• Journal of Periodontal and Implant Science
• /
• v.23 no.3
• /
• pp.507-516
• /
• 1993

The Chlorhexidine(CHX) has been a widely used adjunt in periodontal therapy due to its bactericidal effect. In spite of the effects of CHX exhibits cytotoxic to human cells and delays granulation tissue formation. Therefore, understanding the effects of CHX on fibroblast attachment and cell growth will provide the rationale for its use during healing phase of periodontal surgery. This study was undertaken to examine the effects of standardized CHX-pretreated dentin slices and direct CHX exposure on human gingival fibroblasts. The results were as follow : 1. In experiment 1, there was a significant reduction in the number of fibroblast attachment in 0.12, 1%-pretreated groups relative to the control, 0.05%-pretreated groups(P<0.05). 2. In experiment 1, the control, 0.05%-pretreated groups showed considerable attachment and typical fibroblastic morphology, but 0.12, 1%-pretreated groups showed irregular, round-up (unattached) fibroblastic morphology. 3. In experiment 2, it appeared that all experimental groups exhibits significant inhibition of cell growth when compared with the control group.

• The Transactions of the Korea Information Processing Society
• /
• v.5 no.3
• /
• pp.824-832
• /
• 1998

In this paper, wc proposed new method for corner point detection on digital contours using directional angle and area dcviation_ First of all, dircctional angle was detccted according to contours by lookup table, then corner point was detected using arca deviation aftcr the pixels over standard value had selected as a candidate point. This method has the advantage the rcduction of processing time for real time processing and the reduction of round-off error on digital image reprcsentation. For vcrification of the proposed method simulation results which applied on various tcst pattern were compared with existing methods.

• Proceedings of the KIEE Conference
• /
• 2007.07a
• /
• pp.1061-1062
• /
• 2007

In this paper, the analysis of some possibilities for increasing the induction motor efficiency is reported. This approach does not require a complete redesign of new laminations with a consistent cost in terms of investments. This paper shows the efficiency of the rectangular core types according to core-cutting-degree and compares the efficiency of the rectangular core types with the round core types. In particular, for obtaining an increase in efficiency, increase of the core axial length has been taken into consideration. The paper shows the results obtained by the finite element method(FEM) and IEEE Std. 112-96 Method B and analyzes the results to get a high efficiency for the induction motor.

• Korean Journal of Applied Biomechanics
• /
• v.13 no.2
• /
• pp.161-173
• /
• 2003

This study was performed to investigate the kinematic and kinetic differences between functional walking shoe(FWS) and general sports shoe(GSS). The subjects for this study were 4 male adults who had the walking pattern of rearfoot strike with normal feet. The movement of one lower leg was measured using force platform and 3 video cameras while the subjects walked at the velocity of 2/1.5 m/s. The findings of this study were as follows 1. The angle of lower leg-ground and angle of knee with FWS was greater than with GSS at the moment of strike the floor and the moment of second peak ground reaction force. The decreasing rate of angle of ankle was smaller in FWS from the strike phase to the second peak ground reaction force. These mean upright walking and round walking along the shoe surface. 2. The maximal Increased angle of Achilles tendon and the minimal decreased angle of rearfoot were smaller in FWS very significantly(p<0.001). Thus FWS prevent the excessive pronation of ankle and have good of rear-foot control. 3. The vortical ground reaction force and the rate of it to the BW were smaller in FWS statistically(p<0.001). The loading rate was smaller in FWS, too, and thess represent the reduction of load on ankle joint and prevention of injuries on it.

• Transactions of Materials Processing
• /
• v.24 no.3
• /
• pp.187-193
• /
• 2015

The objective of the current study is to determine cross-sectional profile of intermediate dies in order to improve the plastic strain homogeneity which directly affects not only the dimensional accuracy but also the mechanical properties of final product by redesigning the intermediate dies using the conventional electric field analysis (EFA) method. Initially, the multi-pass shape wire drawing was designed by using the equivalent potential lines from EFA. The area reduction ratio was calculated from the number of passes in multi-pass shape wire drawing but constrained by the capacity of the drawing machine and the drawing force. In order to compensate for a concentration of strain in a region of the cross section of the wire, the process for multi pass wire drawing from initial round material to an intermediate die was redesigned again using the electric field analysis. Both drawing process designs were simulated by the finite element method in which the strain distribution and standard deviation plastic strain of the cross section of drawn wires were examined.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2011.06a
• /
• pp.261-262
• /
• 2011

Conventional automatic transmission system includes a hydrodynamic torque converter to transfer engine torque from an engine crank shaft to a rotatable input members, which are of complex design permitting them to serve several functions. These are clutches or brakes which couple the rotatable input member to member of a planetary gear set. The annulus gear for an automatic transmission is a monolithic gear having a set of gear teeth formed on an inner surface which is coupling with a set of planetary gear. In this study, the flow forming method is applied to the manufacturing of the annulus gear. This cold forming is proper method in order to manufacture dimensionally precise and round hollow components such as annulus gear. By pre-calculated amount of wall thickness reduction, the seamless tube of SAE1026 is compressed above its yield strength, plastically deformed and made to flow in several roll passes. According to this study, the desired geometry of the annulus gear can be achieved when the outer diameter and the thickness of the tube are properly decreased by compressed roll passes and the available material volume is easily forced to flow longitudinally over the shape of mandrel.

• Animal cells and systems
• /
• v.11 no.1
• /
• pp.17-22
• /
• 2007

The effects of antimetabolite 6-AN (6-amino-nicotinamide) on viability and morphology of L6 myoblast cells have been investigated. 6-AN ($100{\mu}M$) induced a time-dependent decrease in cell viability with respect to the untreated control cells. Following 6-AN administration the viability rate started to decline sharply, reaching about 23% of the untreated control cells at 48 h. Inverted phase-contrast microscopy revealed that 6-AN caused characteristic morphological changes such as irregularly elongated and stellate shape of cells, round-shaped nucleus, cytoplasmic vacuolization, irregular cell arrangements and formation of large spaces among cell clusters. The concentrations of ATP and $NAD^{+}$ in the 6-AN treated cells were significantly lower (p < 0.01) than those of the untreated control cells. In contrast, the concentration of AMP was significantly increased by the 6-AN treatment. Activities of catalase, superoxide dismutase and glutathione peroxidase in 6-AN treated cells were significantly higher (p < 0.01) than those of the untreated control cells. The activities of glyceraldehyde-3-phosphate dehydrogenase in 6-AN treated cells were significantly lower (p < 0.01) than those of the untreated control cells. The results suggest that 6-AN caused marked reduction of cell viability and alterations of some important metabolites and enzymes.

• ETRI Journal
• /
• v.41 no.3
• /
• pp.358-370
• /
• 2019

The main aim of this study is to select the optimal set of genes from microarray cancer datasets that contribute to the prediction of specific cancer types. This study proposes the enhancement of the feature selection filter algorithm based on Joe's normalized mutual information and its use for gene selection. The proposed algorithm is implemented and evaluated on seven benchmark microarray cancer datasets, namely, central nervous system, leukemia (binary), leukemia (3 class), leukemia (4 class), lymphoma, mixed lineage leukemia, and small round blue cell tumor, using five well-known classifiers, including the naive Bayes, radial basis function network, instance-based classifier, decision-based table, and decision tree. An average increase in the prediction accuracy of 5.1% is observed on all seven datasets averaged over all five classifiers. The average reduction in training time is 2.86 seconds. The performance of the proposed method is also compared with those of three other popular mutual information-based feature selection filters, namely, information gain, gain ratio, and symmetric uncertainty. The results are impressive when all five classifiers are used on all the datasets.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2019.05a
• /
• pp.587-590
• /
• 2019

This paper is about to improve the network life's reduction due to the deviation of sensor node and frequently change of network, the main problem of sensor network. The existing Scalable Topology Organization(STO)-based ZigBee Tree Topology Control Algorithm did not consider ways to consume power so the network lifetime is too short. Accordingly, per each round, electing a new parent node and consisting of the new network topology technique, The Cluster Header Selection, extending the network's overall lifetime. The OMNet++ Simulator yielded results from the existing STO Algorithm and the proposed Cluster Header Selection Technique in the same experimental environment, which resulted in an increase in overall network life by about 40% and an improvement of about 10% in performance in the remaining portion of the battery.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.26 no.5A
• /
• pp.817-822
• /
• 2006

Post-tensioning the full-depth precast slab longitudinally is to eliminate the tensile stresses in the transverse joints and to prevent any leakage through the joints. When the prestressing is applied to full-depth precast slab which does not composite steel girder, stress concentration occurs at the corners of shear pocket, and compressive stress is not uniformly distributed in the section of precast slab. In this paper, full-depth precast slabs using four different shapes of shear pockets are analyzed by commercial finite element program. Round type of shear pockets is superior to reduction in stress concentration.