jr. D.R.,University of Oslo | Vandenberg L.N.,University of Massachusetts Amherst
Endocrine Reviews | Year: 2014

Persistent organic pollutants (POPs) are lipophilic compounds that travel with lipids and accumulate mainly in adipose tissue. Recenthumanevidence links low-dose POPs to an increased risk of type 2 diabetes (T2D). Because humans are contaminated by POP mixtures and POPs possibly have nonmonotonic dose-response relations with T2D, critical methodological issues arise in evaluating human findings. This review summarizes epidemiological results on chlorinated POPs and T2D, and relevant experimental evidence. It also discusses how features of POPs can affect inferences in humans. The evidence as a whole suggests that, rather than a few individual POPs, background exposure to POP mixtures-including organochlorine pesticides and polychlorinated biphenyls- can increase T2D risk in humans. Inconsistent statistical significance for individual POPs may arise due to distributional differences in POP mixtures among populations. Differences in the observed shape of the doseresponse curvesamonghumanstudies may reflect an inverted U-shaped association secondary to mitochondrial dysfunction or endocrine disruption. Finally, we examine the relationship between POPs and obesity. There is evidence in animal studies that low-dose POP mixtures are obesogenic. However, relationships between POPs and obesity in humans have been inconsistent. Adipose tissue plays a dual role of promoting T2D and providing a relatively safe place to store POPs. Large prospective studies with serial measurements of a broad range of POPs, adiposity, and clinically relevant biomarkers are needed to disentangle the interrelationships among POPs, obesity, and the development of T2D. Also needed are laboratory experiments that more closely mimic real-world POP doses, mixtures, and exposure duration in humans. © 2014 by the Endocrine Society.

News Article | December 5, 2016
Site: www.materialstoday.com

The recipient of the 2017 Acta Biomaterialia Gold Medal is Professor Allan S. Hoffman,             Emeritus Professor of Bioengineering at the University of Washington in Seattle. The Award will be presented at the 2017 Meeting of the Society for Biomaterials to be held in Minneapolis in April 2017. Professor Hoffman studied at M.I.T., where he received his B.S., M.S., and Sc.D. degrees in Chemical Engineering between 1953 and 1957. He taught on the faculty of the Chemical Engineering Department at M.I.T. for a total of ten years. He then spent 46 years as Professor of Bioengineering and Chemical Engineering at the University of Washington in Seattle, Washington. Prof. Hoffman’s major research interests are in drug delivery; diagnostic assays; “smart”, stimuli-responsive polymers; hydrogels; and chemical and biological modification of biomaterial surfaces. He has published over 400 peer-reviewed articles and is co-inventor on over 35 issued patents.  He is co-Editor (along with Buddy D. Ratner, Fred J. Schoen and Jack E. Lemons) of “Biomaterials Science”, Elsevier Publishers, now in its 3rd Edition. His early work in 1984 on the use of “smart” polymers in a temperature-driven phase separation immunoassay sparked a huge worldwide interest in such stimuli-responsive polymers as biomaterials.  Biomedical applications of “smart” polymers continue to grow rapidly around the world at the present time. He has been an Honorary Professor at: Sichuan University, Chengdu, China; South China University of Technology, Guangzhou, China; Wuhan University, Wuhan, China; Shanghai University, Shanghai, China; and Aarhus University, Aarhus, Denmark. In 2013 he completed a four-year appointment (2009-2013) as WCU (“World Class University”) Distinguished Professor at the Kyungpook National University Medical School in Daegu, South Korea. Professor Hoffman was elected to the US National Academy of Engineering in 2005.  His other recognitions and awards include Presidency of the US Society for Biomaterials (1983); the “Biomaterials Science Prize” of the Japanese Society for Biomaterials (1990); the Founders’ Award of the US Society for Biomaterials (in 2000); the Chandra Sharma Award of the Society for Biomaterials and Artificial Organs of India (2003); the “International Polymer Research Award” of the Japanese Society of Polymer Science (2006), and the Founder’s Award of the US Controlled Release Society (2007); Special symposia have been organized in Maui, Hawaii by his colleagues to celebrate his 60th, 70th and 80th birthdays. Former students, along with many academic colleagues, have also organized symposia which they have called “Hoffman Family Symposia” (HFS) and since 2010 there have been four, the first two were in Tokyo, Japan in 2012 and 2014, the third was in Gwangju, Korea in 2015, and a fourth was in Taipei, Taiwan September, 2016.  A fifth HFS will be held in Shanghai, China this coming October, 2017.

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.

Kang U.,Kyungpook National University | Park H.,Kyungpook National University
Applied Catalysis B: Environmental | Year: 2013

A quick electrochemical Li ion insertion into TiO2 nanotube arrays (TNTs) markedly enhances the photoelectrochemical and photoelectrocatalytic performance. Potential pulses (-1.0~-1.7VSCE for 1-11s in 1M LiClO4) to pre-annealed TNTs effectively insert Li ions (pre-annealed Li-TNTs) into the mouth/wall and bottom TiO2 depending on the insertion condition. Pre-annealed Li-TNTs prepared under an optimal Li ion insertion condition (-1.4VSCE for 3s) exhibit ~70%-enhanced photocurrent generation, ~2.5 fold-higher incident photon-to-current efficiency, and an improved photoelectrocatalytic activity for the degradation of phenolic compounds in 1M KOH electrolyte. A change in photoluminescence (PL) emission spectra and decrease in charge transfer resistance by Li ion insertion suggest that the inserted Li ions play a role in inhibiting charge recombination by compensating for the photogenerated Ti3+ charges (Li+-Ti3+-OH). However, as KOH concentration is diluted such enhanced Li+ effects gradually vanish primarily due to liberation of reversibly inserted Li ions. To insert Li ions irreversibly, the potential pulses were applied to non-annealed TNTs followed by annealing (post-annealed Li-TNTs). Comparison between pre-annealed and post-annealed Li-TNTs in circum-neutral pH (0.1M Na2SO4 at pH ~6) indicates that the former exhibits a similar performance to bare TNTs (absence of Li ion effect), whereas the latter shows a superior performance with ca. 2.5-fold higher photoelectrochemical and photoelectrocatalytic activities. Detailed surface analyses (XPS, XRD, PL, SEM, ICP-MS, etc.) and Li+-induced reaction mechanism were discussed. © 2013 Elsevier B.V.

Kim Y.K.,Kyungpook National University | Park H.,Kyungpook National University
Applied Catalysis B: Environmental | Year: 2012

The aim of this study is to find key physicochemical properties of carbon materials in catalyzing the photocatalytic H 2 production from visible light-irradiated aqueous suspensions of carbon/CdSe composites. For this, we have employed five different carbon materials (activated carbons, carbon fibers, multi- and single-walled nanotubes, and graphites) without and with acid treatment, and two carbon materials obtained from graphite (graphite oxides and reduced graphene oxides). Detailed surface analyses for the bare carbon materials and carbon/CdSe composites were completed to characterize their physicochemical properties. Most virgin (non-treated) carbon materials are beneficial in catalyzing the photocatalytic H 2 production of carbon/CdSe composites, and such catalytic effects are significantly enhanced by their acid treatment by a factor of 3-7. Systematic investigation indicates that the surface area, the degree of disordered carbon (i.e., I D/I G ratios), and the electrical conductivity (σ) of carbon materials display the correlations with H 2 production of carbon/CdSe composites. However, the first two factors could not explain well the enhanced H 2 production by acid treatment of carbon materials, whereas the last factor exhibits the linearity with the H 2 amounts even for the acid-treated carbon materials. High electrical conductivity appears to facilitate the photogenerated electron transfer from CdSe to neighboring carbon materials, leading to inhibition of charge pair recombination as evidenced by photoluminescence study. © 2012 Elsevier B.V.

Jo W.-K.,Kyungpook National University | Kang H.-J.,Kyungpook National University
Powder Technology | Year: 2013

Titanium dioxide-graphene oxide (TiO2-GO) composites with different ratios of GO to TiO2 were synthesized using a colloidal blending process and evaluated for their heterogeneous photocatalytic purification of toxic aromatic vapors using a Pyrex tube reactor. Both SEM and FTIR demonstrated the presence of a carbon component in the as-prepared TiO2-GO composites. Unlike unmodified TiO2, the TiO2-GO composites showed a light-absorbance shift into the longer wavelength regions, indicating band-gap narrowing. The time-series ratios of outlet to inlet concentrations of selected aromatic vapors determined using the TiO2-GO composites under visible-light and UV exposure were lower than or similar to those obtained using unmodified P25 TiO2, suggesting that the TiO2-GO composites had superior photocatalytic activity to P25 TiO2 for degradation of vaporous aromatic pollutants. In addition, the time-series ratios of outlet to inlet concentrations determined using the TiO2-GO composites under both visible-light and UV irradiation decreased, as the ratio of GO to TiO2 increased from 0.01 to 0.10, while they increased as the ratio increased from 0.10 to 0.15, suggesting the presence of an optimal GO to TiO2 ratio. Overall, TiO2-GO composites supported by Pyrex tubes could be utilized effectively for degradation of toxic vaporous aromatic pollutants. © 2013 Elsevier B.V.

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.

Lee S.,Kyungpook National University
Toxicological Research | Year: 2013

Toxicoproteomics integrates the proteomic knowledge into toxicology by enabling protein quantification in biofluids and tissues, thus taking toxicological research to the next level. Post-translational modification (PTM) alters the three-dimensional (3D) structure ofproteins by covalently binding small molecules to them and therefore represents a major protein function diversification mechanism. Because of the crucial roles PTM plays in biological systems, the identification of novel PTMs and study of the role of PTMs are gaining much attention in proteomics research. Of the 300 known PTMs, protein acylation, including lysine formylation, acetylation, propionylation, butyrylation, malonylation, succinylation, and crotonylation, regulates the crucial functions of many eukaryotic proteins involved in cellular metabolism, cell cycle, aging, growth, angiogenesis, and cancer. Here, I reviewed recent studies regarding novel types of lysine acylation, their biological functions, and their applicationsin toxicoproteomics research.

Jeong H.W.,Kyungpook National University | Park H.,Kyungpook National University
Catalysis Today | Year: 2014

The catalytic effects of four different carbon materials (graphite, multi-walled carbon nanotubes, carbon fibers, and activated carbon) on dye-sensitized solar hydrogen production were investigated under a simulated solar light (AM 1.5G, 100 mW/cm2). Eosin-Y (EY) and triethanolamine (TEOA) were employed as a sensitizer and electron donor, respectively. All the tested carbon materials enhanced the sensitized H2 production, while multi-walled carbon nanotubes (CNT) exhibited the highest catalytic activity with 9- and 4-fold enhanced H2 production and photocurrent generation, respectively. This suggests that CNT is highly effective in catalyzing charge injection and thus sensitized H2 production. With Pt loading onto the carbon materials, the H2 production was further improved by a maximum of 10 times. With the bare carbon materials, EY underwent simultaneous spectral shifts and decreases in absorbance presumably due to stepwise de-bromination and cleavage of chromophoric groups. With CNT/Pt, however, only the former was observed despite far higher H2 production. This indicates that the regeneration of EY is significantly enhanced with CNT/Pt. A detailed comparison of carbon materials and the sensitized mechanism was discussed. © 2013 Elsevier B.V.

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.

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.

Sohn K.-S.,Sejong University | Park W.B.,Sejong University | Timilsina S.,Kyungpook National University | Kim J.S.,Kyungpook National University
Optics Letters | Year: 2014

The mechanoluminescence (ML) of SrAl2O4:Eu 2+, Dy3+ (SAO) has been of particular interest based on the possibility that these materials could be used as nondestructive, reproducible stress (or load) sensors. However, there has been no in-depth study of ML under a cyclic load. It was found that a cyclic load generated harmonics in the ML response. The second harmonic term exhibiting a doubled frequency was significant, but the others could be ignored. In addition, hysteresis behavior was observed in the ML and was examined by comparison with the hysteresis that is typical in piezoelectricity. © 2014 Optical Society of America.

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.

Sohn S.K.,Kyungpook National University | Moon J.H.,Kyungpook National University
Transfusion | Year: 2014

While previous studies have shown comparable clinical results for related and unrelated bone marrow transplantation (BMT), the transplantation outcomes for related and unrelated peripheral blood stem cell transplantation (PBSCT) may not follow the same pattern due to a higher incidence of graft-versus-host disease (GVHD)-related morbidity and mortality in the case of long-term survival after unrelated PBSCT. Thus, given the higher possibility of an impaired quality of life due to severe GVHD in long-term survivors who receive unrelated PBSCT, the selection of the stem cell source needs to be decided very carefully. In addition, strategic approaches, such as the extended use of immunosuppressant as a GVHD prophylaxis, the use of antithymocyte globulins (ATGs), choosing a younger donor, and optimizing the CD34+ cell dose, need to be adopted to improve the transplantation outcomes by minimizing GVHD-related morbidity and mortality in an unrelated PBSCT setting. This review article provides a comparison of BMT and PBSCT, and related and unrelated PBSCT, plus introduces several adoptable strategies to improve the outcomes of unrelated PBSCT. © 2013 AABB.

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.

Lee S.H.,Kyungpook National University | Bae S.C.,Cheongju University | Kim K.W.,Seoul National University | Lee Y.M.,Kyungpook National University
Oncogene | Year: 2014

RUNX3 is silenced by histone modification and hypoxia-inducible factor (HIF)-1α is stabilized under hypoxia, but little is known of cross-talk between RUNX3 and HIF-1α under hypoxia. In the present study, the authors investigated the effect of RUNX3 on HIF-1α stability in gastric cancer cells. RUNX3 overexpression was found to downregulate HIF-1α stability under normoxic and hypoxic conditions. Furthermore, the activity of a luciferase reporter containing five copies of vascular endothelial growth factor (VEGF) promoter hypoxia-responsive element (5 × HRE) and the amount of secreted VEGF, were diminished in RUNX3-expressing but increased in RUNX3-knockdown cells. When expression of RUNX3 was recovered using epigenetic reagents the expressions of HIF-1α and VEGF were clearly suppressed under hypoxic conditions. RUNX3 also significantly attenuated the half-life of HIF-1α protein, and induced the cytosolic localization and ubiquitination of HIF-1α. In addition, RUNX3 directly interacted with the C-terminal activation domain of HIF-1α and prolyl hydroxylase (PHD) 2 and enhanced the interaction between HIF-1α and PHD2, which potentiated proline hydroxylation and promoted the degradation of HIF-1α. Furthermore, RUNX3 overexpression significantly inhibited hypoxia-induced angiogenesis in vitro and in vivo. Taken together, these results suggest that RUNX3 destabilizes HIF-1α protein by promoting the proline hydroxylation of HIF-1α through binding to HIF-1α/PHD2. RUNX3 appears to be a novel suppressor of HIF-1α and of hypoxia-mediated angiogenesis in gastric cancer cells. © 2014 Macmillan Publishers Limited All rights reserved.

Kim H.-K.,Kyungpook National University | Jung H.K.,Kyungpook National University | Cho J.,Kyungpook National University | Lee J.-M.,Kyungpook National University | Huh S.,Kyungpook National University
Journal of Vascular Surgery | Year: 2014

Objective To determine the clinical and radiological outcomes of patients with symptomatic spontaneous isolated dissection of the superior mesenteric artery (SIDSMA) who were treated with conservative management. Methods This retrospective study included 27 consecutive patients who were diagnosed with symptomatic SIDSMA and managed conservatively from April 2007 to April 2013. Twenty-six patients were treated using anticoagulation therapy, and one patient with chronic liver disease underwent observation only. For evaluation, patients were divided into two groups, those with a patent false lumen with both entry and re-entry (group I), and those with partial or complete thrombosis of the false lumen (group II). In general, the patients underwent follow-up computed tomography angiography (CTA) 1 week, 1 month, and 6 months after admission. Thereafter, they underwent annual CTAs. Results There were five group I and 22 group II patients. During hospitalization, none of the patients needed additional endovascular or surgical intervention, and after conservative management, every patient was asymptomatic upon discharge. The mean duration of clinical follow-up was 27.3 months. There was no recurrent abdominal pain associated with SIDSMA, and no invasive procedures due to SIDSMA were needed. During a mean of 17.1 months of CTA follow-up in group I patients, serial CTAs found sustained patent false lumen and no angiographic changes in all patients. Among 22 group II patients, despite anticoagulation and symptomatic relief, CTA 1 week after admission revealed increased stenosis of the true lumen in 84.2% (16/19) of patients including six cases of progressive SMA occlusion. Five patients, including the three patients initially presenting with SMA occlusion, had no interval changes, and only one patient had improved compression of the true lumen. During a mean of 18.0 months of CTA follow-up in group II patients, serial CTAs revealed improvement in the occlusion or stenosis of the true lumen in 89% (16/18) of patients and progressive resolution of false lumen thrombosis in all patients. Aneurysmal dilatation greater than 2 cm was not detected in either group of patients during follow-up. Conclusions During the acute stage of SIDSMA, we found a discrepancy between the clinical and angiographic findings. The therapeutic regimen should be based on clinical symptoms, and conservative management is feasible in most cases. SMA stenosis could not be an indication for invasive treatment, because stenosis of the true lumen has been seen to improve after the acute stage of dissection. © 2014 by the Society for Vascular Surgery.

Shehzad A.,Kyungpook National University | Rehman G.,Kyungpook National University | Lee Y.S.,Kyungpook National University
BioFactors | Year: 2013

Curcumin (diferuloylmethane), a yellow coloring agent extracted from turmeric is also used as a remedy for the treatment and prevention of inflammatory diseases. Acute and chronic inflammation is a major factor in the progression of obesity, type II diabetes, arthritis, pancreatitis, cardiovascular, neurodegenerative and metabolic diseases, as well as certain types of cancer. Turmeric has a long history of use in Ayurvedic medicine for the treatment of inflammatory disorders. Recent studies on the efficacy and therapeutic applicability of turmeric have suggested that the active ingredient of tumeric is curcumin. Further, compelling evidence has shown that curcumin has the ability to inhibit inflammatory cell proliferation, invasion, and angiogenesis through multiple molecular targets and mechanisms of action. Curcumin is safe, non-toxic, and mediates its anti-inflammatory effects through the down-regulation of inflammatory transcription factors, cytokines, redox status, protein kinases, and enzymes that all promote inflammation. In addition, curcumin induces apoptosis through mitochondrial and receptor-mediated pathways, as well as activation of caspase cascades. In the current study, the anti-inflammatory effects of curcumin were evaluated relative to various chronic inflammatory diseases. Based on the available pharmacological data obtained from in vitro and in vivo research, as well as clinical trials, an opportunity exists to translate curcumin into clinics for the prevention of inflammatory diseases in the near future. © 2012 International Union of Biochemistry and Molecular Biology, Inc.

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.

Shehzad A.,Kyungpook National University | Lee Y.S.,Kyungpook National University
BioFactors | Year: 2013

Chemoprevention represents one of the most highly effective anti-cancer strategies and is accompanied by minimal secondary effects as compared to conventional chemotherapies. Many new anti-inflammatory and anti-cancer drug candidates have been derived from chemical scaffolds engineered from natural products discovered just a few decades ago. This approach is widely utilized in drug discovery in order to produce novel molecular entities with enhanced drug activities mediated through various signal transduction pathways for the treatment of different diseases. Curcumin, a polyphenolic derivative of turmeric, is a naturally occurring compound isolated from Curcuma longa that suppresses and inverts carcinogenesis via multifaceted molecular targets. Several reports have demonstrated that curcumin inhibits animal and human cancers, suggesting that it may serve as a chemopreventive agent. Numerous in vitro and in vivo experimental models have also revealed that curcumin regulates several molecules in cell signal transduction pathway including NF-κB, Akt, MAPK, p53, Nrf2, Notch-1, JAK/STAT, β-catenin, and AMPK. Modulation of cell signaling pathways through the pleiotropic effects of curcumin likely activate cell death signals and induce apoptosis in cancer cells, thereby inhibiting the progression of disease. This article provides insights into the natural chemopreventive role of curcumin via cellular transduction pathways and provides an in depth assessment of its physiological activities in the management of diseases. © 2013 International Union of Biochemistry and Molecular Biology, Inc.

Shehzad A.,Kyungpook National University | Lee J.,Kyungpook National University | Lee Y.S.,Kyungpook National University
BioFactors | Year: 2013

Curcumin (diferuloylmethane), an active constituent of turmeric, is a well-described phytochemical, which has been used since ancient times for the treatment of various diseases. The dysregulation of cell signaling pathways by the gradual alteration of regulatory proteins is the root cause of cancers. Curcumin modulates regulatory proteins through various molecular mechanisms. Several research studies have provided in-depth analysis of multiple targets through which curcumin induces protective effects against cancers including gastrointestinal, genitourinary, gynecological, hematological, pulmonary, thymic, brain, breast, and bone. The molecular mechanisms of action of curcumin in treating different types of cancers remain under investigation. The multifaceted role of this dietary agent is mediated through its inhibition of several cell signaling pathways at multiple levels. Curcumin has the ability to inhibit carcinogenicity through the modulation of the cell cycle by binding directly and indirectly to molecular targets including transcription factors (NF-kB, STAT3, β-catenin, and AP-1), growth factors (EGF, PDGF, and VEGF), enzymes (COX-2, iNOS, and MMPs), kinases (cyclin D1, CDKs, Akt, PKC, and AMPK), inflammatory cytokines (TNF, MCP, IL-1, and IL-6), upregulation of proapoptotic (Bax, Bad, and Bak) and downregulation of antiapoptotic proteins (Bcl2 and Bcl-xL). A variety of animal models and human studies have proven that curcumin is safe and well tolerated even at very high doses. This study elaborates the current understanding of the chemopreventive effects of curcumin through its multiple molecular pathways and highlights its therapeutic value in the treatment and prevention of a wide range of cancers. © 2013 International Union of Biochemistry and Molecular Biology, Inc.

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

By calculating the second-order pole in the operator product expansion (OPE) between the spin-3 Casimir operator and the spin-4 Casimir operator known previously, the spin-5 Casimir operator is obtained in the coset model based on (AN-1 (1)⊕ AN-1 (1)A N-1 (1)) at level (k, 1). This spin-5 Casimir operator consisted of the quintic, quartic (with one derivative) and cubic (with two derivatives) WZW currents contracted with SU(N) invariant tensors. The three-point functions with two scalars for all values of 't Hooft coupling in the large N limit were obtained by analyzing the zero-mode eigenvalue equations carefully. These three-point functions were dual to those in AdS 3 higher spin gravity theory with matter. Furthermore, the exact three-point functions that hold for any finite N and k are obtained. The zero mode eigenvalue equations for the spin-5 current in CFT coincided with those of the spin-5 field in asymptotic symmetry algebra of the higher spin theory on the AdS 3. This paper also describes the structure constant appearing in the spin-4 Casimir operator from the OPE between the spin-3 Casimir operator and itself for N = 4, 5 in the more general coset minimal model with two arbitrary levels (k 1, k 2). © 2014 SISSA.

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

In the N = 1 supersymmetric coset minimal model based on (B N (1)⊕ DN (1),DN (1)) at level (k, 1) studied recently, the standard N = 1 super stress tensor of spins (3/2,2) is reviewed. By considering the stress tensor in the coset (BN (1) DN (1)) at level k, the higher spin-2′ Casimir current was obtained previously. By acting the above spin- 2/3 current on the higher spin-2′ Casimir current, its superpartner, the higher spin-2/5 current, can be generated and combined as the first higher spin supercurrent with spins (2′, 5/2). By calculating the operator product expansions (OPE) between the higher spin supercurrent and itself, the next higher spin supercurrent can be generated with spins (7/2, 4). Moreover, the other higher spin supercurrent with spins (4′, 9/2) can be generated by calculating the OPE between the first higher spin supercurrent with spins (2′, 5/2) and the second higher spin supercurrent with spins (7/2, 4). Finally, the higher spin supercurrent, (11/2,6), can be extracted from the right hand side of OPE between the higher spin supercurrents, (2′ 5/2) and (4', 9/2). © 2014 SISSA.

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

We obtain the 16 higher spin currents with spins (Formula presented) in the N = 4 superconformal Wolf space coset (Formula presented). The antisymmetric second rank tensor occurs in the quadratic spin-1/2 Kac-Moody currents of the higher spin-1 current. Each higher spin-3/2 current contains the above antisymmetric second rank tensor and three symmetric (and traceless) second rank tensors (i.e. three antisymmetric almost complex structures contracted by the above antisymmetric tensor) in the product of spin-1/2 and spin-1 Kac-Moody currents respectively. Moreover, the remaining higher spin currents of spins 2, 5/2 , 3 contain the combinations of the (symmetric) metric, the three almost complex structures, the antisymmetric tensor or the three symmetric tensors in the multiple product of the above Kac-Moody currents as well as the composite currents from the large N = 4 nonlinear superconformal algebra. © 2014, The Author(s).

Lee H.-J.,Kyungpook National University
Experimental Biology and Medicine | Year: 2013

MicroRNAs (miRNAs) are small, endogenous, non-coding RNAs that regulate the expression of target genes in eukaryotic cells and have been extensively studied in the past decade. However, recent evidence suggests that miRNAs have additional, important roles and functions other than post-transcriptional regulation through binding at the 3′ untranslated regions of their target genes. This review describes newly discovered information about the biogenesis and functions of miRNAs as well as presents different points of view about the miRNA system. Our increasing knowledge of the exceptional stories of miRNAs will offer new insights into these powerful gene regulators from virus and bacteria to animals. © 2013 by the Society for Experimental Biology and Medicine.

Jang H.-S.,Kyungpook National University | Kim J.I.,Keimyung University | Han S.J.,Kyungpook National University | Park K.M.,Kyungpook National University
American Journal of Physiology - Renal Physiology | Year: 2014

Acute kidney injury (AKI) is an independent risk factor of the development of chronic kidney disease. Kidney fibrosis is a typical feature of chronic kidney disease and is characterized as an expansion of the interstitium due to increases in extracellular matrix molecules and interstitial cells caused by accumulations of extrarenal cells and by the proliferation or differentiation of intrarenal cells. However, the role of bone marrow-derived cells (BMDCs) in AKI-induced kidney fibrosis remains to be defined. Here, we investigated the role of BMDCs in kidney fibrosis after ischemia-reperfusion injury (IRI)-induced AKI in green fluorescent protein (GFP)-expressing bone marrow chimeric mice. IRI resulted in severe fibrotic changes in kidney tissues and dramatically increased interstitial cell numbers. Furthermore, GFP-expressing BMDCs accounted for >80% of interstitial cells in fibrotic kidneys. Interstitial GFP-expressing cells expressed α-smooth muscle actin (a myofibroblast marker), fibroblast-specific protein-1 (a fibroblast marker), collagen type III, and F4/80 (a macrophage marker). Over 20% of interstitial cells were bromodeoxyuridine-incorporating (proliferating) cells, and of these, 80% cells were GFP-expressing BMDCs. Daily treatment of IRI mice with apocynin (a NADPH oxidase inhibitor that functions as an antioxidant) from the day after surgery until euthanization slightly inhibited these changes with a small reduction of fibrosis. Taken together, our findings show that BMDCs make a major contribution to IRI-induced fibrosis due to their infiltration, subsequent differentiation, and proliferation in injured kidneys, suggesting that BMDCs be considered an important target for the treatment of kidney fibrosis. © 2014 the American Physiological Society.

Gopalan A.I.,Kyungpook National University | Lee K.-P.,Kyungpook National University | Komathi S.,Kyungpook National University
Biosensors and Bioelectronics | Year: 2010

Polyaniline chains were grafted onto nanodiamond (PANI-g-ND) through electrochemical polymerization of aniline in the presence of amine functionalized ND. A robust and effective composite film comprising PANI-g-ND/gold particles was subsequently prepared. Cytochrome c was successfully immobilized onto PANI-g-ND/Au film. Field emission scanning electron microscope (FESEM) image of PANI-g-ND/Au reveals the presence of fibrous PANI embedded into ND galleries with uniformly distributed Au clusters (∼1 μm). Direct electrochemistry and electrocatalysis of cyt c were investigated. PANI-g-ND/Au film showed an obvious direct electron transfer between cyt c and the underlying electrode. Cyclic voltammograms revealed that PANI-g-ND/Au/cyt c exhibited an excellent electrocatalysis towards the detection of nitrite ions. Differential pulse voltammetry of PANI-g-ND/Au/cyt c revealed a wide linear concentration range (0.5 μM-3. mM) for current responses, sensitivity (88.2 μA/mM) and low detection limit (0.16 μM) towards the electrochemical detection of nitrite ions. © 2010 Elsevier B.V.

Hwang I.-S.,Kyungpook National University | Lee J.,Kyungpook National University | Hwang J.H.,Kyungpook National University | Kim K.-J.,Tae Kyeung College | Lee D.G.,Kyungpook National University
FEBS Journal | Year: 2012

Silver nanoparticles have been shown to be detrimental to fungal cells although the mechanism(s) of action have not been clearly established. In this study, we used Candida albicans cells to show that silver nanoparticles exert their antifungal effect through apoptosis. Many studies have shown that the accumulation of reactive oxygen species induces and regulates the induction of apoptosis. Furthermore, hydroxyl radicals are considered an important component of cell death. Therefore, we assumed that hydroxyl radicals were related to apoptosis and the effect of thiourea as a hydroxyl radical scavenger was investigated. We measured the production of reactive oxygen species and investigated whether silver nanoparticles induced the accumulation of hydroxyl radicals. A reduction in the mitochondrial membrane potential shown by flow cytometry analysis and the release of cytochrome c from mitochondria were also verified. In addition, the apoptotic effects of silver nanoparticles were detected by fluorescence microscopy using other confirmed diagnostic markers of yeast apoptosis including phosphatidylserine externalization, DNA and nuclear fragmentation, and the activation of metacaspases. Cells exposed to silver nanoparticles showed increased reactive oxygen species and hydroxyl radical production. All other phenomena of mitochondrial dysfunction and apoptotic features also appeared. The results indicate that silver nanoparticles possess antifungal effects with apoptotic features and we suggest that the hydroxyl radicals generated by silver nanoparticles have a significant role in mitochondrial dysfunctional apoptosis. © 2012 FEBS.

Khan N.A.,Kyungpook National University | Jhung S.H.,Kyungpook National University
Journal of Hazardous Materials | Year: 2013

Liquid phase adsorption of benzothiophene (BT) has been studied over CuCl2-loaded analogous metal-organic frameworks (MOFs), metal-benzenedicarboxylates (Me-BDCs, Me: Al, Cr and V), to understand the effect of central metal ions on the adsorptive removal of BT from a model fuel. Among the central metal ions (Al3+, Cr3+ and V3+) of the Me-BDCs only V3+ was oxidized by the loaded CuCl2 (or Cu2+) at ambient condition resulting in V4+ and Cu+ species. Different from the CuCl2-loaded Al- and Cr-BDCs, the CuCl2/V-BDC adsorbed BT remarkably well compared to the virgin V-BDCs which suggests a specifi{ligature}c favorable interaction (π-complexation) between the obtained Cu+ in the CuCl2/V-BDC and BT. © 2013 Elsevier B.V.

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.

Bae T.-W.,Kyungpook National University | Sohng K.-I.,Kyungpook National University
Journal of Infrared, Millimeter, and Terahertz Waves | Year: 2010

Bilateral filter (BF) performs sharpness enhancement and noise removal by using two Gaussian filters, the domain filter in spatial domain and the range filter in intensity domain. To apply the BF to infrared (IR) small target detection, the standard deviation of the two Gaussian filters need to be changed adaptively between the background region and the target region. This paper presents a new BF for small target detection with the adaptive standard deviation based on the analysis of the edge component, also having the variable filter size. At first, threshold of pixel edge components for four directions decides whether any pixel is potential small targets or not. For the proposed BF operation for the potential small target pixels, its edge component is mapped to two standard deviations of the domain filter and the range filter in the proposed BF by mapping function. When the BF comes to a target region, the two standard deviations increase in proportion to the edge component to blur the small targets. To further blur the small targets, the filter size of the BF also increases by its edge component. This enables the BF to perform better and become more suitable in the field of small target detection Experimental results demonstrate that the proposed method is more robust and efficient than the conventional methods. © Springer Science+Business Media, LLC 2010.

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.

Ahmed I.,Kyungpook National University | Hasan Z.,Kyungpook National University | Khan N.A.,Kyungpook National University | Jhung S.H.,Kyungpook National University
Applied Catalysis B: Environmental | Year: 2013

To understand the effect of the acidity or basicity of porous metal-organic frameworks (MOFs) on the adsorptive removal of nitrogen-containing compounds (NCCs), an MOF (MIL-100(Cr)) was modified to impart acidity or basicity onto the MOFs. The modification was done by grafting ethylenediamine and aminomethanesulfonic acid onto coordinatively unsaturated sites of the MOF, MIL-100(Cr). The adsorptive removal of a basic quinoline or benzothiophene can be improved noticeably, especially at low concentrations, with the introduction of an acidic site; however, a basic MOF causes a severe decrease in the adsorptive performance for a basic adsorbate such as quinoline. The effect of the interaction of the base-base on adsorption was more severe or detrimental for a hard base quinoline than for a soft base benzothiophene. Functionalized MOFs show a slightly decreased adsorption for a neutral adsorbate such as indole probably because of the decreased porosity of the MOFs compared with the virgin MOF without functionalization. Moreover, a functionalized MOF (with SO3H group) can be used several times after simple washing with acetone. From the present research, it may be concluded that acid-base interactions between NCCs and MOFs will lead to favorable adsorptive removal of NCCs. However, for the adsorptive removal of a neutral adsorbate such as indole, another adsorption mechanism (such as π-complexation or hydrogen-bonding) is needed for high uptake and efficient removal. © 2012 Elsevier B.V.

Yoon E.-J.,Kyungpook National University | Yoo K.-Y.,Kyungpook National University
Journal of Supercomputing | Year: 2013

Conventional single-server authentication schemes suffer a significant shortcoming. If a remote user wishes to use numerous network services, he/she must register his/her identity and password at these servers. It is extremely tedious for users to register numerous servers. In order to resolve this problem, various multi-server authentication schemes recently have been proposed. However, these schemes are insecure against some cryptographic attacks or inefficiently designed because of high computation costs. Moreover, these schemes do not provide strong key agreement function which can provide perfect forward secrecy. Based on these motivations, this paper proposes a new efficient and secure biometrics-based multi-server authentication with key agreement scheme for smart cards on elliptic curve cryptosystem (ECC) without verification table to minimize the complexity of hash operation among all users and fit multi-server communication environments. By adopting the biometrics technique, the proposed scheme can provide more strong user authentication function. By adopting the ECC technique, the proposed scheme can provide strong key agreement function with the property of perfect forward secrecy to reduce the computation loads for smart cards. As a result, compared with related multi-serve authentication schemes, the proposed scheme has strong security and enhanced computational efficiency. Thus, the proposed scheme is extremely suitable for use in distributed multi-server network environments such as the Internet and in limited computations and communication resource environments to access remote information systems since it provides security, reliability, and efficiency. © 2010 Springer Science+Business Media, LLC.

Choi S.K.,Kyungpook National University | Yang H.S.,Yeungnam University | Kim J.H.,Yeungnam University | Park H.,Kyungpook National University
Applied Catalysis B: Environmental | Year: 2012

This study explores the applicability of organic dye-sensitized TiO 2 particles in the production of molecular hydrogen and remediation of environmental pollutants (4-chlorophenol and Cr(VI)) under visible light (λ>420nm). In order to examine the effect of number of anchoring groups, Ru-free organic dyes of donor-π-acceptor configuration are prepared with different numbers (n) of carboxylate anchoring groups (n=1, 2, and 3; referred to as D1, D2, and D3, respectively). All the three dyes are found to be effective at producing H 2 in the presence of electron donors (triethanolamine (TEOA) and ethylenediaminetetra-acetic acid (EDTA)) with the following orders: D3-D2>D1 (TEOA) and D3>D2-D1 (EDTA). FTIR studies reveal that D1 and D3 are anchored to the TiO 2 surface primarily via bidentate modes with a single carboxylate and two carboxylates, respectively. D2, in contrast, is anchored with one or two carboxylates, depending on the competing electron donors. The number of carboxylates is less important in the sensitized remediation of pollutants likely due to different photochemical conditions (oxic vs. anoxic) and various reaction pathways. A detailed systematic study is performed, including the UV-vis absorption characterization of free dyes and dye/TiO 2 samples, the photoelectrochemical behaviors of dye/TiO 2 electrodes, and the effects of dye concentrations, solution pH, and TiO 2 kind (Degussa P25 vs. Hombikat UV-100). © 2012 Elsevier B.V.

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.

Park J.,Kyungpook National University | Boo Y.C.,Kyungpook National University
Evidence-based Complementary and Alternative Medicine | Year: 2013

Tyrosinase (TYR) catalyzes rate-limiting reactions of cellular melanin synthesis, and its inhibitors are of commercial interest as potential skin whitening agents. However, the limited availability of human TYR makes the screening of TYR inhibitors difficult. To overcome this hurdle, we transformed nonmelanocytic human embryonic kidney (HEK) 293 cells to express human TYR constitutively. Using these cells as a source of human TYR, the ethanolic extracts of 52 medicinal plants grown in Korea were tested for human TYR activity, and the extract of Vitis Viniferae Caulis (dried stems of the grape tree, Vitis vinifera L.) was found to inhibit human TYR activity potently. An active compound was isolated from this extract by solvent fractionation followed by liquid column chromatography and identified as resveratrol by spectroscopic and chromatographic analyses. Resveratrol was determined to be a highly potent inhibitor of human TYR (IC 50 = 0.39 g mL-1) as compared with p-coumaric acid (IC 50 = 0.66 g mL-1) and arbutin (IC 50 > 100 g mL-1) and inhibited melanin synthesis by human epidermal melanocytes at subtoxic concentrations. This study suggests that resveratrol and resveratrol-containing extracts of Vitis Viniferae Caulis have a potential use as skin whitening agents. © 2013 Jiaa Park and Yong Chool Boo.

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 Y.-H.,Kyungpook National University | Kim S.Y.,Kyungpook National University | Bae Y.-S.,Kyungpook National University
Molecules and Cells | Year: 2014

We have previously shown that microRNAs (miRNAs) miR-760, miR-186, miR-337-3p, and miR-216b stimulate premature senescence through protein kinase CK2 (CK2) downregulation in human colon cancer cells. Here, we examined whether these four miRNAs are involved in the replicative senescence of human lung fibroblast IMR-90 cells. miR-760 and miR-186 were significantly upregulated in replicatively senescent IMR-90 cells, and their joint saction with both miR-337-3p and miR-216b was necessary for efficient downregulation of the α subunit of CK2 (CK2 α) in IMR-90 cells. A mutation in any of the four miRNA-binding sequences within the CK2α 3′-untranslated region (UTR) indicated that all four miRNAs should simultaneously bind to the target sites for CK2α downregulation. The four miRNAs increased senescence-associated β-galactosidase (SA-β-gal) staining, p53 and p21Cip1/WAF1 expression, and reactive oxygen species (ROS) production in proliferating IMR-90 cells. CK2α overexpression almost abolished this event. Taken together, the present results suggest that the upregulation of miR-760 and miR-186 is associated with replicative senescence in human lung fibroblast cells, and their cooperative action with miR-337-3p and miR-216b may induce replicative senescence through CK2α downregulation-dependent ROS generation. © The Korean Society for Molecular and Cellular Biology. All rights reserved.

Lee Y.-H.,Kyungpook National University | Bae Y.-S.,Kyungpook National University
FEBS Letters | Year: 2014

The expression of phospholipase D1 (PLD1) and PLD2 were found to decrease at the transcription level during both replicative and premature senescence in human lung fibroblast IMR-90 cells. Knockdown of PLD2 dramatically induced senescent phenotype in proliferating IMR-90 cells and wild-type HCT116 colon cancer cells, whereas this response was nearly abolished in p53- or p21 Cip1/WAF1-null HCT116 cells. PLD2 knockdown increased the intracellular reactive oxygen species (ROS). Antioxidant N-acetyl-l-cysteine, NADPH oxidase inhibitor apocynin, and p22phox small interfering RNA (siRNA) reduced ROS generation and thus suppressed the appearance of senescence markers. Elevated CK2 α subunit (CK2α) expression repressed PLD2 downregulation-mediated senescence. PLD2 overexpression increased protein kinase CK2 (also known as casein kinase 2) (CK2) activity. Taken together, these results show that PLD2 downregulation causes senescence through the p53-p21 Cip1/WAF1 pathway by stimulating ROS production, which is induced by CK2 inhibition. © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

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.

Background: One of the most difficult procedures through a deep and narrow surgical corridor is tying a knot following microsuturing, even though microvascular suturing is a fundamental technique for neurovascular surgeons. Methods: A novel technique replacing the conventional knot-tying method was devised. The proposed clip-knotting technique uses an aneurysm clip to hold both remaining ends of a thread that is sutured in a running manner. Conclusions: The proposed clip-knotting technique can facilitate the microsuturing procedure for intracranial arterial repair in a deep and narrow operative field. © 2015, Springer-Verlag Wien.

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.

Koo D.-M.,Kyungpook National University | Choi Y.-Y.,Kyungpook National University
Computers in Human Behavior | Year: 2010

Porter sites have tried to increase their business potentials by helping users easily engage in diverse online activities such as search, entertainment, online communities, and others. Knowledge search engine is one of the most successful killer applications increasing user loyalty. However, most studies have independently focused on search engine technology such as search keyword algorithm, presentation of information and user characteristics such as cognitive style, search experiences, and skill levels. However, these previous studies lack an integrated understanding of causal links among critical factors predicting user motives and intention involving more situation-specific user characteristics. To fill these gaps in the literature, the present study focuses on whether knowledge characteristics such as specialization, preciseness, and diversity, and system characteristics such as interactivity, responsiveness, and communication richness are important in forming user motives and intention. The present study also identifies a moderating role of epistemic curiosity in the links between motives and intention. Two hundred and fifty-five data from Korean university students confirmed that knowledge and services characteristics such as specialty, preciseness, diversity, communication richness improve user motives, which have a positive impact on intention. Epistemic curiosity has a moderating effect on the links between motives and intention. Theoretical and practical implications are discussed in conclusion. © 2009 Elsevier Ltd. All rights reserved.

Substantial halophilic organisms have been found in 100-200‰ salinities. These ranges represent a highly specialized halophilic environment to which only a few halotolerant species have adapted. Recent studies have underlined the existence of diverse obligately halophilic protozoa in the salinity ranges of 100-200‰. The ranges of salinity under which these organisms can grow have been examined to some extent, but the balance of specific ions that will support growth has not been investigated. The heterotrophic nanoflagellate Halocafeteria, the type strain of which grows optimally at 150‰ salinity and 35°C, is a commonly encountered obligate halophile found in very hypersaline environments. These extreme environments can vary in their Mg:Ca ratios (i. e. weight ratios) and sulfate concentrations. To examine growth response of Halocafeteria to the different chemical compositions, densities of Halocafeteria seosinensis strain EHF34 were monitored in seven different ion composition media for 9 days at 1- to 2-day intervals (at 150‰ salinity and 35°C, with no prey limitation). Halocafeteria does not grow at Mg:Ca ratios of 35 and 100 and at high sulfate concentrations of 11. 6 and 31. 6 g l -1. It grows well in 0. 6 g l -1 sulfate media at Mg:Ca ratios of 2, 10 or 35, but not 100. The present study demonstrates that the growth of the obligate halophile Halocafeteria can be affected by different ion compositions in hypersaline environments. Therefore, Halocafeteria may not be ubiquitous in hypersaline environments due to its ionic requirements. © 2011 Springer.

Cui X.,Kyungpook National University | Choo K.-H.,Kyungpook National University
Water Research | Year: 2013

Fine iron oxide particles (IOPs) are effective in removing natural organic matter (NOM) that causes membrane fouling in water treatment, but the separation of used IOPs is problematic. This study focused on the fabrication and use of granular iron oxide adsorbents, in combination with ultrafiltration (UF) membranes while investigating the NOM removal efficiency and fouling control. Sulfonated styrene-divinylbenzene copolymer beads were coated with two types of iron oxides (ferrihydrite and magnetite) and their performances were compared to that of fine IOPs. A significant amount of iron oxide coating (52-63mg of Fe per g bead) was achieved by means of electrostatic binding and hydrolysis of iron ions. Iron oxide coated polymer (IOCP) beads were able to remove some amounts (~20%) of dissolved organic carbon (DOC) comparable to that achieved by IOPs within a short period of time (<15min). Regenerated IOCPs exhibited the same sorption capacity as the fresh ones. The integrated IOCP/UF system operation with a 15-min empty bed contact time and 10-h cyclic regeneration maintained the 20% DOC removal with no sign of significant membrane fouling. In contrast, a sharp transmembrane pressure buildup occurred in the UF system when no iron oxide pretreatment was applied, regardless of the types of membranes tested. Iron oxide adsorbed the NOM fraction with molecular weights of > 1000kDa which is believed to be responsible for severe UF fouling. © 2013 Elsevier Ltd.

Ahmed I.,Kyungpook National University | Khan N.A.,Kyungpook National University | Hasan Z.,Kyungpook National University | Jhung S.H.,Kyungpook National University
Journal of Hazardous Materials | Year: 2013

A metal-organic framework (MOF) MIL-101 was impregnated with phosphotungstic acid (PWA) and used as an adsorbent in liquid phase adsorption of nitrogen-containing compounds (NCCs) from a model fuel. The model fuel contained one sulfur-containing compound (SCC), benzothiophene (BT); one basic NCC, quinoline (QUI); and one neutral NCC, indole (IND). In both MIL-101 and PWA-impregnated MIL-101s, NCC adsorption selectivity was very high compared to the SCC selectivity. Additionally, the adsorption capacity of basic QUI increased by 20% with only 1% PWA impregnation in MIL-101. The adsorption of a neutral compound, IND, was slightly reduced with PWA impregnation in the MOF. The adsorption capacity/selectivity can be remarkably improved by a slight modification of MOFs, for example, to impart acidity. The MOF impregnated with PWA may be very interesting in commercial denitrogenation, especially for coal-derived fuels which contain mainly basic NCCs, by adsorption since the selectivity for NCCs (compared to SCCs) over the adsorbent is very high and the adsorbent can be reused many times. © 2013 Elsevier B.V.

Choi Y.K.,Kyungpook National University | Park K.-G.,Kyungpook National University
Molecules and Cells | Year: 2013

Metformin is one of the most widely used anti-diabetic agents in the world, and a growing body of evidence suggests that it may also be effective as an anti-cancer drug. Observational studies have shown that metformin reduces cancer incidence and cancer-related mortality in multiple types of cancer. These results have drawn attention to the mechanisms underlying metformin's anti-cancer effects, which may include triggering of the AMP-activated protein kinase (AMPK) pathway, resulting in vulnerability to an energy crisis (leading to cell death under conditions of nutrient deprivation) and a reduction in circulating insulin/IGF-1 levels. Clinical trials are currently underway to determine the benefits, appropriate dosage, and tolerability of metformin in the context of cancer therapy. This review highlights fundamental aspects of the molecular mechanisms underlying metformin's anti-cancer effects, describes the epidemiological evidence and ongoing clinical challenges, and proposes directions for future translational research. © 2013 The Korean Society for Molecular and Cellular Biology and Springer Netherlands.

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.

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 J.E.,Kyungpook National University | Lee S.W.,Korea Advanced Institute of Science and Technology | Lee S.J.,Kyungpook National University
Psychiatry Research | Year: 2014

The aims of this study were to evaluate early maladaptive schemas (EMSs) of patients with obsessive-compulsive disorder (OCD) and to clarify relationships between particular EMSs and the five factor-analyzed symptom dimensions and other clinical variables. Fifty-seven patients with OCD and 70 normal controls completed the Young Schema Questionnaire, the Yale-Brown Obsessive Compulsive Scale (Y-BOCS), the Y-BOCS symptom checklist, and the Beck Depression Inventory. Patients with OCD had significantly higher scores for schema related to defectiveness/shame, social isolation/alienation, and failure than did normal controls. Among the five OCD symptom dimensions, the sexual/religious dimension was only significantly correlated with two schemas of vulnerability to harm or illness and enmeshment/undeveloped self. These two schemas were significant predictors of the sexual/religious dimension, accounting for 33% of the total variance in this dimension. Any EMSs in patients with OCD were not related to clinical variables such as severity of OCD and duration of illness. These findings may constitute evidence to improve our understandings of OCD from a perspective of schema theory. © 2013 Elsevier Ireland Ltd.

Koo D.-M.,Kyungpook National University | Ju S.-H.,Kyungpook National University
Computers in Human Behavior | Year: 2010

With increasing importance of online stores, a great number of studies have focused on extending our knowledge related to successful functional aspects increasing ease of use and usefulness. More recent studies have focused on identifying the effects produced by hedonic aspects of online store environment such as web atmospherics on emotional responses of customers. However, previous studies have been somewhat deficient in their investigation of studying diverse aspects of online consumer characteristics, which may have an impact on customer evaluation of atmospheric cues. Building on this research tradition, the present study addresses two critical issues. The present study adopting a well validated S-O-R framework tests the effect of atmospheric cues of online stores on the intervening affective emotional states of consumers, which have a subsequent impact on behavioral intention. Additionally, the model hypothesizes that perceptual curiosity (PC) moderates the relationships between atmospheric cues and shoppers' emotional reactions. Structure equation model confirmed that online atmospherics such as graphics, colors, and links have an impact on customer emotions such as pleasure and arousal, both of which have subsequent effects on intention. The moderating effect of perceptual curiosity has also been supported. Theoretical and practical implications, limitations, and directions for future research are discussed in conclusion. © 2009 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.

Lee Y.-H.,Kyungpook National University | Kang B.S.,Kyungpook National University | Bae Y.-S.,Kyungpook National University
Life Sciences | Year: 2014

Aims Cellular senescence is an important tumor suppression process in vivo. Tamoxifen is a well-known anti-breast cancer drug; however, its molecular function is poorly understood. Here, we examined whether tamoxifen promotes senescence in breast cancer and colon cancer cells for the first time. Main methods Human breast cancer MCF-7, T47D, and MDA-MB-435 and colorectal cancer HCT116 cells were treated with tamoxifen. Cellular senescence was measured by SA-β-gal staining and based on the protein expression of p53 and p21 Cip1/WAF1. The production of reactive oxygen species (ROS) was determined by staining with CM-H2DCFDA and dihydroethidium (DHE). CK2 activity was assessed with a specific peptide substrate. Key findings Tamoxifen promoted senescence phenotype and ROS generation in MCF-7 and HCT116 cells. The ROS scavenger, N-acetyl-l-cysteine (NAC), and the NADPH oxidase inhibitor, apocynin, almost completely abolished this event. Tamoxifen inhibited the catalytic activity of CK2. Overexpression of CK2α antagonized senescence mediated by tamoxifen, indicating that tamoxifen induced senescence via a CK2-dependent pathway. A well-known CK2 inhibitor, 5,6-dichloro-1-β-d- ribofuranosylbenzimidazole (DRB), also stimulated ROS production and senescence in MCF-7 cells. Finally, experiments using T47D (wild-type p53) and MDA-MB-435 (mutant p53) cell lines suggested that tamoxifen induces p53-independent ROS production as well as p53-dependent senescence in breast cancer cells. Significance These results demonstrate that tamoxifen promotes senescence through a ROS-p53-p21Cip1/WAF1 dependent pathway by inhibiting CK2 activity in breast cancer and colon cancer cells. © 2013 Elsevier Inc.

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.

Jo W.K.,Kyungpook National University | Shin S.H.,Kyungpook National University | Hwang E.S.,Kyungpook National University
Journal of Hazardous Materials | Year: 2011

The present study investigated the adsorptional photocatalytic decomposition (APD) efficiency of activated carbon fiber-supported TiO 2 (ACF/TiO 2) in a continuous-flow reactor for the removal of dimethyl sulfide (DMS). The SEM analysis identified that the ACF/TiO 2 exhibited the same tridimensional shape as uncovered ACF and that a TiO 2 photocatalyst could be embedded in the surface of the ACF. In the absence of UV light, the time-series removal efficiencies by ACF and the ACF/TiO 2 units exhibited a similar pattern, which decreased gradually as it reached close to zero. However, the APD efficiency determined via the ACF/TiO 2 with UV light remained at nearly 60% during the remaining courses of the 13-h period, after decreasing from a maximum APD of 80%. The APD efficiencies depended upon the weights of the TiO 2 embedded into the ACFs, the UV sources, the relative humidity, and DMS input concentrations. During a long-term (219-h) APD test, the APD efficiencies dropped from 80% to ca 60% within 1h after the initiation of the APD process and then fluctuated between 52% and 60%. No byproducts were measurable or observable in the effluent gas or on the ACF/TiO 2 surface. Consequently, the continuous-flow ACF/TiO 2 system could effectively be applied to control DMS without any significant functional deterioration. © 2011 Elsevier B.V.

Seo J.-G.,Kyungpook National University | Park S.-P.,Kyungpook National University
Journal of Headache and Pain | Year: 2015

Background: Psychiatric problems have been commonly reported in patients with migraine. This study investigated the reliability and validity of the Patient Health Questionnaire-9 (PHQ-9) and Patient Health Questionnaire-9 (PHQ-2) in patients with migraine. Methods: Patients with migraine (with or without aura) were consecutively recruited from our headache clinic. They completed several instruments, including the Mini International Neuropsychiatric Interview-Plus Version 5.0.0 (MINI), the PHQ-9, the Beck Depression Inventory-II (BDI-II), the Migraine Disability Assessment Scale (MIDAS), the Headache Impact Test-6 (HIT-6), and the Migraine-Specific Quality of Life (MSQoL). Results: Among 132 participants, 39 patients (29.5 %) had a major depressive disorder (MDD) as determined by the MINI. Cronbach’s α coefficients for the PHQ-9 and PHQ-2 were 0.894 and 0.747, respectively. At a cutoff score of 7, the PHQ-9 had a sensitivity of 79.5 %, a specificity of 81.7 %, a positive predictive value (PPV) of 64.6 %, and a negative predictive value (NPV) of 90.5 %. At a cutoff score of 2, the PHQ-2 had a sensitivity of 66.7 %, a specificity of 90.3 %, a PPV of 74.3 %, and a NPV of 86.6 %. The scores of the PHQ-9 and PHQ-2 well correlated with the BDI-II score, the MIDAS score, the HIT-6 score, and the MSQoL score. Conclusions: The PHQ-9 and PHQ-2 are both reliable and valid screening instruments for MDD in patients with migraine. © 2015, Seo and Park.

Jeong S.,Kyungpook National University | Lee M.,Kyungpook National University
Neural Networks | Year: 2012

This paper presents an adaptive object recognition model based on incremental feature representation and a hierarchical feature classifier that offers plasticity to accommodate additional input data and reduces the problem of forgetting previously learned information. The incremental feature representation method applies adaptive prototype generation with a cortex-like mechanism to conventional feature representation to enable an incremental reflection of various object characteristics, such as feature dimensions in the learning process. A feature classifier based on using a hierarchical generative model recognizes various objects with variant feature dimensions during the learning process. Experimental results show that the adaptive object recognition model successfully recognizes single and multiple-object classes with enhanced stability and flexibility. © 2011 Elsevier Ltd.

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.

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.

Wahid F.,Kyungpook National University | Shehzad A.,Kyungpook National University | Khan T.,COMSATS Institute of Information Technology | Kim Y.Y.,Kyungpook National University
Biochimica et Biophysica Acta - Molecular Cell Research | Year: 2010

MicroRNAs (miRNAs) are a class of small, endogenous RNAs of 21-25 nucleotides (nts) in length. They play an important regulatory role in animals and plants by targeting specific mRNAs for degradation or translation repression. Recent scientific advances have revealed the synthesis pathways and the regulatory mechanisms of miRNAs in animals and plants. miRNA-based regulation is implicated in disease etiology and has been studied for treatment. Furthermore, several preclinical and clinical trials have been initiated for miRNA-based therapeutics. In this review, the existing knowledge about miRNAs synthesis, mechanisms for regulation of the genome, and their widespread functions in animals and plants is summarized. The current status of preclinical and clinical trials regarding miRNA therapeutics is also reviewed. The recent findings in miRNA studies, summarized in this review, may add new dimensions to small RNA biology and miRNA therapeutics. © 2010 Elsevier B.V.

Lee M.K.,Kyungpook National University
European Journal of Oncology Nursing | Year: 2016

Purpose Advanced age is a significant risk factor for cancer and functional disabilities increase with age. The purpose of this case-control study of Korean individuals was to determine the effect of cancer and cancer treatment on functional disability and quality of life (QOL). Thus, we compared community-dwelling elderly cancer patients (ECPs) with individuals from the general elderly population (GEP) who never had diagnoses of cancer. Methods We selected 1776 ECP who were at least 65 years-old from the 2008 Korean Community Health Survey data and used propensity score matching to randomly select 1766 individuals from the GEP who closely resembled the ECPs. Functional disability was measured using the Instrumental Activities of Daily Living (IADL) scale, and QOL was measured by the EuroQol Group EQ-5D. Results ECPs were more dependent in preparation of food, doing laundry, and shopping (IADL scale), and in mobility and usual activities (EQ-5D). Although ECP had more problems with pain, discomfort, anxiety, and depression, they were more independent in self-care and handling of financial responsibilities. Conclusions ECPs had multiple physical and psychological symptoms that adversely affected functional disability and QOL, but higher functional ability, such as self-care and handling of financial responsibilities. Promotion of self-care by ECPs is pivotal for effective management in community practice. © 2016 Elsevier Ltd

Kavitha T.,PSGR Krishnammal College For Women | Kavitha T.,Kyungpook National University | Yuvaraj H.,Yeungnam University
Journal of Materials Chemistry | Year: 2011

This report describes a new approach to successfully synthesize high-quality nickel oxide (NiO) nanorods with an average diameter of about 60 nm and a length of less than one micrometre via thermal decomposition of a precursor complex nickel benzoate dihydrazinate at 100 °C. The structural features, crystallinity, purity and morphology of the as-synthesized NiO nanorods were investigated by Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), selected area electron diffraction (SAED) and transmission electron microscopy (TEM). The electrochemical property of the as-synthesized NiO nanorods was investigated to determine their suitability as anode materials for lithium-ion batteries. The nanorod electrode exhibited better reversibility and high capacity. In addition, the nanorods showed good antibacterial properties. The magnetic measurement demonstrated that the NiO nanorods are ferromagnetic and may be used in the fields of MR imaging and magnetic drug delivery. © 2011 The Royal Society of Chemistry.

Jeon T.H.,Kyungpook National University | Choi W.,Pohang University of Science and Technology | Park H.,Kyungpook National University
Physical Chemistry Chemical Physics | Year: 2011

BiVO4 semiconductor electrodes were coupled with cobalt-phosphate complexes (CoPi) to enhance the photoelectrochemical (PEC) performance for water oxidation reaction. CoPi was deposited on a 550 nm-thick BiVO4 film via electrodeposition (ED) and photodeposition (PD) methods for comparison of their effects. The CoPi on BiVO4 exhibited Co:P atomic ratios of approximately 1:7 for the electrodeposited sample and approximately 1:18 for the photodeposited sample, and Co2+ and Co3+ co-existed in both samples. Optimized CoPi ED resulted in a CoPi overlayer of approximately 850 nm thick, which showed an electrochromic-like behavior that was likely due to limited access of phosphate into BiVO 4 across the CoPi layer. Optimized CoPi PD, however, had very thin and rather uniform CoPi dispersion and did not show electrochromic-like behavior. Despite the lesser amount of CoPi, the PEC performance of BiVO 4/CoPi (PD) was comparable to that of BiVO4/CoPi (ED). Real-time measurements of the headspace molecular oxygen that evolved from water oxidation indicated that CoPi enhances O2 production and photocurrent generation at BiVO4 by a factor of around 15 and a maximum of 20, respectively, at 0.576 VSCE (equivalent to 1.23 V RHE) under air mass 1.5 irradiation (400 mW cm-2). Prolonged irradiation of BiVO4/CoPi (ED) resulted in a reduced Co:P ratio to 1:1.77 without changing the mixed valency of Co(ii/iii). This finding indicates that incorporation of phosphate into the CoPi was kinetically slower than water oxidation. The primary role of CoPi has been suggested as a hole-conducting electrocatalyst making the photogenerated electrons more mobile and, consequently, increasing conductivity and boosting the PEC water oxidation performance of BiVO4. © 2011 the Owner Societies.

Kim H.J.,Kyungpook National University | Choi G.-S.,Kyungpook National University | Park J.S.,Kyungpook National University | Park S.Y.,Kyungpook National University
Diseases of the Colon and Rectum | Year: 2014

BACKGROUND: Little data are available about the learning curve for robotic rectal resection. OBJECTIVE: The purpose of this work was to provide a multidimensional analysis of the learning process in patients undergoing robotic total mesorectal excision for rectal cancer. DESIGN: This was a retrospective review of a prospectively collected database designed to evaluate the results of robotic rectal resection. SETTINGS: The study was conducted at a tertiary-care hospital. PATIENTS: From December 2007 to August 2012, 167 patients who underwent robotic total mesorectal excision for rectal cancer were included. MAIN OUTCOME MEASURES: A single hybrid variable including operative time, conversion, perioperative morbidity, and circumferential margin was generated to measure the success of the procedure. A moving average method for operative time and a risk-adjusted cumulative sum analysis were used to derive the learning curve. RESULTS: Overall conversion was noted in 2 cases (1.2%). The cumulative sum plot of a single hybrid variable representing the success of each operation demonstrated that the composite event was more frequent at the beginning of the series and began to decrease after 32 cases. The moving average for robotic console time decreased steadily and showed 2 plateaus; the first plateau was noted after 33 cases, and the second plateau was noted after 72 cases. The learning process was divided into 3 phases based on 2 cutoff points. The robotic console time decreased significantly with each phase (p < 0.001). Complicated rectal cancer was more frequent in the later phases; however, the incidence of postoperative complications remained constant throughout the series (p = 0.82). LIMITATIONS: This study is limited by a single surgeon's experience. CONCLUSIONS: The learning process for robotic total mesorectal excision has a greater effect on the first 32 cases. These results help form a basis for performance monitoring of robotic total mesorectal excision. © The ASCRS 2014.

Baek W.-Y.,Kyungpook National University | Kim J.-E.,Kyungpook National University
Frontiers in Bioscience - Scholar | Year: 2011

Bone formation in vertebrates depends on the proliferation and differentiation of chondrocytes and osteoblasts, which are derived from a mesenchymal precursor cells and are required for skeletal development. This process relies on many transcription factor genes that have functions in bone cell proliferation and differentiation. Over the years, various transcription factors that play essential roles for skeletal formation have been identified in in vivo and/or in vitro molecular and genetic studies. In regulation of bone formation, signaling pathways with these factors have also been established. Major transcription factors including Sox9, Runx2, and Osterix, which are active in chondrocytes or osteoblasts or even in both cells, are indispensable for chondrocyte and/or osteoblast differentiation. Here, the transcriptional regulation of these genes for bone formation will be reviewed on the basis of in vivo mouse models.

Lee S.-J.,Kyungpook National University | Park S.-Y.,Dongguk University | Jung M.-Y.,Kyungpook National University | Bae S.M.,Kyungpook National University | Kim I.-S.,Kyungpook National University
Blood | Year: 2011

Aged or damaged RBCs are effectively removed from the blood circulation by Kupffer cells in the liver, but little is known regarding the mechanism of the clearance process. Here we show that stabilin-1 and stabilin-2 in hepatic sinusoidal endothelial cells (HSECs) are critical in effectively clearing damaged RBCs in mouse liver. Damaged RBCs and phosphatidylserine (PS)-coated beads were effectively sequestered in the hepatic sinusoid regardless of the presence of Kupffer cells, suggesting a role for HSECs in PS-dependent sequestration of PS-exposed RBCs in the liver. HSECs mediate tethering of damaged RBCs in a PS-dependent manner via stabilin-1 and stabilin-2. In a sinusoid-mimicked coculture system consisting of macrophages layered over HSECs, there was significant enhancement of the phagocytic capacity of macrophages, and this was mediated by stabilin-1 and stabilin-2 in HSECs. Liver-specific knockdown of stabilin-1 and stabilin-2 inhibited the sequestration of damaged RBCs in the hepatic sinusoid and delayed the elimination of damaged cells in an in vivo animal model. Thus, the roles of stabilin-1 and stabilin-2 in hepatic sequestration of PS-exposed RBCs may represent a potential mechanism for the clearance of damaged RBCs by Kupffer cells and for the control of some pathologic conditions such as hemolytic anemia. © 2011 by The American Society of Hematology.

Khan A.A.,Kyungpook National University | Cha H.,Kyungpook National University | Kim H.-G.,Kyungpook National University
IEEE Transactions on Industrial Electronics | Year: 2016

In this paper, a family of three-phase direct pulse-width modulated (PWM) ac-ac converters consisting of buck, boost, and buck-boost converters is proposed. The proposed converters have no commutation problem even if all of the switches are turned on or off simultaneously. They do not use lossy snubbers and do not sense the voltage polarity for commutation, and produce high-quality output voltage waveforms. The proposed converters allow the use of power MOSFETs and fast recovery freewheeling diodes independently. The use of power MOSFETs as active switches and freewheeling diodes with extremely fast recovery features lower the switching losses and enable us to reduce the volume of passive components by increasing switching frequency. The input (or output) filter inductor experiences twice of the converter switching frequency and thus can be designed with minimum size. To increase power density of the proposed converters, a three-phase three-limb coupled inductor is proposed. Three-phase coupled inductor integrates three separate coupled inductors of the proposed converters in one three-limb core. In comparison with separate coupled inductors, the three-phase coupled inductor has a smaller size with large currenthandling capability. Experimental results obtained for the boost-type converter show the robustness of the proposed three-phase ac-ac converters. © 2015 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.

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.

Seo J.H.,Kyungpook National University | Sohn S.H.,Kyungpook National University
Materials Letters | Year: 2010

The surface of (Y,Gd)BO3:Eu3+ phosphor, red-emitting source in the plasma display panel (PDP), was dual-coated with SiO2 and Al2O3 nano-particles. The surface modification of the phosphor was performed by a modified sol-gel method using the colloidal alumina and silica as surface coating precursors. We observed the oxide nano-particles on the surface of the single coated and the dual-coated phosphors and it was found that the luminance intensity was increased in the photoluminescence (PL) by a suppression of the nonradiative recombination via surface defects. The experimental results suggest that the surface modification of phosphors with nano-particles of the oxides leads to an increase in the luminance intensity of phosphors in the PDP (plasma display panel) and the gas discharge lamps. © 2010 Elsevier B.V. All rights reserved.

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.

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.

Park C.-S.,Kyungpook National University | Tae H.-S.,Kyungpook National University
Applied Physics Letters | Year: 2010

It is found that temporal image sticking in ac plasma display panels (PDPs) is predominantly induced by organic impurities, such as CxH y, on the MgO surface. The vacuum ultraviolet produced during a short sustain discharge dissociates these organic impurities, such as C xHy, into C and H, where the latter then combines with the O from the MgO surface, resulting in the production of chemical compounds, including H2O, that lower the luminance by hindering the visible conversion of the phosphor layer. Thus, according to this mechanism, minimizing the residual organic impurities, such as CxHy, on the MgO surface is a key factor for removing temporal image sticking. Therefore, to reduce the residual impurity level on the MgO layer of a 50 in. full-high definition (HD) ac-PDP with an He (35%)-Xe (11%) content, the MgO layer is given rf-plasma treatment using various gases, and the experimental results show that Ar plasma treatment was most effective in eliminating the residual impurities on the MgO layer and thereby improving the temporal image sticking. © 2010 American Institute of Physics.

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.

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.

Zhang Q.,Samsung | Jeong S.,Kyungpook National University | Lee M.,Kyungpook National University
Neurocomputing | Year: 2012

In this paper, we propose an autonomous emotion development system with incremental learning for interacting with human subjects, and autonomously understanding the emotional status of humans. For the understanding of human emotion the proposed system needs human-like visual senses perceiving natural scenes as stimuli. According to the relationship between emotional factors and characteristics of an image, we incorporate the fuzzy concept to extract emotional features using L*C*H* color and orientation information. Additionally, it can sense inputs that have no analog in human senses-reading brain signals in human subjects. We consider the electroencephalography (EEG) signals which are stimulated by natural stimuli to form the semantic emotional features as well. We develop a novel adaptive neuro-fuzzy inference system (ANFIS) based on an incremental learning algorithm to autonomously develop the capability of understanding complex emotions. The proposed incremental modified ANFIS needs only the newly arrived data to adjust the shape of Gaussian membership functions with full covariance matrix, to generate new membership functions or new rules for labeling emotion according to the characteristics of the new data. Utilizing the developmental process, the proposed system can autonomously develop the mental ability to understand more complex human emotions by mining the characteristics of emotional features and interacting with human subjects. © 2012 Elsevier B.V.

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.

Yang S.H.,Kyungpook National University | Natarajan U.,Kyungpook National University
International Journal of Advanced Manufacturing Technology | Year: 2010

Optimization techniques using evolutionary algorithm (EA) are becoming more popular in engineering design and manufacturing activities because of the availability and affordability of high-speed computers. In this work, an attempt was made to solve multi-objective optimization problem in turning by using multi-objective differential evolution (MODE) algorithm and non-dominated sorting genetic algorithm(NSGA-II). Optimization in turning means determination of the optimal set of machining parameters to satisfy the objectives within the operational constraints. These objectives may be minimum tool wear, maximum metal removal rate or any weighted combination of both. The main machining parameters which are considered as variables of the optimization are cutting speed, feed rate, and depth of cut. The optimum set of these three input parameters is determined for a particular job-tool combination of EN24 steel and tungsten carbide during a single-pass turning which minimizes the tool wear and maximizes the metal removal rate after satisfying the constraints of temperature and surface roughness. The regression models, developed for tool wear, temperature, and surface roughness were used for the problem formulation. The non-dominated solution set obtained from MODE was compared with NSGA-II using the performance metrics and reported © 2009 Springer-Verlag London Limited.

Cui X.,Kyungpook National University | Choo K.-H.,Kyungpook National University
Environmental Engineering Research | Year: 2014

Natural organic matter (NOM) is a primary component of fouling in low-pressure membrane filtration, either solely, or in concert with colloidal particles. Various preventive measures to interfere with NOM fouling have been developed and extensively tested, such as coagulation, oxidation, ion exchange, carbon adsorption, and mineral oxide adsorption. Therefore, this article aims to conduct a literature review covering the topics of low-pressure membrane processes, NOM characteristics and fouling behaviors, and diverse fouling control strategies. In-depth explanations and discussion are made regarding why some treatment options are able to remove NOM from source water, but do not reduce fouling. This review provides insight for hybridized membrane processes with respect to NOM removal and fouling mitigation in water treatment. © 2014 Korean Society of Environmental Engineers.

Younis A.,Kyungpook National University | Younis A.,University of Agriculture at Faisalabad | Hwang Y.-J.,Sahmyook University | Lim K.-B.,Kyungpook National University
Plant Cell Reports | Year: 2014

Key Message: Efficient induction of unreduced gamete in different crops and its genetic consequences will open new avenues for plant breeding. Unreduced gamete formation derived via abnormal meiotic cell division is an important approach to polyploidy breeding. This process is considered the main driving force in spontaneous polyploids formation in nature, but the potential application of these gametes to plant breeding has not been fully exploited. An effective mechanism for their artificial induction is needed to attain greater genetic variation and enable efficient use of unreduced gametes in breeding programs. Different approaches have been employed for 2n-pollen production including interspecific hybridization, manipulation of environmental factors and treatment with nitrous oxide, trifluralin, colchicine, oryzalin and other chemicals. These chemicals can act as a stimulus to produce viable 2n pollen; however, their exact mode of action, optimum concentration and developmental stages are still not known. Identification of efficient methods of inducing 2n-gamete formation will help increase pollen germination of sterile interspecific hybrids for inter-genomic recombination and introgression breeding to develop new polyploid cultivars and increase heterozygosity among plant populations. Additionally, the application of genomic tools and identification and isolation of genes and mechanisms involved in the induction of 2n-gamete will enable increased exploitation in different plant species, which will open new avenues for plant breeding. © 2013 Springer-Verlag Berlin Heidelberg.

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.

Kim E.,Kyungpook National University | Choi J.,Kyungpook National University
Fibers and Polymers | Year: 2011

Dyeing characteristics and fastness of 100 % m-aramid fiber with some commercial dyes were investigated on various dyeing conditions, such as using a swelling agent and electrolyte as auxiliaries. Among commercial dyes used, the basic dyes showed comparatively higher exhaustion yield comparing to those of disperse dyes and acid dyes. Under acidic conditions in the range pH 3 to 5, preferably between pH 3 and 4, the stability of cationic dyes could be enhanced leading to higher adsorption. Dye exhaustions of trichromatic dyes were increased proportionally to concentration of swelling agents ranging from 1 to 4 g/l. The addition of electrolyte provided increased K/S values after washing process compared with those of blank dyeings, where the greatest effect was observed with NaNO3. © 2011 The Korean Fiber Society and Springer Netherlands.

Chae D.W.,Kyungpook National University | Hong S.M.,Korea Institute of Science and Technology
Macromolecular Research | Year: 2011

Poly(vinylidene fluoride) (PVDF) composites containing multiwalled carbon nanotubes (MWNTs) in the range from 0.1 to 5 wt% were prepared at 220 °C using a melt-mixer. The storage modulus (G′) of the PVDF/MWNT composites increased with increasing MWNT content. In particular, there was a significant increase in G′ between 1 and 3 wt%. In the Cole-Cole plot, the PVDF composites with up to 1 wt% MWNTs exhibited a single master curve with a slope of 1.25, but the composites containing 3 and 5 wt% MWNTs showed a decreased slope of 1.13 and 1.03, respectively. From the addition of 3 wt% MWNTs, the yield of the PVDF composites was observed in complex viscosity versus complex modulus plot with little dependence on the loss tangent (tan δ) on the frequency was shown. Both the induction time and crystallization time obtained from the G′ versus time plot decreased with increasing MWNT content. The promoting effect of the MWNTs on the overall crystallization behavior was more profound at higher crystallization temperatures. Pure PVDF and PVDF with 0.1 wt% MWNTs showed only α phase crystals, but the PVDF composites with high concentrations of MWNTs (1-5 wt%) appeared to contain a mixture of β and γ phases in addition to the α phase. [Figure not available: see fulltext.] © 2011 The Polymer Society of Korea and Springer Netherlands.

Seong W.J.,Kyungpook National University
Archives of Gynecology and Obstetrics | Year: 2016

Objective: The purpose of this study was to investigate whether amniotic fluid (AF) CA-125 in patients with preterm labor or preterm premature rupture of membranes can help predict intra-amniotic inflammation (IAI), microbial invasion of the amniotic cavity (MIAC) and imminent delivery. Methods: We recruited 36 women who admitted with impending preterm delivery and suspicious AF infection. AF matrix metalloproteinase-8 (MMP-8), white blood cell (WBC) count, glucose levels, and CA-125 levels were measured, and the MMP-8 bedside rapid test was also performed. AF culture and PCR were subsequently performed to confirm MIAC. We compared AF CA-125 levels according to the presence of IAI or MIAC and assessed its predictive value for delivery within 7 days of admission. Results: AF CA-125 levels were significantly higher in the IAI group than in the non-IAI group (mean ± standard deviation: 5608 ± 864 vs 904 ± 84 IU/ml; p = 0.001). AF CA-125 levels showed a negative correlation with gestational age and a positive correlation with AF WBC counts and MMP-8 levels. AF CA-125 levels were higher in the MIAC group, though this difference was not statistically significant (p = 0.064). Delivery within 7 days of admission was significantly more common in patients with higher AF CA-125 levels (cut-off: 1650 IU/ml, sensitivity: 71.4 %, specificity: 86.4 %, p = 0.005). Conclusion: AF CA-125 levels are increased in patients with AF inflammation and can be a predictor of imminent preterm delivery. © 2015, Springer-Verlag Berlin Heidelberg.

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.

Kim Y.,Kyungpook National University | Lee C.,Kyungpook National University
Virus Research | Year: 2013

Porcine reproductive and respiratory syndrome virus (PRRSV) and porcine epidemic diarrhea virus (PEDV) are porcine nidoviruses that represent emerging viral pathogens causing heavy economic impacts on the swine industry. Although ribavirin is a well-known antiviral drug against a broad range of both DNA and RNA viruses in vitro, its inhibitory effect and mechanism of action on porcine nidovirus replication remains to be elucidated. Therefore, the present study was conducted to determine whether ribavirin suppresses porcine nidovirus infection. Our results demonstrated that ribavirin treatment dose-dependently inhibited the replication of both nidoviruses. The antiviral activity of ribavirin on porcine nidovirus replication was found to be primarily exerted at early times post-infection. Treatment with ribavirin resulted in marked reduction of viral genomic and subgenomic RNA synthesis, viral protein expression, and progeny virus production in a dose-dependent manner. Investigations into the mechanism of action of ribavirin against PRRSV and PEDV revealed that the addition of guanosine to the ribavirin treatment significantly reversed the antiviral effects, suggesting that depletion of the intracellular GTP pool by inhibiting IMP dehydrogenase may be essential for ribavirin activity. Further sequencing analysis showed that the mutation frequency in ribavirin-treated cells was similar to that in untreated cells, indicating that ribavirin did not induce error-prone replication. Taken together, our data indicate that ribavirin might not only be a good therapeutic agent against porcine nidovirus, but also a potential candidate to be evaluated against other human and animal coronaviruses. © 2012 Elsevier B.V.

Mun G.I.,Kyungpook National University | Boo Y.C.,Kyungpook National University
American Journal of Physiology - Heart and Circulatory Physiology | Year: 2010

The mechanism that is responsible for progression of atherosclerosis seen with increasing age remains controversial. This issue was addressed in the present study, by searching for genes that are uniquely expressed in senescent endothelial cells and functionally involved in inflammatory leukocyte adhesion recognized as a critical step in the initiation of atherogenesis. Senescent human umbilical vein endothelial cells (HUVECs) prepared by continuous subculturing in vitro showed higher binding affinity for monocytes (THP-1 cells, human acute monocytic leukemia cell line) compared with young cells. Gene expression profiles between young and senescent endothelial cells were compared by the cDNA microarray method, and CD44 was identified as one of the "senescence-induced cell adhesion genes" whose expression was upregulated in senescent cells and whose gene ontology annotation indicated their role in cell adhesion. The enhanced gene expression of CD44 in senescent endothelial cells was verified both at the mRNA and protein levels. Adhesion of monocytes to senescent endothelial cells was significantly reduced following pretreatment of endothelial cells with the CD44 antibody or small-interfering RNA, thus reinforcing the critical role of CD44 in the inflammatory event. Exogenous expression of CD44 in young HUVECs and in human aortic endothelial cells led to an increase in monocyte adhesion. CD44 expression levels in the rat aorta endothelium were found to increase in an age-dependent manner, as determined by immunohistochemistry and Western blotting. CD44 and other senescence-induced cell adhesion genes identified in this study may provide the novel targets for the prevention of inflammatory leukocyte adhesion leading to the development atherosclerosis. Copyright © 2010 the American Physiological Society.

Kim J.,Kyungpook National University | Jung K.-J.,Kyungpook National University | Park K.M.,Kyungpook National University
American Journal of Physiology - Renal Physiology | Year: 2010

Reactive oxygen species (ROS) function as an inducer of cell death and survival or proliferative factor, in a cell-type-specific and concentration-dependent manner. All of these roles are critical to ischemia-induced renal functional impairment and progressive fibrotic changes in the kidney. In an effort to define the role of ROS in the proliferation of tubular epithelial cells and of interstitial cells in kidneys recovering after ischemia and reperfusion (I/R) injury, experimental mice were subjected to 30 min of bilateral kidney ischemia and administered with manganese(III) tetrakis(1-methyl-4-pyridyl) porphyrin (MnTMPyP), a superoxide dismutase mimetic, from 2 to 15 days after I/R for 14 days daily (earlier and longer) and from 8 to 15 days after I/R for 8 days daily (later and shorter). Cell proliferation was assessed via 5′-bromo-2′-deoxyuridine (BrdU) incorporation assays for 20 h before the harvest of kidneys. After I/R, the numbers of BrdU-incorporating cells increased both in the tubules and interstitium. MnTMPyP administration was shown to accelerate the proliferation of tubular epithelial cells, presenting tubule-specific marker proteins along tubular segments, whereas it attenuated the proliferation of interstitial cells, evidencing α-smooth muscle actin, fibroblast-specific protein-1, F4/80, and NADPH oxidase-2 proteins; these results indicated that ROS attenuates tubular cell regeneration, but accelerates interstitial cell proliferation. Earlier and longer MnTMPyP treatment more effectively inhibited tissue superoxide formation, the increment of interstitial cells, and the decrement of epithelial cells compared with later and shorter treatment. After I/R, apoptotic cells appeared principally in the tubular epithelial cells, but not in the interstitial cells, thereby indicating that ROS is harmful in tubule cells, but is not in interstitial cells. In conclusion, ROS generated after I/R injury in cell proliferation and death performs a cell-type-specific and concentration-dependent role, even within the same tissues, and timely intervention of ROS is crucial for effective therapies. Copyright © 2010 the American Physiological Society.

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.

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.

Charchoghlyan H.,Kyungpook National University | Park H.-D.,Kyungpook National University
Food Hydrocolloids | Year: 2013

A bacterial strain, designated KMBL 5781, producing a high level of extracellular biopolymer was isolated from soil and identified as Mitsuaria chitosanitabida based on the 16S rRNA gene sequences. The biopolymer was purified by the sequential precipitation using ethanol, cethyl trimethyl ammonium bromide and then ethanol again. Its molecular weight was estimated to be about 54.7 kDa by the MALDI-TOF analysis. GC-MS analysis revealed that it is a polysaccharide consisting of glucose, mannose and galactose with approximate molar ratio of 18:6:1. In lower concentrations such as 0.5% and 1% viscosities of the EPS solution was higher than that of the xanthan gum used as a control. At the final range of shear rate the viscosity of 0.5% EPS was 34 cP while 0.5% xanthan showed 19.8 cP. The 1% EPS solution at the same rate has shown 59 cP and the viscosity of 1% Xanthan was 35 cP. When heated from 20 to 92 °C, the EPS solution (2%) remain stable from room temperature until 60 °C and showed significantly higher viscosity at 92 °C than 2% xanthan. The EPS hydrogel (2%) was strongly stable, which released no water during the incubation at 4 °C for 20 days and even after the tubes containing the gel was centrifuged at 4000× g for 10 min. Addition of the EPS into the starch solution resulted in the increase the weight and volume of the gel. © 2012 Elsevier Ltd.

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.

Park C.,Kyungpook National University | Lee D.G.,Kyungpook National University
Biochemical and Biophysical Research Communications | Year: 2010

Melittin is a well-known antimicrobial peptide with membrane-active mechanisms. In this study, it was found that Melittin exerted its antifungal effect via apoptosis. Candida albicans exposed to Melittin showed the increased reactive oxygen species (ROS) production, measured by DHR-123 staining. Fluorescence microscopy staining with FITC-annexin V, TUNEL and DAPI further confirmed diagnostic markers of yeast apoptosis including phosphatidylserine externalization, and DNA and nuclear fragmentation. The current study suggests that Melittin possesses an antifungal effect with another mechanism promoting apoptosis. © 2010 Elsevier Inc. All rights reserved.

Jung U.J.,Kyungpook National University | Choi M.-S.,Kyungpook National University
International Journal of Molecular Sciences | Year: 2014

Accumulating evidence indicates that obesity is closely associated with an increased risk of metabolic diseases such as insulin resistance, type 2 diabetes, dyslipidemia and nonalcoholic fatty liver disease. Obesity results from an imbalance between food intake and energy expenditure, which leads to an excessive accumulation of adipose tissue. Adipose tissue is now recognized not only as a main site of storage of excess energy derived from food intake but also as an endocrine organ. The expansion of adipose tissue produces a number of bioactive substances, known as adipocytokines or adipokines, which trigger chronic low-grade inflammation and interact with a range of processes in many different organs. Although the precise mechanisms are still unclear, dysregulated production or secretion of these adipokines caused by excess adipose tissue and adipose tissue dysfunction can contribute to the development of obesity-related metabolic diseases. In this review, we focus on the role of several adipokines associated with obesity and the potential impact on obesity-related metabolic diseases. Multiple lines evidence provides valuable insights into the roles of adipokines in the development of obesity and its metabolic complications. Further research is still required to fully understand the mechanisms underlying the metabolic actions of a few newly identified adipokines. © 2014 by the authors; licensee MDPI, Basel, Switzerland.

Jo W.-K.,Kyungpook National University | Kim J.-D.,Kyungpook National University
Chemosphere | Year: 2010

The present study measured the levels of 24 selected volatile organic compounds (VOCs) in the personal air samples obtained from graduate students attending the college of natural sciences (GSNSs) or social science (GSSSs) during their daily activities on campus along with associated indoor and outdoor air samples. In addition, the sources of their personal exposure were characterized using multivariate statistical models. In the personal samples of GSNSs and GSSSs, 16 and 15 different VOCs were always detected, respectively. The personal exposure of five chlorinated hydrocarbons and six aromatics was significantly higher for GSNSs than for GSSSs. Consistently, the indoor levels of these compounds were higher for GSNSs (in research and laboratory rooms) than for GSSSs (in research rooms). However, the personal exposure of two aromatic VOCs (1,2,4- and 1,3,5-trimethylbenzene) was higher for GSSSs. Moreover, the personal exposure of the five chlorinated and six aromatic compounds was significantly correlated with VOC concentrations both in the research and laboratory rooms of GSNSs and with those in the research rooms of GSSSs. For certain VOCs, outdoor sources were also a major contributor to the personal exposure of both GSNSs and GSSSs. The multivariate models identified five factors that accounted for 81% of the total variance and four factors that explained 76% of the total variance. It was further suggested that multiple indoor sources in research rooms such as office equipment, building finishing materials, and air fresheners were the main source for the personal exposure to VOCs for GSNSs, whereas building finishing materials were the main source for GSSSs. © 2010 Elsevier Ltd.

Lee S.M.,Kyungpook National University | Park J.Y.,Kyungpook National University | Kim D.S.,Kyungpook National University
Molecules and Cells | Year: 2012

Lung cancer remains a global health problem with a high mortality rate. CpG island methylation is a common aberration frequently associated with gene silencing in multiple tumor types, emerging as a highly promising biomarker. The transmembrane protein with a single EGF-like and two follistatin domains (TMEFF2) is epigenetically silenced in numerous tumor types, suggesting a potential role as a potential tumor suppressor. However, the role of TMEFF2 in lung cancer remains to be fully elucidated. We explored the methylation status of TMEFF2 gene in 139 patients with non-small cell lung cancer (NSCLC) and the feasibility of detecting circulating methylated DNA as a screening tool for NSCLC using methylation-specific PCR in 316 patients and 50 age-matched health controls. TMEFF2 methylation in tumor tissues was found in 73 of the 139 NSCLCs (52.5%) and was related to gene expression. The frequency of TMEFF2 methylation was higher in females and never-smokers than in males and smokers with borderline significance (65.8% vs 47.8%, p = 0.06; 65.7% vs 48.1%, p = 0.07). Notably, in adenocarcinomas, TMEFF2 methylation was significantly more frequent in tumors without EGFR mutation than those with EGFR mutation (adjusted odds ratio = 7.13, 95% confidence interval = 2.05-24.83, P = 0.002). Furthermore, TMEFF2 methylation was exclusively detected in the serum of NSCLC patients at a frequency of 9.2% (29/316). These findings suggest that methylation-Associated down-regulation of TMEFF2 gene may be involved in lung tumorigenesis and TMEFF2 methylation can serve as a specific blood-based biomarker for NSCLC. © The Korean Society for Molecular and Cellular Biology. All rights reserved.

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.

Helal A.,Kyungpook National University | Kim H.-S.,Kyungpook National University
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2013

An electron donating carbazole incorporated thiazole (3) based Zn 2+ selective intrinsic chemosensor has been synthesized and investigated. It was found that electron donating substituents such as methyl and carbazole on chemosensor (1) produce remarkable red shift in emission upon complexation with Zn2+. The sensor shows a selective fluorescence response with Zn2+ over biologically relevant cations (Ca 2+, Mg2+, Na+, and K+) and biologically non-relevant cations (Cd2+, In3+ and Ga 3+) in an aqueous ethanol system. It also produce an enhancement in the quantum yield and a longer emission wavelength shift on Zn2+ binding with the potential of a ratiometric assay. © 2012 Elsevier B.V. All rights reserved.

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.

Khan M.,Kyungpook National University
Proceedings of the ACM Symposium on Applied Computing | Year: 2015

Providing uninterrupted internet services in heterogeneous wireless networks is a difficult job to accomplish. Traditional approaches are limited to specific scenarios. Therefore, to provide a generic connectivity in heterogeneous wireless networks, we proposed a vertical handover management scheme based on the data rate of a mobile user. The proposed scheme performs handover triggering using Simple Additive Weighting (SAW) and Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) to select the optimal network for the handover. The proposed scheme is compared with Media Independent Handover (MIH) standard in the context of handover delay, packet loss ratio, throughput, and failed handovers. The proposed scheme outperform MIH standard and due to its simple architecture it can be used with existing technologies. Copyright 2015 ACM.

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.

Hyun D.C.,Kyungpook National University
Macromolecular Rapid Communications | Year: 2015

This paper describes a simple system for multi-agent delivery. The system consists of a biodegradable polymer particle with a hollow interior, together with a hole on its surface that can be completely or partially sealed via thermal annealing. A hydrophobic dye, Nile-red, entrapped within the shell of hollow particles presents a sustained release behavior while methylene blue, a hydrophilic model agent, encapsulated in the hollow interior shows a fast release manner. The release profiles of the probes can be further independently controlled by encapsulating methylene blue-loaded polymer nanoparticles, instead of free dye, in the hollow particle with a small hole on its surface. A simple dual-agent delivery system, consisting of a hollow particle entrapping Nile-red in its shell and methylene blue-loaded nanoparticles, can deliver the agents in a temporally distinct manner. A small-sized hole on the surface of the hollow particle prevents the undesired escape of the encapsulated nanoparticles from the hollow interiors, thereby keeping the independent release of methylene blue. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Moon P.-G.,Kyungpook National University | You S.,Pohang University of Science and Technology | Lee J.-E.,Kyungpook National University | Hwang D.,Pohang University of Science and Technology | Baek M.-C.,Kyungpook National University
Mass Spectrometry Reviews | Year: 2011

A number of highly abundant proteins in urine have been identified through proteomics approaches, and some have been considered as disease-biomarker candidates. These molecules might be clinically useful in diagnosis of various diseases. However, none has proven to be specifically indicative of perturbations of cellular processes in cells associated with urogenital diseases. Exosomes could be released into urine which flows through the kidney, ureter, bladder and urethra, with a process of filtration and reabsorption. Urinary exosomes have been recently suggested as alternative materials that offer new opportunities to identify useful biomarkers, because these exosomes secreted from epithelial cells lining the urinary track might reflect the cellular processes associated with the pathogenesis of diseases in their donor cells. Proteomic analysis of such urinary exosomes assists the search of urinary biomarkers reflecting pathogenesis of various diseases and also helps understanding the function of urinary exosomes in urinary systems. Thus, it has been recently suggested that urinary exosomes are one of the most valuable targets for biomarker development and to understand pathophysiology of relevant diseases. © 2011 Wiley Periodicals, Inc.

Shehzad A.,Kyungpook National University | Khan S.,Seoul National University | Sup Lee Y.,Kyungpook National University
Future Oncology | Year: 2012

Obesity is characterized as an increased BMI, which is associated with the increased risk of several common cancers, including colorectal, breast, endometrial, renal, esophageal, gallbladder, melanoma, multiple myeloma, leukemia, lymphoma and prostate cancer. The increased risk of obesity-related cancers could be mediated by insulin resistance, adipokines, obesity-related inflammatory cytokines, sex hormones, transcription factors and oxidative stress, which disrupt the balance between cell proliferation and apoptosis. The yellowish compound, curcumin (diferuloylmethane), is known to possess multifaceted pharmacological effects. The molecular mechanisms linking obesity to cancer risk, and how curcumin mediates anticancer and obesity activities, have not yet been publicized. Curcumin modulates multiple molecular targets and reverses insulin resistance as well as other symptoms that are associated with obesity-related cancers. In this study, we show that ample evidence exists to support recommendations that curcumin mediates multiple molecular pathways, and is considered to be of therapeutic value in the treatment and prevention of obesity-related cancers. © 2012 Future Medicine Ltd.

Jeon H.,Kyungpook National University | Boo Y.C.,Kyungpook National University
Biochemical and Biophysical Research Communications | Year: 2013

The senescent endothelial cells show various phenotypes which can increase the incidence of inflammatory cardiovascular diseases, but the fundamental basis for such phenotypic changes of senescing cells remains to be elucidated. This study was undertaken to find transmembrane receptors that might be highly expressed in senescent endothelial cells and play a key role in cell death signal transduction. Comparison of mRNA expression in young and senescent human umbilical vein endothelial cells, using a cDNA microarray method, provided a list of transmembrane receptors including the FAS receptor (tumor necrosis factor receptor superfamily member 6) whose expression levels were significantly increased by cellular senescence. Additional studies focused on FAS demonstrated that a high expression of FAS receptor in senescent endothelial cells is responsible for the susceptibility to apoptotic cell death, as the siRNA-mediated suppression of FAS expression in senescent cells prevented the cell death, and overexpression of exogenous FAS in young cells increased cell death. We also verified that FAS expression level was closely associated with the activation of caspase-3 and caspase-9 involved in apoptosis. The senescence-induced transmembrane receptors including the FAS receptor may provide novel therapeutic targets to prevent cardiovascular diseases. © 2013 Elsevier Inc.

Jo W.-K.,Kyungpook National University | Kim J.-T.,Kyungpook National University
Journal of Chemical Technology and Biotechnology | Year: 2010

BACKGROUND: Unlike many water pollution applications, visible-light-driven photocatalysis of gas-phase pollutants has been reported only rarely. The present study was performed to investigate the feasibility of applying S-doped visible-light-induced TiO2 to treat gas-phase aromatic hydrocarbons, using a continuous air-flow annular-type reactor. RESULTS: The prepared S-enhanced TiO2 powders, along with a commercially available TiO 2 powder (Degussa P-25), were characterized using diffuse reflectance UV-VIS-NIR spectrophotometry, Fourier transform infrared (FTIR) spectrophotometry, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and thermogravimetry (TG) analyses. A photocatalytic activity test exhibited an increasing trend in degradation reaction rates with increase in flow rate but a decreasing trend in terms of degradation efficiencies. Several experimental conditions induced reasonably high decomposition efficiencies with respect to toluene, ethyl benzene and o,m,p-xylenes (close to or above 90%), although benzene exhibited a somewhat lower decomposition efficiency. CONCLUSIONS: The S-doped TiO2 and undoped P25 TiO2 powders exhibited different catalyst characteristics. The results demonstrate that an annular-type reactor coatedwith visible-light-activated S-doped TiO2 can serve as an effective tool to treat gas-phase aromatic hydrocarbon streams. © 2009 Society of Chemical Industry.

Lee C.,Keimyung University | Park G.H.,Kyungpook National University | Lee S.-R.,Keimyung University | Jang J.-H.,Keimyung University
Oxidative Medicine and Cellular Longevity | Year: 2013

β -amyloid peptide (A β), a major component of senile plaques, plays important roles in neuropathology of Alzheimer's disease (AD). An array of in vitro and in vivo data indicates that A β -induced neuronal death is mediated by oxidative stress. In this study, we aimed to investigate effects of sulforaphane (SUL), an isothiocyanate in cruciferous vegetables, on A β -induced oxidative cell death in SH-SY5Y cells. Cells treated with A β 25 - 35 exhibited decreased cell viability and underwent apoptosis as determined by MTT assay and TUNEL, respectively. A β 25 - 35 -induced cytotoxicity and apoptotic characteristics such as activation of c-JNK, dissipation of mitochondrial membrane potential, altered expression of Bcl-2 family proteins, and DNA fragmentation were effectively attenuated by SUL pretreatment. The antiapoptotic activity of SUL seemed to be mediated by inhibition of intracellular accumulation of reactive oxygen species and oxidative damages. SUL exerted antioxidant potential by upregulating expression of antioxidant enzymes including γ-glutamylcysteine ligase, NAD(P)H:quinone oxidoreductase-1, and heme oxygenase-1 via activation of NF-E2-related factor 2(Nrf2). The protective effect of SUL against A β 25 - 35 -induced apoptotic cell death was abolished by siRNA of Nrf2. Taken together, the results suggest that pharmacologic activation of Nrf2 signaling pathway by SUL might be a practical prevention and/or protective treatment for the management of AD. © 2013 Chan Lee et al.

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 about 31 taxa of the green algae (Chlorophytes) collected from several swamps, reservoir and highland wet-lands in the South Korea from 2010 to 2013. This paper deals with a total 31 taxa including of 26 genera which are recorded for the first time in Korea. Among these algae, 18 genera including Pyrobotrys Arnoldi, Volvulina Playfair, Dicellula Svirenko, Echinocoleum Jao & Lee, Hofmania Chodat, Gloeotila Kützing, Tetrachlorella Korschikov, Botryospherella P.C.Silva etc., were newly recorded in Korean fresh-water algal flora. © 2013 The Ecological Society of Korea. All rights are 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.

Kim J.,Kyungpook National University | Roh Y.,Kyungpook National University
Sensors and Actuators, A: Physical | Year: 2014

The objective of this work is to derive the full material constants of an equivalent single phase material to replace the complex-structured PMN-28%PT (lead magnesium niobate-28%lead titanate)/epoxy 1-3 composite in finite element analysis (FEA) of acoustic transducers. No attempts have been made to derive full material constants of the homogenized PMN-PT/epoxy piezocomposites. In this study, the equivalent properties were derived by extensive resonance analyses and the FEM. The PMN-28%PT crystals have tetragonal 4 mm symmetry and thus have eleven independent material constants in total. FE models of piezocomposite resonators of six different configurations were constructed to analyze all possible vibration modes of the composite. All the material constants of the equivalent single phase material were extracted from the simulation data with the FE models so that the equivalent material can have identical resonant characteristics as the full complex-structured PMN-PT/epoxy composite. The validity of the homogenization technique and the accuracy of the equivalent material constants were verified by comparing the impedance spectra of the single phase resonators with those of the full-structured piezocomposite resonators. The accuracy and efficacy of the homogenized material constants was verified further by comparing the performance of multi-layered hydrophones made of the full-structured 1-3 piezocomposite as well as the equivalent single phase material. The homogenization procedure can be applied to 1-3 piezocomposites with an arbitrary volume fraction of the PMN-PT single crystal. © 2013 Elsevier B.V.

Chen L.,Kyungpook National University | Kang Y.-H.,Kyungpook National University
Journal of Functional Foods | Year: 2013

Red pepper stalks, an agricultural waste product, are casually discarded at landfills where they oxidize and harm the local ecology. To our knowledge, no feasible method has been designed to evaluate the bioavailability of red pepper stalks. Therefore, the present study focused on the stalk waste investigating its superoxide dismutase (SOD) activity and inhibitory effect on nitric oxide (NO) production in macrophages. Interestingly, by comparison with red pepper pericarp and placenta extracts, the stalks were found to have higher phenolic, flavonoid, and capsaicin contents. Chromatographic data showed differences in the amounts of phenolic compounds in various parts of red pepper. At a concentration of 100. μg/mL, the stalk, placenta, and pericarp had SOD activities of 52.3%, 7.4%, and 10.4%, respectively. A very high level of chlorogenic acid (3.82. mg/g. d. w) and p-coumaric acid (2.98. mg/g. d. w) gave the stalks of red peppers the most powerful antioxidant activity among the three tested parts. The high phenolic and SOD activity-containing stalks also had the most significant NO inhibitory effect (53.5%) in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. These results demonstrated that there is an opportunity to develop a new anti-inflammatory agent from agricultural wastes. © 2013 Elsevier Ltd.

Kim B.,Inje University | Chae Y.H.,Kyungpook National University | Choi H.S.,Hongik University
Tribology International | Year: 2014

The purpose of this study is to investigate the effects of the geometry and distribution of microdimples on the frictional behavior of surfaces for applications in automotive engines. A square array of microscale circular dimples was selected as the texture pattern. A laser beam was used to create microdimples with various dimensions on cast iron surfaces. Frictional tests were performed with selected loads and speeds to simulate the operation conditions of automotive engine parts. The effects of dimple distribution were also investigated. The aspect ratio of the dimples was found to be the most significant factor, while the effect of the surface density of the dimples on the coefficient of friction was found to be only marginal. © 2013 Elsevier Ltd.

Kim S.,Kyungpook National University | Park T.I.,Kyungpook National University
International Journal of Clinical and Experimental Medicine | Year: 2013

Naringenin is present abundantly in citrus fruits and is one of the natural alternatives to synthetic estrogen, but the mechanism of how naringenin functions is not well known. Our study revealed that the relative estro-genic potency of the substances was E2 > genistein > naringenin. Naringenin (at 5 μM) was found to repress both lu-ciferase activity and pS2 mRNA expression, which was induced by E2 (at 0.1 μM) or genistein (at 5 μM). Naringenin, as well as E2 and genistein, was found to modulate the transcription of pS2 and TGFβ3 in T47D-KBluc cells through an estrogen receptor-dependent mechanism. Results of our study indicated that naringenin was a weak estrogen agonist that exhibits anti-estrogenic effect in estrogen-rich states and estrogenic activity in estrogen-defcient states in T47D-KBluc breast cancer cells.

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.

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.

Ahmed I.,Kyungpook National University | Jhung S.H.,Kyungpook National University
Materials Today | Year: 2014

Metal-organic frameworks (MOFs) are one of the most discussed materials of the last decade. Their extraordinary porosity and functionality from metals and organic linkers make them one of the most promising materials for a vast array of applications. The easy tunability of their pore size and shape from the micro- to meso-scale, by changing the connectivity of the inorganic moiety and the nature of the organic linkers, makes these materials special. Moreover, by combining with other suitable materials, the properties of MOFs can be improved further for enhanced functionality/stability, ease of preparation and selectivity of operation. In this review, various methods and paths for the preparation of composites are discussed, especially for those which have been successfully applied to gas and liquid phase adsorptions. In the second part of this paper, several applications in adsorptive processes are discussed. © 2014 Elsevier Ltd. All rights reserved.

Kim H.B.,Kyungpook National University | Lee H.S.,Kyungpook National University
Thin Solid Films | Year: 2014

Solution-processed thin film transistors (TFTs) using a magnesium zinc tin oxide (MZTO, Ma-Zn-Sn-O) channel layer were fabricated and bias-stress stability during device operation was evaluated. The cause of the bias-stress instability was investigated through comparison with zinc tin oxide (ZTO, Zn-Sn-O) TFTs. The MZTO layers had a significantly lower oxygen vacancy concentration than the ZTO layer, which affected the electrical characteristics as well as bias-stress stability of MZTO TFTs. When 2 mol% Mg was added, a more stable transistor was attained, showing a typical semiconductor behavior with a saturation mobility of 0.27 cm2/V·s, on/off ratio of 3.3 × 106, off-current of 5.3 × 10- 12A, and threshold voltage of 5.4 V. © 2013 Elsevier B.V.

Kim J.S.,Kyungpook National University | Kim G.-W.,Kyungpook National University
Sensors and Actuators, A: Physical | Year: 2014

This paper presents a preliminary study investigating the development of a new type of non-contacting torque sensor based on the mechanoluminescence (ML) of a new microparticle (ZnS:Cu), which is intended to address the ML intensity decay present in a previous prototype torque measurement system with a conventional microparticle (SAO). An ad hoc heuristic model of hysteresis is proposed to characterize the loading rate-dependent characteristics of the ML intensity emitted from ZuS:Cu microparticle, and to estimate the torque input. The sinusoidal torque applied to a rotational shaft is successfully measured with a small error range by sensing the ML intensity without contacting. This study provides potential applications for the development of new non-contacting torque sensing technology widely used in various industrial areas such as automotives, robotics, rotors, and turbines. © 2014 Elsevier B.V.

Chen L.,Kyungpook National University | Kang Y.-H.,Kyungpook National University
Journal of Functional Foods | Year: 2013

As the world's population continues to increase, the agricultural discards of plant origin have attracted considerable attention for various purposes in the pharmaceutical and food industry. The objective of present study was to evaluate the potential of oriental melon (Cucumis melo L. var. makuwa Makino) seed for management of hyperglycaemia-linked to type 2 diabetes. Ethanol and hexane extracts from oriental melon seed were used to evaluate their inhibitory activities against α-glucosidase and α-amylase. Low phenolic-containing hexane extract exhibited much higher inhibitory activities against α-glucosidase and α-amylase than ethanol extract. The GC-MS result revealed that hexane extract constituted linoleic acid (29.6%), oleic acid (17.3%), and palmitic acid (6.5%). At high concentration, hexane extract exhibited strong inhibitory activities against α-glucosidase (35.3%) and α-amylase (61.8%). These in vitro studies indicated that hexane extract of oriental melon seed could be used as a potent alternative for controlling type 2 diabetes. © 2013 Elsevier Ltd.

Lee W.,Kyungpook National University | Ku S.-K.,Daegu Haany University | Bae J.-S.,Kyungpook National University
Vascular Pharmacology | Year: 2014

Endothelial cell protein C receptor (EPCR) can be shed from the cell surface, and this process is mediated by tumor necrosis factor-α converting enzyme (TACE), and high levels of soluble EPCR are involved in vascular inflammation. Orientin, one of the C-glycosyl flavonoids, has been known to have anxiolytic and antioxidative activities. However, the effect of orientin on lipopolysaccharide (LPS)-induced inflammatory response has not been studied. Here we investigated the barrier protective effects of orientin against pro-inflammatory responses induced by LPS and the associated signaling pathways. We found that orientin inhibited LPS-induced barrier disruption, expression of cell adhesion molecules (CAMs), and adhesion/transendothelial migration of monocytes to human endothelial cells. Orientin induced potent inhibition of phorbol-12-myristate 13-acetate (PMA) and LPS-induced EPCR shedding. Orientin also suppressed LPS-induced hyperpermeability and leukocyte migration in vivo. Furthermore, orientin suppressed the production of tumor necrosis factor-α (TNF-α) or Interleukin (IL)-6 and the activation of nuclear factor-κB (NF-κB) or extracellular regulated kinases (ERK) 1/2 by LPS. Moreover, treatment with orientin resulted in reduced LPS-induced lethal endotoxemia. These results suggest that orientin protects vascular barrier integrity by inhibiting hyperpermeability, expression of CAMs, and adhesion and migration of leukocytes, thereby endorsing its usefulness as a therapy for vascular inflammatory diseases. © 2014 Elsevier Inc.

Jung H.Y.,Kyungpook National University | Yi S.,Kyungpook National University
Journal of Alloys and Compounds | Year: 2013

The effect of Cu addition on the glass forming ability, nanocrystallization process and soft magnetic properties of the Fe76.5C 6.0Si3.3B5.5P8.7 bulk metallic glass has been studied. In spite of relatively high C contents of the alloy, with only 0.5% Cu addition, the primary phase was successfully changed from metastable carbide Fe23C6 phase to stable alpha-Fe phase and the nucleation rate at the early stage of crystallization was significantly increased. Nanocrystallization of the Fe76.0C6.0Si 3.3B5.5P8.7Cu0.5 (at.%) bulk metallic glass was studied through isothermal annealing treatments at temperature below the crystallization temperature of the alloy. With annealing at Tx - 50 °C for 30 min, a large number of very fine regions (<3 nm) with ordered atomic arrangements embedded in the amorphous matrix were observed. Upon further annealing, nanocrystals of alpha-Fe phase were formed improving soft magnetic properties of the sample, which confirms the soft magnetic nanocrystallization phenomenon in Fe76.0C 6.0Si3.3B5.5P8.7Cu0.5 (at.%) bulk metallic glass. By controlling the annealing parameters as well as minor Cu contents, magnetic properties of the Fe76.5C 6.0Si3.3B5.5P8.7 (at.%) bulk metallic glass were effectively optimized for practical applications. © 2013 Elsevier B.V. All rights reserved.

Jeong Y.S.,Kyungpook National University | Kim H.,Kyungpook National University | Lee H.S.,Kyungpook National University
Journal of Alloys and Compounds | Year: 2013

p-Cu2O/n-ZnO nanorod heterojunctions were fabricated by a two-step process. The process was performed with potentiostatic deposition of n-ZnO nanorods on conductive indium-tin-oxide (ITO) glasses followed by potentiostatic deposition of p-Cu2O to form p-Cu2O/n-ZnO nanorod heterojunctions. The deposition condition required to form the cuprous oxide layer affected significantly the formation and microstructure of the p-Cu2O/n-ZnO nanorod heterojunctions. In particular, the high-quality p-Cu2O/n-ZnO nanorod heterojunctions were obtained only at relatively high temperatures of 90 and 100 C. The p-Cu2O/n-ZnO nanorod heterojunctions exhibited a well-defined p-n diode characteristic with an ideality factor of about 4.3. © 2013 Elsevier B.V. All rights reserved.

Cheng J.,Kyungpook National University | Yi S.,Kyungpook National University | Park J.S.,Hanbat National University
International Journal of Refractory Metals and Hard Materials | Year: 2013

The oxidation behavior of Nb-Si-B alloys with NbSi2 coating layers was investigated at 1100 C under ambient atmosphere. Continuous NbSi 2 layers with a thickness of 40-60 μm were coated by depositing Si on the alloy surfaces at 900 C using a pack cementation technique. A sharp interface was observed between the NbSi2 layer and the pure Nb, while a (Nb5Si3 + T2) two-phase region formed between the NbSi2 layer and the alloy with the T2 phase composition. During oxidation, a glassy SiO2 layer formed significantly increasing the oxidation resistance of the coated alloys. However, evaporation of B occurred forming a porous SiO2 layer during the oxidation of the alloys with high B content. The oxidation behavior of the coated pure Nb and T2 phase alloys is discussed based on a microstructural analysis of the oxidized samples. © 2013 Elsevier Ltd. All rights reserved.

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.

Tatinati S.,Kyungpook National University | Veluvolu K.C.,Kyungpook National University
The Scientific World Journal | Year: 2013

We propose a hybrid method for forecasting the wind speed. The wind speed data is first decomposed into intrinsic mode functions (IMFs) with empirical mode decomposition. Based on the partial autocorrelation factor of the individual IMFs, adaptive methods are then employed for the prediction of IMFs. Least squares-support vector machines are employed for IMFs with weak correlation factor, and autoregressive model with Kalman filter is employed for IMFs with high correlation factor. Multistep prediction with the proposed hybrid method resulted in improved forecasting. Results with wind speed data show that the proposed method provides better forecasting compared to the existing methods. © 2013 Sivanagaraja Tatinati and Kalyana C. Veluvolu.

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

Withaferin A (WFA), an active compound from Withania somnifera, is widely researched for its anti-inflammatory, cardioactive and central nervous system effects. However, antiplatelet, anticoagulant, and profibrinolytic properties of WFA have not been studied. In this study, the anticoagulant activities of WFA were measured by monitoring activated partial thromboplastin-time (aPTT), prothrombin time (PT), fibrin polymerization, platelet aggregation, thrombus formation, and the activities of cell-based thrombin and activated factor X (FXa). The effects of WFA on the expressions of plasminogen activator inhibitor type 1 (PAI-1) and tissue-type plasminogen activator (t-PA) were also tested in tumor necrosis factor-α (TNF-α) activated human umbilical vein endothelial cells (HUVECs). Our data showed that WFA inhibited thrombin-catalyzed fibrin polymerization and platelet aggregation, FeCl3-induced thrombus formation, prolonged aPTT and PT significantly and inhibited the activities and production of thrombin and FXa. WFA prolonged in vivo and ex vivo bleeding time and inhibited TNF-α induced PAI-1 production. Furthermore, PAI-1/t-PA ratio was significantly decreased by WFA. Collectively, these results indicate that WFA possesses antithrombotic activities and suggest that the current study could provide bases for the development of new anticoagulant agents. © 2014 Elsevier Inc.

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.

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.

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.

Bae J.-S.,Kyungpook National University | Lee W.,Kyungpook National University | Rezaie A.R.,Saint Louis University
Journal of Thrombosis and Haemostasis | Year: 2012

Background: Recent results have indicated that polyphosphate, released by activated platelets, can function as a procoagulant to modulate the proteolytic activity of serine proteases of the blood clotting cascade. Objective: To determine whether polyphosphate is involved in inducing signal transduction in cellular and animal models. Methods: The effect of polyphosphate on human umbilical vein endothelial cells was examined by monitoring cell permeability, apoptosis and activation of NF-κB after treating cells with different concentrations of polyphosphate. Moreover, the expression of cell surface adhesion molecules (VCAM-1, ICAM-1 and E-selectin) and the adhesion of THP-1 cells to polyphosphate-treated cells were monitored using established methods. In the in vivo model, the pro-inflammatory effect of polyphosphate was assessed by monitoring vascular permeability and migration of leukocytes to the peritoneal cavity of mice injected with polyphosphate. Results: Polyphosphate, comprised of 45, 65 and 70 phosphate units, enhanced the barrier permeability and apoptosis in cultured endothelial cells and up-regulated the expression of cell adhesion molecules, thereby mediating the adhesion of THP-1 cells to polyphosphate-treated endothelial cells. These effects of polyphosphate were mediated through the activation of NF-κB and could not be recapitulated by another anionic polymer, heparin. Polyphosphate also increased the extravasation of the bovine serum albumin (BSA)-bound Evans blue dye and the migration of leukocytes to the mouse peritoneal cavity, which was prevented when activated protein C (APC) was intravenously (i.v.) injected 2h before the challenge. Conclusion: Polyphosphate, in addition to up-regulation of coagulation, can elicit potent pro-inflammatory responses through the activation of NF-κB, possibly contributing to the pro-inflammatory effect of activated platelets. © 2012 International Society on Thrombosis and Haemostasis.

Wang S.,Kyungpook National University | Park J.-T.,Kyungpook National University
IEEE Communications Letters | Year: 2010

Network reliability is very important in wireless body area network since the vital human life might be jeopardized, unless managed properly. In this article, a new modeling and analysis of node behaviors in wireless body area networks is presented for increasing reliability in the presence of multi-type failures, while saving energy. First, the nodes are classified into types with regard to their capabilities on relaying and sensing. Then, the node behaviors in the presence of failures such as energy exhaustion and/or malicious attacks have been modeled using a novel semi-Markov process. Finally, simulation has been done to evaluate the performance. © 2010 IEEE.

Shrestha Y.K.,Kyungpook National University | Lee K.-Y.,Kyungpook National University
Journal of Invertebrate Pathology | Year: 2012

The oral toxicity of culture media of the symbiotic bacteria, Photorhabdus temperata, mutually associated with entomopathogenic nematode Heterorhabditis megidis and Photorhabdus luminescens ssp. laumondii (TT01) mutually associated with Heterorhabditis bacteriophora, were investigated in the adults of Bemisia tabaci. The oral ingestion of sucrose diet solutions (20%) containing bacteria-free supernatant of the culture media from symbiotic bacteria gradually increased mortalities and was completely lethal at 60. h after the treatments, whereas the mortalities of the controls, sucrose solutions with or without media that uncultured with bacteria, were less than 17% up to 84. h of incubation. The effects of oral ingestion of symbiont culture media were demonstrated on the expression rates of several genes of B. tabaci using quantitative real-time RT-PCR analysis. Genes associated with immunity (knottin) and nervous system (acetylcholine receptor, acetylcholine esterase and sodium channel) were up-regulated while genes involved in metabolism (cytochrome p450 and carboxylesterase) were down-regulated, but genes involved in development (ecdysone receptor), reproduction (vitellogenin) and stress (hsp70, hsp90 and shsp) did not change transcription rates. Our results provide information for the understanding of the mechanism of symbiont pathogenic factors for the manipulation of host physiology at the transcription level. © 2011 Elsevier Inc.

Khan N.A.,Kyungpook National University | Jhung S.H.,Kyungpook National University
Angewandte Chemie - International Edition | Year: 2012

A molecular sieve: A metal-organic framework (MOF) MIL-47 loaded with CuCl 2 shows the highest adsorption capacity for benzothiophene because of the presence of Cu I ions derived from Cu II ions and porous MIL-47. The Cu I ions were obtained by reduction of Cu II with V III ions in MIL-47. The modified MOF could be successfully used for the desulfurization of a liquid fuel (see picture). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

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.

Choi Y.,Kyungpook National University
IEICE Transactions on Information and Systems | Year: 2013

An automotive operating system is a typical safety-critical software and therefore requires extensive analysis w.r.t its effect on system safety. Our earlier work [1] reported a systematic model checking approach for checking the safety properties of the OSEK/VDX-based operating system Trampoline. This article reports further performance improvement using embeddedC constructs for efficient verification of the Trampoline model developed in the earlier work. Experiments show that the use of embeddedC constructs greatly reduces verification costs. Copyright © 2013 The Institute of Electronics, Information and Communication Engineers.

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.

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.

Hoang K.T.,Kyungpook National University | Yang S.H.,Kyungpook National University
Journal of Materials Processing Technology | Year: 2013

In micro electrical discharge machining (μEDM), since the discharge energy is very low and is usually performed by a resistor-capacitor (RC) generator the discharge process is highly complex and unpredictable. In addition, due to low discharge energy the discharge is unstable and the machining efficiency is reduced as a result of poor flushing condition in a very small gap. This greatly affects the productivity and limits micro EDM applications. This paper presents development methods to improve the machining efficiency of a widely accepted non-traditional machining process, micro wire electrical discharge machining (WEDM), using non-ultrasonic vibration. It is found that when vibration is applied to the micro-WEDM process, discharge is much more effective with fewer short circuits. From experiment results, it is observed that greater improvement can be achieved when the vibration is applied to the workpiece rather than to the wire. With vibration applied to the workpiece, machining efficiency can be increased by 2.5 times greater than without vibration and 1.5 times compared to the case vibration is applied to the wire. In addition, there exists an optimum relation between vibration parameters, energy and feedrate such that EDM at a constant feedrate can further improve the machining efficiency. © 2013 Elsevier B.V. All rights reserved.

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.

Yoon T.H.,Kyungpook National University | Joo E.K.,Kyungpook National University
IEEE Signal Processing Magazine | Year: 2010

Regarding window functions used in spectral analysis, the most important performance measures are 3-dB bandwidth and sidelobe attenuation. For many window functions, Hanning and Hamming for example, we have no control over a window's 3-dB bandwidth and sidelobe attenuation for a given window length. For other window functions¿Kaiser, Gaussian, and Chebyshev "we can reduce those windows" 3-dB bandwidth to get improved spectral resolution. However, with these later window functions (what we refer to as "conventional windows"), spectral resolution improvement comes at the expense of sidelobe attenuation reduction that degrades our ability to avoid undesirable spectral leakage. Likewise we can increase those windows sidelobe attenuation, but only by sacrificing desirable spectral resolution. This article describes a novel window function that enables us to control both its 3-dB bandwidth (spectral resolution) and sidelobe attenuation (spectral leakage) independently. © 2006 IEEE.

Baek D.K.,Kyungpook National University | Ko T.J.,Yeungnam University | Yang S.H.,Kyungpook National University
Journal of Materials Processing Technology | Year: 2013

We present a new fabrication method that enables precision hole machining to be achieved by sacrificing the coating on the substrate in ultrasonic machining (USM). A hard wax coating is deposited on the glass substrate, and holes are precisely fabricated in the coated glass using USM. Finally, a wax coating is removed using a cleaning process. The wax coating protects the surface of the glass so that cracks are generated in the wax rather than on the surface. The surface accuracy of the glass substrate is evaluated at the hole entrance using the new tools in USM as a function of the thickness of the coating. The entrance diameters of the machined holes and the machining forces at the beginning of cutting are measured as a function of the thickness of the coating. The entrance cracks and out-of-roundness of the machined holes are generated in the sacrificed coating on the glass substrate; hence, the surface quality of the glass holes is enhanced in USM. © 2012 Elsevier B.V. All rights reserved.

Lee Y.J.,Kyungpook National University | Lee C.,Kyungpook National University
Virus Research | Year: 2010

Viruses are known to develop the ability to manipulate a variety of host cell signal transduction pathways in order to facilitate successful virus survival. However, to date, little is known about the intracellular signaling mechanisms involved in porcine reproductive and respiratory syndrome virus (PRRSV) replication. The extracellular signal-regulated kinase (ERK) pathway that transduces signals to modulate a wide range of cellular functions has been shown to regulate a number of viral infections. The present study therefore aimed to determine the role of this pathway during PRRSV infection in porcine alveolar macrophages. We found that the PRRSV infection induces early robust but transient activation of ERK1/2 by 6. h postinfection and thereafter the progressive decrease of its phosphorylation. However, the maximal induction of phosphorylated ERK1/2 seen at 6. h postinfection was inconsistent with synthesis of a viral nucleocapsid protein that was first evident by 12. h postinfection. These results indicate that ERK1/2 activation is mediated independently of viral gene expression during PRRSV replication. Notably, infection with UV-irradiated, inactivated virus, which is capable of receptor binding and internalization but prevents viral gene synthesis, was sufficient to trigger ERK1/2 phosphorylation, suggesting that the viral entry process may be responsible for early ERK activation. Treatment of cells with U0126, a selective ERK1/2 inhibitor, markedly diminished PRRSV infection and its inhibitory effect on PRRSV replication was exerted at the early stage in virus infection. Furthermore, inhibition of ERK activation resulted in significant suppression of subgenomic RNA transcription, viral protein translation, and progeny virus production. Taken together, the findings in this study suggest that the ERK signaling pathway plays an important role in postentry steps of the PRRSV replication cycle and beneficially contributes to viral infection. © 2010 Elsevier B.V.

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.

Helal A.,Kyungpook National University | Kim S.H.,Kyungpook National University | Kim H.-S.,Kyungpook National University
Tetrahedron | Year: 2013

A new reactive and highly selective fluorescent chemosensor (1) based on thiazole was synthesized for the quantification of aluminum ions in ethanol. The mechanism of fluorescence was based on the aluminum-promoted hydrolysis of the ester moiety and subsequent complexation. © 2013 Elsevier Ltd. All rights reserved.

Lee A.J.-H.,Columbia University | Awano T.,Columbia University | Park G.-H.,Kyungpook National University | Monani U.R.,Columbia University
PLoS ONE | Year: 2012

The selective vulnerability of motor neurons to paucity of Survival Motor Neuron (SMN) protein is a defining feature of human spinal muscular atrophy (SMA) and indicative of a unique requirement for adequate levels of the protein in these cells. However, the relative contribution of SMN-depleted motor neurons to the disease process is uncertain and it is possible that their characteristic loss and the overall SMA phenotype is a consequence of low protein in multiple cell types including neighboring spinal neurons and non-neuronal tissue. To explore the tissue-specific requirements for SMN and, especially, the salutary effects of restoring normal levels of the protein to neuronal tissue of affected individuals, we have selectively expressed the protein in neurons of mice that model severe SMA. Expressing SMN pan-neuronally in mutant mice mitigated specific aspects of the disease phenotype. Motor performance of the mice improved and the loss of spinal motor neurons that characterizes the disease was arrested. Proprioceptive synapses on the motor neurons were restored and defects of the neuromuscular junctions mitigated. The improvements at the cellular level were reflected in a four-fold increase in survival. Nevertheless, mutants expressing neuronal SMN did not live beyond three weeks of birth, a relatively poor outcome compared to the effects of ubiquitously restoring SMN. This suggests that although neurons and, in particular, spinal motor neurons constitute critical cellular sites of action of the SMN protein, a truly effective treatment of severe SMA will require restoring the protein to multiple cell types including non-neuronal tissue. © 2012 Lee et al.

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.

Son J.-W.,Kyungpook National University | Park S.-B.,Kyungpook National University
Applied Soft Computing Journal | Year: 2013

A table is a well-organized and summarized knowledge expression for a domain. Therefore, it is of great importance to extract information from tables. However, many tables in Web pages are used not to transfer information but to decorate pages. One of the most critical tasks in Web table mining is thus to discriminate meaningful tables from decorative ones. The main obstacle of this task comes from the difficulty of generating relevant features for discrimination. This paper proposes a novel discrimination method using a composite kernel which combines parse tree kernels and a linear kernel. Because a Web table is represented as a parse tree by an HTML parser, it is natural to represent the structural information of a table as a parse tree. In this paper, two types of parse trees are used to represent structural information within and around a table. These two trees define the structure kernel that handles the structural information of tables. The contents of a Web table are manipulated by a linear kernel with content features. Support vector machines with the composite kernel distinguish meaningful tables from decorative ones with high accuracy. A series of experiments show that the proposed method achieves state-of-the-art performance. © 2012 Elsevier B.V. All rights reserved.

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.

We compared the antiemetic efficacy of aprepitant plus palonosetron versus aprepitant plus ramosetron in patients after laparoscopic cholecystectomy. A total of 88, nonsmoking, female patients undergoing laparoscopic cholecystectomy were randomly allocated to 2 groups of 44 each who received palonosetron 0.075 mg (aprepitant plus palonosetron group) and ramosetron 0.3 mg (aprepitant plus ramosetron group) after induction of anesthesia. All patients received aprepitant 80 mg 2 hours before surgery. The incidence of postoperative nausea and vomiting (PONV), use of rescue antiemetic, pain severity, and any side effects were assessed for 24 hours after surgery. The incidence of PONV and use of rescue antiemetic were less in aprepitant plus palonosetron group than in aprepitant plus ramosetron group for 24 hours after surgery (P<0.05, respectively). There was no difference in pain severity and side effects including headache and drowsiness. Aprepitant plus palonosetron significantly prevents PONV, compared with aprepitant plus ramosetron in patients at high risk for PONV after laparoscopic cholecystectomy. Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.

Cinchona-based primary amine-catalyzed cascade aza-Michael-aldol reactions of α,β-unsaturated ketones with 2-(1H-pyrrol-2-yl)-2-oxoacetates provided highly functionalized chiral pyrrolizines bearing multistereocenters including a chiral quaternary carbon center in good yields (up to 92%) with excellent levels of stereocontrol (90-95% ee, >20:1 dr in all cases). The ketone group in the cascade product was asymmetrically reduced to chiral secondary hydroxyl groups in good yields. © 2013 American Chemical Society.

Shehzad A.,Kyungpook National University
Molecules and cells | Year: 2013

Curcumin (diferuloylmethane), the yellow pigment of turmeric, is one of the most commonly used and extensively studied phytochemicals due to its pleiotropic effects in several human cancers. In the current study, the therapeutic efficacy of curcumin was investigated in human colorectal carcinoma HCT-15 cells. Curcumin inhibited HCT-15 cells proliferation and induced apoptosis in a dose- and time-dependent manner. Hoechst 33342 and DCFHDA staining revealed morphological and biochemical features of apoptosis as well as ROS generation in HCT-15 cells treated with 30 and 50 μM curcumin. Over-expression of pre-mRNA processing factor 4B (Prp4B) and p53 mutations have been reported as hallmarks of cancer cells. Western blot analysis revealed that curcumin treatment activated caspase-3 and decreased expression of p53 and Prp4B in a time-dependent manner. Transfection of HCT-15 cells with Prp4B clone perturbed the growth inhibition induced by 30 μM curcumin. Fractionation of cells revealed increased accumulation of Prp4B in the nucleus, following its translocation from the cytoplasm. To further evaluate the underlying mechanism and survival effect of Prp4B, we generated siRNA-Prp4B HCT15 clones. Knockdown of Prp4B with siRNA diminished the protective effects of Prp4B against curcumin-induced apoptosis. These results suggest a possible underlying molecular mechanism in which Prp4B over-expression and activity are closely associated with the survival and regulation of apoptotic events in human colon cancer HCT-15 cells.

Yeo J.,Kyungpook National University | Jeon Y.,Kyungpook National University
Pain Physician | Year: 2015

Background: The sympathetic nervous system plays an important role in the arousal response. Recently, the stellate ganglion block (SGB) was found to effectively treat anxiety and night awakening in humans and decrease electroencephalogram (EEG) indices of arousal responses in rat. But, the role of the sympathetic block in human arousal responses has not yet been studied. Objective: We performed this prospective, double-blinded, controlled volunteer study to investigate the sedative effects and bispectral index (BIS) changes of SGB. Study Design: A randomized, double-blind trial. Setting: Single academic medical center. Methods: This study was approved by the Ethics Committee of Kyungpook National University Hospital (ref: KNUH_10-1081) and registered with CRiS (Clinical Research Information Service, http://cris.cdc.go.kr, ref: KCT0000036, 2010. 9.24). Twenty healthy volunteers were enrolled in this study. The volunteers were randomly assigned to one of 2 groups: the SGB group (n = 10) and the sham group (n =10). Volunteers in SGB group received SGB and volunteers in the sham group received a sham procedure. BIS value, heart rate, and blood pressure were measured before and 5, 10, 20, and 30 minutes after the procedure. Observer’s Assessment of Alertness/Sedation (OAA/S) scores were assessed before and 10 and 30 minutes after the intervention. Results: In the SGB group, BIS values and OAA/S scores significantly decreased after the intervention as compared to baseline (P < 0.05). The values were also significantly decreased in the SGB group when compared to the values in sham group after the intervention (P < 0.05). There was a significant change of mean blood pressure 10 to 30 minutes after SGB (P < 0.05). There were no differences in heart rate during study period between groups. Limitations: This study is limited by a relatively small sample size. Conclusions: This study showed that SGB has a sedative effect in normal healthy volunteers, as evidenced by decreased OAA/S scores and BIS values. © 2015, Association of Pain Management Anesthesiologists. All rights reserved.

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.

Choi H.-J.,Kyungpook National University | Jung H.J.,Kyungpook National University | Kwon T.-H.,Kyungpook National University
American Journal of Physiology - Renal Physiology | Year: 2015

Kidney collecting duct cells are continuously exposed to the changes of extracellular pH (pHe). We aimed to study the effects of altered pHe on desmopressin (dDAVP)-induced phosphorylation (Ser256, Ser261, Ser264, and Ser269) and apical targeting of aquaporin-2 (AQP2) in rat kidney inner medullary collecting duct (IMCD) cells. When freshly prepared IMCD tubule suspensions exposed to HEPES buffer with pH 5.4, 6.4, 7.4, or 8.4 for 1 h were stimulated with dDAVP (10-10 M, 3 min), AQP2 phosphorylation at Ser256, Ser264, and Ser269 was significantly attenuated under acidic conditions. Next, IMCD cells primary cultured in transwell chambers were exposed to a transepithelial pH gradient for 1 h (apical pH 6.4, 7.4, or 8.4 vs. basolateral pH 7.4 and vice versa). Immunocytochemistry and cell surface biotinylation assay revealed that exposure to either apical pH 6.4 or basolateral pH 6.4 for 1 h was associated with decreased dDAVP (10-9 M, 15 min, basolateral)-induced apical targeting of AQP2 and surface expression of AQP2. Fluorescence resonance energy transfer analysis revealed that the dDAVP (10-9 M)-induced increase of PKA activity was significantly attenuated when LLC-PK1 cells were exposed to pHe 6.4 compared with pHe 7.4 and 8.4. In contrast, forskolin (10-7 M)-induced PKA activation and dDAVP (10-9 M)-induced increases of intracellular Ca2+ were not affected. Taken together, dDAVPinduced phosphorylation and apical targeting of AQP2 are attenuated in IMCD cells under acidic pHe, likely via an inhibition of vasopressin V2 receptor-G protein-cAMP-PKA actions. © 2015 the American Physiological Society.

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.

Park I.,Kyungpook National University | Lee H.-S.,Kyungpook National University
Molecules and Cells | Year: 2015

Eph receptors and their ligands, ephrins, represent the largest group of the receptor tyrosine kinase (RTK) family, and they mediate numerous developmental processes in a variety of organisms. Ephrins are membrane-bound proteins that are mainly divided into two classes: A class ephrins, which are linked to the membrane by a glycosylphosphatidylinositol (GPI) linkage, and B class ephrins, which are transmembrane ligands. Based on their domain structures and affinities for ligand binding, the Eph receptors are also divided into two groups. Trans-dimerization of Eph receptors with their membrane-tethered ligands regulates cell-cell interactions and initiates bidirectional signaling pathways. These pathways are intimately involved in regulating cytoskeleton dynamics, cell migration, and alterations in cellular dynamics and shapes. The EphBs and ephrinBs are specifically localized and modified to promote higher-order clustering and initiate of bidirectional signaling. In this review, we present an in-depth overview of the structure, mechanisms, cell signaling, and functions of EphB/ephrinB in cell adhesion and migration. © The Korean Society for Molecular and Cellular Biology.

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.

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.

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.

Sen D.,Kyungpook National University | Heo N.H.,Kyungpook National University | Seff K.,University of Hawaii at Manoa
Journal of Physical Chemistry C | Year: 2012

Indium ions were introduced into zeolite X (FAU, Si/Al = 1.09) by anhydrous vapor-phase ion exchange (VPIE). In 14 +(In 5 7+) 4Na 50 +-X (approximate formula) was prepared by the reaction of fully dehydrated Na 92 +-X with 13 Torr of InCl(g) at T = 673 K. Its structure was determined using single-crystal crystallography with synchrotron X-radiation and was refined in the space group Fd3̄ (a = 24.996(1) Å) with all 1566 unique data; the final error index R 1 is 0.076. InCl(g) reacted with about 46% of the Na + ions in the zeolite, to give In 5 7+ (centered tetrahedral, In-In = 2.684(7) Å) and In + cations. In 5 7+ centers exactly half of the sodalite cavities, strongly suggesting alternating occupancy; each terminal atom (at site I′) bonds to three framework oxygen atoms of a double 6-ring (In-O = 2.248(6) Å and O-In-O = 102.2(2)°). The In + ions occupy four crystallographically distinct cationic sites: 5.8(3) per unit cell are in the sodalite cavities (site I′), 2.7(7) are near single 6-rings in the supercage (site II), 2.6(4) are near triple 4-rings in the supercage (site III′), and 3.1(5) are at second III′ site. About half of the Na + ions complete the filling of the single 6-rings; the remainder are at 12-ring sites. Most In + ions are easily approachable by guest molecules through the zeolite's 12-ring channel system. © 2012 American Chemical Society.

Hennayaka H.M.M.N.,Kyungpook National University | Lee H.S.,Kyungpook National University
Thin Solid Films | Year: 2013

ZnS thin films were grown on indium-tin-oxide coated glass substrates using pulsed electrodeposition and the effect of the deposition temperature on the structural and optical properties of the ZnS films was investigated. Polycrystalline cubic ZnS films were obtained at all the deposition temperatures. At temperatures below 70 C, less dense films were obtained and particle agglomeration was visible. On the other hand, at temperatures above 70 C, more dense films with well-defined grains were obtained. With increasing deposition temperatures, the optical transmittance and bandgap of the ZnS films decreased. These results are attributed to the increase in the thickness of ZnS films and their particle size. The ZnS films grown at 90 C exhibited the highly (200) preferred orientation and n-type conductivity with a wide bandgap of 3.75 eV. Copyright © 2013 Published by Elsevier B.V. All rights reserved.

Kim B.C.,Dong - A University | Mun D.,Kyungpook National University
Computers and Graphics (Pergamon) | Year: 2014

When computer-aided design (CAD) models generated in the design phase are used for engineering activities such as engineering analysis, distributed collaborative design, and virtual prototyping, a process for simplifying the CAD models is needed. In this study, a feature-based simplification method of boundary representation (B-rep) models using sequential iterative volume decomposition is proposed. This method generates a feature-based model from a B-rep model by sequentially and iteratively applying the four volume decomposition methods (fillet, round, and chamfer decomposition; wrap-around decomposition; volume split decomposition; and cell-based decomposition). Then, feature-based simplification is applied to the generated feature-based model. To demonstrate the proposed method, a prototype system is implemented, and experiments with test cases are performed. Based on the experimental results, we verified that the proposed method successfully simplified B-rep models. © 2013 Elsevier Ltd. All rights reserved.

Khan N.A.,Kyungpook National University | Jhung S.H.,Kyungpook National University
Coordination Chemistry Reviews | Year: 2015

Microwave (MW) and ultrasonic (US) irradiation are the most simple, inexpensive, and efficient nonconventional heating methods available in applied chemistry. Both techniques are well established in the field of organic transformations/syntheses, even though the utilization of alternative methods in the synthesis of emerging materials, including inorganic nanomaterials, nanoporous materials, and hybrid materials, is rapidly materializing. The rapidly growing number of publications regarding the synthesis of such materials via MW and US irradiation clearly suggests that these techniques will play a role in materials chemistry. In this review, we have given an overview of the synthesis of porous metal-organic frameworks (MOFs) materials with MW and US irradiation. MOFs are very interesting materials due to their various potential applications. This review is not meant to serve as a thorough overview of MW- or US-assisted synthesis of MOFs, but is meant to describe the degree of acceleration, phase-selective crystallization, and crystal size reduction in MOF synthesis. Considering these particular aspects of MOF synthesis, the advantages of MW or US irradiation compared with conventional heating have been expounded in detail. © 2014 Elsevier B.V.

Hasan Z.,Kyungpook National University | Jhung S.H.,Kyungpook National University
Journal of Hazardous Materials | Year: 2015

Provision of clean water is one of the most important issues worldwide because of continuing economic development and the steady increase in the global population. However, clean water resources are decreasing everyday, because of contamination with various pollutants including organic chemicals. Pharmaceutical and personal care products, herbicides/pesticides, dyes, phenolics, and aromatics (from sources such as spilled oil) are typical organics that should be removed from water. Because of their huge porosities, designable pore structures, and facile modification, metal-organic frameworks (MOFs) are used in various adsorption, separation, storage, and delivery applications. In this review, the adsorptive purifications of contaminated water with MOFs are discussed, in order to understand possible applications of MOFs in clean water provision. More importantly, plausible adsorption or interaction mechanisms and selective adsorptions are summarized. The mechanisms of interactions such as electrostatic interaction, acid-base interaction, hydrogen bonding, π-π stacking/interaction, and hydrophobic interaction are discussed for the selective adsorption of organics over MOFs. The adsorption mechanisms will be very helpful not only for understanding adsorptions but also for applications of adsorptions in selective removal, storage, delivery and so on. © 2014 Elsevier B.V.

Oh J.,Kyungpook National University | Lee C.,Kyungpook National University
Virus Research | Year: 2012

Porcine reproductive and respiratory syndrome virus (PRRSV) emerged in the late 1980s in both Europe and North America is an arterivirus causing great economic losses in the pig industry worldwide. Recently, a novel structural protein, ORF5a, encoded by an alternative ORF of a subgenomic mRNA encoding the major envelope glycoprotein, GP5, has been discovered in all arteriviruses, suggesting its important role in arterivirology. The present study attempted to investigate compensatory changes of cellular gene expression in natural target cells regulated by the ORF5a. We thus established sublines of PAM cells to stably express the PRRSV ORF5a protein and assessed alterations in cellular protein productions of ORF5a-expressing PAM (PAM-ORF5a) cells at different time courses by the use of proteomic analysis. A total of 36 protein spots were initially found to be differentially expressed in PAM-ORF5a cells compared with normal PAM cells by high-resolution two-dimensional gel electrophoresis (2DE). Of these spots, 16 protein spots with statistically significant alteration, including 13 up-regulated and 3 down-regulated protein spots, were picked out for subsequent protein identification by peptide mass fingerprinting after matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF/MS). The altered cellular proteins identified in this study were grouped into the functions associated with a variety of cellular processes such as cell growth, cytoskeleton networks and cell communication, metabolism, protein biosynthesis, RNA processing, and transportation. The proteomics data will provide valuable information for better understanding the specific cellular response to the novel ORF5a protein during PRRSV replication. © 2012 Elsevier B.V.

Choi K.-M.,Korea Institute of Science and Technology | Choi S.-H.,Korea Institute of Science and Technology | Jeon H.,Korea Institute of Science and Technology | Kim I.-S.,Kyungpook National University | Ahn H.J.,Korea Institute of Science and Technology
ACS Nano | Year: 2011

For the efficient cytoplasmic delivery of siRNA, we designed a chimeric capsid protein composed of a capsid shell, integrin targeting peptide, and p19 RNA binding protein. This recombinant protein assembled into a macromolecular container-like structure with capsid shell and provided a nanocarrier for siRNA delivery. Our capsid nanocarriers had dual affinity both for siRNA within the interior and integin receptors on the exterior, and the capsid shell structure allowed the encapsulated siRNAs to be protected from the external nucleases, leading to the enhanced stability of siRNA in serum conditions. The capsid nanocarriers could complex with siRNA in a size-dependent and sequence-independent manner and showed the pH-dependent complexing/dissocation behaviors with siRNA. Moreover, RGD peptides on the exterior surface of the capsid shell enabled the capsid nanocarriers to deliver siRNA into the cytosol of the target cells. Here, we demonstrated the superior efficiency of our siRNA/capsid nanocarrier complexes in RFP gene silencing, compared to untreated cells. These results provide an alternative approach to enhancing the stability of siRNA as well as to achieving targeted siRNA delivery. © 2011 American Chemical Society.

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.

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.

Kwon M.J.,Kyungpook National University | Shin Y.K.,Seoul National University | Shin Y.K.,Advanced Institutes of Convergence Technology
International Journal of Molecular Sciences | Year: 2013

Cancer stem cells or tumor-initiating cells (CSC/TICs), which can undergo self-renewal and differentiation, are thought to play critical roles in tumorigenesis, therapy resistance, tumor recurrence and metastasis. Tumor recurrence and chemoresistance are major causes of poor survival rates of ovarian cancer patients, which may be due in part to the existence of CSC/TICs. Therefore, elucidating the molecular mechanisms responsible for the ovarian CSC/TICs is required to develop a cure for this malignancy. Recent studies have indicated that the properties of CSC/TICs can be regulated by microRNAs, genes and signaling pathways which also function in normal stem cells. Moreover, emerging evidence suggests that the tumor microenvironments surrounding CSC/TICs are crucial for the maintenance of these cells. Similarly, efforts are now being made to unravel the mechanism involved in the regulation of ovarian CSC/TICs, although much work is still needed. This review considers recent advances in identifying the genes and pathways involved in the regulation of ovarian CSC/TICs. Furthermore, current approaches targeting ovarian CSC/TICs are described. Targeting both CSC/TICs and bulk tumor cells is suggested as a more effective approach to eliminating ovarian tumors. Better understanding of the regulation of ovarian CSC/TICs might facilitate the development of improved therapeutic strategies for recurrent ovarian cancer. © 2013 by the authors; licensee MDPI, Basel, Switzerland.

Ahmed I.,Kyungpook National University | Jhung S.H.,Kyungpook National University
Chemical Engineering Journal | Year: 2014

CuCl impregnated MIL-100(Cr) was prepared with a facile method and then utilized for the adsorptive denitrogenation of model fossil fuels. CuCl was produced from CuCl2 solution at ambient temperature and pressure by reduction of CuCl2 using sodium sulfite as a mild reducing agent. Although the porosity of the adsorbent was reduced after impregnation, the adsorption of nitrogen-containing compounds (NCCs) increased. However, the adsorption of NCCs over CuCl2/MIL-100(Cr), which was produced in a similar manner but in the absence of Na2SO3, was decreased as a result of the reduced porosity. The maximum adsorption capacities of CuCl/MIL-100(Cr) as compared to pristine MIL-100(Cr) for quinoline (QUI) and indole (IND) were improved by 9% and 15%, respectively, which may be attributed to the π-complexation effect of the Cu+ sites of CuCl. © 2014.

Kim S.Y.,Kyungpook National University | Lee Y.-H.,Kyungpook National University | Bae Y.-S.,Kyungpook National University
Biochemical and Biophysical Research Communications | Year: 2012

We previously demonstrated that downregulation of protein kinase CKII induces cellular senescence in human colon cancer HCT116 cells. To investigate the role of microRNAs (miRNAs) in CKII downregulation during senescence, we employed computational algorithms. Four miRNAs (miR-186, miR-216b, miR-337-3p, and miR-760) were predicted to be miRNAs against CKIIα mRNA. Mimics of all four miRNAs jointly downregulated CKIIα expression in HCT116 cells. Reporter analysis and RT-PCR have suggested that these four miRNAs may stimulate degradation of CKIIα mRNA by targeting its 3' untranslated regions (UTRs). The four miRNA mimics increased senescent-associated β-galactosidase (SA-β-gal) staining, p53 and p21Cip1/WAF1 expression, and reactive oxygen species (ROS) production. In contrast, concomitant knockdown of the four miRNAs by antisense inhibitors increased the CKIIα protein level and suppressed CKII inhibition-mediated senescence. Finally, CKIIα overexpression antagonized senescence induced by the four miRNA mimics. Therefore, the present results show that miR-186, miR-216b, miR-337-3p, and miR-760 cooperatively promote cellular senescence through the p53-p21Cip1/WAF1 pathway by CKII downregulation-mediated ROS production in HCT116 cells. © 2012 Elsevier Inc.

Kamal T.,Kyungpook National University | Park S.-Y.,Kyungpook National University
Chemical Communications | Year: 2014

A single layer, mono-component, fast, stable, and controllable curling motion actuator is prepared from a mixture of di-acrylate mesogenic monomer and 5CB using a photo-polymerization induced phase separation method. This actuator is capable of sensing water in acetone. © 2014 The Royal Society of Chemistry.

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.

Chung D.E.,Kyungpook National University | Um I.C.,Kyungpook National University
Fibers and Polymers | Year: 2014

Wet spun silk fibroin (SF) filaments have attracted considerable attention because of their potential in biotechnological applications including surgical sutures, tissue engineering and wound dressing. Although the molecular weight (MW) of polymers is one of key factors affecting the wet spinnability of dope along with the structural characteristics and properties of wet spun filament, no related study has been conducted. In this study, regenerated SFs with different MWs and concentrations were prepared by wet spinning. The effects of the SF concentration and MW on 1) wet spinnability and rheology of silk dope solution and 2) crystallinity index and post drawing performance of wet spun silk filament were examined. Their relationships were also investigated. The rheological measurements showed that an 80 mPa·s viscosity is needed to obtain a continuous wet spun SF filament. As the MW of SF increased, the peak position of the maximum draw ratio shifted to a lower SF concentration with a concomitant increase in the maximum draw ratio value at the peak. Interestingly, the crystallinity index obtained from Fourier transform infrared spectroscopy (FTIR) revealed a similar trend to the maximum draw ratio suggesting that the post drawing ability is strongly affected by the quantity of short-ordered crystalline regions in wet spun SF filaments. On the other hand, X-ray diffraction did not detect any crystallinity change in the SF filament produced from the formic acid solvent system. It was concluded that MW strongly affected the dope solution viscosity and the crystallinity index from FTIR and these determined the fiber formation of dope and post drawing performance of fiber. © 2014 The Korean Fiber Society and Springer Science+Business Media Dordrecht.

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.

Choi W.I.,Gwangju Institute of Science and Technology | Kim J.-Y.,Gwangju Institute of Science and Technology | Kang C.,Gwangju Institute of Science and Technology | Byeon C.C.,Kyungpook National University | And 2 more authors.
ACS Nano | Year: 2011

We developed a very effective hyperthermia system for successful photothermal cancer therapy. Instead of applying individual gold nanorods (GNRs) that can absorb NIR light, GNRs were loaded into functional nanocarriers that could provide stable storage of GNRs and selective delivery to a target tumor site. The functional nanocarriers (chitosan-conjugated, Pluronic-based nanocarriers) were prepared by chemically cross-linking Pluronic F 68 with chitosan conjugation to form a flexible, soft, and excellent reservoir for biomacromolecules as well as tumor targeting. In vivo characteristics of the nanocarriers including a long circulation time, a good tumor accumulation, and low liver uptake were previously characterized by us. When GNRs were delivered by using these nanocarriers, much enhanced in vitro cellular uptake and a photothermal effect were observed for a cancer cell line. More importantly, an intravenous injection of this system followed by NIR laser irradiation to the tumor site resulted in a very efficient thermolysis in vivo. Thus, apparently complete tumor resorption was achieved without damage to the surrounding tissue, suggesting a promising candidate for clinical phototherapeutic applications. © 2011 American Chemical Society.

Oh Y.,Kyungpook National University
AIP Conference Proceedings | Year: 2011

The reactions of KΣ(1385) photoproduction, i.e., γp→K +Σ0(1385) and γn→K+Σ -(1385), are investigated in the resonance energy region for studying the role of the nucleon and Δ resonances of masses around 2GeV. The Lagrangians for describing the decays of these resonances into the KΣ(1385) channel are constructed and the decay amplitudes are obtained, which allows us to determine the coupling constants using the predictions of quark models or the data listed by the Particle Data Group. The resulting cross sections are compared to the data from the Thomas Jefferson National Accelerator Facility and the SPring-8, which indicates nontrivial contributions from the two-star-rated resonances in the Particle Data Group as well as from some missing resonances predicted by a quark model. © 2011 American Institute of Physics.

Kim S.,Kyungpook National University | Park H.,Kyungpook National University
International Journal of Information Management | Year: 2012

The development of social networking sites (SNSs) has given rise to a new e-commerce paradigm called social commerce (s-commerce). S-commerce is a subset of e-commerce and uses SNSs for social interactions and user contributions to facilitate the online buying and selling of various products and services. Recent years have witnessed the rapid growth of s-commerce in Korea, but this growth has involved a number of transaction-related issues such as no delivery and the delivery of wrong items. In particular, consumers' trust has become a crucial factor in the success of s-commerce firms, requiring these firms to make more effort to gain this trust. In this regard, this study identifies the key factors in s-commerce [reputation, size, information quality, transaction safety, communication, economic feasibility, and word-of-mouth (WOM) referrals], that is, the characteristics of s-commerce influencing Korean consumers' trust in s-commerce. In addition, the study assesses the effects of trust on trust performance (purchase intentions and WOM intentions). The results of an empirical analysis based on a sample of 371 s-commerce users indicate that all the characteristics of s-commerce (except for economic feasibility) had significant effects on trust and that trust had significant effects on purchase and WOM intentions. The results have important implications for s-commerce firms wishing to develop a successful business model for providing their customers with trustworthy services. © 2012 Elsevier Ltd. All rights reserved.

Choi K.-H.,Kyungpook National University | Nakamura M.,Kyungpook National University | Jang I.-S.,Kyungpook National University
Neural Plasticity | Year: 2013

The periaqueductal gray (PAG) is involved in the central regulation of nociceptive transmission by affecting the descending inhibitory pathway. In the present study, we have addressed the functional role of presynaptic glycine receptors in spontaneous glutamatergic transmission. Spontaneous EPSCs (sEPSCs) were recorded in mechanically dissociated rat PAG neurons using a conventional whole-cell patch recording technique under voltage-clamp conditions. The application of glycine (100 μM) significantly increased the frequency of sEPSCs, without affecting the amplitude of sEPSCs. The glycine-induced increase in sEPSC frequency was blocked by 1 μM strychnine, a specific glycine receptor antagonist. The results suggest that glycine acts on presynaptic glycine receptors to increase the probability of glutamate release from excitatory nerve terminals. The glycine-induced increase in sEPSC frequency completely disappeared either in the presence of tetrodotoxin or Cd 2+, voltage-gated Na+, or Ca2+ channel blockers, suggesting that the activation of presynaptic glycine receptors might depolarize excitatory nerve terminals. The present results suggest that presynaptic glycine receptors can regulate the excitability of PAG neurons by enhancing glutamatergic transmission and therefore play an important role in the regulation of various physiological functions mediated by the PAG. © 2013 Kwi-Hyung Choi et al.

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.

Yang J.-M.,Kyungpook National University
Automatica | Year: 2014

In this note, we address a fault-tolerant control scheme for asynchronous sequential machines with permanent faults. The considered asynchronous machine is influenced by faults that change perpetually a portion of its state transition logic. If the asynchronous machine has appropriate analytic redundancy in its reachability, we can design a corrective controller so that the stable-state behavior of the closed-loop system can match that of a reference model despite occurrences of permanent faults. It is assumed that the controller is always fault-free. The existence condition and design procedure for an appropriate controller are presented based on the corrective control scheme. We also provide a controller synthesis example for validating the proposed scheme. © 2014 Elsevier Ltd. All rights reserved.

Shoaib M.A.,Kyungpook National University | Choi C.H.,Kyungpook National University
Journal of Physical Chemistry C | Year: 2013

Adsorptions of formic (FA) and acetic acids (AA) on Ih ice surface were studied using quantum mechanical/effective fragment potential (QM/EFP) scheme. Contrasting to the earlier studies in which trans-conformers were found as major surface configurations, our QM/EFP models found various cis-and trans-conformers on ice surfaces with the cis-conformers being more stable. The surface binding energies and configurations were largely dependent on surface heterogeneity yielding the various surface conformers. In addition, the overall binding energies of acetic acid are slightly higher as compared to formic acid, implying the stabilization effect of methyl group. Our study also found a feasible deprotonation route of adsorbed trans-formic acid. In contrast, acetic acid prefers molecular form due to the unfavorable hydrophobic methyl group. Therefore it is interesting to note that the additional methyl group of acetic acid enhances surface binding energies. But at the same time it reduces the chance of its deprotonation. Our ice model clearly demonstrated the significant effects of intrinsic surface heterogeneity on the distributions of surface binding energies and configurations, which cannot be represented by small water clusters. © 2013 American Chemical Society.

The hippocampus is an important brain area where abnormal morphological characteristics are often observed in patients with temporal lobe epilepsy (TLE), typically showing the loss of the principal neurons in the CA1 and CA3 areas of the hippocampus. TLE is frequently associated with widening of the granule cell layer of the dentate gyrus (DG), termed granule cell dispersion (GCD), in the hippocampus, suggesting that the control of GCD with protection of hippocampal neurons may be useful for preventing and inhibiting epileptic seizures. We previously reported that eugenol (EUG), which is an essential component of medicinal herbs and has anticonvulsant activity, is beneficial for treating epilepsy through its ability to inhibit GCD via suppression of mammalian target of rapamycin complex 1 (mTORC1) activation in the hippocampal DG in a kainic acid (KA)-treated mouse model of epilepsy in vivo. In addition, we reported that naringin, a bioflavonoid in citrus fruits, could exert beneficial effects, such as antiautophagic stress and antineuroinflammation, in the KA mouse model of epilepsy, even though it was unclear whether naringin might also attenuate the seizure-induced morphological changes of GCD in the DG. Similar to the effects of EUG, we recently observed that naringin treatment significantly reduced KA-induced GCD and mTORC1 activation, which are both involved in epileptic seizures, in the hippocampus of mouse brain. Therefore, these observations suggest that the utilization of natural materials, which have beneficial properties such as inhibition of GCD formation and protection of hippocampal neurons, may be useful in developing a novel therapeutic agent against TLE. © Copyright 2016, Mary Ann Liebert, Inc. and Korean Society of Food Science and Nutrition 2016.

Karim M.N.,Kyungpook National University | Lee J.E.,Korea Institute of Science and Technology | Lee H.J.,Kyungpook National University
Biosensors and Bioelectronics | Year: 2014

A novel amperometric biosensor for catechol was developed using the layer-by-layer (LbL) self-assembly of positively charged hexadecyltrimethylammonium stabilized gold nanocubes (AuNCs), negatively charged poly(sodium 4-styrenesulfonate) and tyrosinase on a screen printed carbon electrode (SPCE). A carboxylic acid terminated alkanethiol assembled on electrochemically deposited Au nanoparticles on a SPCE was used as a platform for LbL assembly. Each SPCE sensor surface was terminated with tyrosinase and the electrocatalytic response due to the tyrosinase reaction with catechol was measured using cyclic voltammetry and square wave voltammetry (SWV). The effect of introducing AuNCs into the LbL assembly to further enhance the catechol detection performance was then investigated by comparing the SWV results to those from biosensors created using both the tyrosinase modified LbL assembly in the absence of NCs and the covalent attachment of tyrosinase. A wide dynamic range from 10. nM to 80. μM of catechol with an excellent sensitivity of 13.72 A/M and a detection limit of 0.4. nM were both achieved alongside a good selectivity and reproducibility for the AuNC-modified electrodes. As a demonstration, the optimized biosensor design was applied to determine catechol concentrations in tea samples. © 2014 Elsevier B.V.

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.

Jang H.W.,Yeungnam University | Lee H.J.,Kyungpook National University
Journal of Clinical Neuroscience | Year: 2010

Posterior leukoencephalopathy syndrome is a rare complication of triple H therapy, which is the treatment for symptomatic vasospasm occurring following subarachnoid hemorrhage. This complication must be considered when neurological deterioration of a patient continues or worsens during triple H therapy. We report a patient diagnosed with posterior leukoencephalopathy syndrome during triple H therapy. © 2009 Elsevier Ltd. All rights reserved.

Park D.H.,Kyungpook National University | Shin J.P.,Kyungpook National University | Kim S.Y.,Kyungpook National University
Retina | Year: 2010

Purpose: The purpose of this study was to compare the clinical outcomes and complications between 23-gauge transconjunctival sutureless vitrectomy and 20-gauge vitrectomy in patients with proliferative diabetic retinopathy. Methods: This is a retrospective comparative study comprising 101 eyes from 90 consecutive patients who had diabetic vitrectomy due to nonclearing vitreous hemorrhage. Thirty-five eyes underwent 23-gauge transconjunctival sutureless vitrectomy, and 66 eyes underwent 20-gauge vitrectomy. Main outcome measures were best-corrected visual acuity, intraocular pressure, and incidence of intraoperative and postoperative complications with at least 6 months of follow-up. Results: Best-corrected visual acuity of both groups at postoperative months 1, 3, and 6 significantly improved from the preoperative best-corrected visual acuity (P < 0.0001, respectively). There was no difference for best-corrected visual acuity between the 2 groups at each follow-up period (P > 0.05, respectively). Intraocular pressure of the 23-gauge group at postoperative Day 1 and Week 1 was less than the preoperative intraocular pressure (P < 0.0001 and 0.017). Operating time of the 23-gauge group was shorter than the 20-gauge group (P < 0.0001). There was no difference in the incidence of intraoperative and postoperative complications except transient postoperative hypotony, which occurred in 8 eyes (22.9%) from the 23-gauge group (P < 0.0001). Conclusion: Twenty three-gauge transconjunctival sutureless vitrectomy appears to be as effective for proliferative diabetic retinopathy as 20-gauge vitrectomy. Copyright © 2010 Lippincott Williams & Wilkins. All rights reserved.

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.

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.

Jeong H.W.,Kyungpook National University | Jeon T.H.,Pohang Accelerator Laboratory | Jang J.S.,Pohang Accelerator Laboratory | Choi W.,Pohang Accelerator Laboratory | Park H.,Kyungpook National University
Journal of Physical Chemistry C | Year: 2013

To improve the photoelectrochemical (PEC) performance of BiVO4, three different modifications (doping, heterojunction, and catalyst deposition) using earth-abundant elements are performed and their effects are compared in a 0.1 M phosphate electrolyte at pH 7 under AM1.5 light (100 mW/cm2). When a hexavalent element (Cr6+, W6+, or Mo6+) is doped at various levels, the Mo6+-doping effect is most significant at 10 atomic % with about two times higher photocurrent generation at the oxygen evolution potential (1.23 VRHE). Such enhancement is attributed to a decrease in charge transfer resistance (Rct) by donor doping, resulting in an approximate 2-fold increase in charge separation efficiency (ηsep) to about 25%. W6+ is less effective than Mo6+, whereas Cr6+ has a detrimental effect. To further improve the charge separation efficiency of Mo6+-doped BiVO4 (Mo-BiVO4), a approximate 600 nm thick WO 3 layer is deposited under a similarly thick Mo-BiVO4 layer. This binary heterojunction (WO3/Mo-BiVO4) exhibits ηsep of about 50% along with more than 3 times higher photocurrent generation. On the other hand, an oxygen evolving cobalt-phosphate (Co-Pi) catalyst electrodeposited to Mo-BiVO4 (Mo-BiVO 4/Co-Pi) enhances charge injection efficiency (ηinj) from ∼50 to ∼70% at 1.23 VRHE. These two binaries are coupled into a ternary heterojunction (WO3/Mo-BiVO4/Co-Pi) in order to improve the charge transfer efficiencies (ηsep and ηinj). The PEC performance of this ternary is significantly high with photocurrent density of about 2.4 mA/cm2 at 1.23 VRHE (corresponding to the solar-to-hydrogen efficiency of ca. 3%) due to ηsep and ηinj of ∼60 and 90%, respectively. © 2013 American Chemical Society.

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.

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.

Moon E.,Korean University of Science and Technology | Kim M.,Kyungpook National University | Roh J.,Korean University of Science and Technology | Kim H.,Korean University of Science and Technology | Hahn J.,Kyungpook National University
Optics Express | Year: 2014

A compact head-mounted holographic three-dimensional display with an RGB light-emitting diode (LED) light source is developed. Issues regarding full-color holographic image design and the quality associated with the use of an LED light source are investigated. The accommodation effect and background noise in the proposed system are discussed based on experimental observation. © 2014 Optical Society of America.

Cho N.H.,Kyungpook National University | Jang J.H.,Kyungpook National University | Jung W.,Ulsan National Institute of Science and Technology | Kim J.,Kyungpook National University
Optics Express | Year: 2014

We developed an augmented-reality system that combines optical coherence tomography (OCT) with a surgical microscope. By sharing the common optical path in the microscope and OCT, we could simultaneously acquire OCT and microscope views. The system was tested to identify the middle-ear and inner-ear microstructures of a mouse. Considering the probability of clinical application including otorhinolaryngology, diseases such as middle-ear effusion were visualized using in vivo mouse and OCT images simultaneously acquired through the eyepiece of the surgical microscope during surgical manipulation using the proposed system. This system is expected to realize a new practical area of OCT application. © 2014 Optical Society of America.

Cho H.Y.,Kyungpook National University | Kang B.S.,Kyungpook National University
Biochemical and Biophysical Research Communications | Year: 2014

A sensor kinase, DosS, and its corresponding response regulator, DosR, constitute a two component system for regulating gene expression under hypoxic conditions in Mycobacterium tuberculosis. Among response regulators in M. tuberculosis, NarL has high sequence similarity to DosR, and autophosphorylated DosS transfers its phosphate group not only to DosR but also to NarL. Phosphorylated DosR is more rapidly dephosphorylated than phosphorylated NarL. DosR and NarL differ with respect to the amino acids at positions T + 1 and T + 2 around the phosphorylation sites in the N-terminal phosphoacceptor domain; NarL has S83 and Y84, whereas DosR has A90 and H91. A DosR S83A mutant shows prolonged phosphorylation. Structural comparison with a histidinol phosphate phosphatase suggests that the hydroxyl group of DosR S83 could play a role in activating the water molecule involved in the triggering of autodephosphorylation. © 2014 Elsevier Inc. All rights reserved.

Cho S.-J.,Kyungpook National University | Jung U.J.,Kyungpook National University | Choi M.-S.,Kyungpook National University
British Journal of Nutrition | Year: 2012

Consumption of a high-fat diet (HFD) enriched in saturated fat induces excessive weight gain due to adiposity, which can lead to metabolic complications, as well as increased risk of fatty liver disease and CVD. The present study investigated the underlying mechanism and dose-response effects of resveratrol (RV) on obesity, hepatic steatosis and dyslipidaemia in mice fed a HFD. Male C57BL/6J mice were fed a normal diet or a HFD (20 % fat, w/w) combined with 0·005 or 0·02 % (w/w) RV for 10 weeks. As expected, mice fed a HFD developed obesity, as shown by increased body weight gain, visceral fat, hepatic fat and plasma cholesterol. RV significantly reduced visceral fat and plasma NEFA. In the liver of HFD-fed mice, RV significantly reduced TAG and cholesterol, as well as lipid droplet number and size. A low dose of RV (0·005 %) appeared to be more effective than a higher dose of RV (0·02 %) for suppressing adiposity and hepatic steatosis development with a significant decrease in body weight gain, plasma TAG and total cholesterol levels. These changes were seemingly attributable to a suppression of the fatty acid (FA) synthase, glucose-6-phosphate dehydrogenase, and phosphatidate phosphohydrolase and/or an activation of FA oxidation in the liver and epididymal adipose tissue. In conclusion, daily consumption of a low dose of RV is effective for protecting against diet-induced obesity, hepatic steatosis and dyslipidaemia in HFD-fed mice. Copyright © The Authors 2012.

Lee K.-I.,Kyungpook National University | Yang S.-H.,Kyungpook National University
International Journal of Precision Engineering and Manufacturing | Year: 2013

In this study, we propose a robust and simple method using double ball-bar to measure position-independent geometric errors of a rotary axis involving single axis control during the measurement. The standard uncertainty for the proposed method is analyzed to quantify the confidence interval of the measurement result. Two measurement paths are planned to measure the position-independent geometric errors, including two offset errors and two squareness errors of a rotary axis. An error synthesis model using homogenous transform matrices and a ball-bar equation to represent the relation between the positions of two balls and the measured distance between them are used. Set-up errors, which are inevitable during the installation of the balls, are modeled as constants and added to the design position of the balls. Their effects on the measurement result are investigated in detail. Furthermore, a novel fixture consisting of flexure-hinges located at the tool nose is developed to minimize the set-up errors of the ball and to robustly keep the position of the ball during measurements. Finally, the proposed method is validated using simulation and is applied to the rotary axis located on a five-axis machine tool. © 2013 Korean Society for Precision Engineering and Springer-Verlag Berlin Heidelberg.

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.

The rust fungus Puccinia miscanthi on the naturally infected leaves of eulalia grass were investigated by light and electron microscopy. Many black telia were present on both the adaxial and abaxial leaf surfaces. The telia were often confluent, protruding distinctly from the leaf surface, and had numerous teliospores. Light microscopy revealed that the teliospores were club-like in shape (clavate), chestnut brown, and produced pedicels from one end. They were measured to be approximately 45. μm. ×. 20. μm in size, and slightly constricted at the septa. Using stereo imaging, it was possible to generate images with more three-dimensionality than conventional scanning electron micrographs. Without the need for the mechanical sectioning of telia, the height of telia from the leaf epidermis could be measured at approximately 230. μm using three-dimensional surface reconstruction. Urediniospores were also found on the leaf surface, and possessed spines on the surface (echinulate). The internal features of the nonembedded teliospores could be unveiled using a focused ion beam system with a field emission scanning electron microscope, allowing for the in situ site-specific cutting of the non-embedded teliospores. These results show that three-dimensional surface reconstruction and targeted cutting are a potential alternative to mechanical sectioning of resin-embedded blocks, and have the potential to eliminate the uncertainty involved in selecting the region of interest. © 2015 Elsevier Ltd.

Shin S.H.,Kyungpook National University | Jo W.K.,Kyungpook National University
Chemosphere | Year: 2012

The present study investigated the indoor concentrations of selected volatile organic compounds (VOCs) and formaldehyde and their indoor emission characteristics in newly-built apartments at the pre-occupancy stage. In total, 107 apartments were surveyed for indoor and outdoor VOC concentrations in two metropolitan cities and one rural area in Korea. A mass balanced model was used to estimate surface area-specific emission rates of individual VOCs and formaldehyde. Seven (benzene, ethyl benzene, toluene, m,p-xylene, o-xylene, n-hexane, and n-heptane) of 40 target compounds were detectable in all indoor air samples, whereas the first five were detected in all outdoor air samples. Formaldehyde was also predominant in the indoor air samples, with a high detection frequency of 96%. The indoor concentrations were significantly higher than the outdoor concentrations for aromatics, alcohols, terpenes, and ketones. However, six halogenated VOCs exhibited similar concentrations for indoor and outdoor air samples, suggesting that they are not major components emitted from building materials. It was also suggested that a certain portion of the apartments surveyed were constructed by not following the Korean Ministry of Environment guidelines for formaldehyde emissions. Toluene exhibited the highest emission rate with a median value of 138μgm-2h-1. The target compounds with median emission rates greater than 20μgm-2h-1 were toluene, 1-propanol, formaldehyde, and 2-butanone. The wood panels/vinyl floor coverings were the largest indoor pollutant source, followed by floorings, wall coverings, adhesives, and paints. The wood panels/vinyl floor coverings contributed nearly three times more to indoor VOC concentrations than paints. © 2012 Elsevier Ltd.

Lee K.-I.,Kyungpook National University | Yang S.-H.,Kyungpook National University
International Journal of Machine Tools and Manufacture | Year: 2013

In this study, position-independent geometric errors, including offset errors and squareness errors of rotary axes of a five-axis machine tool are measured using a double ball-bar and are verified through compensation. In addition, standard uncertainties of measurement results are calculated to establish their confidence intervals. This requires two measurement paths for each rotary axis, which are involving control of single rotary axis during measurement. So, the measurement paths simplify the measurement process, and reduce measurement cost including less operator effort and measurement time. Set-up errors, which are inevitable during the installation of the balls, are modeled as constants. Their effects on the measurement results are investigated to improve the accuracy of the measurement result. A novel fixture consisting of flexure hinges and two pairs of bolts is used to minimize set-up error by adjusting the ball's position located at the tool nose. Simulation is performed to check the validation of measurement and to analyze the standard uncertainties of the measurement results. Finally, the position-independent geometric errors of the five-axis machine tool (involving a rotary axis and a trunnion axis) are measured using proposed method. © 2013 Elsevier Ltd.

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.

Lee K.-I.,Kyungpook National University | Yang S.-H.,Kyungpook National University
International Journal of Machine Tools and Manufacture | Year: 2013

In this study, the accuracy of a machine tool was evaluated by modeling the spherical deviation based on double ball-bar measurements under unloaded conditions. Circular measurement paths on the XY-, YZ-, and ZX-planes were planned, and three linear axis drives were commanded to follow the paths describing a nominal sphere. The spherical deviation, defined as the maximum radial range of deviations around a least-squares sphere, is affected by the accuracies of the three linear axes together. Therefore, the spherical deviation represents the accuracy of machine tools by quantifying the effect of the accuracies of three linear axes, whereas the circular deviation only quantifies the accuracies of two linear axes among the three linear axes. In this experimental study, spherical deviations of vertical/horizontal machine tools were measured and analyzed under various nominal lengths of a double ball-bar for various feed rates. The measurement uncertainty of the measured spherical deviation was investigated to determine the confidence interval. © 2013 Published by Elsevier Ltd.

Jang S.Y.,Kyungpook National University | Kim S.Y.,Kyungpook National University | Bae Y.-S.,Kyungpook National University
FEBS Letters | Year: 2011

Cellular senescence is thought to be an important tumor suppression process in vivo. We have previously shown that p53 activation is necessary for CKII inhibition-mediated cellular senescence. Here, CKII inhibition induced acetylation of p53 at K382 in HCT116 and HEK293 cells. This acetylation event was suppressed by SIRT1 activation. CKIIα and CKIIβ were co-immunoprecipitated with SIRT1 in a p53-independent manner. Maltose binding protein pull-down and yeast two-hybrid indicated that SIRT1 bound to CKIIβ, but not to CKIIα. CKII inhibition reduced SIRT1 activity in cells. CKII phosphorylated and activated human SIRT1 in vitro. Finally, SIRT1 overexpression antagonized CKII inhibition-mediated cellular senescence. These results reveal that CKII downregulation induces p53 stabilization by negatively regulating SIRT1 deacetylase activity during senescence. © 2011 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Kwon E.-Y.,Kyungpook National University | Jung U.J.,Kyungpook National University | Park T.,Yonsei University | Yun J.W.,Daegu University | Choi M.-S.,Kyungpook National University
Diabetes | Year: 2015

The flavonoid luteolin has various pharmacological activities. However, few studies exist on the in vivo mechanism underlying the actions of luteolin in hepatic steatosis and obesity. The aim of the current study was to elucidate the action of luteolin on obesity and its comorbidity by analyzing its transcriptional and metabolic responses, in particular the luteolin-mediated cross-talk between liver and adipose tissue in diet-induced obese mice. C57BL/6J mice were fed a normal, high-fat, and high-fat + 0.005% (weight for weight) luteolin diet for 16 weeks. In high fat-fed mice, luteolin improved hepatic steatosis by suppressing hepatic lipogenesis and lipid absorption. In adipose tissue, luteolin increased PPARγ protein expression to attenuate hepatic lipotoxicity, which may be linked to the improvement in circulating fatty acid (FA) levels by enhancing FA uptake genes and lipogenic genes and proteins in adipose tissue. Interestingly, luteolin also upregulated the expression of genes controlling lipolysis and the tricarboxylic acid (TCA) cycle prior to lipid droplet formation, thereby reducing adiposity. Moreover, luteolin improved hepatic insulin sensitivity by suppressing SREBP1 expression that modulates Irs2 expression through its negative feedback and gluconeogenesis. Luteolin ameliorates the deleterious effects of diet-induced obesity and its comorbidity via the interplay between liver and adipose tissue. © 2015 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

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.

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.

Yang J.-M.,Kyungpook National University
IEEE Transactions on Automatic Control | Year: 2016

This note presents a model for switched asynchronous sequential machines (ASMs) and utilizes corrective control to solve their model matching problem. A switched ASM comprising a number of single ASMs or submachines can change its mode or the submachine in which it is operating in an asynchronous mechanism. We obtain a matrix expression for the reachability of switched ASMs, based on which we present the existence condition and design algorithm for a corrective controller that matches the stable-state behavior of the closed-loop system to that of a reference model. The corrective controller for switched ASMs provides not only control input characters but also switching signals to utilize the reachability of each submachine in generating required feedback paths. The constraint on the switching operation caused by the asynchronous mechanism is also discussed. © 1963-2012 IEEE.

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.

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.

Choi K.-S.,Kyungpook National University | Song M.-C.,Kyungpook National University
Virus Genes | Year: 2011

Bovine viral diarrhea virus (BVDV) is an important worldwide disease in the livestock industry. To date, little research has been done on BVDV circulating in the Republic of Korea (ROK). The cases outlined in our research originated from rectal swabs taken from calves up to 80 days of age. Twenty-two of 99 Korean indigenous calves with diarrhea were identified as BVDV positive and 3 different 50-untranslated region (UTR) sequences were determined. The results indicated that BVDV infections in the ROK were found mostly in winter and when calves were less than 20 days old. Phylogenetic analysis based on the 50-UTR revealed that our cases from Korean indigenous calves belonged to BVDV-2a. Therefore, the result of this study will be useful to understand epidemiology and allow producers in the ROK to better protect their livestock. © Springer Science+Business Media, LLC 2010.

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.

Yeum J.H.,Kyungpook National University
Polymer - Plastics Technology and Engineering | Year: 2011

Poly(vinyl alcohol) (PVA)/montmorillonite (MMT) clay nanocomposite microspheres were synthesized through suspension polymerization followed by the heterogeneous saponification for the first time. The effects of MMT on the saponification rate of poly (vinyl acetate) (PVAc) microspheres were studied. It was found that the saponification rate of PVAc significantly increased in the presence of MMT particles. The molecular weight of extracted PVA from the PVA/MMT was lower than that of pure PVA synthesized under similar conditions. TGA, TEM and XRD measurements illustrated that the clay platelets were intercalated in the polymer matrix. © Taylor & Francis Group, LLC.

Cho M.-J.,Kyungpook National University | Park B.-D.,Kyungpook National University
Journal of Industrial and Engineering Chemistry | Year: 2011

This work reports on the mechanical and thermal properties of poly(vinyl alcohol) (PVA) nanocomposites reinforced with nanocelluloses isolated by the sulfuric acid hydrolysis using commercial microcrystalline cellulose (MCC). Nanocellulose-reinforced PVA nanocomposite films were prepared by the casting method with different nanocellulose loadings, which were exposed to tensile test, thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). The nanocellulose obtained by the acid hydrolysis was a rod-like whisker form. Wet particle size analysis resulted in an average size of about 340. nm. But, the measurements of individual nanocelluloses using transmission electron microscopy (TEM) provided the dimensions of about 6.96. nm wide and 178. nm long. The crystallinity of the nanocellulose was quite high (85.2%), which was greater than that of the MCC. The tensile modulus and strength of the nanocomposites were improved with an increase in the nanocellulose content, but decreased at the nanocellulose content of 7. wt%. Thermal stability of the nanocomposites was improved as the nanocellulose content increased up to 7. wt%. The DMA result shows a significant increase of the storage modulus of the nanocomposite at the 3. wt% nanocellulose. These results indicate that the nanocellulose has a great potential to reinforce PVA polymers. © 2010 The Korean Society of Industrial and Engineering Chemistry.

Khan N.A.,Kyungpook National University | Jung B.K.,Kyungpook National University | Hasan Z.,Kyungpook National University | Jhung S.H.,Kyungpook National University
Journal of Hazardous Materials | Year: 2015

ZIF-8 (zinc-methylimidazolate framework-8), one of the zeolitic imidazolate frameworks (ZIFs), has been used for the removal of phthalic acid (H2-PA) and diethyl phthalate (DEP) from aqueous solutions via adsorption. The adsorption capacity of the ZIF-8 for H2-PA was much higher than that of a commercial activated carbon or other typical metal-organic frameworks (MOFs). Because the surface area and pore volume of the adsorbents showed no favorable effect on the adsorption of H2-PA, the remarkable adsorption with ZIF-8 suggests a specific favorable interaction (electrostatic interaction) between the positively charged surface of ZIF-8 and the negatively charged PA anions. In addition, acid-base interactions also have a favorable contribution in the adsorption of H2-PA, based on the adsorptive performances of pristine and amino-functionalized MOFs and adsorption over ZIF-8 at acidic condition (pH=3.5). The reusability of ZIF-8 was also demonstrated after simple washing with methanol. On the other hand, ZIF-8 was not effective in adsorbing DEP probably because of little charge of DEP in a water solution. © 2014 Elsevier B.V.

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.

Kamal T.,Kyungpook National University | Park S.-Y.,Kyungpook National University
ACS Applied Materials and Interfaces | Year: 2014

Actuation of various shape changes, including bending, helical twisting, and reversible hinging, has been achieved from a single-layer sheet of poly(1,4-di(4-(3-acryloyloxypropyloxy)benzoyloxy)-2-methylbenzene) [poly(RM257)]. This actuator was developed through photopolymerization of a reactive liquid-crystal (LC) monomer (RM257) mixed with 4-pentyl-4′-cyanobiphenyl (5CB, nematic LC at room temperature) in a planar polyimide-coated LC cell. The UV beam perpendicular to one side of the LC cell produced an asymmetric phase separation between the poly(RM257) network and 5CB that resulted in an asymmetric porous structure along the thickness direction when the 5CB was extracted, in which the UV-exposed surface was pore-free and compact while the opposite surface was highly porous. As a result of this structure, the dry and curled poly(RM257) film exhibits actuation behavior when placed in acetone because of a difference in swelling between the two morphologically different sides, the film UV-exposed and nonexposed sides. The actuation of a three-dimensional tetrahedron (pyramidal) structure is also demonstrated for the first time by using a simple photopatterning technique to selectively control its asymmetric morphology at specific locations. © 2014 American Chemical Society.

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.

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).

Park M.-W.,Kyungpook National University | Yeo S.-D.,Kyungpook National University
Chemical Engineering Research and Design | Year: 2012

Carbamazepine was crystallized from organic solutions using an antisolvent crystallization technique. Ethanol was used as a solvent for the carbamazepine and distilled water was used as an a