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Search Results: 1 - 10 of 22190 matches for " Bu-Yeo Kim "
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Pogostemon cablin as ROS Scavenger in Oxidant-Induced Cell Death of Human Neuroglioma Cells
Hyung Woo Kim,Su Jin Cho,Bu-Yeo Kim,Su In Cho,Young Kyun Kim
Evidence-Based Complementary and Alternative Medicine , 2010, DOI: 10.1093/ecam/nem176
Abstract: Reactive oxygen species (ROS) have been implicated in the pathogenesis of a wide range of acute and long-term neurodegenerative diseases. This study was undertaken to examine the efficacy of Pogostemon cablin, a well-known herb in Korean traditional medicine, on ROS-induced brain cell injury. Pogostemon cablin effectively protected human neuroglioma cell line A172 against both the necrotic and apoptotic cell death induced by hydrogen peroxide (H2O2). The effect of Pogostemon cablin was dose dependent at concentrations ranging from 0.2 to 5?mg ml?1. Pogostemon cablin significantly prevented depletion of cellular ATP and activation of poly ADP-ribose polymerase induced by H2O2. The preservation of functional integrity of mitochondria upon the treatment of Pogostemon cablin was also confirmed by 3-(4,5-dimethyl-2-thiazyl)-2,5-diphenyl-2-H-tetrazolium bromide assay. Furthermore, Pogostemon cablin significantly prevented H2O2-induced release of cytochrome c into cytosol. Determination of intracellular ROS showed that Pogostemon cablin might exert its role as a powerful scavenger of intracellular ROS. The present study suggests the beneficial effect of Pogostemon cablin on ROS-induced neuroglial cell injury. The action of Pogostemon cablin as a ROS-scavenger might underlie the mechanism.
Genetic Approach to Elucidation of Sasang Constitutional Medicine
Bu-Yeo Kim,Seongwon Cha,Hee-Jeong Jin,Sangkyun Jeong
Evidence-Based Complementary and Alternative Medicine , 2009, DOI: 10.1093/ecam/nep058
Abstract: Sasang Constitutional Medicine (SCM) offers a medical principle that classifies humans into four constitution groups and guides their treatment with constitution-matched medical assistance. The principle of this traditional medicine, although requires significant scientific support, appears to suggest a genetic influence on constitution type. The relative frequency of constitution types in a population, for instance, has remained relatively constant since Jema Lee first described them from his observations. In addition, the body compartment concept of SCM appears to be related to the anterio–posterior patterning of the embryonic gut and associated internal organs. This study describes the attributes of the constitution concept of SCM that can be interpreted in the language of genetics and current approaches to identity the genetic factors that make up the constitution. These efforts should make it possible to interpret the principle of this traditional medicine scientifically. Considering the recent trend in medicine that pursues individualized or tailored medical offerings, once SCM is proven to be explainable with scientific evidence, it will be able to contribute to and take a place in the rapidly evolving medicine environment.
Biphasic Functional Regulation in Hippocampus of Rat with Chronic Cerebral Hypoperfusion Induced by Permanent Occlusion of Bilateral Common Carotid Artery
Jihye Bang, Won Kyung Jeon, In Sun Lee, Jung-Soo Han, Bu-Yeo Kim
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0070093
Abstract: Background Chronic cerebral hypoperfusion induced by permanent occlusion of the bilateral common carotid artery (BCCAO) in rats has been commonly used for the study of Alzheimer’s disease and vascular dementia. Despite the apparent cognitive dysfunction in rats with BCCAO, the molecular markers or pathways involved in the pathological alternation have not been clearly identified. Methods Temporal changes (sham, 21, 35, 45, 55 and 70 days) in gene expression in the hippocampus of rats after BCCAO were measured using time-course microarray analysis. Gene Ontology (GO) and pathway analyses were performed to identify the functional involvement of temporally regulated genes in BCCAO. Results Two major gene expression patterns were observed in the hippocampus of rats after BCCAO. One pattern, which was composed of 341 early up-regulated genes after the surgical procedure, was dominantly involved in immune-related biological functions (false discovery rate [FDR]<0.01). Another pattern composed of 182 temporally delayed down-regulated genes was involved in sensory perception such as olfactory and cognition functions (FDR<0.01). In addition to the two gene expression patterns, the temporal change of GO and the pathway activities using all differentially expressed genes also confirmed that an immune response was the main early change, whereas sensory functions were delayed responses. Moreover, we identified FADD and SOCS3 as possible core genes in the sensory function loss process using text-based mining and interaction network analysis. Conclusions The biphasic regulatory mechanism first reported here could provide molecular evidence of BCCAO-induced impaired memory in rats as well as mechanism of the development of vascular dementia.
Experimental Study on the Flow Characteristics around the Refraction Groyne  [PDF]
Joongu Kang, Hongkoo Yeo, Sungjung Kim
Engineering (ENG) , 2011, DOI: 10.4236/eng.2011.38103
Abstract: The refraction groyne is a complex structure consisted with groyne and groyne’s arm. This study conducted a experiment on the flow influences around the refraction groyne due to changes in the arm angle (θ) and length (AL). Results of experiment were analyzed on the impacts of the refraction groyne according to the projection length (L’). Velocity increase in main channel occurred greater the upward groynes than downward groynes. The vortices occurring at recirculation area of the upward and downward refraction groynes were formed in different shapes. The thalweg height did not have great impact vis-a-vis the extended arm length ratio and refraction angle change. The length of the recirculation area showed a gradual uptrend as the arm length of the groyne increased. Such area was formed at the range of 29% - 47%. For the length of the recirculation area, it was observed to be 10.2 - 14.7 times (URG), 8.4 - 12.7 times (DRG), and 10.6 - 13.8 times (right angle groyne) the projection length (L’) incensement.
Experimental Study on Local Scour in the Downstream Area of Low Drop Structure Types  [PDF]
Changsung Kim, Joongu Kang, Hongkoo Yeo
Engineering (ENG) , 2012, DOI: 10.4236/eng.2012.48060
Abstract: Although ecologically disadvantageous since a river is interrupted because of drop structure installation, such structure installation is also deemed ecologically advantageous in terms of scour and complex flows in the direct downstream area. This study started from the premise that scour hole carries value as a habitat and sought to analyze quantitatively the local scour adjustment possibility in the downstream area through drop structure type change and to offer a habitat through scouring. This study provided changes in drop structure types, such as straight line type and V type. For local scour analysis impacting the downstream area by drop structure type, quantitative analysis of scour scope, depth, and length was comparatively performed for a tentative physical habitat through hydraulic experiments. As a result of the experiments, this study found that scour scope increases and various water depth conditions are offered as the angle of the drop structure’s apex becomes smaller. Future studies accompanied by various fish habitation evaluations are considered useful in finding an alternative to upgrade the ecological environment.
An Experimental Study on a Characteristics of Flow around Groyne Area by Install Conditions  [PDF]
Joongu Kang, Hongkoo Yeo, Changsung Kim
Engineering (ENG) , 2012, DOI: 10.4236/eng.2012.410081
Abstract: In designing group groynes, the space of the groynes is an important factor, and the flow between the groyne areas will vary along the space. Since the flow in the groyne field significantly affects the flow change, the bed change, the bank erosion and the condition of the habitat, an assessment of the flow along the space of the groynes will yield important data needed to diversify the object of the groyne installation. To provide basic data for the determination of the proper space of groynes in a groyne group, the flow in the channel and groyne field, which varies with the installation of the groyne, is herein analyzed. The space of the groynes was set from the same length to 12 times the length of the groyne, and the flow range was measured using the LSPIV method and ADV. The influence of the angle of the installation was also analyzed. As a result, through the flow configuration in the groyne field and the flow range at the center of the groyne field against the space of the groyne, the decreasing influence of groyne erosion was suggested by the analysis of the shelter effect of aquatics and the countercurrent in the bank line.
Assessment of Habitats according to Groyne Types (Using Pale Chub)  [PDF]
Joongu Kang, Hongkoo Yeo, Changsung Kim
Engineering (ENG) , 2013, DOI: 10.4236/eng.2013.51004

A groyne zone formed by installing groynes functions as habitat or shelter for aquatic organisms during a flood. Since flow characteristics over a groyne zone are affected directly by groynes, understanding flow patterns due to shapes and types of groynes is of importance for designing groynes. In order to use groynes as an eco-friendly river structure, the ecological effects should also be considered at the design stage. In Korea, the ecological effects of groynes have rarely been examined or included for the actual design. In this study, a set of experiments were carried out to investigate flow pattern changes depending on different types of groynes. Based on the flow characteristics in the groyne zone, the scales of habitats and shelters by the groyne types were estimated. In addition, to test the applicability of a habitat evaluation model to the ecological design of groynes, River2D was used for a virtual river. For assessment of the groyne’s function of ecological habitat, the suitability index of a habitat for pale chub, one of the popular fishes in Korea, was used and the habitat areas by the groyne types were analyzed. The flow changes depending on the groyne types simulated by River2D show the applicability for the simulation of an ecological habitat to the groyne design.

A Study on Physical Model Test for Cheongpyeong Dam Discharge Recalculation  [PDF]
Joongu Kang, Sungjoong Kim, Hongkoo Yeo
Engineering (ENG) , 2014, DOI: 10.4236/eng.2014.611071
Abstract: Cheongpyeong Dam was built in 1943 for the purpose of power generation. Since its construction, discharge flow data based on a theoretical formula have been used to the present times and this leads to a problem of accurate discharge flow information not being available. In particular, Cheongpyeong Dam has been partially repaired and modified to maintain the dam structure over a long period of time and is not being properly reflected with changes at the downstream of the river caused by river improvement projects and sedimentation in reservoir. With a goal to improve Cheongpyeong Dam discharge flow calculation, this study aimed at verifying discharge capability and discharge flow by damper opening in relation to the previously suggested discharge flow through a hydraulic model test based on an accurate reproduction of the dam structure and surrounding topographies as in the present conditions. In this study, a hydraulic model test was conducted to examine the discharge flow of Cheongpyeong Dam. In addition, a comparative examination was carried out against the existing discharge flow proposed using theoretical equations. As a verification of the discharge flow of Cheongpyeong Dam, discharge flows in all sluices and a single sluice were examined. Then, the impact of sluice interference caused by the dam structure consisting with 24 sluices was investigated. As a result of the examination, it was found that the difference between discharge flow calculated using the existing theoretical equations and discharge flow derived from the hydraulic model test was insignificant. Based on the results of hydraulic model test, a formula to estimate stage-discharge flow at a sluice was derived and suggested.
Harmonic Suppression Characteristic of a CPW-FED Circular Slot Antenna Using Single Slot on a Ground Conductor
Junho Yeo;Dongho Kim
PIER Letters , 2009, DOI: 10.2528/PIERL09072108
Abstract: A CPW-fed circular slot antenna with a slot on a ground conductor is presented for harmonic suppression. The antenna has a multi-band rejection characteristic where the second and higher rejection bands are integer-multiple of the first band, and this is generated by inserting single slot on a ground conductor of the antenna. Good agreement between the simulated and measured results is reported and the integer-multiple notch bands can be adjustable by changing the length of the slot on the ground plane.
Habitat Evaluation on Scour Hole Downflow Low Drop Structure Types Using Large-Scale Experiment  [PDF]
Joongu Kang, Changsung Kim, Sanghwa Jung, Hongkoo Yeo
Engineering (ENG) , 2012, DOI: 10.4236/eng.2012.49071
Abstract: This study sought to review whether large-scale experimentation can apply to actual rivers concerning the effect of topographical change by scour in the downstream area of natural-type low drop structures on the fish habitat. The large-scale applicability experiment performed in this study installed low drop structures as the study object within the experiment channel and precisely surveyed topography in the downstream area of drop structures along with the hydraulic amount including water level and flow velocity under certain flow conditions. Based on topographical data acquired through the survey after the experiment ended, this study reviewed the change of suitability index and difference of weighted usable area by performing 2D habitat simulation. Ultimately, through the habitat simulation results in cases of considering and not considering scour in the downstream area of drop structures, this study analyzed the effects of topographical change in actual rivers on the habitat.
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