• Journal of Soil and Groundwater Environment
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• v.14 no.6
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• pp.87-94
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• 2009

Surfactant-enhanced air sparging (SEAS) was developed to suppress the surface tension of groundwater prior to air sparging resulting in higher air saturation and larger contact area between NAPL and gas during air sparging. Larger contacting interface between NAPL and gas means faster mass transfer of contaminants from NAPL to gas phase. This new technique, however, is limited to relatively volatile contaminants because vaporization is its basic mechanism of mass transfer. In this study, SEAS was tested at an elevated temperature for a semi-volatile n-decane, which is expected not to be a good candidate of SEAS application due to its low vapor pressure at ambient temperature. Three sparging experiments were conducted using 1-dimensional column (5 cm id, 80 cm length) packed with sand; (1) ambient temperature ($23^{\circ}C$), column saturated with distilled water, (2) SEAS at ambient temperature ($23^{\circ}C$), for n-decane contaminated sand, (3) SEAS at elevated temperature ($73^{\circ}C$), for n-decane contaminated sand. Higher air saturation was achieved by SEAS compared to that by air sparging without surfactant application. The n-decane removal efficiency of SEAS at elevated temperature was significantly higher(> 10 times) than that of ambient SEAS. The n-decane concentrations in the gas effluent from column during SEAS at $73^{\circ}C$ are found to be 10 times of those measured at ambient temperature. Thus, SEAS technique can be applied for removal of semi-volatile contaminants provided that an appropriate technique for elevating aquifer temperature is available.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.5C
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• pp.199-210
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• 2012

The effects of tunnelling in weak weathered rock on the behaviour of a pre-existing single pile and pile groups ($3{\times}3$ and $5{\times}5$ pile groups) above a tunnel have been studied by carrying out three-dimensional (3D) elasto-plastic numerical analyses. Numerical modelling of such effects considers the response of the single pile and pile groups in terms of tunnelling-induced ground and pile settlement as well as changes of the shear transfer mechanism at the pile-soil interface due to tunnelling. Due to changes in the relative shear displacement between the pile and the soil at the pile-soil interface with tunnel advancement, the shear stresses and axial pile force distributions along the pile change drastically. Based on the computed results, upward shear stresses are induced up to about Z/L=0.775 from the pile top, while downward shear stresses are mobilised below Z/L=0.775, resulting in a reduction in the axial pile force distribution with depth equivalent to a net increase in the tensile force on the pile. A maximum tensile force of about $0.36P_a$ developed on the single pile solely due to tunnelling, where $P_a$ is the service axial pile loading prior to tunnelling. The degree of interface shear strength mobilisation at the pile-soil interface was found to be a key factor governing pile-soil-tunnelling interaction. Overall it has been found that the larger the number of piles, the greater is the effect of tunnelling on the piles in terms of pile settlement, while changes of the axial pile forces for the piles in the groups are smaller than for a single pile due to the shielding effect. The reduction of apparent allowable pile capacity due to tunnelling-induced pile head settlement was significant, in particular for piles inside the groups.

• Journal of Korean Tunnelling and Underground Space Association
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• v.14 no.5
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• pp.529-545
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• 2012

Three-dimensional (3D) finite element analyses have been performed to study the behaviour of a single pile to open face tunnelling in stiff clay. Several key factors such as tunnelling-induced ground and pile settlement, and shear transfer mechanism have been studied in detail. Tunnelling resulted in the development of pile settlement larger than the Greenfield soil surface settlement. In addition, due to changes in the shear transfer between the pile and the soil next to the pile with tunnel advancement, axial force distributions along the pile change drastically. The apparent allowable pile capacity was reduced up to about 30% due to the development of tunnelling-induced pile head settlement. The skin friction on the pile was increased with tunnel advancement associated with the changes of soil stresses and ground deformation and hence axial pile force distribution was reduced. Maximum tunnelling-induced tensile force on the pile was about 21% of the designed pile capacity. The zone of influence on the pile behaviour in the longitudinal direction may be identified as ${\pm}1$-2D (D: tunnel diameter) from the pile centre (behind and ahead of the pile axis in the longitudinal direction) based on the analysis conditions assumed in the current study. Negative excess pore pressure was mobilised near the pile tip, while positive excess pore pressure was computed at the upper part of the pile. It has been found that the serviceability of a pile experiencing adjacent tunnelling is more affected by pile settlement than axial pile force changes.

• Korean Chemical Engineering Research
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• v.55 no.4
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• pp.456-466
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• 2017

This work investigated the particle morphology change to difference in milling media in a metal based composite fabrication process using a stirred ball mill with ball behavior of DEM simulation. A simulation of the three dimensional motion of grinding media in the stirred ball mill for the research of grinding mechanism to clarify the force, kinetic energy, and medium velocity of grinding media were calculated. In addition, the rotational speed of the stirred ball mill was changed to the experimental conditions for the composite fabrication, and change of the input energy was also calculated while changing the ball material, the flow velocity, and the friction coefficient under the same conditions. As the rotating speed of the stirred ball mill increased, the impact energy between the grinding media to media, media to wall, and media and the stirrer increased quantitatively. Also, we could clearly analyze the change of the particle morphology under the same experimental conditions, and it was found that the ball behavior greatly influences in the particle morphology changes.

• The Journal of Korean Physical Therapy
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• v.20 no.1
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• pp.57-65
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• 2008

Purpose: Heat shock proteins (HSPs) are a group of proteins that are activated when cells are exposed to a variety of environmental stresses, such as infection, inflammation, exposure to toxins, starvation, hypoxia, brain injury, or water deprivation. The activation of HSPs by environmental stress plays a key role in signal transduction, including cytoprotection, molecular chaperone, anti-apoptotic effect, and anti-aging effects. However, the precise mechanism for the action of small HSPs, such as HSP27 and mitogen-activated protein kinases (MAPKs: extracellular-regulated protein kinase 1/2 (ERK1/2), p38MAPK, stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK), is not completely understood, particularly in application of cell stimulators including platelet-derived growth factor (PDGF), angiotensin II (AngII), tumor necrosis factor $\alpha$ (TNF$\alpha$), and $H_2O_2$. This study examined the relationship between stimulators-induced enzymatic activity of HSP27 and MAPKs from rat smooth and skeletal muscles. Methods: 2-dimensional electrophoresis (2DE) and matrix assisted laser desorption ionizationtime-of-flight/time-of-flight (MALDI-TOF/TOF) analysis were used to identify HSP27 from the intact vascular smooth and skeletal muscles. Three isoforms of HSP27 were detected on silver-stained gels of the whole protein extracts from the rat aortic smooth and skeletal muscle strips. Results: The expression of PDGF, AngII, TNF$\alpha$, and $H_2O_2$-induced activation of HSP27, p38MAPK, ERK1/2, and SAPK/JNK was higher in the smooth muscle cells than the control. SB203580 (30${\mu}$M), a p38MAPK inhibitor, increased the level of HSP27 phosphorylation induced by stimulators in smooth muscle cells. Furthermore, the age-related and starvation-induced activation of HSP27 was higher in skeletal muscle cells (L6 myoblast cell lines) and muscle strips than the control. Conclusion: These results suggest, in part, that the activity of HSP27 and MAPKs affect stressors, such as PDGF, AngII, TNF$\alpha$, $H_2O_2$, and starvation in rat smooth and skeletal muscles. However, more systemic research will be needed into physical therapy, including thermotherapy, electrotherapy, radiotherapy and others.

• Journal of Digital Contents Society
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• v.15 no.6
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• pp.663-673
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• 2014

The WBAN technology means a short distance wireless network which provides each device interactive communication by connecting devices inside and outside of body. Standardization on the physical layer, data link layer, network layer and application layer is in progress by IEEE 802.15.6 TG BAN. Wireless body area network is usually configured in energy efficient using sensor and zigbee device due to the power limitation and the characteristics of human body. Wireless sensor network consist of sensor field and sink node. Sensor field are composed a lot of sensor node and sink node collect sensing data. Wireless sensor network has capacity of the self constitution by protocol where placed in large area without fixed position. In this paper, we proposed the efficient addressing scheme for improving the performance of routing algorithm by using ZigBee in WBAN environment. A distributed address allocation scheme used an existing algorithm that has wasted in address space. Therefore proposing x, y and z coordinate axes from divided address space of 16 bit to solve this problems. Each node was reduced not only bitwise but also multi hop using the coordinate axes while routing than Cskip algorithm. I compared the performance between the standard and the proposed mechanism through the numerical analysis. Simulation verified performance about decrease averaging multi hop count that compare proposing algorithm and another. The numerical analysis results show that proposed algorithm reduced the multi hop better than ZigBee distributed address assignment

• Investigative Magnetic Resonance Imaging
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• v.2 no.1
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• pp.58-66
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• 1998

Purpose : This paper introduces a new three dimensional magnetic Resonance Image classification which is based on Mar kov Random Field-Gibbs Random Field with a line model. Material and Methods : The performance of the Gibbs Classifier over a statistically heterogeneous image can be improved if the local stationary regions in the image are disassociated from each other through the mechanism of the interaction parameters defined at the local neighborhood level. This usually involves the construction of a line model for the image. In this paper we construct a line model for multisignature images based on the differential of the image which can provide an a priori estimate of the unobservable line field, which may lie in regions with significantly different statistics. the line model estimated from the original image data can in turn be used to alter the values of the interaction parameters of the Gibbs Classifier. Results : MRF-Gibbs classifier for volumetric MR images is developed under the condition that the domain of the image classification is $E^{3}$ space rather thatn the conventional $E^{2}$ space. Compared to context free classification, MRF-Gibbs classifier performed better in homogeneous and along boundaries since contextual information is used during the classification. Conclusion : We construct a line model for multisignature, multidimensional image and derive the interaction parameter for determining the energy function of MRF-Gibbs classifier.

• Journal of Life Science
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• v.17 no.5 s.85
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• pp.723-727
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• 2007

Resistance to metronidazole in Helicobacter pylori results from inactivation of rdxA and frxA, the chromosomal genes for a nitroreductase that normally converts metronidazole from prodrug to bactericidal agent. Two types of metronidazole susceptible strains had been found distinguishable by their apparent levels of frxA expression. Most common in the populations we had studied were strains that required only rdxA inactivation to become resistant to moderate levels of metronidazole(type I strains). The second strain type required inactivation of both frxA and rdxA to become resistance to metronidazole(type II strains): this was linked to a relatively high level of frxA gene transcription in the type II strains. The fdxA gene regulated fdxA as well as rdxA gene. Thus, to study the function of fdxA as a regulatory gene we constructed a null mutant of fdxA in H. pylori genome and identified over-and under-expressed proteins by fdxA using two-dimensional(2-D) electrophoresis and MALDI-TOP-MS. There were four over-expressed proteins in fdxA mutant; nifU-like protein(HP0221), frxA(HP0642), nonheme ferritin(HP0653), and hypothetical protein(HP0902). Three under-expressed proteins were also identified in fdxA mutant, including 5'-methylthioadenosine/S-adenosylhomocysteine nucleosidase (HP0089), (3R)-hydroxymyristoyl ACP dehydratase(HP1376), and thioredoxin(HP1458).

• Journal of the Korean GEO-environmental Society
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• v.16 no.6
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• pp.13-22
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• 2015

In the current work, a series of three-dimensional (3D) numerical modelling has been performed in order to study the effects of the relative locations of tunnels with respect to the position of pile tips which governs the behaviour of pre-existing, adjacent single piles. In the numerical analyses, several governing factors, such as tunnelling-induced pile head settlements, relative displacements, volume losses, axial pile forces, interface shear stresses and apparent factors of safety have been analysed. When the pile tips are inside the tunnelling influence zone, of which the pile tip location is considered with respect to the tunnel position, tunnelling-induced pile head settlements are larger than the ground surface settlements, resulting in tunnelling-induced tensile pile forces. On the contrary, when the pile tips are outside the influence zone, compressive pile forces associated with downward shear stresses at the upper part of the piles are developed. Based on computed load and displacement relation of the pile, the apparent factors of safety of the piles inside the tunnelling influence zone have been reduced by 36% in average. The shear transfer mechanism based on the relative tunnel locations has been analysed in great detail by considering tunnelling-induced pile forces, interface shear stresses and the apparent factors of safety.

• Microbiology and Biotechnology Letters
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• v.47 no.1
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• pp.164-171
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• 2019

Radiation therapy has many side effects, such as digestive mucosal ulcers, without regard to its efficacy. The purpose of this study is to address an alternative method to replace the limitation of radiation therapy using radiomimetic microbial ribotoxins. In the evaluation of cancer therapy, we analyzed the formation of colorectal cancer (CRC) cell spheroids, which can take into account the heterogeneous cellular constitution, tumor stem cells, and the surrounding microenvironment. Ribotoxic stress interfered with the spheroid structure composed of relatively small clusters. Spheroids under ribotoxic stress were structurally sparse and their shrinkage was very slow. In the control group, the clusters of strongly aggregated cells were resistant to physical stress, but the ribotoxic stress-exposed spheroids were easily broken up by the physical stress. Moreover, the ribosome-insulted CRC cells slowly migrated to form clusters and the cell-cell junctional points in the ribosome-insulted spheroids were rarer than those in the control CRC spheroid. Moreover, levels of the cell-to-cell junctional protein E-cadherin were suppressed by ribotoxic stress in both allograft and xenograft spheroids. In conclusion, the radiomimetic microbial ribotoxins induced structural defects in CRC cell spheroids via retardation of migration and cell-cell junction in the formation of three-dimensional structures, and provides a basis for the mechanism of pharmacological radiomimetic anticancer actions as an alternate to radiotherapy against cancer.