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Showing papers by "Chonbuk National University published in 2012"


Journal ArticleDOI
TL;DR: These guidelines are presented for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes.
Abstract: In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.

4,316 citations


Journal ArticleDOI
TL;DR: The RENO experiment has observed the disappearance of reactor electron antineutrinos, consistent with neutrino oscillations, with a significance of 4.9 standard deviations.
Abstract: The RENO experiment has observed the disappearance of reactor electron antineutrinos, consistent with neutrino oscillations, with a significance of 4.9 standard deviations. Antineutrinos from six $2.8\text{ }\text{ }{\mathrm{GW}}_{\mathrm{th}}$ reactors at the Yonggwang Nuclear Power Plant in Korea, are detected by two identical detectors located at 294 and 1383 m, respectively, from the reactor array center. In the 229 d data-taking period between 11 August 2011 and 26 March 2012, the far (near) detector observed 17102 (154088) electron antineutrino candidate events with a background fraction of 5.5% (2.7%). The ratio of observed to expected numbers of antineutrinos in the far detector is $0.920\ifmmode\pm\else\textpm\fi{}0.009(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.014(\mathrm{syst})$. From this deficit, we determine ${sin }^{2}2{\ensuremath{\theta}}_{13}=0.113\ifmmode\pm\else\textpm\fi{}0.013(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.019(\mathrm{syst})$ based on a rate-only analysis.

1,979 citations


Journal ArticleDOI
TL;DR: A detailed review on the advances of chemical functionalization of graphene is presented in this article, where the surface modification of graphene oxide followed by reduction has been carried out to obtain functionalized graphene.

1,517 citations


Journal ArticleDOI
TL;DR: In this article, a critical review of carbon-based nanostructured materials and their composites for use as supercapacitor electrodes is provided, focusing on basic principles of supercapACitors and various factors affecting their performance.
Abstract: This critical review provides an overview of current research on carbon-based nanostructured materials and their composites for use as supercapacitor electrodes. Particular emphasis has been directed towards basic principles of supercapacitors and various factors affecting their performance. The focus of the review is the detailed discussion regarding the performance and stability of carbon-based materials and their composites. Pseudo-active species, such as, conducting polymer/metal oxide have been found to exhibit pseudo-capacitive behavior and carbon-based materials demonstrate electrical double layer capacitance. Carbon-based materials, such as, graphene, carbon nanotubes, and carbon nanofibers, provide high surface area for the deposition of conducting polymer/metal oxide that facilitates the efficient ion diffusion phenomenon and contribute towards higher specific capacitance of the carbon based composite materials with excellent cyclic stability. However, further scope of research still exists from the view point of developing high energy supercapacitor devices in a cost effective and simple way. This review will be of value to researchers and emerging scientists dealing with or interested in carbon chemistry.

655 citations


Journal ArticleDOI
TL;DR: In this article, different manufacturing processes and their suitability for natural fibre composites, based on the materials, mechanical and thermal properties of the fibres and matrices are discussed in detail.
Abstract: Elevated environmental awareness of the general public in reducing carbon footprints and the use nonnaturally decomposed solid wastes has resulted in an increasing use of natural materials, biodegradable and recyclable polymers and their composites for a wide range of engineering applications. The properties of natural fibre reinforced polymer composites are generally governed by the pre-treated process of fibre and the manufacturing process of the composites. These properties can be tailored for various types of applications by properly selecting suitable fibres, matrices, additives and production methods. Besides, due to the complexity of fibre structures, different mechanical performances of the composites are obtained even with the use of the same fibre types with different matrices. Some critical issues like poor wettability, poor bonding and degradation at the fibre/matrix interface (a hydrophilic and hydrophobic effect) and damage of the fibre during the manufacturing process are the main causes of the reduction of the composites’ strength. In this paper, different manufacturing processes and their suitability for natural fibre composites, based on the materials, mechanical and thermal properties of the fibres and matrices are discussed in detail.

486 citations


Journal ArticleDOI
TL;DR: The results indicate that the introduced scaffold might be an ideal biomaterial for wound dressing applications and showed good bactericidal activity against both of Gram-positive and Gram-negative bacteria.

402 citations


Journal ArticleDOI
TL;DR: The hardware and spice simulation of the proposed emulator showed promising results that provides an alternative solution of hp TiO2 memristor model in real circuit.
Abstract: A memristor emulator which imitates the behavior of a TiO2 memristor is presented. Our emulator is built from off-the-shelf solid state components. To develop real world memristor circuit applications, the emulator can be used for breadboard experiments in real time. Two or more memristor emulators can be connected in serial, in parallel, or in hybrid (serial and parallel combined) with identical or opposite polarities. With a simple change of connection, each memristor emulator can be switched between a decremental configuration or an incremental configuration. The hardware and spice simulation of the proposed emulator showed promising results that provides an alternative solution of hp TiO2 memristor model in real circuit.

351 citations


Journal ArticleDOI
01 Mar 2012-Carbon
TL;DR: A green approach for the reduction of graphene oxide (GO) using wild carrot root is reported in this paper, which avoids the use of toxic and environmentally harmful reducing agents commonly used in the chemical reduction of GO to obtain graphene.

332 citations


Journal ArticleDOI
TL;DR: A pulse-based programmable memristor circuit for implementing synaptic weights for artificial neural networks is proposed, and both positive and negative multiplications are performed via a charge-dependent Ohm's law.
Abstract: A pulse-based programmable memristor circuit for implementing synaptic weights for artificial neural networks is proposed. In the memristor weighting circuit, both positive and negative multiplications are performed via a charge-dependent Ohm's law (). The circuit is composed of five memristors with bridge-like connections and operates like an artificial synapse with pulse-based processing and adjustability. The sign switching pulses, weight setting pulses and synaptic processing pulses are applied through a shared input terminal. Simulations are done with both linear memristor and window-based nonlinear memristor models.

324 citations


Journal ArticleDOI
09 Jan 2012-Sensors
TL;DR: In this paper, the authors present a comprehensive taxonomy of multipath routing protocols for wireless sensor networks and highlight the primary motivation behind the development of each protocol category and explain the operation of different protocols in detail, with emphasis on their advantages and disadvantages.
Abstract: A wireless sensor network is a large collection of sensor nodes with limited power supply and constrained computational capability. Due to the restricted communication range and high density of sensor nodes, packet forwarding in sensor networks is usually performed through multi-hop data transmission. Therefore, routing in wireless sensor networks has been considered an important field of research over the past decade. Nowadays, multipath routing approach is widely used in wireless sensor networks to improve network performance through efficient utilization of available network resources. Accordingly, the main aim of this survey is to present the concept of the multipath routing approach and its fundamental challenges, as well as the basic motivations for utilizing this technique in wireless sensor networks. In addition, we present a comprehensive taxonomy on the existing multipath routing protocols, which are especially designed for wireless sensor networks. We highlight the primary motivation behind the development of each protocol category and explain the operation of different protocols in detail, with emphasis on their advantages and disadvantages. Furthermore, this paper compares and summarizes the state-of-the-art multipath routing techniques from the network application point of view. Finally, we identify open issues for further research in the development of multipath routing protocols for wireless sensor networks.

320 citations


Journal ArticleDOI
TL;DR: In this article, the cobalt-based metal-organic-frameworks (Co-MOF) was explored as a promising material for supercapacitors and a good pseudocapacitor behavior with the specific capacitance up to 206.76 F ǫ n−1.

Journal ArticleDOI
TL;DR: The use of memristor bridge synapse in the proposed architecture solves one of the major problems, regarding nonvolatile weight storage in analog neural network implementations, and a modified chip-in-the-loop learning scheme suitable for the proposed neural network architecture is proposed.
Abstract: Analog hardware architecture of a memristor bridge synapse-based multilayer neural network and its learning scheme is proposed. The use of memristor bridge synapse in the proposed architecture solves one of the major problems, regarding nonvolatile weight storage in analog neural network implementations. To compensate for the spatial nonuniformity and nonideal response of the memristor bridge synapse, a modified chip-in-the-loop learning scheme suitable for the proposed neural network architecture is also proposed. In the proposed method, the initial learning is conducted in software, and the behavior of the software-trained network is learned by the hardware network by learning each of the single-layered neurons of the network independently. The forward calculation of the single-layered neuron learning is implemented on circuit hardware, and followed by a weight updating phase assisted by a host computer. Unlike conventional chip-in-the-loop learning, the need for the readout of synaptic weights for calculating weight updates in each epoch is eliminated by virtue of the memristor bridge synapse and the proposed learning scheme. The hardware architecture along with the successful implementation of proposed learning on a three-bit parity network, and on a car detection network is also presented.

Journal ArticleDOI
TL;DR: The endoplasmic reticulum is the major site of calcium storage and protein folding, and Alterations in the oxidative environment of the ER and also intra-ER Ca2+ cause the production of ER stress-induced reactive oxygen species (ROS).
Abstract: The endoplasmic reticulum (ER) is the major site of calcium storage and protein folding. It has a unique oxidizing-folding environment due to the predominant disulfide bond formation during the process of protein folding. Alterations in the oxidative environment of the ER and also intra-ER Ca2+ cause the production of ER stress-induced reactive oxygen species (ROS). Protein disulfide isomerases, endoplasmic reticulum oxidoreductin-1, reduced glutathione and mitochondrial electron transport chain proteins also play crucial roles in ER stress-induced production of ROS. In this article, we discuss ER stress-associated ROS and related diseases, and the current understanding of the signaling transduction involved in ER stress.

Journal ArticleDOI
30 May 2012-Talanta
TL;DR: A convenient method is proposed to assess the presence of magnetite-maghemite mixture and to further quantify its phase composition using the conventional peak deconvolution technique and it is believed that the proposed method would be a convenient tool for the study of the magnetites-magemite mixture which otherwise requires highly sophisticated equipments and techniques.

Journal ArticleDOI
01 Jun 2012
TL;DR: This paper proposes a memristor bridge circuit consisting of four identical memristors that is able to perform zero, negative, and positive synaptic weightings together with three additional transistors to perform synaptic operation for neural cells.
Abstract: In this paper, we propose a memristor bridge circuit consisting of four identical memristors that is able to perform zero, negative, and positive synaptic weightings. Together with three additional transistors, the memristor bridge weighting circuit is able to perform synaptic operation for neural cells. It is compact as both weighting and weight programming are performed in a memristor bridge synapse. It is power efficient, since the operation is based on pulsed input signals. Its input terminals are utilized commonly for applying both weight programming and weight processing signals via time sharing. In this paper, features of the memristor bridge synapses are investigated using the TiO memristor model via simulations.

Journal ArticleDOI
TL;DR: This paper presents a rigorous and comprehensive nonlinear circuit-theoretic foundation for the memristive Hodgkin–Huxley Axon Circuit model.
Abstract: This paper presents a rigorous and comprehensive nonlinear circuit-theoretic foundation for the memristive Hodgkin–Huxley Axon Circuit model. We show that the Hodgkin–Huxley Axon comprises a potass...

Journal ArticleDOI
TL;DR: In this article, an environmentally friendly, cost effective, and simple methodology for the preparation of surface modified graphene has been described, where Baker's yeast containing nicotinamide adenine dinucleotide phosphate (NADPH) has been used as reducing and functionalizing agent.

Journal ArticleDOI
TL;DR: A facile one-pot strategy was developed for the assembly of gold nanoparticles (Au NPs) onto single crystalline ZnO nanorods using cetyltrimethylammonium bromide (CTAB) as a capping agent.
Abstract: A facile one-pot strategy was developed for the assembly of gold nanoparticles (Au NPs) onto single crystalline ZnO nanorods using cetyltrimethylammonium bromide (CTAB) as a capping agent. Zinc oxide nanorods were synthesized by hydrothermal method whereas the Au NPs (below 5 nm) were deposited on the surface of ZnO nanorods by the solution growth method. Gas sensing properties of Au/ZnO nanorods were studied at various temperatures for various concentrations of reducing (CO) and oxidizing (NO 2 ) gases in synthetic air and compared with pristine ZnO nanorods. Sensor fabricated by Au/ZnO nanorods showed significantly enhanced sensing performances for CO gas while opposite was the case with NO 2 gas as compared to pristine ZnO nanorods. The highest response of Au/ZnO nanorods for CO gas was 12 at 150 °C while for ZnO nanorods, it was 6.12 at 400 °C. Whereas the highest response of Au/ZnO nanorods for NO 2 gas was 4.14 while for ZnO nanorods, it was 10 at 300 °C. It was found that Au NPs acted as promoter for CO gas while inhibiter for NO 2 gas sensing due to their different sensing mechanisms. This study suggested that noble metals decoration of ZnO nanorods can be used for selectivity issue between CO and NO 2 gases.

Journal ArticleDOI
TL;DR: In this article, the reduction of graphite oxide using glycine as both a chemical functionalizer and a reducing agent is reported. But the reduction could occur under mild conditions and the as-produced graphene sheets show impressive crystalline behavior and admirable aqueous dispersibility without employing any external stabilizing reagents.
Abstract: Here we report a simple, efficient, and environmentally friendly approach towards the reduction of graphite oxide using glycine as both a chemical functionalizer and a reducing agent. The reduction could occur under mild conditions and the as-produced graphene sheets show impressive crystalline behavior and admirable aqueous dispersibility without employing any external stabilizing reagents. Formation of graphene has been confirmed by Raman spectroscopy and transmission electron microscopy. X-Ray photoelectron spectroscopic analysis reveals the successful removal of oxygen moieties upon reduction using glycine. The method is cost-effective and presents an alternative route to produce large-scale, reduced graphite oxide nanosheets.

Journal ArticleDOI
TL;DR: This feature article collates the various MONs and their potential applications in the chemical and biological sensors for clinical and non-clinical applications.

Journal ArticleDOI
TL;DR: A holistic animal management approach such as stringent control of antimicrobial agents in the livestock industry, early clinical and microbiological diagnosis, appropriate treatment, and implementation of strict sanitary standards in the food industry are also needed to significantly reduce the overall burden of salmonellosis on human health.

Journal ArticleDOI
TL;DR: It is concluded that when MC‐fMRI studies are organized well with careful attention to unification of hardware, software and procedural aspects, the process can be a highly effective means for accessing a desired participant demographics while accelerating scientific discovery.
Abstract: This report provides practical recommendations for the design and execution of multicenter functional MRI (MC-fMRI) studies based on the collective experience of the Function Biomedical Informatics Research Network (FBIRN). The study was inspired by many requests from the fMRI community to FBIRN group members for advice on how to conduct MC-fMRI studies. The introduction briefly discusses the advantages and complexities of MC-fMRI studies. Prerequisites for MC-fMRI studies are addressed before delving into the practical aspects of carefully and efficiently setting up a MC-fMRI study. Practical multisite aspects include: (i) establishing and verifying scan parameters including scanner types and magnetic fields, (ii) establishing and monitoring of a scanner quality program, (iii) developing task paradigms and scan session documentation, (iv) establishing clinical and scanner training to ensure consistency over time, (v) developing means for uploading, storing, and monitoring of imaging and other data, (vi) the use of a traveling fMRI expert, and (vii) collectively analyzing imaging data and disseminating results. We conclude that when MC-fMRI studies are organized well with careful attention to unification of hardware, software and procedural aspects, the process can be a highly effective means for accessing a desired participant demographics while accelerating scientific discovery.

Journal ArticleDOI
TL;DR: A solution-based approach to the preparation of Pt-based alloy with early transition metals and realistic parameters for the stability and activity of Pt(3)M nanocatalysts for oxygen reduction reaction (ORR) are reported.
Abstract: The design of electrocatalysts for polymer electrolyte membrane fuel cells must satsify two equally important fundamental principles: optimization of electrocatalytic activity and long-term stability in acid media (pH <1) at high potential (0.8 V). We report here a solution-based approach to the preparation of Pt-based alloy with early transition metals and realistic parameters for the stability and activity of Pt(3)M (M = Y, Zr, Ti, Ni, and Co) nanocatalysts for oxygen reduction reaction (ORR). The enhanced stability and activity of Pt-based alloy nanocatalysts in ORR and the relationship between electronic structure modification and stability were studied by experiment and DFT calculations. Stability correlates with the d-band fillings and the heat of alloy formation of Pt(3)M alloys, which in turn depends on the degree of the electronic perturbation due to alloying. This concept provides realistic parameters for rational catalyst design in Pt-based alloy systems.

Journal ArticleDOI
A. Adare1, S. Afanasiev2, Christine Angela Aidala3, N. N. Ajitanand4  +381 moreInstitutions (56)
TL;DR: In the p(T) < 4 GeV/c region dominated by thermal photons, a substantial direct-photon v(2) comparable to that of hadrons is found, whereas model calculations for thermal photons in this kinematic region underpredict the observed v( 2).
Abstract: The second Fourier component v(2) of the azimuthal anisotropy with respect to the reaction plane is measured for direct photons at midrapidity and transverse momentum (p(T)) of 1-12 GeV/c in Au + Au collisions at root s(NN) = 200 GeV. Previous measurements of this quantity for hadrons with p(T) 6 GeV/c a reduced anisotropy is interpreted in terms of a path-length dependence for parton energy loss. In this measurement with the PHENIX detector at the Relativistic Heavy Ion Collider we find that for p(T) > 4 GeV/c the anisotropy for direct photons is consistent with zero, which is as expected if the dominant source of direct photons is initial hard scattering. However, in the p(T) < 4 GeV/c region dominated by thermal photons, we find a substantial direct-photon v(2) comparable to that of hadrons, whereas model calculations for thermal photons in this kinematic region underpredict the observed v(2).

Journal ArticleDOI
TL;DR: The study suggests that DPP IV inhibitors may ameliorate diabetic nephropathy as well as reduce the overproduction of TGF-β1.
Abstract: Dipeptidyl peptidase (DPP) IV inhibitors are probably beneficial for preventing diabetic complication and modulating glucagon-like peptide-1 receptor (GLP-1R) expression. The aim of this study was to determine whether the DPP IV inhibitor LAF237 (vildagliptin) has renoprotective qualities in streptozotocin-induced diabetic rats. Diabetic and nondiabetic rats were treated with an oral dose of 4 or 8 mg/kg/day LAF237 or placebo for 24 weeks, and renal injury was observed by light and electron microscopy. We also assessed DPP IV activity, active GLP-1 level, cAMP and 8-hydroxy-deoxyguanosine excretion, and GLP-1R, cleaved caspase 3, and transforming growth factor-β1 (TGF-β1) expression. LAF237 significantly decreased proteinuria, albuminuria, and urinary albumin/creatinine ratio, improved creatinine clearance, and dose-dependently inhibited interstitial expansion, glomerulosclerosis, and the thickening of the glomerular basement membrane in diabetic rats. It is noteworthy that LAF237 markedly down-regulated DPP IV activity and increased active GLP-1 levels, which probably prevented oxidative DNA damage and renal cell apoptosis by activating the GLP-1R and modulating cAMP. Renoprotection was also associated with a reduction in TGF-β1 overexpression. Our study suggests that DPP IV inhibitors may ameliorate diabetic nephropathy as well as reduce the overproduction of TGF-β1. The observed renoprotection is probably attributable to inhibition of DPP IV activity, mimicking of incretin action, and activation of the GLP-1R.

Journal ArticleDOI
TL;DR: In this paper, a batch of Jatropha curcas pods were used for activated carbon preparation and successfully employed as adsorbent for the removal of reactive dye, Remazol Brilliant Blue R (RBBR).

Journal ArticleDOI
TL;DR: In vitro investigations using cell cultures and in vivo animal models have indicated ginseng’s potential cardiovascular benefits through diverse mechanisms that include antioxidation, modifying vasomotor function, reducing platelet adhesion, influencing ion channels, altering autonomic neurotransmitters release, and improving lipid profiles.

Journal ArticleDOI
TL;DR: It is pointed out that isolate MN3-4 could potentially reduce heavy metal phytotoxicity and increase Pb accumulation in A. firma plants.


Journal ArticleDOI
TL;DR: Dodecyl amine-modified graphene (DA-G)/linear low density polyethylene (LLDPE) nanocomposites were prepared through solution mixing in this article.