oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 36 )

2018 ( 69 )

2017 ( 69 )

2016 ( 95 )

Custom range...

Search Results: 1 - 10 of 27555 matches for " Jong Kook Lee "
All listed articles are free for downloading (OA Articles)
Page 1 /27555
Display every page Item
A Study on the Seismic Isolation Systems of Bridges with Lead Rubber Bearings  [PDF]
Woo-Suk Kim, Dong-Joon Ahn, Jong-Kook Lee
Open Journal of Civil Engineering (OJCE) , 2014, DOI: 10.4236/ojce.2014.44031
Abstract: This study consists of the development and presentation of example of seismic isolation system analysis and design for a continuous, 3-span, cast-in-place concrete box girder bridge. It is expected that example is developed for all Lead-Rubber Bearing (LRB) seismic isolation system on piers and abutments which placed in between super-structure and sub-structure. Design forces, displacements, and drifts are given distinctive consideration in accordance with Caltrans Seismic Design Criteria (2004). Most of all, total displacement\"\" on design for all LRBs case is reduced comparing with combined lead-rubber and elastomeric bearing system\"\" . Therefore, this represents substantial reduction in cost because of reduction of expansion joint. This presents a summary of analysis and design of seismic isolation system by energy mitigation with LRB on bridges.
Two Gnaphosid Spiders (Araneae: Gnaphosidae) New to Korean Spider Fauna  [PDF]
Sue Yeon Lee, Seung Tae Kim, Joon-Ho Lee, Jung Sun Yoo, Jong Kook Jung, Jae Won Lim
Open Journal of Animal Sciences (OJAS) , 2014, DOI: 10.4236/ojas.2014.43018
Abstract: Drassyllus yaginumai Kamura, 1987 and Zelotes tortuosus Kamura, 1987 belonging to Gnaphosidae were captured by pitfall trap in maize and soybean fields during the survey of arthropod fauna of agricultural ecosystem in Korea. Present work describes these 2 species with illustrations of taxonomic characters.
A Study on Water Repellent Effectiveness of Natural Oil-Applied Soil as a Building Material  [PDF]
Jong-Kook Lee, Jee-Eun Lee, Seong-Cheol Park, Hee-Dong Cho, Hye-Woong Yoo, Young-Sang Kim, Seong-Ryong Ryu, Woo-Suk Kim, Dong-Joon Ahn
Open Journal of Civil Engineering (OJCE) , 2015, DOI: 10.4236/ojce.2015.51014
Abstract: This study was performed to investigate the water repellent effectiveness of natural oil-applied soil when it is used as a building material. Natural oil types such as olive oil, bean oil, perilla oil and linseed oil, which are being used for producing water repellent timber, are selected for the experiments. It is expected that perilla oil and in seed oil, which are drying oil types will have better water repellent effectiveness than the other types. For the evaluation of water repellence of natural oil-applied soil, a contact angle test was performed. A contact angle of water drop on various surface conditions were tested, and large differences were seen between the natural oil-applied soil and untreated soil. As a result, it is showed that all natural oil types have water repellent effectiveness. However, linseed oil, which is a drying oil type, shows an outstanding water repellent effectiveness value, while perila oil, which is also a drying oil type, shows the lowest value. Additionally, results show that there is no link between water repellent effectiveness and the number of applications of natural oil. Nevertheless, existing commercial water repellents show better performance than natural oil, and it is anticipated that the results of this study will provide essential information for further research to enhance the water repellent effectiveness of soil as a building material.
Selective Algicidal Action of Peptides against Harmful Algal Bloom Species
Seong-Cheol Park, Jong-Kook Lee, Si Wouk Kim, Yoonkyung Park
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0026733
Abstract: Recently, harmful algal bloom (HAB), also termed “red tide”, has been recognized as a serious problem in marine environments according to climate changes worldwide. Many novel materials or methods to prevent HAB have not yet been employed except for clay dispersion, in which can the resulting sedimentation on the seafloor can also cause alteration in marine ecology or secondary environmental pollution. In the current study, we investigated that antimicrobial peptide have a potential in controlling HAB without cytotoxicity to harmless marine organisms. Here, antimicrobial peptides are proposed as new algicidal compounds in combating HAB cells. HPA3 and HPA3NT3 peptides which exert potent antimicrobial activity via pore forming action in plasma membrane showed that HPA3NT3 reduced the motility of algal cells, disrupted their plasma membrane, and induced the efflux of intracellular components. Against raphidoflagellate such as Heterosigma akashiwo, Chattonella sp., and C. marina, it displayed a rapid lysing action in cell membranes at 1~4 μM within 2 min. Comparatively, its lysing effects occurred at 8 μM within 1 h in dinoflagellate such as Cochlodium polykrikoides, Prorocentrum micans, and P. minimum. Moreover, its lysing action induced the lysis of chloroplasts and loss of chlorophyll a. In the contrary, this peptide was not effective against Skeletonema costatum, harmless algal cell, even at 256 μM, moreover, it killed only H. akashiwo or C. marina in co-cultivation with S. costatum, indicating to its selective algicidal activity between harmful and harmless algal cells. The peptide was non-hemolytic against red blood cells of Sebastes schlegeli, the black rockfish, at 120 μM. HAB cells were quickly and selectively lysed following treatment of antimicrobial peptides without cytotoxicity to harmless marine organisms. Thus, the antibiotic peptides examined in our study appear to have much potential in effectively controlling HAB with minimal impact on marine ecology.
Isolation and Purification of a Novel Deca-Antifungal Peptide from Potato (Solanum tuberosum L. cv. Jopung) Against Candida albicans
Jong-Kook Lee,Ramamourthy Gopal,Chang Ho Seo,Hyeonsook Cheong,Yoonkyung Park
International Journal of Molecular Sciences , 2012, DOI: 10.3390/ijms13044021
Abstract: In a previous study, an antifungal protein, AFP-J, was purified from tubers of the potato ( Solanum tuberosum cv. L Jopung) and by gel filtration and HPLC. In this study, the functional peptide was characterized by partial acid digestion using HCl and HPLC. We obtained three peaks from the AFP-J, the first and third peaks were not active in the tested fungal strain. However, the second peak, which was named Potide-J, was active (MIC; 6.25 μg/mL) against Candida albicans. The amino acid sequences were analyzed by automated Edman degradation, and the amino acid sequence of Potide-J was determined to be Ala-Val-Cys-Glu-Asn-Asp-Leu-Asn-Cys-Cys. Mass spectrometry showed that its molecular mass was 1083.1 Da. Finally, we confirmed that a disulfide bond was present between Cys 3 and Cys 9 or Cys 10. Using this structure, Potide-J was synthesized via solid-phase methods. In these experiments, only the linear sequence was shown to display strong activity against Candida albicans. These results suggest that Potide-J may be an excellent candidate compound for the development of commercially applicable antibiotic agents.
Ground beetle (Coleoptera: Carabidae) assemblage in the urban landscape, Korea
Jong-Kook Jung,Seung-Tae Kim,Sue-Yeon Lee,Chang-Kyu Park
Journal of Ecology and Field Biology , 2012,
Abstract: This study was conducted with the intention of clarifying the effects of land-use types on a species of ground beetle’s richness,abundance, and composition; the study focused on urban landscapes. We also selected the potential bioindicatorsclassifying land-use types; eleven sites were selected from an urban landscape in Korea. Overall, land-use types in urbanlandscapes did not appear to cause significant decrease in species richness or the abundance of total ground beetle assemblage.According to habitat preferences, several land-use types and distances from the forest significantly affectedthe species richness and abundance, while the open-habitat species were not affected by these variables. Land-use typeswere classified into two major groups, forest and non-forest areas, based on ground beetle assemblage; several indicators,such as Dolichus halensis halensis and subfamily Carabinae species, were of particular consideration. In conclusion, environmentalchange by anthropogenic disturbance can cause different effects on ground beetle assemblages, and forestspecialists can be negatively affected.
Effect of Repetitive Lysine-Tryptophan Motifs on the Eukaryotic Membrane
Ramamourthy Gopal,Jong Kook Lee,Jun Ho Lee,Young Gwon Kim,Gwang Chae Oh,Chang Ho Seo,Yoonkyung Park
International Journal of Molecular Sciences , 2013, DOI: 10.3390/ijms14012190
Abstract: In a previous study, we synthesized a series of peptides containing simple sequence repeats, (KW) n–NH 2 ( n = 2,3,4 and 5) and determined their antimicrobial and hemolytic activities, as well as their mechanism of antimicrobial action. However, (KW) 5 showed undesirable cytotoxicity against RBC cells. In order to identify the mechanisms behind the hemolytic and cytotoxic activities of (KW) 5, we measured the ability of these peptides to induce aggregation of liposomes. In addition, their binding and permeation activities were assessed by Trp fluorescence, calcein leakage and circular dichrorism using artificial phospholipids that mimic eukaryotic liposomes, including phosphatidylcholine (PC), PC/sphingomyelin (SM) (2:1, w/ w) and PC/cholesterol (CH) (2:1, w/ w). Experiments confirmed that only (KW) 5 induced aggregation of all liposomes; it formed much larger aggregates with PC:CH (2:1, w/ w) than with PC or PC:SM (2:1, w/ w). Longer peptide (KW) 5, but not (KW) 3 or (KW) 4, strongly bound and partially inserted into PC:CH compared to PC or PC:SM (2:1, w/ w). Calcein release experiments showed that (KW) 5 induced calcein leakage from the eukaryotic membrane. Greater calcein leakage was induced by (KW) 5 from PC:CH than from PC:SM (2:1, w/ w) or PC, whereas (KW) 4 did not induce calcein leakage from any of the liposomes. Circular dichroism measurements indicated that (KW) 5 showed higher conformational transition compared to (KW) 4 due to peptide-liposome interactions. Taken together, our results suggest that (KW) 5 reasonably mediates the aggregation and permeabilization of eukaryotic membranes, which could in turn explain why (KW) 5 displays efficient hemolytic activity.
A Proline-Hinge Alters the Characteristics of the Amphipathic α-helical AMPs
Jong Kook Lee, Ramamourthy Gopal, Seong-Cheol Park, Hyun Sook Ko, Yangmee Kim, Kyung-Soo Hahm, Yoonkyung Park
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0067597
Abstract: HP (2–20) is a 19-aa, amphipathic, α-helical peptide with antimicrobial properties that was derived from the N-terminus of Helicobacter pylori ribosomal protein L1. We previously showed that increasing the net hydrophobicity of HP (2–20) by substituting Trp for Gln17 and Asp19 (Anal 3) increased the peptide's antimicrobial activity. In hydrophobic medium, Anal 3 forms an amphipathic structure consisting of an N-terminal random coil region (residues 2–5) and an extended helical region (residues 6–20). To investigate the structure-activity relationship of Anal 3, we substituted Pro for Glu9 (Anal 3-Pro) and then examined the new peptide's three-dimensional structure, antimicrobial activity and mechanism of action. Anal 3-Pro had an α-helical structure in the presence of trifluoroethanol (TFE) and sodium dodecyl sulfate (SDS). NMR spectroscopic analysis of Anal 3-Pro's tertiary structure in SDS micelles confirmed that the kink potential introduced by Pro10 was responsible for the helix distortion. We also found that Anal 3-Pro exhibited about 4 times greater antimicrobial activity than Anal 3. Fluorescence activated flow cytometry and confocal fluorescence microscopy showed that incorporating a Pro-hinge into Anal 3 markedly reduced its membrane permeability so that it accumulated in the cytoplasm without remaining in the cell membrane. To investigate the translocation mechanism, we assessed its ability to release of FITC-dextran. The result showed Anal 3-Pro created a pore <1.8 nm in diameter, which is similar to buforin II. Notably, scanning electron microscopic observation of Candida albicans revealed that Anal 3-Pro and buforin II exert similar effects on cell membranes, whereas magainin 2 exerts a different, more damaging, effect. In addition, Anal 3-Pro assumed a helix-hinge-helix structure in the presence of biological membranes and formed micropores in both bacterial and fungal membranes, through which it entered the cytoplasm and tightly bound to DNA. These results indicate that the bending region of Anal 3- Pro peptide is prerequisite for effective antibiotic activity and may facilitate easy penetration of the lipid bilayers of the cell membrane.
Insulin Facilitates the Recovery of Myocardial Contractility and Conduction during Cardiac Compression in Rabbits with Bupivacaine-Induced Cardiovascular Collapse
Solmon Yang,Tserendorj Uugangerel,In-ki Jang,Hyung-chul Lee,Jong Min Kim,Byeong-Cheol Kang,Chong Soo Kim,Kook-Hyun Lee
Anesthesiology Research and Practice , 2012, DOI: 10.1155/2012/878764
Abstract: Bupivacaine inhibits cardiac conduction and contractility. Insulin enhances cardiac repolarization and myocardial contractility. We hypothesizes that insulin therapy would be effective in resuscitating bupivacaine-induced cardiac toxicity in rabbits. Twelve rabbits were tracheally intubated and midline sternotomy was performed under general anesthesia. Cardiovascular collapse (CVC) was induced by an IV bolus injection of bupivacaine 10?mg/kg. The rabbits were treated with either saline (control) or insulin injection, administered as a 2?U/kg bolus. Internal cardiac massage was performed until the return of spontaneous circulation (ROSC) and the time to the return of sinus rhythm (ROSR) was also noted in both groups. Arterial blood pressure, and electrocardiography were continuously monitored for 30?min and plasma bupivacaine concentrations at every 5?min. The ROSC, ROSR and normalization of QRS duration were attained faster in the insulin-treated group than in the control group. At the ROSC, there was a significant difference in bupivacaine concentration between two groups. Insulin facilitates the return of myocardial contractility and conduction from bupivacaine-induced CVC in rabbits. However, recovery of cardiac conduction is dependent mainly on the change of plasma bupivacaine concentrations. 1. Introduction Resuscitation following bupivacaine-induced cardiovascular collapse (CVC) is difficult and often resistant to conventional treatment [1]. Bupivacaine blocks cardiac Na+ channel [2, 3] and transient outward K+ currents [4]. Increased ECG intervals [5] and decreased R-wave amplitude in lead II [6] are shown by the bupivacaine infusion. Bupivacaine also decreases the maximal rate of depolarization in Purkinje fibers [7]. Alteration of Ca++ recruitment from sarcoplasmic reticulum [8] and mitochondrial ATP production [9] are related to the deterioration of myocardial contractility by bupivacaine. Previous experiments have shown that insulin might be effective in reversing bupivacaine-induced cardiac depression probably by enhancing transient outward K+ current, Ca++ transport activity of sarcoplasmic reticulum, and improving myocardial energetics [5, 10]. In contrast, Stehr et al. demonstrate that insulin has a significant positive inotropic effect without affecting electrophysiologic parameters at a fixed bupivacaine concentration in an in vitro study [11]. Because bupivacaine impairs ventricular conduction in a dose-dependent manner and QRS widening has been shown as a function of bupivacaine concentration in an isolated rabbit heart model [12], we
Bojesodok-eum, a Herbal Prescription, Ameliorates Acute Inflammation in Association with the Inhibition of NF- B-Mediated Nitric Oxide and ProInflammatory Cytokine Production
Kook Ho Sohn,Mi Jeong Jo,Won Joon Cho,Jong Rok Lee,Il Je Cho,Sang Chan Kim,Young Woo Kim,Seon Young Jee
Evidence-Based Complementary and Alternative Medicine , 2012, DOI: 10.1155/2012/457370
Abstract: Bojesodok-eum (BSE) is a herbal prescription consisting of Coptidis Rhizoma and Scutellariae Radix as main components. This paper investigated the effects of BSE on the induction of nitric oxide (NO), prostaglandin E2 (PGE2), and proinflammatory cytokines that are caused by lipopolysaccharide (LPS) in murine macrophage cell line and on the paw edema formation in animals. Administration of BSE (0.3 g/kg and 1 g/kg) in rats significantly inhibited carrageenan-induced paw edema formation, as did dexamethasone, an anti-inflammatory positive control drug. In cell model, treatment of BSE decreased the production of NO and PGE2 in RAW264.7 cells stimulated by LPS. BSE also inhibited the expression of iNOS and COX-2 protein as well as COX activity in a concentration-dependent manner. Consistently, BSE suppressed the ability of LPS to produce TNF-, interleukin-1, and interleukin-6. LPS treatment induced nuclear NF-B level and I-B phosphorylation, which were inhibited subsequent treatment of BSE, suggesting its repression of LPS-inducible NF-B activation. BSE abrogated the induction of NO, PGE2, and proinflammatory cytokines, as well as iNOS and COX-2 protein expression in RAW264.7 cells stimulated by LPS as mediated with NF-B inhibition.
Page 1 /27555
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.